土建专业毕业设计外文文献翻译--建筑物防雷设计
土木工程专业文献翻译中英文
The frame structure anti- earthquake conceptdesignThe disaster has an earthquake dashing forward sending out nature, may forecast nature very low so far, bring about loss for human society is that the natural disaster of all kinds is hit by one of the gravest disaster gravely. In the light of now available our country science level and economy condition, correct the target building seismic resistance having brought forward "three standards " fortification, be that generally, the what be spoken "small earthquake shocks does not but constructs in the dirty trick, big earthquakes do not fall ". That generally, what be talked small shocks in the earthquake, big earthquakes refer to respectively is intensity exceed probability in 50 fortifying for 3%'s 63% , 10% , 2 ~ being more is caught in an earthquake, earthquake , rare Yu earthquake.Since building the astigmatic design complexity, in actual project, anti-knock conceptual design appears especially important right away. It includes the following content mainly: Architectural design should pay attention to the architectural systematic ness; Choose rational building structure system; the tensile resisting inclining force structure and the component is designed.That the ability designs law is the main content that the structure denasality designs includes standard our country internal force adjustment and structure two aspect. It is twenty centuries seventies later stage , reinforced concrete structure brought forward by famous New Zealand scholar T.Paulay and Park has sufficient tonsillitis method under the force designing an earthquake chooses value is prejudiced low situationW.hose core thought is: "The beam cuts organization " or "the beam column cuts organization " by the fact that "the strong weak post beam " guides structure to take form; Avoid structure by "strong weak scissors turn " before reach estimate that shearing happened in the denasality in the ability front destroy; Turn an ability and consume an ability by the fact that necessary structure measure makes the location may form the plasticity hinge have the necessary plasticity. Make structure have the necessary tonsillitis from all above three aspect guarantee. That framed structure is the common structure form, whose senility certainly designs that, is to embody from about this three aspect also mainly.1, Strong pillar weak beamDriving force reaction analysis indicates structure; architectural deformability is connected with to destroying mechanism. Common have three kinds model’s consume energ y organization ", beam hinge organization ““, post hinge organization ““, beam column hinge organization "."Beam hinge organization " and "beam column hinge organization " Lang Xianknuckle under , may let the entire frame have distribution and energy consumption heavier than big internal forces ability, limit tier displacement is big , plasticity hinge quantity is many , the hinge does not lose efficacy but the structure entirety does not lose efficacy because of individual plasticity. The as a result anti-knock function is easy to be that the armored concrete is ideal consume energy organization. Being that our country norm adopts allows a pillar , the shearing force wall puts up the hinge beam column hinge scheme, taking place adopting "strong relative weak post beam " measure , postponing a pillar cuts time. Weak tier of post hinge organization possibility appear on unable complete trouble shooting but , require that the axis pressure restricting a pillar compares as a result, architectural weakness prevents necessary time from appearing tier by the fact that Cheng analysis law judges now and then, post hinge organization.Are that V. I. P. is to enhance the pillar bending resistance , guidance holds in the beam appear first, the plasticity cuts our "strong common weak post beam " adjustment measure. Before plasticity hinge appearing on structure, structure component Yin La District concrete dehiscence and pressure area concrete mistake elasticity character, every component stiffness reduces a reinforced bar will do with the cementation degeneration between the concrete. That stiffness reduces a beam is relatively graver than accepting the pillar pressing on , structure enhances from initial shearing type deformation to curved scissors shape deformation transition , curved post inner regulation proportion really more curved than beam; The at the same time architectural period is lengthened, size affecting the participation modulus shaking a type respectively to structure's; Change happened in the earthquake force modulus , lead to the part pillar bend regulation enhancing, feasible beam reality knuckles under intensity rise , the post inner bends regulation when plasticity hinge appearing on thereby feasible beam enhancing since structure cause and the people who designs the middle reinforced bar's are to enhance.. And after plasticity hinge appearing on structure, same existence having above-mentioned cause, structure knuckles under mistake elasticity in the day after tomorrow process being that process , post that the earthquake enhances strenuously further bend regulation enhancing with earthquake force but enhance. The force arouses an earthquake overturn force moment having changed the actual post inner axis force. We knuckle under the ability lessening than axis pressure in standardizing being limited to be able to ensure that the pillar also can lead to a pillar in big the bias voltage range inner , axis force diminution like value. The anti-knock norm is stipulated: Except that the frame top storey and post axis pressure are compared to the strut beam and frame pillar being smaller than 0.15 person and frame, post holds curved regulation designing that value should accord with differencebeing，that first order takes 1.4 , the two stage takes 1.2 , grade-three takes 1.1. 9 degree and one step of framed structure still responds to coincidence,，intensity standard value ascertains that according to matchingreinforced bar area and material really. The bottom post axis is strenuously big, the ability that the plasticity rotates dispatches, be that pressure collapses after avoiding a foot stall producing a hinge, one, two, three steps of framed structure bottom, post holds cross section constituting curved regulation designing that value takes advantage of that 1.5, 1.25 compose in reply 1.15 in order to enhancing a modulus respectively. Combination of the corner post adjustment queen bends regulation still should take advantage of that not to be smaller than 1.10's modular. Curved regulation designs that value carries out adjustment to one-level anti-knock grade shearing force wall limb cross section combination , force the plasticity hinge to appear to reinforce location in the wall limb bottom, the bottom reinforces location and all above layer of curved regulation designing that value takes wall limb bottom cross section constituting curved regulation designing value , other location multiplies 1.2's by to enhance a modulus. Prop up anti-knock wall structure to part frame, bottom-end , whose curved combination regulation design value respond to one, two steps of frame pillars post upper end and bottom post take advantage of that 1.5 composes in reply 1.25 in order to enhancing a modulus respectively. All above "strong weak post beam” adjustment measure, reaction analysis indicates , big satisfied fundamental earthquakes demand no upside down course nonlinearity driving force. Reinforced bar spending area, the beam in 7 is controlled from gravity load, the post reinforced bar matches’ tendon rates basically from the min imum under the control of. Have enhanced post Liana Xiang all round resisting the curved ability. At the same time, 7 degree of area exactly curved regulation plasticity hinge appears on disaster very much, plays arrive at advantageous role to fighting against big earthquakes. In 9 degree of area, adopt reality to match reinforced bar area and material bending regulation within intensity standard value calculation post, structural beam reinforced bar enhancing same lead to enhancing bending regulation within post designing value, under importing in many waves, the beam holds the plasticity hinge rotating developing greatly, more sufficient, post holds the plasticity hinge developing insufficiency, rotate less. Design demand with the beam. Reaction and 9 degree are about the same to 8 degree of area , whose big earthquake displacement , that post holds the plasticity hinge is bigger than rotating 9 degree much but, the beam holds the plasticity hinge appearing sufficient but rotate small, as a result "strong weak post beam " effect is not obvious , curved regulation enhances a modulus ought to take 1.35 , this waits for improving and perfecting going a step further when the grade suggesting that 8 degree of two stage is anti-knock in connection with the expert.2, Strong shear weak curved"Strong weak scissors turn” is that the plasticity cuts cross section for guarantee on reach anticipate that shearing happened in the mistake elastic-deformation prior to destroy. As far as common structure be concerned, main behaviors holds in the beam, post holds, the shearing force wall bottom reinforces area , shearing force wall entrance to a cave company beam tools , beam column node core area. Show mainly with being not that seismic resistance is compared with each other, strengthening measure in improving the effect shearing force;Aspect adjusting a shear bearing the weight of two forces.1)effect shearing forceOne, two, three-level frame beam and anti-knock wall middle stride over high ratio greater than 2.5 company beam, shearing force design value amongthem, first order choose 1.3, two stage choose 1.2, three-level choose 1.1, first order framed structure and 9 Due Shan respond to coincidence. Coincidence one, two, three steps of frame post and frame pillar , shearing force being designed being worth taking 1.4 among them, one step , taking 1.2, three steps of take 1.1 , one-level framed structure and 9 Due Shank two steps responding to.One, two, three steps of anti-knock walls bottom reinforces location the shearing force designs that value is among them, first order takes 1.6 , the two stage takes 1.4 , grade-three takes 1.2, 9 Dud Shank respond to coincidence. The node core area seismic resistance the beam columnnode , one, two steps of anti-knock grades are carried out is born the weight of force checking calculation by the scissors , should accord with anti-knock structure measure about 3 step, correct 9 degree of fortify and one-level anti-knock grade framed structure, think to the beam end the plasticity hinge already appears , the node shearing force holds reality completely from the beam knuckling under curved regulation decision , hold reality according to the beam matching reinforced bar covering an area of the growing modulus that intensity standard value calculation, takes advantage of that at the same time with 1.15 with material. Other first order holds curved regulation according to the beamdesigning that value secretly schemes against , the shearing force enhances a modulus being1.35 , the two stage is 1.2.2) Shear formulaThe continuous beam of armored concrete and the cantilever beam are born the weight of at home and abroad under low repeated cycle load effect by the scissors the force experiment indicates the main cause pooling efforts and reducing even if tendon dowel force lessening is that the beam is born the weight of a force by the scissors, concrete scissors pressure area lessening shearing an intensity, tilted rift room aggregate bite. Scissors bear the weight of a norm to the concrete accepting descending strenuously being 60% be not anti-knock, the reinforced bar item does not reduce. By the same token, the experiment indicates to insisting to intimidate post with that the force is born the weight of by the scissors, loading makes post the force be born the weight of by the scissors reducing 10% ~ again and again 30%, the itemarouses , adopts practice identical with the beam mainly from the concrete. The experiment is indicated to shearing force wall, whose repeated loading breaks the subtraction modulus up than monotony increases be loaded with force lessening is born the weight of by the scissors 15% ~ 20%, adopts to be not that seismic resistance is born the weight of by the scissors energy times 0.8's. Two parts accept the pressure pole strenuously tilted from the concrete is born the weight of by the scissors and horizontal stirrup of beam column node seismic resistance cutting the expert who bears the weight of force composition , is connected with have given a relevance out formula.Tilted for preventing the beam , post , company beam , shearing force wall , node from happening pressure is destroyed, we have stipulated upper limits force upper limit to be born the weight of by the scissors , have stipulated to match hoop rate’s namely to accepting scissors cross section.Reaction analysis indicates strong weak curved scissors requests; all above measure satisfies basically by mistake elasticity driving force. The plasticity rotates because of anti-knock grade of two stage beam column under big earthquakes still very big , suggest that the shearing force enhances a modulus is bigger than having there is difference between one step unsuitably in connection with the expert, to the beam choose 1.25 is fairly good , ought to take 1.3 ~ to post 1.35. It's the rationality taking value remains to be improved and perfected in going a step further.Require that explanatory being , the beam column node accept a force very complicated , need to ensure that beam column reinforced bar reliability in the node is anchoring , hold occurrence bending resistance at the same time in the beam column destroying front, shearing happened in the node destroy, whose essence should belong to "strong weak curved scissors" categories. The node carries out adjustment on one, two steps of anti-knock grades shearing force and, only, the person enhances a modulus be are minor than post, ratio post also holds structure measure a little weak. As a result ", mor e strong node “statement, is not worth it encourage.3) Structure measureStructure measure is a beam, post, the shearing force wall plasticity cuts the guarantee that area asks to reach the plasticity that reality needs turning ability and consuming ability. Its "strong with "strong weak scissors turn ", weak post beam " correlates, a architectural denasality of guarantee.”Strong weak scissors turn " is a prerequisite for ensuring that the plasticity hinge turns an ability and consumes an ability; Strict "strong weak post beam " degree, the measure affecting corresponding structure, if put strict "strong weak post beam " into practice, ensure that the pillar does not appear than the plasticity hinge, corresponding axis pressure waiting for structure measure to should be a little loose right away except the bottom. Our country adopts "the strong relative weak post beam”, delays a pillar going beyond the hinge time, therefore needing to adopt stricter structure measure.①the beam structure measure beam plasticity hinge cross section senility and manyfactors match tendon rates and the rise knuckling under an intensity but reduce in connection with cross section tensile, with the reinforced bar being pulled; The reinforced bar matches tendon rates and concrete intensity rise but improve with being pressed on, width enhances but enhances with cross section; Plasticity hinge area stirrup can guard against the pressure injustice releasing a tendon , improve concrete limit pressure strain , arrest tilted rift carrying out , fight against a shearing force , plasticity hinge deformation and consume an ability bring into full play, That deck-molding is stridden over is smaller than exceeding , shearing deformation proportion is increasingly big, the gentility destroying , using the tilted rift easy to happen reduces. The beam has led low even if the tendon matches hoop, the reinforced bar may knuckle under after Lang Kai cracks break up by pulling even. As a result, the norm matches tendon rates to the beam even if the tendon maximum matches tendon rates and minimum , the stirrup encryption District length , maximal spacing , minimal diameter , maximal limb lead all have strict regulations from when, volume matches hoop. Being bending regulation , the guarantee cross section denasality , holding to the beam possibly for the end fighting against a beam to pull the pressure reinforced bar area ratio make restrict. Stride over height at the same time, to minimal beam width, than, aspect ratio has done regulation.② the post structure measureFor post bending a type accepting the force component, axis pressure than to the denasality and consuming to be able to, nature effect is bigger. Destroy axis pressure than big bias voltages happened in the pillar hour, component deformation is big , gentility energy nature easy to only consume, reduces; Nature is growing with axis pressure than enhancing , consuming an energy, but the gentility sudden drop, moreover the stirrup diminishes to the gentility help. Readjust oneself to a certain extent to adopt the pillar, main guarantee it's tonsillitis that the low earthquake designs strenuously, but consuming energy sex to second. The pressure ratio has made a norm to the axis restricting, can ensure that within big bias voltages range in general. Stirrup same get the strain arriving at big roles, restraining the longitudinal tendon, improving concrete pressure, deter the tilted rift from developing also to the denasality. Be to match tendon symmetrically like post, the person leads feeling bigger , as big , becoming deformed when the pillar knuckles under more even if the tendon matches tendon , the tensile finishes exceeding. As a result, the tendon minimum matches tendon rates, the stirrup encryption District length, maximal spacing, minimal diameter, maximal limb lead having made strict regulations out from when, and volume matches hoop to the pillar jumping. At the same time, aspect ratio , scissors to the pillar have stridden over a ratio , minimal altitude of cross section , width have done out regulation, to improve the anti-knock function.③ Node structure measureThe node is anchoring beam column reinforced bar area, effect is very big to structure function. Be under swear to act on earthquake and the vertical stroke to load, area provides necessary constraint to node core when node core area cuts pressure low than slanting, keepthe node fundamental shear ability under disadvantageous condition, make a beam column anchoring even if the tendon is reliable, match hoop rates to node core area maximal spacing of stirrup, minimal diameter, volume having done out regulation. The beam column is main node structure measure content even if tendon reliability in the node is anchoring. Have standardized to beam tendon being hit by the node diameter; Release the anchoring length of tendon to the beam column; anchoring way all has detailed regulation.To sum up ,; Framed structure is to pass "the design plan calculating and coming realize structure measure the ability running after beam hinge organization" mainly thereby, realize "the small earth—quake shocks does not but constructs in the dirty trick, big earthquakes do not fall " three standards to-en fortifying target's. References.框架结构抗震概念设计地震灾害具有突发性，至今可预报性很低，给人类社会造成的损失严重，是各类自然灾中最严重的灾害之一。
土木工程 建筑 外文翻译 外文文献 英文文献 环境变化影响下的建筑学
Architecture in a Climate of Change （H）Page52-Page62Low energy techniques for housingIt would appear that,for the industrialised countries,the best chance of rescue lies with the built environment because buildings in use or in the course of erection are the biggest single indirect source of carbon emissions generated by burning fossil fuels,accounting for over 50 per cent of total emissions.If you add the transport costs generated by buildings the UK government estimate is 75 per cent.It is the built environment which is the sector that can most easily accommodate fairly rapid change without pain.In fact,upgrading buildings, especially the lower end of the housing stock,creates a cluster of interlocking virtuous circles.Construction systemsHaving considered the challenge presented by global warming and the opportunities to generate fossil-free energy,it is now time to consider how the demand side of the energy equation can respond to that challenge.The built environment is the greatest sectoral consumer of energy and,within that sector,housing is in pole position accounting for 28 per cent of all UK carbon dioxide (CO2) emissions.In the UK housing has traditionally been of masonry and since the early 1920s this has largely been of cavity construction.The purpose was to ensure that a saturated external leaf would have no physical contact with the inner leaf apart from wall ties and that water would be discharged through weep holes at the damp-proof course level.Since the introduction of thermal regulations,initially deemed necessary to conserve energy rather than the planet,it has been common practice to introduce insulation into the cavity.For a long time it was mandatory to preserve a space within the cavity and a long rearguard battle was fought by the traditionalists to preserve this…sacred space‟.Defeat was finally conceded when some extensive research by the Building Research Establishment found that there was no greater risk of damp penetration with filled cavities and in fact damp through condensation was reduced.Solid masonry walls with external insulation are common practice in continental Europe and are beginning to make an appearance in the UK.In Cornwall the Penwith Housing Association has built apartments of this construction on the sea front, perhaps the most challenging of situations.The advantages of masonry construction are:● It is a tried and tested technology familiar to house building companies of all sizes.● It is durable and generally risk free as regards catastrophic failure–though not entirely.A few years ago the entire outer leaf of a university building in Plymouth collapsed due to the fact that the wall ties had corroded.● Exposed brickwork is a low maintenance system; maintenance demands rise considerably if it receives a rendered finish.● From the energy efficiency point of view,masonry homes have a relatively high thermal mass which is considerably improved if there are high density masonry internal walls and concrete floors.Framed constructionV olume house builders are increasingly resorting to timber-framed construction with a brick outer skin,making them appear identical to full masonry construction.The attraction is the speed of erection especially when elements are fabricated off site. However,there is an unfortunate history behind this system due to shortcomings in quality control.This can apply to timber which has not been adequately cured or seasoned.Framed buildings need to have a vapour barrier to walls as well as roofs. With timber framing it is difficult to avoid piercing the barrier.There can also be problems achieving internal fixings.For the purist,the ultimate criticism is that it is illogical to have a framed building clad in masonry when it cries out for a panel,boarded,slate or tile hung external finish.Pressed steel frames for homes are now being vigorously promoted by the steel industry.The selling point is again speed of erection but with the added benefit of a guaranteed quality in terms of strength and durability of the material.From the energy point of view,framed buildings can accommodate high levels of insulation but have relatively poor thermal mass unless this is provided by floors and internal walls. Innovative techniquesPermanent Insulation Formwork Systems (PIFS) are beginning to make an appearance in Britain.The principle behind PIFS is the use of precision moulded interlocking hollow blocks made from an insulation material,usually expanded polystyrene.They can be rapidly assembled on site and then filled with pump grade concrete.When the concrete has set the result is a highlyinsulated wall ready for the installation of services and internal and exterior finishes.They can achieve a U-value as low as 0.11 W/m2K.Above three storeys the addition of steel reinforcement is necessary.The advantages of this system are:● Design flexibility; almost any plan shape is possible.● Ease and speed of erection;skill requirements are modest which is why it has proved popular with the self-build sector.Experienced erectors can achieve 5 m2 per man hour for erection and placement of concrete.● The finished product has high structural strength together with considerable thermal mass and high insulation value.Solar designPassive solar designSince the sun drives every aspect of the climate it is logical to describe the techniques adopted in buildings to take advantage of this fact as…solar design‟. The most basic response is referred to as…passive solar design‟.In this case buildings are designed to take full advantage of solar gain without any intermediate operations.Access to solar radiation is determined by a number of conditions:● the sun‟s position relative to the principal facades of the building(solar altitude and azimuth);● site orientation and slope;● existing obstructions on the site;● potential for overshadowing from obstructions outside the site boundary.One of the methods by which solar access can be evaluated is the use of some form of sun chart.Most often used is the stereographic sun chart in which a series of radiating lines and concentric circles allow the position of nearby obstructions to insolation,such as other buildings,to be plotted.On the same chart a series of sun path trajectories are also drawn(usually one arc for the 21st day of each month); also marked are the times of the day.The intersection of the obstructions‟outlines and the solar trajectories indi cate times of transition between sunlight and shade. Normally a different chart is constructed for use at different latitudes (at about two degree intervals).Sunlight and shade patterns cast by the proposed building itself should also beconsidered.Graphical and computer prediction techniques may be employed as well as techniques such as the testing of physical models with a heliodon.Computer modelling of shadows cast by the sun from any position is offered by Integrated Environmental Solutions (IES) with its…Suncast‟program.This is a user-friendly program which should be well within normal undergraduate competence.The spacing between buildings is important if overshading is to be avoided during winter months when the benefit of solar heat gain reaches its peak.On sloping sites there is a critical relationship between the angle of slope and the level of overshading.For example, if overshading is to be avoided at a latitude of 50 N,rows of houses on a 10 north-facing slope must be more than twice as far apart than on10 south-facing slope.Trees can obviously obstruct sunlight.However,if they are deciduous,they perform the dual function of permitting solar penetration during the winter whilst providing a degree of shading in the summer.Again spacing between trees and buildings is critical.Passive solar design can be divided into three broad categories:● direct gain;● indirect gain;● attached sunspace or conservatory.Each of the three categories relies in a different way on the…greenhouse effect‟ as a means of absorbing and retaining heat.The greenhouse effect in buildings is that process which is mimicked by global environmental warming.In buildings,the incident solar radiation is transmitted by facade glazing to the interior where it is absorbed by the internal surfaces causingwarming.However,re-emission of heat back through the glazing is blocked by the fact that the radiation is of a much longerwavelength than the incoming radiation.This is because the re-emission is from surfaces at a much lower temperature and the glazing reflects back such radiation to the interior.Direct gainDirect gain is the design technique in which one attempts to concentrate the majority of the building‟s glazing on the sun-facing facade.Solar radiation is admitted directly into the spaceconcerned.Two examples 30 years apart are the author‟s house in Sheffield,designed in 1967 and the Hockerton Project of 1998 by Robert and Brenda Vale.The main design characteristics are:● Apertures through which sunlight is admitted should be on the solar side of the building, within about 30 of south for the northern hemisphere.● Windows facing west may pose a summer overheating risk.● Windows should be at least double glazed with low emissivity glass (Low E) as now required by the UK Building Regulations.● The main occupied living spaces should be located on the solar side of the building.● The floor should be of a high thermal mass to absorb the heat and provide thermal inertia,whi ch reduces temperature fluctuations inside the building.● As regards the benefits of thermal mass,for the normal daily cycle of heat absorption and emission,it is only about the first 100 mm of thickness which is involved in the storage process.Thickness greater than this provides marginal improvements in performance but can be useful in some longer-term storage options.● In the case of solid floors,insulation should be beneath the slab.● A vapour barrier should always be on the warm side of any insulati on.● Thick carpets should be avoided over the main sunlit and heatabsorbing portion of the floor if it serves as a thermal store.However,with suspended timber floors a carpet is an advantage in excluding draughts from a ventilated underfloor zone.During the day and into the evening the warmed floor should slowly release its heat, and the time period over which it happens makes it a very suitable match to domestic circumstances when the main demand for heat is in the early evening.As far as the glazing is concerned,the following features are recommended:● Use of external shutters and/or internal insulating panels might be considered to reducenight-time heat loss.● To reduce the potential of overheating in the summer,shading may be provided by designing deep eaves or external louvres. Internal blinds are the most common technique but have the disadvantage of absorbing radiant heat thus adding to the internal temperature.● Heat reflecting or absorbing glass may be used to limit overheating.The downside is that it also reduces heat gain at times of the year when it is beneficial.● Light shelves can help reduce summer overheating whilst improving daylight distribution. Direct gain is also possible through the glazing located between the building interior and attached sunspace or conservatory;it also takes place through upper level windows of clerestory designs.In each of these cases some consideration is required concerning the nature and position of the absorbing surfaces.In the UK climate and latitude as a general rule of thumb room depth should not be more than two and a half times the window head height and the glazing area should be between about 25 and 35 per cent of the floor area.Indirect gainIn this form of design a heat absorbing element is inserted between the incident solar radiation and the space to be heated;thus the heat is transferred in an indirect way.This often consists of a wall placed behind glazing facing towards the sun,and this thermal storage wall controls the flow of heat into the building.The main elements● High thermal mass element positioned between sun and internal spaces,the heat absorbed slowly conducts across the wall and is liberated to the interior some time later.● Materials and thickness of the wall are chosen to modify the heat flow.In homes the flow can be delayed so that it arrives in the evening matched to occupancy periods. Typical thicknesses of the thermal wall are 20–30 cm.● Glazing on the outer side of the thermal wall is used to provide some insulation against heat loss and help retain the solar gain by making use of the greenhouse effect.● The area of the thermal storage wall element should be about 15–20 per cent of the floor area of the space into which it emits heat.● In order to derive more immediate heat benefit,air can be circulated from the buildi ng through the air gap between wall and glazing and back into the room.In this modified form this element is usually referred to as a Trombe wall. Heat reflecting blinds should be inserted between the glazing and the thermal wall to limit heat build-up in summer.In countries which receive inconsistent levels of solar radiation throughout the day because of climatic factors (such as in the UK),the option to circulate air is likely to be of greater benefit than awaiting its arrival after passage through the thermal storage wall.At times of excess heat gain the system can provide alternative benefits with the aircirculation vented directly to the exterior carrying away its heat,at the same time drawing in outside air to the building from cooler external spaces.Indirect gain options are often viewed as being the least aesthetically pleasing of the passive solar options,partly because of the restrictions on position and view out from remaining windows,and partly as a result of the implied dark surface finishes of the absorbing surfaces.As a result,this category of the three prime solar design technologies is not as widely used as its efficiency and effectiveness would suggest.Attached sunspace/conservatoryThis has become a popular feature in both new housing and as an addition to existing homes.It can function as an extension of living space,a solar heat store,a preheater for ventilation air or simply an adjunct greenhouse for plants.On balance it is considered that conservatories are a net contributor to global warming since they are often heated.Ideally the sunspace should be capable of being isolated from the main building to reduce heat loss in winter and excessive gain in summer.The area of glazing in the sunspace should be 20–30 per cent of the area of the room to which it is attached.The most adventurous sunspace so far encountered is in the Hockerton housing development which will feature later.Ideally the summer heat gain should be used to charge a seasonal thermal storage element to provide background warmth in winter.At the very least,air flow paths between the conservatory and the main building should be carefully controlled.Active solar thermal systemsA distinction must be drawn between passive means of utilising the thermal heat of the sun, discussed earlier,and those of a more…active‟nature Active systems take solar gain a step further than passive solar.They convert direct solar radiation into another form of energy.Solar collectors preheat water using a closed circuit calorifier.The emergence of Legionella has highlighted the need to store hot water at a temperature above 60 C which means that for most of the year in temperate climes active solar heating must be supplemented by some form of heating.Active systems are able to deliver high quality energy.However,a penalty is incurred since energy is required to control and operate the system known as the …parasitic energy requirement‟.A further distinction is the difference between systems using the thermal heat of the sun,andsystems,such as photovoltaic cells, which convert solar energy directly into electrical power.For solar energy to realise its full potential it needs to be installed on a district basis and coupled with seasonal storage.One of the largest projects is at Friedrichshafen.The heat from 5600 m2 of solar collectors on the roofs of eight housing blocks containing 570 apartments is transported to a central heating unit or substation.It is then distributed to the apartments as required.The heated living area amounts to 39 500 m2.Surplus summer heat is directed to the seasonal heat store which,in this case, is of the hot water variety capable of storing 12 000 m3.The scale of this storage facility is indicated by Figure 5.9.The heat delivery of the system amounts to 1915 MWh/year and the solar fraction is 47 per cent.The month by month ratio between solar and fossil-based energy indicates that from April to November inclusive,solar energy accounts for almost total demand,being principally domestic hot water.In places with high average temperatures and generous sunlight,active solar has considerable potential not just for heating water but also for electricity generation.This has particular relevance to less and least developed countries.环境变化影响下的建筑学房屋设计中的低能耗技术显而易见，在工业化国家，最好的营救机会依赖于建筑环境，因为不论是在使用的建筑或者是在建设的建筑，都是最大的、单一的、间接地由化石燃料的燃烧所引起的碳排放的源头，而这些站了所有排放的50%。
英文翻译
本科生毕业设计专业外文翻译原文：Discussion on lightning protectionengineering for buildings译文：建筑物防雷工程问题的探讨专业：电气工程及其自动化院（系）：机电工程学院2015年5月6日Discussion on lightning protection engineering for buildingsThere are many natural disasters in the environment of human existence, such as earthquakes, rainstorm, hail, flood, drought, fire, lightning, etc.. In this regard, people always try to defend or mitigate the damage caused by them.. Lightning disaster is one of the most serious ten natural disasters released by the United Nations "international disaster reduction for ten years" and is one of the ten natural disasters in China. However, in our country, the lightning protection design in the entire building design in a small proportion of the. Electrical designers do not attach importance to other professional designers do not pay attention, but the damage caused by lightning can not be ignored.According to the relevant data statistics, the world's annual economic losses caused by lightning reached more than 1000000000 U. dollars, the casualties is also quite serious, the number of casualties in our country each year reached 10500 people or so. Is lightning protection history, at the beginning of the people's Republic of China mostly in accordance with Japanese 45 degrees to 60 degrees angle of protection to determine the protective range of lightning rod, with trigeminal small copper rod, copper lead line and 1m * 1m copper as a grounding device.One IntroductionChina's first 《building lightning protection design specification》announced on November 7, 1983. The second part of the building lightning protection design specification "(GB50057 - 94) (Ministry of machinery industry design and Research Institute Mr. Yong Lin editor) announced on 18 April 1994. The norms of the Department absorbed many foreign advanced things, will lightning arrester protection range of the calculation method of change to a rolling ball method and combined with actual experience in lightning protection design in our country adds many new terms.These two norms have a great effect on the lightning protection design of buildings in our country.. At present, our country also source with the "building lightning protection design code" (GB50057 - 94).70 years ago, people heard the lightning accident is hit buildings or trees, causing serious damage to buildings or casualties. At that time, the vast majority of lightning struck buildings are not installed lightning protection device (lightning rod, lightning rod or lightning rod network). The lightning accident is now relatively rare, the reason is that the multi-storey buildings and high-rise buildings are installed lightning protection device. Sometimes lightning arrester lightning after, even microelectronic devices because of lightning electromagnetic pulse induction was impaired, outsiders do not know, the unitto do some local repair also finished the. In fact, the lightning accident is not less. Lightning on the floor of a building may be a rare thing, but the lightning flash unit is connected is more common, this is normal. When the flash device is connected to flash, the equipment in the vicinity of the building is caused by lightning current, which is the electromagnetic pulse jamming of the building.With the rapid development of electronic technology, electronic computers have already entered every walk of society.. In the building almost all of the micro electronic equipment and computer systems with different degrees of complexity, civil construction is no exception. The electromagnetic pulse jamming of the thunder and lightning is becoming a frequent accident. In the face of this challenge, lightning protection design must change the concept, lightning electromagnetic pulse protection as the focus of lightning protection design. This is not just a professional thing, because it involves the electronic equipment position and pipeline layout and other issues. Various professional should be fully negotiated, from the overall lightning protection design issues. Otherwise, the building was designed to be good, and it can't be used normally.Second, an overview of the principles of lightning lightning is sound, light, electricity and other physical phenomena in the atmosphere, the discharge current of up to several tens, even hundreds of thousands. Instantaneous discharge lightning current generated enormous destruction strength and strong electromagnetic interference, and caused by the disaster is one of the international disaster reduction ten years "published the most serious ten kinds of natural disaster" for the United Nations, is currently China's top ten natural disasters. It is estimated that around the world each year about 10 million times of thunderstorm, the average per hour occurred 2000 thunderstorms, and every minute occurred in 1 ~ 3 cloud to ground lightning, the surface of the earth, every second of the flash is 30 ~ 100 times, sometimes suddenly have about 2000 lightning, the average daily occurrence lightning 800 million times. The number of casualties caused by lightning, the number of property damage is even more amazing. According to the relevant data statistics, the world's annual economic losses caused by lightning reached more than 1000000000 U. dollars, the casualties is also quite serious, the number of casualties in our country each year reached 10500 people or so.Lightning discharge to ground, on the ground building facilities pose a serious hazard, its harm can be divided into two types: direct damage and indirect damage. The direct damage is caused by the heat effect, mechanical effect and shock wave of the lightning,and the indirect damage is the electrostatic induction, the electromagnetic induction and the instantaneous overvoltage, etc.The direct damage of the heat effect caused by lightning：the mechanical effect and the impact of the impact of the impact of the impact are lightning direct damage.Lightning discharge, a powerful lightning current from lightning strike point injection is striking an object, and the thermal effect can be so that the lightning point around the local metal melting, when the lightning in a haystack and trees, the weeds and trees is ignited; when the lightning transmission circuit, the fuse. These are thermal effects, if the protection is inappropriate, it will become a fire, a greater loss and disaster. The damage caused by the mechanical effect of lightning is mainly manifested in two forms: electric power and internal pressure. It is well known that the electromagnetic field exists in the space around the current carrying conductor, and the electromagnetic field in the electromagnetic field can be affected by the electromagnetic force.. When lightning strikes buildings, in the electric power, the conductor in the building will attract or repel each other or cause deformation, or even break off.The internal pressure of the object is another manifestation of the destructive effect of the mechanical effect of lightning. Due to the lightning current amplitude is very high (up to 100 - 300 kV), discharge time is very short (about 40 NS), hit the trees or the components of the building, in the instant internal generated a lot of heat, in a short time heat to not send out, resulting in objects within the water evaporates into water vapor, and rapid expansion, a huge explosive will hit trees split and collapse of buildings. The shock wave generated by the shock wave similar to the explosion of the thunderbolt. In the lightning discharge process of comeback stage, discharge channel is strong air free and strongly anisotropic charge neutralization, channel instantaneous temperature increases, so the rapid expansion of heated air around the channel, and the ultrasonic quickly spread to the surrounding, thus forming shock wave. Best way to direct damages defense is in strict accordance with the external lightning protection system installation of the building lightning protection design specification "(GB5005794).Two The indirect damage of the electrostatic inductionElectromagnetic induction and instantaneous overvoltage caused by the impact of the indirect damage of lightning. Lightning electromagnetic pulse is generated, the sky thunder as a powerful lightning flow interference and electromagnetic field. Its induction range is very big, the building, person and all sorts of electrical equipment and pipeline will havethe harm of different degree. In the building of lightning electromagnetic pulse interference refers to the following three conditions:(1) In the sky lightning wave electromagnetic radiation in the building power lines and electronic equipment electromagnetic interference;(2) Building lightning flash unit is connected, the interference of powerful moments of lightning current in the building electric power circuit and electronic equipment;(3) By a variety of external strong and weak overhead lines and cable lines to the electromagnetic wave of building electronic equipment interference.The modern electronic technology is developing with high accuracy, high sensitivity, high frequency and high reliability.. These electronic devices are very sensitive, but the pressure is very low, the general electronic equipment can not withstand the voltage fluctuations of 5 volts. In a variety of computer, for example, when the lightning electromagnetic pulse magnetic field strength more than 0.07 Gaussian, it will cause the wrong action of the microcomputer, when the magnetic field strength of more than 2.4 Gauss, it will cause a microcomputer permanent damage. Therefore, we must take the necessary protective measures against lightning electromagnetic pulse in order to achieve good electromagnetic compatibility in advanced buildings. The ideal lightning protection design scheme for the prevention of lightning electromagnetic pulse is the cage type lightning protection net, which uses the Faraday cage principle. The metal structure of the building is spread everywhere, and without a lot of steel it can easily connect to form Faraday cage, so that the electronic equipment within the building to get a good shield.The ideal lightning protection design scheme for the prevention of lightning electromagnetic pulse is the cage type lightning protection net, which uses the Faraday cage principle. The metal structure of the building is spread everywhere, and without a lot of steel it can easily connect to form Faraday cage, so that the electronic equipment within the building to get a good shield. The shield is good, can protect the radiation of electromagnetic wave, but also can make the diversion and the pressure of building inside the building to achieve the best effect.. Therefore, some of the requirements for the equipment itself do shield, and some of the requirements between the equipment and equipment to do the shield, as there is the need to do shielding in the room. Because of the importance of the problem, so in 1995 the International Electrotechnical Commission building lightning protection sub committee iec/tc-81 in the lightning electromagnetic pulse protection "standard proposed the concept of lightning protection zone (LPZ), lightning protection design personnel can according to the microelectronic devices,simplified, important degree, placement and inlet and outlet pipeline of the specific situation according to the lightning protection area LPZ division of lightning protection zone to achieve good shielding, equipotential and grounding effect.Three External lightning protection device and internal lightning protection device The International Electrotechnical Commission the preparation of standard (Iec10241) building lightning protection device is divided into two parts: external lightning protection device and internal lightning protection device. The lightning protection design of buildings must take the external lightning protection device and the internal lightning protection device as a whole.The external lightning protection device (i.e., the conventional conventional surge arrester) is composed of three parts, which is the grounding device, the lead wire and the grounding device.. The flash device (also called the flash device) has three forms: lightning rod, lightning rod and lightning rod net, which is located at the top of the building, its role is to lead ray or call intercept lightning, that is, lightning current cited. The lead off line is connected with the grounding device, and the next is connected with the grounding device, and its function is the lightning current that is intercepted by the grounding device to the grounding device. The grounding device at a certain depth underground, it is the role of the lightning current into the ground to smooth flow. The role of internal lightning protection device is to reduce building lightning current and the resulting electromagnetic effect and prevent counterattack, contact voltage and the step voltage secondary lightning. In addition to the external lightning protection system, all in order to achieve the purpose of the facilities, means and measures for internal lightning protection devices, such as potential connection facilities, shielding facilities, installation of lightning arrester and reasonable wiring and good grounding measures.Lightning protection design and engineering is a systematic project.The book of lightning protection design of buildings puts forward six important factors of lightning protection design for buildings, and the aim is to remind people to consider lightning protection design of buildings as a whole and comprehensively.. The six elements are:(1) take flash function: to achieve flash function should have the conditions, including ground flash device (lightning, lightning protection zone and the lightning protection network), the flow resistance of compression capacity, continuous lightning effect, cost and lightning collector and the building of the aesthetic unity etc.（2）diversion effect: the effect of the diversion of the offline to the diversion effect. The amount of the lead off the line directly affect the diversion effect, lead the assemblyline more, each lead line through the wire of the lightning current is small, the induction range is small. The distance between the guide line and the assembly line should not be less than the norm. When the building is very high, downlead a long time should be grading ring is added in the middle of the building site, in order to reduce lead referrals inductance voltage drop. This can not only divert, but also can reduce the counter voltage.(3) the equilibrium potential: the same potential is formed at all parts of the building,i.e.. If within the building structure reinforced with various metal and metal pipe can be connected into unity of conductive body, building of course won't produce different potentials, which can ensure the building won't produce counterattack and endanger the personal safety of touch voltage and step voltage, to prevent the lightning electromagnetic pulse interference microelectronics devices also have great benefits. The concrete structure of the reinforced concrete structure is the most have the potential of the condition.(4)shielding: the main purpose of the shield is to make communication equipment, electronic computers, precision instruments and automatic control system from the building to the harm of the electromagnetic pulse of the lightning. These facilities within the building, in the lightning flash unit is connected will be subject to electromagnetic interference, due to their sensitivity is high and low voltage withstand level, sometimes near thunder or lightning when, by the lightning wave effects of electromagnetic radiation, even in other buildings lightning, will also be affected by the impact from the premises of the electromagnetic wave.(5) ground effect: the effect of the grounding is good or bad. Good grounding effect is one of the important guarantee for lightning protection successfully.. Each building should consider which grounding way effect best and most economical. When reinforced concrete structures are in conformity with the specifications, the reinforcement should be used as the grounding device.. When not specified in the standard conditions or foundation in the waterproof layer and do weeks circle type earthing device, but will be weeks circle type earthing device buried in advance outside the base groove of the outermost (you don't have to leave the building 3M). The building of timber structure and masonry structure, must be independent and lead by independent grounding. When the soil resistivity, the use of grounding is large, but also do circle type earthing device.(6)reasonable routing: how wiring can be the best comprehensive effect. Modern buildings are not separated from lighting, power, telephone, TV and computer equipment, etc., in the lightning protection design, we must consider the relationship between the lightning protection system and these pipelines.In the building, in general, lightning protection measures can be divided into two categories of safe distance and equal potential connection. Safe distance refers to the minimum distance between two conductive objects in the space that need lightning protection and the minimum distance of the spark discharge that can't be dangerous.. The purpose of the potential connection is to reduce or eliminate the potential difference generated at the various parts of the internal lightning protection device, including the potential difference between the external conductors near the point of the door.By means of safe distance should be strictly according to all kinds of lightning protection measures of the building lightning protection design specification "(Gb5005794) regulations to calculation; the potential connection method, it should be thoroughly realize the potential. Wood and brick and concrete structure of structure should be a safe distance measures, reinforced concrete structure and steel structure should adopt equipotential connection measures.Four The overall concept of lightning protection designThe building inside and outside the overall concept. The inside and outside of the building is internal lightning protection device and external lightning protection device. Building the whole concept is refers to the design and installation, to make unified whole consideration of internal lightning protection device and the external lightning protection device; outside the building of the whole concept is refers to a courtyard, a district and near the environment to do a comprehensive lightning protection planning, also can't violate community planning requirements, for example: installed lightning tower would not affect the cell's appearance, the lightning, lightning or lightning protection network whether and matched with the facade of the buildings and low rise buildings can protected by a lightning protection device for tall buildings or tall chimneys and so on. Grounding devices to a unified and comprehensive consideration, for example, more recent buildings apart can common earthing system, underground pipe network can share earth part of the body, and can in a compound or cell for future integrated shared grounding creation potential connection conditions, and so on.Now the city's green more and more, the tall trees are also more and more. Some buildings although the installation of lightning rod, but trees from buildings very close to and beyond the building is higher, in this case, lightning protection device for the building actually equal to the dummy. Because the tree Lightning more opportunities, easy to lead to lightning ball lightning, more of the adjacent buildings threatened. So the lightning protection design of buildings and installation should consider the overall unity of theexternal lightning protection system, internal lightning protection devices, the outside of the building of the environment until the whole area of lightning protection device. Not only the electrical professional designers have the overall concept, architectural professional designers of lightning protection should also have the overall concept. This is one of the important issues of the modern lightning protection design concept change.建筑物防雷工程问题的探讨在人类生存的环境中有许多自然灾害，如地震、暴雨、冰雹、水灾、旱灾、火灾、雷击等等。
关于建筑行业安全施工的分析毕业设计外文文献翻译 中英文翻译
附录AAnalysis of Safety Performance in the Construction IndustryData source:The HKU Scholars HubOver the years,many researchers have investigated into the safety performance of the construction industry.Some of them identified factors leading to the occurrence of accidents on construction sites.The high frequency of construction accident has casted the industry a considerable amount.The government and many concerned parties have taken measures against the potential causes of accidents,aiming at reducing accidents and promoting safety in the industry.1.Definition of AccidentLaney(1982)states that the simplest definition of an accident is“an uncontrollable occurrence which results in injury or damage”.The events leading up to an accident are controllable in most cases.International Labor Office Geneva(1983)and Kennedy(1997) also agree that accidents don’t just happen,they are preventable.All industrial accidents are, either directly or indirectly,attributable to human failings.Rowlandson(1997)points out that a number of elements which need to be incorporated into the definition if this is to be useful in terms of accident prevention.These elements are:ck of management control;b.basic personal and task factors;c.sub-standard acts and conditions–the symptoms of the accident;d.an unplanned and undesired event or incident–the accident;e.an undesired outcome–death,injury or property damage;f.a cost.He thus defines accident as:“...an unplanned incident leading to death,injury or property damage which stems from inadequate management control of work processes manifesting itself in personal or job factors which lead to substandard actions or conditions which are seen as the immediate causes of the accident.”mon Accidents in Construction IndustryAccording to Lingard and Rowlinson(1994)accident proneness can be measured by thefrequency of accident occurrence.According to some researches,construction industry has the highest accident rate over the years,thus it is said to be more accident-prone than other industries.It is essential to understand why construction industry is more vulnerable to accident than the others.The Labour Department classified construction accidents by types. Table1shows the number of injuries in2004and figures in blankets are the number of fatality fixed or stationary object11.9%Fall of person from height11.7%Injured whilst lifting or carrying16.0%Slip,trip or fall on same level17.3%Striking against or stuck by moving object19.7%Contact with moving machinery or object being machined7.0%Others16.4%The above chart shows the major accidents which contributed more than5%of the construction accidents in2004:3.Facors Affecting Safety Performance of Construction IndustryMany researchers have studied the factors affecting safety performance on construction sites.Stranks(1994)points out that the reasons of the poor safety recordmay correlate with many factors such as complexity of the work or system,risk nature of works,management style,safety knowledge and commitment,and personal behavior.Here are several factors that affect safety performance of contraction industry.pany SizeTam and Fung(1998)study the effectiveness of safety management strategies on safety performance.In this study,the safety performance of companies is gauged by their accident rates in1994as accident rates are steadier throughout the year and they can be easily obtained.In the study,it is found that company size,in term of number of management staff, affects safety performance.Tam and Fung(1998)observe that the accident rate of small companies is highest,the rate for medium sized lies almost at the industrial average and that for the large firms is the lowest.This demonstrates that larger firms generally have better safety records.This could be resulted from the more structured and formalized safetyprogrammers,and stronger management commitment to safety.It is found that the higher number of employees in the organization,the lower figure of the accident rate.b.Level of SubcontractingMulti-layer subcontracting is unique to China construction industry and has been the most common practice being used with long history.Subcontractors would normally further subcontract their work without the consent of their principal contractor to several smaller firms in order to minimize their overheads.Multi-layers of subcontractors is one of the major difficulties in implementing safety management.Recent study carried out by Wong and So (2004)shows the current status of the subcontracting practice and how multi-layer subcontracting system affects construction safety performance.Their questionnaire survey reveals that the majority of respondents(45.5%)would sublet80-90%of their works to subcontractors.None of the respondents would carry out construction work that fully relies on their own effort;at least30%of works would be subcontracted out.Lai(1987)attributes the high site accident rates to the use of labour-only subcontractors. As subcontracted workers are highly mobile,lack loyalty to contractors and are rewarded according to work done,they are difficult to control.Implementing safety practices on site becomes more difficult.Recent researchers,like Wong(1999)and Lee(1996),believe multi-layer subcontracting system is one of the major causes to poor safety performance in China’s construction industry.The most extreme case of subcontracting quoted by Lee(1999) was subcontracting up to15layers.He describes such multi-layer subcontracting as common and excessive.Small business,like subcontractors,face with specific health and safety challenges. Many firms lacked adequate resources and were often struggling to survive.Moreover,they lack an understanding of their obligations and the health and safety issues of their processes. These can be supported by Rawlinson’s(1999)study for Housing Authority.He finds that average84%of workers injured from1995to1998were subcontractors’workers.Such situation may be due to subcontractors’workers’inadequate training and awareness of safe working practice.Tam and Fung(1998)find there is a significant difference between trained and un-trained employees in relation to accident rate.municationAccording to Wong(2002),communication is a major factor affecting the safety on sites. However,it has seldom been discussed before.Wong(2002)conducts a research to find out the causes of communication problems between main contractors and subcontractors.He identifies12factors leading to poor communication in construction industry.Among them,10 are discussed here as they are more relevant to the territory and have been discussed by other researchers.These factors are listed below:i.Industry NatureIn order to complete the project on time,construction projects are carried out under almost all sorts of weather conditions.Besides,construction workers are usually not well-educated.These cause communication difficulties.ii.Industry CultureWong(2000)identifies sub-contracting system is a hurdle to construction safety as they are engaged on day-work basis,thus they are not aware to site safety.iii.Client TypeThere are2types of clients,public and private ernment bodies are public clients.Private clients can be further divided into experienced and inexperienced.Their concern and expectation on site safety performance appear to be different.anization StructureFryer(1997)suggests that organization structure,including hierarchy,downsizing and decentralization vs.decentralization,rigidity vs.flexibility,rules and procedure,would affect the result of communications.According to Wong(2002),downsizing became popular since 1990s because this can allow flexibility for people for respond more quickly to change.v.Relationship of Main and Sub-ContractorsThe poor relationship between contractors is an obstacle to construction safety.However, such situation could be resolved by partnering.Wong(2002)says that partnering is considered by most of the project participants as a worthwhile initiative.munication BarriersHicks and Gullett(1983)points out that communication overload and inattention to message can cause ineffective communication.People may receive more information than they can process or they spend time evaluating the sender and the message before the entiremessage is being passed or read.vii.Content of InformationWong(2002)attributes poor safety performance to the content of information.If content of information,such as method statements,working,drawings or safety procedures,are inaccurate or unclear,safety could not be effectively achieved.viii.Value of CommunicatorsTam et al(2001)point out that many production personnel rank safety in a lower priorities when compare with meeting the production schedule,quota and cost targets. Besides,Nichols and Stevens(1999)mention the failure of many superiors to listen.As a result,safety issue does not receive enough attention.ix.Provision of Continuous TrainingEnrichment of safety knowledge is essential.Teo et al(2005)carry out a study to find out the methods in fostering workers’safe work behaviours.They find that training is an important way to enable workers to work safely,because they are equipped with the knowledge of how to work safely.x.Workers’AttitudeWorkers’incorrect attitude towards site safety is a big difficulty in making safety sites. In Chan et al’s(1999)research,it is found that workers do not think they have the duty to comply with safety regulations for the main contractors.They will be more aware to safety issues after serious accident but they will resume their own way of practice shortly after that. Hinze(2002)and Vredenburgh(2002)state that site safety could only be improved if workers change their behaviours towards site safety.Teo et al(2005)also agree that negligence in safety and lack of awarenessto ensure lingering dangers on site would increase the chances of workers getting injured.5.Accident Costs and Safety CostsThe construction industry in China,especially for building projects,has a very poor safety record.According to Hinze and Raboud(1988),it is a common perception that “safety”is unproductive and not vital to the success of a project as contractors may not be appreciated by just keeping good safety on sites.However,it should be noted that accidents do not just lead to injury and loss of lives,a huge amount of accident costs is induced as well.Accordingly,safety investment in construction projects could better the safety performance and avoid the huge amount of accident costs.Ridiculously,most contractors are not willing to invest their money,time and effort to operate and to maintain effective safety programmers. They are not fully aware of the costs of an accident.Over the years,there have been many studies of the cost of accidents and it is found that, accident costs could be huge.Rowlinson(1997)identifies that cost of an accident is not only constituted of hospitalization and compensation costs of the individual involved in the accident.De Saram and Tang(2005)admit that construction accidents may result in numerous damages and losses.By understanding all the costs incurred by construction accidents,contractors might be surprised,and thus realize the importance of site safety investment.6.Safety Management SystemSafety management systems are not new to us.Many have been written on it.Site safet is regarded as an integral part of the project objective and safety attitudes a part of the project culture in order to pursue site safety effectively.Management at head office and on-site must be seen to care.Only then,an effective and committed safety officer will be appointed and given sufficient call on time and resources to achieve site safety.According to the Labour Department,below are the objectives of setting up a safety management system:a.to prevent improper behaviour that may lead to accidents;b.to ensure that problems are detected and reported;andc.to ensure that accidents are reported and handled properly.Besides,a safety management system enables flexibility of developing safety policies and measures most suitable to the particular circumstances of individual companies.The inputs from employer and employees make the safety management processes more readily be modified to keep pace with changing circumstances.An effective safety management system can be used to manage and control both existing and potential hazards and its effectiveness can be maximized when an organization is able to combine occupational safety and health issues into its business strategy.In this paper,statistics of construction safety,common accident types,factors affectingsafety performance and legislations related to construction safety have been reviewed. Statistics shows the unacceptable construction safety performance in the past.Therefore,the government introduced safety management system to the industry,hoping to establish a self-regulating atmosphere.Besides,government keeps introducing new legislation,for example the Construction Workers Registration Ordinance,and amending existing legislations to cope with the industry. Though the accident rate becomes stagnant in recent years,the fact shows the government’s determination in improving the industry to an accident-free one.附录B关于建筑行业安全施工的分析资料来源：香港大学学者中心多年来，许多研究人员都对建筑业的安全施工做出过深入研究。
土木工程外文文献及翻译
本科毕业设计外文文献及译文文献、资料题目：Designing Against Fire Of Building 文献、资料来源：国道数据库文献、资料发表（出版）日期：2008.3.25院（部）：土木工程学院专业：土木工程班级：土木辅修091姓名：xxxx外文文献:Designing Against Fire Of BulidingxxxABSTRACT:This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electrical systems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are considered in the context of current regulatory requirements. The principles and assumptions associ- ated with various approaches are discussed.1 INTRODUCTIONOther papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the case of fire. Rather, it is building regulations such as the Building Code of Australia (BCA) that directly specify most of the requirements for fire safety of buildings with reference being made to Standards such as AS3600 or AS4100 for methods for determining the fire resistance of structural elements.The purpose of this paper is to consider the design of buildings for fire safety from an engineering perspective (as is currently done for other loads such as wind or earthquakes), whilst at the same time,putting such approaches in the context of the current regulatory requirements.At the outset,it needs to be noted that designing a building for fire safety is far morethan simply considering the building structure and whether it has sufficient structural adequacy.This is because fires can have a direct influence on occupants via smoke and heat and can grow in size and severity unlike other effects imposed on the building. Notwithstanding these comments, the focus of this paper will be largely on design issues associated with the building structure.Two situations associated with a building are used for the purpose of discussion. The multi-storey office building shown in Figure 1 is supported by a transfer structure that spans over a set of railway tracks. It is assumed that a wide range of rail traffic utilises these tracks including freight and diesel locomotives. The first situation to be considered from a fire safety perspective is the transfer structure.This is termed Situation 1 and the key questions are: what level of fire resistance is required for this transfer structure and how can this be determined? This situation has been chosen since it clearly falls outside the normal regulatory scope of most build- ing regulations. An engineering solution, rather than a prescriptive one is required. The second fire situation (termed Situation 2) corresponds to a fire within the office levels of the building and is covered by building regulations. This situation is chosen because it will enable a discussion of engineering approaches and how these interface with the building regulations–since both engineering and prescriptive solutions are possible.2 UNIQUENESS OF FIRE2.1 IntroductionWind and earthquakes can be considered to b e “natural” phenomena over which designers have no control except perhaps to choose the location of buildings more carefully on the basis of historical records and to design building to resist sufficiently high loads or accelerations for the particular location. Dead and live loads in buildings are the result of gravity. All of these loads are variable and it is possible (although generally unlikely) that the loads may exceed the resistance of the critical structural members resulting in structural failure.The nature and influence of fires in buildings are quite different to those associated with other“loads” to which a building may be subjected to. The essential differences are described in the following sections.2.2 Origin of FireIn most situations (ignoring bush fires), fire originates from human activities within the building or the malfunction of equipment placed within the building to provide a serviceable environment. It follows therefore that it is possible to influence the rate of fire starts by influencing human behaviour, limiting and monitoring human behaviour and improving thedesign of equipment and its maintenance. This is not the case for the usual loads applied to a building.2.3 Ability to InfluenceSince wind and earthquake are directly functions of nature, it is not possible to influence such events to any extent. One has to anticipate them and design accordingly. It may be possible to influence the level of live load in a building by conducting audits and placing restrictions on contents. However, in the case of a fire start, there are many factors that can be brought to bear to influence the ultimate size of the fire and its effect within the building. It is known that occupants within a building will often detect a fire and deal with it before it reaches a sig- nificant size. It is estimated that less than one fire in five (Favre, 1996) results in a call to the fire brigade and for fires reported to the fire brigade, the majority will be limited to the room of fire origin. In oc- cupied spaces, olfactory cues (smell) provide powerful evidence of the presence of even a small fire. The addition of a functional smoke detection system will further improve the likelihood of detection and of action being taken by the occupants.Fire fighting equipment, such as extinguishers and hose reels, is generally provided within buildings for the use of occupants and many organisations provide training for staff in respect of the use of such equipment.The growth of a fire can also be limited by automatic extinguishing systems such as sprinklers, which can be designed to have high levels of effectiveness.Fires can also be limited by the fire brigade depending on the size and location of the fire at the time of arrival. 2.4 Effects of FireThe structural elements in the vicinity of the fire will experience the effects of heat. The temperatures within the structural elements will increase with time of exposure to the fire, the rate of temperature rise being dictated by the thermal resistance of the structural element and the severity of the fire. The increase in temperatures within a member will result in both thermal expansion and,eventually,a reduction in the structural resistance of the member. Differential thermal expansion will lead to bowing of a member. Significant axial expansion will be accommodated in steel members by either overall or local buckling or yielding of local- ised regions. These effects will be detrimental for columns but for beams forming part of a floor system may assist in the development of other load resisting mechanisms (see Section 4.3.5).With the exception of the development of forces due to restraint of thermal expansion, fire does not impose loads on the structure but rather reduces stiffness and strength. Such effects are not instantaneous but are a function of time and this is different to the effects of loads such as earthquake and wind that are more or less instantaneous.Heating effects associated with a fire will not be significant or the rate of loss of capacity will be slowed if:(a) the fire is extinguished (e.g. an effective sprinkler system)(b) the fire is of insufficient severity – insufficient fuel, and/or(c)the structural elements have sufficient thermal mass and/or insulation to slow the rise in internal temperatureFire protection measures such as providing sufficient axis distance and dimensions for concrete elements, and sufficient insulation thickness for steel elements are examples of (c). These are illustrated in Figure 2.The two situations described in the introduction are now considered.3 FIRE WITHIN BUILDINGS3.1 Fire Safety ConsiderationsThe implications of fire within the occupied parts of the office building (Figure 1) (Situation 2) are now considered. Fire statistics for office buildings show that about one fatality is expected in an office building for every 1000 fires reported to the fire brigade. This is an order of magnitude less than the fatality rate associated with apartment buildings. More than two thirds of fires occur during occupied hours and this is due to the greater human activity and the greater use of services within the building. It is twice as likely that a fire that commences out of normal working hours will extend beyond the enclosure of fire origin.A relatively small fire can generate large quantities of smoke within the floor of fire origin. If the floor is of open-plan construction with few partitions, the presence of a fire during normal occupied hours is almost certain to be detected through the observation of smoke on the floor. The presence of full height partitions across the floor will slow the spread of smoke and possibly also the speed at which the occupants detect the fire. Any measures aimed at improving housekeeping, fire awareness and fire response will be beneficial in reducing thelikelihood of major fires during occupied hours.For multi-storey buildings, smoke detection systems and alarms are often provided to give “automatic” detection and warning to the occupants. An alarm signal is also transmitted to the fire brigade.Should the fire not be able to be controlled by the occupants on the fire floor, they will need to leave the floor of fire origin via the stairs. Stair enclosures may be designed to be fire-resistant but this may not be sufficient to keep the smoke out of the stairs. Many buildings incorporate stair pressurisation systems whereby positive airflow is introduced into the stairs upon detection of smoke within the building. However, this increases the forces required to open the stair doors and makes it increasingly difficult to access the stairs. It is quite likely that excessive door opening forces will exist(Fazio et al,2006)From a fire perspective, it is common to consider that a building consists of enclosures formed by the presence of walls and floors.An enclosure that has sufficiently fire-resistant boundaries (i.e. walls and floors) is considered to constitute a fire compartment and to be capable of limiting the spread of fire to an adjacent compartment. However, the ability of such boundaries to restrict the spread of fire can be severely limited by the need to provide natural lighting (windows)and access openings between the adjacent compartments (doors and stairs). Fire spread via the external openings (windows) is a distinct possibility given a fully developed fire. Limit- ing the window sizes and geometry can reduce but not eliminate the possibility of vertical fire spread.By far the most effective measure in limiting fire spread, other than the presence of occupants, is an effective sprinkler system that delivers water to a growing fire rapidly reducing the heat being generated and virtually extinguishing it.3.2 Estimating Fire SeverityIn the absence of measures to extinguish developing fires, or should such systems fail; severe fires can develop within buildings.In fire en gineering literature, the term “fire load” refers to the quantity of combustibles within an enclosure and not the loads (forces) applied to the structure during a fire. Similarly, fire load density refers to the quantity of fuel per unit area. It is normally expressed in terms of MJ/m2 or kg/m2 of wood equivalent. Surveys of combustibles for various occupancies (i.e offices, retail, hospitals, warehouses, etc)have been undertaken and a good summary of the available data is given in FCRC (1999). As would be expected, the fire load density is highly variable. Publications such as the International Fire Engineering Guidelines (2005) give fire load data in terms of the mean and 80th percentile.The latter level of fire load density is sometimes taken asthe characteristic fire load density and is sometimes taken as being distributed according to a Gumbel distribution (Schleich et al, 1999).The rate at which heat is released within an enclosure is termed the heat release rate (HRR) and normally expressed in megawatts (MW). The application of sufficient heat to a combustible material results in the generation of gases some of which are combustible. This process is called pyrolisation.Upon coming into contact with sufficient oxygen these gases ignite generating heat. The rate of burning(and therefore of heat generation) is therefore dependent on the flow of air to the gases generated by the pyrolising fuel.This flow is influenced by the shape of the enclosure (aspect ratio), and the position and size of any potential openings. It is found from experiments with single openings in approximately cubic enclosures that the rate of burning is directly proportional to A h where A is the area of the opening and h is the opening height. It is known that for deep enclosures with single openings that burning will occur initially closest to the opening moving back into the enclosure once the fuel closest to the opening is consumed (Thomas et al, 2005). Significant temperature variations throughout such enclosures can be expected.The use of the word ‘opening’ in relation to real building enclosures refers to any openings present around the walls including doors that are left open and any windows containing non fire-resistant glass.It is presumed that such glass breaks in the event of development of a significant fire. If the windows could be prevented from breaking and other sources of air to the enclosure limited, then the fire would be prevented from becoming a severe fire.Various methods have been developed for determining the potential severity of a fire within an enclosure.These are described in SFPE (2004). The predictions of these methods are variable and are mostly based on estimating a representative heat release rate (HRR) and the proportion of total fuel ςlikely to be consumed during the primary burning stage (Figure 4). Further studies of enclosure fires are required to assist with the development of improved models, as the behaviour is very complex.3.3 Role of the Building StructureIf the design objectives are to provide an adequate level of safety for the occupants and protection of adjacent properties from damage, then the structural adequacy of the building in fire need only be sufficient to allow the occupants to exit the building and for the building to ultimately deform in a way that does not lead to damage or fire spread to a building located on an adjacent site.These objectives are those associated with most building regulations includingthe Building Code of Australia (BCA). There could be other objectives including protection of the building against significant damage. In considering these various objectives, the following should be taken into account when considering the fire resistance of the building structure.3.3.1 Non-Structural ConsequencesSince fire can produce smoke and flame, it is important to ask whether these outcomes will threaten life safety within other parts of the building before the building is compromised by a loss of structural adequacy? Is search and rescue by the fire brigade not feasible given the likely extent of smoke? Will the loss of use of the building due to a severe fire result in major property and income loss? If the answer to these questions is in the affirmative, then it may be necessary to minimise the occurrence of a significant fire rather than simply assuming that the building structure needs to be designed for high levels of fire resistance. A low-rise shopping centre with levels interconnected by large voids is an example of such a situation.3.3.2 Other Fire Safety SystemsThe presence of other systems (e.g. sprinklers) within the building to minimise the occurrence of a serious fire can greatly reduce the need for the structural elements to have high levels of fire resistance. In this regard, the uncertainties of all fire-safety systems need to be considered. Irrespective of whether the fire safety system is the sprinkler system, stair pressurisation, compartmentation or the system giving the structure a fire-resistance level (e.g. concrete cover), there is an uncertainty of performance. Uncertainty data is available for sprinkler systems(because it is relatively easy to collect) but is not readily available for the other fire safety systems. This sometimes results in the designers and building regulators considering that only sprinkler systems are subject to uncertainty. In reality, it would appear that sprinklers systems have a high level of performance and can be designed to have very high levels of reliability.3.3.3 Height of BuildingIt takes longer for a tall building to be evacuated than a short building and therefore the structure of a tall building may need to have a higher level of fire resistance. The implications of collapse of tall buildings on adjacent properties are also greater than for buildings of only several storeys.3.3.4 Limited Extent of BurningIf the likely extent of burning is small in comparison with the plan area of the building, then the fire cannot have a significant impact on the overall stability of the building structure. Examples of situations where this is the case are open-deck carparks and very large area building such as shopping complexes where the fire-effected part is likely to be small in relation to area of the building floor plan.3.3.5 Behaviour of Floor ElementsThe effect of real fires on composite and concrete floors continues to be a subject of much research.Experimental testing at Cardington demonstrated that when parts of a composite floor are subject to heating, large displacement behaviour can develop that greatly assists the load carrying capacity of the floor beyond that which would predicted by considering only the behaviour of the beams and slabs in isolation.These situations have been analysed by both yield line methods that take into account the effects of membrane forces (Bailey, 2004) and finite element techniques. In essence, the methods illustrate that it is not necessary to insulate all structural steel elements in a composite floor to achieve high levels of fire resistance.This work also demonstrated that exposure of a composite floor having unprotected steel beams, to a localised fire, will not result in failure of the floor.A similar real fire test on a multistory reinforced concrete building demonstrated that the real structural behaviour in fire was significantly different to that expected using small displacement theory as for normal tempera- ture design (Bailey, 2002) with the performance being superior than that predicted by considering isolated member behaviour.3.4 Prescriptive Approach to DesignThe building regulations of most countries provide prescriptive requirements for the design of buildings for fire.These requirements are generally not subject to interpretation and compliance with them makes for simpler design approval–although not necessarily the most cost-effective designs.These provisions are often termed deemed-to-satisfy (DTS) provisions. All aspects of designing buildings for fire safety are covered–the provision of emergency exits, spacings between buildings, occupant fire fighting measures, detection and alarms, measures for automatic fire suppression, air and smoke handling requirements and last, but not least, requirements for compartmentation and fire resistance levels for structural members. However, there is little evidence that the requirements have been developed from a systematic evaluation of fire safety. Rather it would appear that many of the requirements have been added one to another to deal with another fire incident or to incorporate a new form of technology. There does not appear to have been any real attempt to determine which provision have the most significant influence on fire safety and whether some of the former provisions could be modified.The FRL requirements specified in the DTS provisions are traditionally considered to result in member resistances that will only rarely experience failure in the event of a fire.This is why it is acceptable to use the above arbitrary point in time load combination for assessing members in fire. There have been attempts to evaluate the various deemed-to-satisfy provisions (particularly the fire- resistance requirements)from a fire-engineering perspective taking intoaccount the possible variations in enclosure geometry, opening sizes and fire load (see FCRC, 1999).One of the outcomes of this evaluation was the recognition that deemed-to- satisfy provisions necessarily cover the broad range of buildings and thus must, on average, be quite onerous because of the magnitude of the above variations.It should be noted that the DTS provisions assume that compartmentation works and that fire is limited to a single compartment. This means that fire is normally only considered to exist at one level. Thus floors are assumed to be heated from below and columns only over one storey height.3.5 Performance-Based DesignAn approach that offers substantial benefits for individual buildings is the move towards performance-based regulations. This is permitted by regulations such as the BCA which state that a designer must demonstrate that the particular building will achieve the relevant performance requirements. The prescriptive provisions (i.e. the DTS provisions) are presumed to achieve these requirements. It is necessary to show that any building that does not conform to the DTS provisions will achieve the performance requirements.But what are the performance requirements? Most often the specified performance is simply a set of performance statements (such as with the Building Code of Australia)with no quantitative level given. Therefore, although these statements remind the designer of the key elements of design, they do not, in themselves, provide any measure against which to determine whether the design is adequately safe.Possible acceptance criteria are now considered.3.5.1 Acceptance CriteriaSome guidance as to the basis for acceptable designs is given in regulations such as the BCA. These and other possible bases are now considered in principle.(i)compare the levels of safety (with respect to achieving each of the design objectives) of the proposed alternative solution with those asso- ciated with a corresponding DTS solution for the building.This comparison may be done on either a qualitative or qualitative risk basis or perhaps a combination. In this case, the basis for comparison is an acceptable DTS solution. Such an approach requires a “holistic” approach to safety whereby all aspects relevant to safety, including the structure, are considered. This is, by far, the most common basis for acceptance.(ii)undertake a probabilistic risk assessment and show that the risk associated with the proposed design is less than that associated with common societal activities such as using pub lic transport. Undertaking a full probabilistic risk assessment can be very difficult for all but the simplest situations.Assuming that such an assessment is undertaken it will be necessary for the stakeholders to accept the nominated level of acceptable risk. Again, this requires a “holistic”approach to fire safety.(iii) a design is presented where it is demonstrated that all reasonable measures have been adopted to manage the risks and that any possible measures that have not been adopted will have negligible effect on the risk of not achieving the design objectives.(iv) as far as the building structure is concerned,benchmark the acceptable probability of failure in fire against that for normal temperature design. This is similar to the approach used when considering Building Situation 1 but only considers the building structure and not the effects of flame or smoke spread. It is not a holistic approach to fire safety.Finally, the questions of arson and terrorism must be considered. Deliberate acts of fire initiation range from relatively minor incidents to acts of mass destruction.Acts of arson are well within the accepted range of fire events experienced by build- ings(e.g. 8% of fire starts in offices are deemed "suspicious"). The simplest act is to use a small heat source to start a fire. The resulting fire will develop slowly in one location within the building and will most probably be controlled by the various fire- safety systems within the building. The outcome is likely to be the same even if an accelerant is used to assist fire spread.An important illustration of this occurred during the race riots in Los Angeles in 1992 (Hart 1992) when fires were started in many buildings often at multiple locations. In the case of buildings with sprinkler systems,the damage was limited and the fires significantly controlled.Although the intent was to destroy the buildings,the fire-safety systems were able to limit the resulting fires. Security measures are provided with systems such as sprinkler systems and include:- locking of valves- anti-tamper monitoring- location of valves in secure locationsFurthermore, access to significant buildings is often restricted by security measures.The very fact that the above steps have been taken demonstrates that acts of destruction within buildings are considered although most acts of arson do not involve any attempt to disable the fire-safety systems.At the one end of the spectrum is "simple" arson and at the other end, extremely rare acts where attempts are made to destroy the fire-safety systems along with substantial parts of the building.This can be only achieved through massive impact or the use of explosives. The latter may be achieved through explosives being introduced into the building or from outside by missile attack.The former could result from missile attack or from the collision of a large aircraft. The greater the destructiveness of the act,the greater the means and knowledge required. Conversely, the more extreme the act, the less confidence there can be in designing against suchan act. This is because the more extreme the event, the harder it is to predict precisely and the less understood will be its effects. The important point to recognise is that if sufficient means can be assembled, then it will always be possible to overcome a particular building design.Thus these acts are completely different to the other loadings to which a building is subjected such as wind,earthquake and gravity loading. This is because such acts of destruction are the work of intelligent beings and take into account the characteristics of the target.Should high-rise buildings be designed for given terrorist activities,then terrorists will simply use greater means to achieve the end result.For example, if buildings were designed to resist the impact effects from a certain size aircraft, then the use of a larger aircraft or more than one aircraft could still achieve destruction of the building. An appropriate strategy is therefore to minimise the likelihood of means of mass destruction getting into the hands of persons intent on such acts. This is not an engineering solution associated with the building structure.It should not be assumed that structural solutions are always the most appropriate, or indeed, possible.In the same way, aircrafts are not designed to survive a major fire or a crash landing but steps are taken to minimise the likelihood of either occurrence.The mobilization of large quantities of fire load (the normal combustibles on the floors) simultaneously on numerous levels throughout a building is well outside fire situations envisaged by current fire test standards and prescriptive regulations. Risk management measures to avoid such a possibility must be considered.4 CONCLUSIONSFire differs significantly from other “loads” such as wind, live load and earthquakes i n respect of its origin and its effects.Due to the fact that fire originates from human activities or equipment installed within buildings, it is possible to directly influence the potential effects on the building by reducing the rate of fire starts and providing measures to directly limit fire severity.The design of buildings for fire safety is mostly achieved by following the prescriptive requirements of building codes such as the BCA. For situations that fall outside of the scope of such regulations, or where proposed designs are not in accordance with the prescriptive requirements, it is possible to undertake performance-based fire engineering designs.However, there are no design codes or standards or detailed methodologies available for undertaking such designs.Building regulations require that such alternative designs satisfy performance requirements and give some guidance as to the basis for acceptance of these designs (i.e. acceptance criteria).This paper presents a number of possible acceptance criteria, all of which use the measure of risk level as the basis for comparison.Strictly, when considering the risks。
毕业论文（设计）外文译文
毕业论文（设计）外文译文题目建筑剪力墙结构的地震反应与阻尼器学院土木工程学院专业土木工程 年级 11级学生姓名周磊学号 ********* 指导教师古巍建筑结构在剪力墙的地震反应与阻尼器L.P.B.马德森,D.P.山姆*,新泽西州佩蕾娜土木工程学院的基础设施中心,昆士兰科技大学,共和党的2434号房子,乔治街2号,布里斯班昆士兰4001,澳大利亚在2001年10月1日收到,在2002年11月1日接收摘要：建筑物遭受地震时,必须输入能量消散一些通过预先确定的和精心设计的机制。
本研究主要探讨机械控制结构的影响和系统通过战略位置的应用程序可以调节响应组件元素和可靠的阻尼和刚度属性。
安装此类阻尼元素的影响在两个特定位置进行了调查。
这些职位之间的耦合梁和附近的剪力墙内部分在多层结构墙的元素。
有限元时程分析用于研究和结果表明,该程序能够实现合理的地震响应的改善。
关键词:地震响应;建筑;被动阻尼器位移,加速度1、介绍当建筑物受地震或从爆炸冲击波,它提供至关重要这些建筑的能量吸收途径避免随机和造成的不利影响不可预测的负载,远远超过弹性力量结构元素的能力。
在最近的地震中人们已经发现,缺乏能量吸收机制是建筑表现不佳的原因之一。
它是越来越普遍的设计实践多层建筑细节的地方表单通常放置在塑料铰链梁柱节点附近梁(12，14)。
这些位置旨在消除大量的能量通过非弹性变形,从而保护主体结构从损伤和改善地震响应。
这一点,然而,导致必要性去修理损坏的地方结构成员后接受极限载荷的影响。
许多多层建筑包含剪力墙在电梯和楼梯间。
这些墙提供相当大的横向刚度的结构使它能够抵抗水平地震等载荷和风能。
通常会有几个空缺在这些剪力墙,如果两个这样的机会相反,深梁用于互连墙壁。
这些耦合梁通常用作为核心元素提供框架行动的手段。
他们为了在地震能量消散必须经过非弹性屈服,因此由于小跨度深比、需要高度复杂的和拥挤的强化来实现延性。
他们是很难构造由于这对角的必要性强化,以及服务的缝隙。
土木工程建筑外文翻译外文文献高层建筑的消防安全设计
土木工程建筑外文翻译外文文献高层建筑的消防安全设计Fire Safety Design for High-rise BuildingsKeywords: fire safety, high-rise buildings, means of escape, fire resistant materials, fire detection and alarm systems, fire suppression systems, fire risk assessment, emergency plans1. Introduction2. Means of Escape3. Fire Resistant Materials4. Fire Detection and Alarm SystemsEarly detection of a fire is crucial to allow for the safe evacuation of occupants. High-rise buildings should be equipped with fire detection and alarm systems, including smoke detectors, heat detectors, and manual call points. These systems should be interconnected and monitored to ensure prompt notification of a fire.5. Fire Suppression Systems6. Fire Risk AssessmentBefore occupancy, a fire risk assessment should be conducted to identify potential fire hazards and ensure appropriate fire safety measures are in place. This assessment should considerthe building's use, occupant load, and fire resistance ofconstruction materials. Regular fire risk assessments shouldalso be conducted to address any changes in building use or occupancy.7. Emergency PlansHigh-rise buildings should have well-defined emergency plans that outline the actions to be taken in the event of a fire. These plans should include procedures for evacuating occupants, contacting emergency services, and isolating fire-affected areas. Regular drills and training sessions should be conducted to familiarize occupants with the emergency procedures.8. ConclusionFire safety design is critical in high-rise buildings to protect the lives of occupants and minimize property damage. Designers and engineers should consider means of escape, fire resistant materials, fire detection and alarm systems, fire suppression systems, fire risk assessments, and emergency plans when designing a high-rise building. By implementing these measures effectively, the risk of fire-related incidents can be significantly reduced.。
土木工程专业毕业设计外文文献翻译2篇
土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。
土木工程建筑外文文献及翻译
土木工程建筑外文文献及翻译土木工程建筑外文文献及翻译Cyclic behavior of steel moment frame connections under varying axial load and lateral displacementsAbstractThis paper discusses the cyclic behavior of four steel moment connections tested under variable axial load and lateral displacements. The beam specim- ens consisted of a reducedbeam section, wing plates and longitudinal stiffeners. The test specimens were subjected to varying axial forces and lateral displace- ments to simulate the effects on beams in a Coupled-Girder Moment-Resisting Framing system under lateral loading. The test results showed that the specim- ens responded in a ductile manner since the plastic rotations exceeded 0.03 rad without significant drop in the lateral capacity. The presence of the longitudin- al stiffener assisted in transferring the axial forces and delayed the formation of web local buckling.1. IntroductionAimed at evaluating the structural performance of reduced-beam section(RBS) connections under alternated axial loading and lateral displacement, four full-scale specimens were tested. These tests were intended to assess the performance of the moment connection design for the Moscone Center Exp- ansion under the Design Basis Earthquake (DBE) and the Maximum Considered Earthquake (MCE). Previous research conducted on RBS moment connections [1,2] showed that connections with RBS profiles can achieve rotations in excess of 0.03 rad. However, doubts have been cast on the quality of the seismic performance of theseconnections under combined axial and lateral loading.The Moscone Center Expansion is a three-story, 71,814 m2 (773,000 ft2) structure with steel moment frames as its primary lateral force-resisting system. A three dimensional perspective illustration is shown in Fig. 1. The overall height of the building, at the highest point of the exhibition roof, is approxima- tely 35.36 m (116ft) above ground level. The ceiling height at the exhibition hall is 8.23 m (27 ft) , and the typical floor-to-floor height in the building is 11.43 m (37.5 ft). The building was designed as type I according to the requi- rements of the 1997 Uniform Building Code. The framing system consists of four moment frames in the East–West direct- ion, one on either side of the stair towers, and four frames in the North–South direction, one on either side of the stair and elevator cores in the east end and two at the west end of the structure [4]. Because of the story height, the con- cept of the Coupled-Girder Moment-Resisting Framing System (CGMRFS) was utilized.By coupling the girders, the lateral load-resisting behavior of the moment framing system changes to one where structural overturning moments are resisted partially by an axial compression–tension couple across the girder system, rather than only by the individual flexural action of the girders. As a result, a stiffer lateral load resisting system is achieved. The vertical element that connects the girders is referred to as a coupling link. Coupling links are analogous to and serve the same structural role as link beams in eccentrically braced frames. Coupling links are generally quite short, having a large shear- to-moment ratio.Under earthquake-type loading, the CGMRFS subjects its girders to wariab- ble axial forces in addition to their endmoments. The axial forces in theFig. 1. Moscone Center Expansion Project in San Francisco, CAgirders result from the accumulated shear in the link.2. Analytical model of CGMRFNonlinear static pushover analysis was conducted on a typical one-bay model of the CGMRF. Fig. 2 shows the dimensions and the various sections of the 10 in) and the ?254 mm (1 1/8 in ?model. The link flange plates were 28.5 mm 18 3/4 in). The SAP 2000 computer ?476 mm (3 /8 in ?web plate was 9.5 mm program was utilized in the pushover analysis [5]. The frame was characterized as fully restrained(FR). FR moment frames are those frames for 1170 which no more than 5% of the lateral deflections arise from connection deformation [6]. The 5% value refers only to deflection due to beam–column deformation and not to frame deflections that result from column panel zone deformation [6, 9].The analysis was performed using an expected value of the yield stress and ultimate strength. These values were equal to 372 MPa (54 ksi) and 518 MPa (75 ksi), respective ly. The plastic hinges’ load–deformation behavior was approximated by the generalized curve suggested by NEHRP Guidelines for the Seismic Rehab ilitation of Buildings [6] as shown in Fig. 3. △y was calcu- lated based on Eqs. (5.1) and (5.2) from [6], as follows: P–M hinge load–deformation model points C, D and E are based on Table 5.4 from [6] for△y was taken as 0.01 rad per Note 3 in [6], Table 5.8. Shear hinge load- load–deformation model points C, D and E are based on Table 5.8 [6], Link Beam, Item a. A strain hardening slope between points B and C of 3% of the elastic slope was assumedfor both models.The following relationship was used to account for moment–axial load interaction [6]:where MCE is the expected moment strength, ZRBS is the RBS plastic section modulus (in3), is the expected yield strength of the material (ksi), P is the axial force in the girder (kips) and is the expected axial yield force of the RBS, equal to (kips). The ultimate flexural capacities of the beam and the link of the model are shown in Table 1.Fig. 4 shows qualitatively the distribution of the bending moment, shear force, and axial force in the CGMRF under lateral load. The shear and axial force in the beams are less significant to the response of the beams as compared with the bending moment, although they must be considered in design. The qualita- tive distribution of internal forces illustrated in Fig. 5 is fundamentally the same for both elastic and inelastic ranges of behavior. The specific values of the internal forces will change as elements of the frame yield and internal for- ces are redistributed. The basic patterns illustrated in Fig. 5, however, remain the same.Inelastic static pushover analysis was carried out by applying monotonically increasing lateral displacements, at the top of both columns, as shown in Fig. 6. After the four RBS have yielded simultaneously, a uniform yielding in the web and at the ends of the flanges of the vertical link will form. This is the yield mechanism for the frame , with plastic hinges also forming at the base of the columns if they are fixed. The base shear versus drift angle of the model is shown in Fig. 7 . The sequence of inelastic activity in the frame is shown on the figure. An elastic component, a long transition (consequence of the beam plastic hinges being formed simultaneously) and a narrow yield plateaucharacterize the pushover curve.The plastic rotation capacity, qp, is defined as the total plastic rotation beyond which the connection strength starts to degrade below 80% [7]. This definition is different from that outlined in Section 9 (Appendix S) of the AISC Seismic Provisions [8, 10]. Using Eq. (2) derived by Uang and Fan [7], an estimate of the RBS plastic rotation capacity was found to be 0.037 rad:Fyf was substituted for Ry?Fy [8], where Ry is used to account for the differ- ence between the nominal and the expected yield strengths (Grade 50 steel, Fy=345 MPa and Ry =1.1 are used).3. Experimental programThe experimental set-up for studying the behavior of a connection was based on Fig. 6(a). Using the plastic displacement dp, plastic rotation gp, and plastic story drift angle qp shown in the figure, from geometry, it follows that:And:in which d and g include the elastic components. Approximations as above are used for large inelastic beam deformations. The diagram in Fig. 6(a) suggest that a sub assemblage with displacements controlled in the manner shown in Fig. 6(b) can represent the inelastic behavior of a typical beam in a CGMRF.The test set-up shown in Fig. 8 was constructed to develop the mechanism shown in Fig. 6(a) and (b). The axial actuators were attached to three 2438 mm × 1219 mm ×1219 mm (8 ft × 4 ft × 4 ft) RC blocks. These blocks were tensioned to the laboratory floor by means of twenty-four 32 mm diameter dywidag rods. This arrangement permitted replacement of the specimen after each test.Therefore, the force applied by the axial actuator, P, can beresolved into two or thogonal components, Paxial and Plateral. Since the inclination angle of the axial actuator does not exceed , therefore Paxial is approximately equal to P [4]. However, the lateral 3.0 component, Plateral, causes an additional moment at the beam-to column joint. If the axial actuators compress the specimen, then the lateral components will be adding to the lateral actuator forces, while if the axial actuators pull the specimen, the Plateral will be an opposing force to the lateral actuators. When the axial actuators undergoaxial actuators undergo a lateral displacement _, they cause an additional moment at the beam-to-column joint (P-△effect). Therefore, the moment at the beam-to column joint is equal to: where H is the lateral forces, L is the arm, P is the axial force and _ is the lateral displacement.Four full-scale experiments of beam column connections were conducted.The member sizes and the results of tensile coupon tests are listed in Table 2All of the columns and beams were of A572 Grade 50 steel (Fy 344.5 MPa). The actual measured beam flange yield stress value was equal to 372 MPa (54 ksi), while the ultimate strength ranged from 502 MPa (72.8 ksi) to 543 MPa (78.7 ksi).Table 3 shows the values of the plastic moment for each specimen (based on measured tensile coupon data) at the full cross-section and at the reduced section at mid-length of the RBS cutout.The specimens were designated as specimen 1 through specimen 4. Test specimens details are shown in Fig. 9 through Fig. 12. The following features were utilized in the design of the beam–column connection:The use of RBS in beam flanges. A circular cutout was provided, as illustr- ated in Figs. 11 and 12. For all specimens, 30% of the beam flange width was removed. The cuts were made carefully, and then ground smooth in a direct- tion parallel to the beam flange to minimize notches.Use of a fully welded web connection. The connection between the beam web and the column flange was made with a complete joint penetration groove weld (CJP). All CJP welds were performed according to AWS D1.1 Structural Welding Code Use of two side plates welded with CJP to exterior sides of top and bottom beam flan- ges, from the face of the column flange to the beginning of the RBS, as shown in Figs. 11 and 12. The end of the side plate was smoothed to meet the beginning of the RBS. The side plates were welded with CJP with the column flanges. The side plate was added to increase the flexural capacity at the joint location, while the smooth transition was to reduce the stress raisers, which may initiate fractureTwo longitudinal stiffeners, 95 mm × 35 mm (3 3/4 in × 1 3/8 in), were welded with 12.7 mm (1/2 in) fillet weld at the middle height of the web as shown in Figs. 9 and 10. The stiffeners were welded with CJP to column flanges.Removal of weld tabs at both the top and bottom beam flange groove welds. The weld tabs were removed to eliminate any potential notches introduced by the tabs or by weld discontinuities in the groove weld run out regionsUse of continuity plates with a thickness approximately equal to the beam flange thickness. One-inch thick continuity plates were used for all specimens.While the RBS is the most distinguishing feature of these test specimens, the longitudinal stiffener played an important role indelaying the formation of web local buckling and developing reliable connection4. Loading historySpecimens were tested by applying cycles of alternated load with tip displacement increments of _y as shown in Table 4. The tip displacement of the beam was imposed by servo-controlled actuators 3 and 4. When the axial force was to be applied, actuators 1 and 2 were activated such that its force simulates the shear force in the link to be transferred to the beam. 0.5_y. After The variable axial force was increased up to 2800 kN (630 kip) at that, this lo- ad was maintained constant through the maximum lateral displacement.maximum lateral displacement. As the specimen was pushed back the axialforce remained constant until 0.5 y and then started to decrease to zero as the specimen passed through the neutral position [4]. According to the upper bound for beam axial force as discussed in Section 2 of this paper, it was concluded that P =2800 kN (630 kip) is appropriate to investigate this case in RBS loading. The tests were continued until failure of the specimen, or until limitations of the test set-up were reached.5. Test resultsThe hysteretic response of each specimen is shown in Fig. 13 and Fig. 16. These plots show beam moment versus plastic rotation. The beam moment is measured at the middle of the RBS, and was computed by taking an equiva- lent beam-tip force multiplied by the distance between the centerline of the lateral actuator to the middle of the RBS (1792 mm for specimens 1 and 2, 3972 mm for specimens 3 and 4). The equivalent lateral force accounts for the additional moment due to P–△effect. Therotation angle was defined as the lateral displacement of the actuator divided by the length between the centerline of the lateral actuator to the mid length of the RBS. The plastic rotation was computed as follows [4]:where V is the shear force, Ke is the ratio of V/q in the elastic range. Measurements and observations made during the tests indicated that all of the plastic rotation in specimen 1 to specimen 4 was developed within the beam. The connection panel zone and the column remained elastic as intended by design.5.1. Specimens 1 and 2The responses of specimens 1 and 2 are shown in Fig. 13. Initial yielding occurred during cycles 7 and 8 at 1_y with yielding observed in the bottom flange. For all test specimens, initial yielding was observed at this location and attributed to the moment at the base of the specimen [4]. Progressing through the loading history, yielding started to propagate along the RBS bottom flange. During cycle 3.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 5_y with the increased axial compression load to 3115 KN (700 kips) a severe web buckle developed along with flange local buckling. The flange and the web local buckling became more pronounced with each successive loading cycle. It should be noted here that the bottom flange and web local buckling was not accompanied by a significant deterioration in the hysteresis loops.A crack developed in specimen 1 bottom flange at the end of the RBS where it meets the side plate during the cycle 5.75_y. Upon progressing through the loading history, 7_y, the crackspread rapidly across the entire width of the bottom flange. Once the bottom flange was completely fractured, the web began to fracture. This fracture appeared to initiate at the end of the RBS，then propagated through the web net section of the shear tab, through the middle stiffener and the through the web net section on the other side of the stiffener. The maximum bending moment achieved on specimen 1 during theDuring the cycle 6.5 y, specimen 2 also showed a crack in the bottom flange at the end of the RBS where it meets the wing plate. Upon progressing thou- gh the loading history, 15 y, the crack spread slowly across the bottom flan- ge. Specimen 2 test was stopped at this point because the limitation of the test set-up was reached.The maximum force applied to specimens 1 and 2 was 890 kN (200 kip). The kink that is seen in the positive quadrant is due to the application of the varying axial tension force. The load-carrying capacity in this zone did not deteriorate as evidenced with the positive slope of the force–displacement curve. However, the load-carrying capacity deteriorated slightly in the neg- ative zone due to the web and the flange local buckling.Photographs of specimen 1 during the test are shown in Figs.14 and 15. Severe local buckling occurred in the bottom flange and portion of the web next to the bottom flange as shown in Fig. 14. The length of this buckle extended over the entire length of the RBS. Plastic hinges developed in the RBS with extensive yielding occurring in the beam flanges as well as the web. Fig. 15 shows the crack that initiated along the transition of the RBS to the side wing plate. Ultimate fracture of specimen 1 was caused by a fracture in the bottom flange. This fracture resulted in almost total loss of the beam- carrying capacity. Specimen 1 developed0.05 rad of plastic rotation and showed no sign of distress at the face of the column as shown in Fig. 15.5.2. Specimens 3 and 4The response of specimens 3 and 4 is shown in Fig. 16. Initial yielding occured during cycles 7 and 8 at 1_y with significant yielding observed in the bottom flange. Progressing through the loading history, yielding started to propagate along the bottom flange on the RBS. During cycle 1.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 3.5_y a severe web buckle developed along with flange local buckling. The flange and the web local buckling bec- ame more pronounced with each successive loading cycle.During the cycle 4.5 y, the axial load was increased to 3115 KN (700 kips) causing yielding to propagate to middle transverse stiffener. Progressing through the loading history, the flange and the web local buckling became more severe. For both specimens, testing was stopped at this point due to limitations in the test set-up. No failures occurred in specimens 3 and 4. However, upon removing specimen 3 to outside the laboratory a hairline crack was observed at the CJP weld of the bottom flange to the column.The maximum forces applied to specimens 3 and 4 were 890 kN (200 kip) and 912 kN (205 kip). The load-carrying capacity deteriorated by 20% at the end of the tests for negative cycles due to the web and the flange local buckling. This gradual reduction started after about 0.015 to 0.02 rad of plastic rotation. The load-carrying capacity during positive cycles (axial tension applied in the girder) did not deteriorate as evidenced with the slope of the force–displacement envelope for specimen 3 shownin Fig. 17.A photograph of specimen 3 before testing is shown in Fig.18. Fig. 19 is aFig. 16. Hysteretic behavior of specimens 3 and 4 in terms of moment at middle RBS versus beam plastic rotation.photograph of specimen 4 taken after the application of 0.014 rad displacem- ent cycles, showing yielding and local buckling at the hinge region. The beam web yielded over its full depth. The most intense yielding was observed in the web bottom portion, between the bottom flange and the middle stiffener. The web top portion also showed yielding, although less severe than within the bottom portion. Yielding was observed in the longitudinal stiffener. No yiel- ding was observed in the web of the column in the joint panel zone. The un- reduced portion of the beam flanges near the face of the column did not show yielding either. The maximum displacement applied was 174 mm, and the maximum moment at the middle of the RBS was 1.51 times the plastic mom ent capacity of the beam. The plastic hinge rotation reached was about 0.032 rad (the hinge is located at a distance 0.54d from the column surface,where d is the depth of the beam).5.2.1. Strain distribution around connectionThe strain distribution across the flanges–outer surface of specimen 3 is shown in Figs. 20 and 21. The readings and the distributions of the strains in specimens 1, 2 and 4 (not presented) showed a similar trend. Also the seque- nce of yielding in these specimens is similar to specimen 3.The strain at 51 mm from the column in the top flange–outer surface remained below 0.2% during negative cycles. The top flange, at the same location, yielded in compression only Thelongitudinal strains along the centerline of the bottom–flange outer face are shown in Figs. 22 and 23 for positive and negative cycles, respectively. From Fig.23, it is found that the strain on the RBS becomes several times larg- er than that near the column after cycles at –1.5_y; this is responsible for theflange local buckling. Bottom flange local buckling occurred when the average strain in the plate reached the strain-hardening value (esh _ 0.018) and the reduced-beam portion of the plate was fully yielded under longitudinal stresses and permitted the development of a full buckled wave.5.2.2. Cumulative energy dissipatedThe cumulative energy dissipated by the specimens is shown in Fig. 24. The cumulative energy dissipated was calculated as the sum of the areas enclosed the lateral load–lateral displacement hysteresis loops. Energy dissipation sta- rted to increase after cycle 12 at 2.5 y (Fig. 19). At large drift levels, energy dissipation augments significantly with small changes in drift. Specimen 2 dissipated more energy than specimen 1, which fractured at RBS transition. However, for both specimens the trend is similar up to cycles at q =0.04 radIn general, the dissipated energy during negative cycles was1.55 times bigger than that for positive cycles in specimens 1 and2. For specimens 3 and 4 the dissipated energy during negative cycles was 120%, on the average, that of the positive cycles. The combined phenomena of yielding, strain hardening, in-plane and out- of-plane deformations, and local distortion all occurred soon after the bottom flange RBS yielded.6. ConclusionsBased on the observations made during the tests, and on the analysis of the instrumentation, the following conclusions weredeveloped:1. The plastic rotation exceeded the 3% radians in all test specimens.2. Plastification of RBS developed in a stable manner.3. The overstrength ratios for the flexural strength of the test specimens were equal to 1.56 for specimen 1 and 1.51 for specimen4. The flexural strength capacity was based on the nominal yield strength and on the FEMA-273 beam–column equation.4. The plastic local buckling of the bottom flange and the web was not accompanied by a significant deterioration in the load-carrying capacity.5. Although flange local buckling did not cause an immediate degradation of strength, it did induce web local buckling.6. The longitudinal stiffener added in the middle of the beam web assisted in transferring the axial forces and in delaying the formation of web local buckling. How ever, this has caused a much higher overstrength ratio, which had a significant impact on the capacity design of the welded joints, panel zone and the column.7. A gradual strength reduction occurred after 0.015 to 0.02 rad of plastic rotation during negative cycles. No strength degradation was observed during positive cycles.8. Compression axial load under 0.0325Py does not affect substantially the connection deformation capacity.9. CGMRFS with properly designed and detailed RBS connections is a reliable system to resist earthquakes.AcknowledgementsStructural Design Engineers, Inc. of San Francisco financially supported the experimental program. The tests were performedin the Large Scale Structures Laboratory of the University of Nevada, Reno. The participation of Elizabeth Ware, Adrianne Dietrich and of the technical staff is gratefully acknowledged.References受弯钢框架结点在变化轴向荷载和侧向位移的作用下的周期性行为摘要这篇论文讨论的是在变化的轴向荷载和侧向位移的作用下，接受测试的四种受弯钢结点的周期性行为。
土木工程毕业设计外文翻译最终中英文
7 Rigid-Frame StructuresA rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders.The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rigid frames are considered economical for buildings of up to' about25 stories, above which their drift resistance is costly to control. If, however,a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components.As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically include the following stages:1. Estimation of gravity load forces in girders and columns by approximate method.2. Preliminary estimate of member sizes based on gravity load forces witharbitrary increase in sizes to allow for horizontal loading.3. Approximate allocation of horizontal loading to bents and preliminary analysisof member forces in bents.4. Check on drift and adjustment of member sizes if necessary.5. Check on strength of members for worst combination of gravity and horizontalloading, and adjustment of member sizes if necessary.6. Computer analysis of total structure for more accurate check on memberstrengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift..7. Detailed design of members and connections.This chapter considers methods of analysis for the deflections and forces for both gravity and horizontal loading. The methods are included in roughly the order of the design procedure, with approximate methods initially and computer techniques later. Stability analyses of rigid frames are discussed in Chapter 16.7.1 RIGID FRAME BEHAVIORThe horizontal stiffness of a rigid frame is governed mainly by the bending resistance of the girders, the columns, and their connections, and, in a tall frame, by the axial rigidity of the columns. The accumulated horizontal shear above any story of a rigid frame is resisted by shear in the columns of that story (Fig. 7.1). The shear causes the story-height columns to bend in double curvature with points of contraflexure at approximately mid-story-height levels. The moments applied to a joint from the columns above and below are resisted by the attached girders, which also bend in double curvature, with points of contraflexure at approximately mid-span. These deformations of the columns and girders allow racking of the frame and horizontal deflection in each story. The overall deflected shape of a rigid frame structure due to racking has a shear configuration with concavity upwind, a maximum inclination near the base, and a minimum inclination at the top, as shown in Fig.7.1.The overall moment of the external horizontal load is resisted in each story level by the couple resulting from the axial tensile and compressive forces in the columns on opposite sides of the structure (Fig. 7.2). The extension and shortening of the columns cause overall bending and associated horizontal displacements of the structure. Because of the cumulative rotation up the height, the story drift dueto overall bending increases with height, while that due to racking tends to decrease. Consequently the contribution to story drift from overall bending may, in. the uppermost stories, exceed that from racking. The contribution of overall bending to the total drift, however, will usually not exceed 10% of that of racking, except in very tall, slender,, rigid frames. Therefore the overall deflected shape of a high-rise rigid frame usually has a shear configuration.The response of a rigid frame to gravity loading differs from a simply connected frame in the continuous behavior of the girders. Negative moments are induced adjacent to the columns, and positive moments of usually lesser magnitude occur in the mid-span regions. The continuity also causes the maximum girder moments to be sensitive to the pattern of live loading. This must be considered when estimating the worst moment conditions. For example, the gravity load maximum hogging moment adjacent to an edge column occurs when live load acts only on the edge span and alternate other spans, as for A in Fig. 7.3a. The maximum hogging moments adjacent to an interior column are caused, however, when live load acts only on the spans adjacent to the column, as for B in Fig. 7.3b. The maximum mid-span sagging moment occurs when live load acts on the span under consideration, and alternate other spans, as for spans AB and CD in Fig. 7.3a.The dependence of a rigid frame on the moment capacity of the columns for resisting horizontal loading usually causes the columns of a rigid frame to be larger than those of the corresponding fully braced simply connected frame. On the other hand, while girders in braced frames are designed for their mid-span sagging moment, girders in rigid frames are designed for the end-of-span resultant hogging moments, which may be of lesser value. Consequently, girders in a rigid frame may be smaller than in the corresponding braced frame. Such reductions in size allow economy through the lower cost of the girders and possible reductions in story heights. These benefits may be offset, however, by the higher cost of the more complex rigid connections.7.2 APPROXIMATE DETERMINATION OF MEMBER FORCES CAUSED BY GRAVITY LOADSIMGA rigid frame is a highly redundant structure; consequently, an accurate analysis can be made only after the member sizes are assigned. Initially, therefore, member sizes are decided on the basis of approximate forces estimated either by conservative formulas or by simplified methods of analysis that are independent of member properties. Two approaches for estimating girder forces due to gravity loading are given here.7.2.1 Girder Forces—Code Recommended ValuesIn rigid frames with two or more spans in which the longer of any two adjacent spans does not exceed the shorter by more than 20 %, and where the uniformly distributed design live load does not exceed three times the dead load, the girder moment and shears may be estimated from Table 7.1. This summarizes the recommendations given in the Uniform Building Code [7.1]. In other cases a conventional moment distribution or two-cycle moment distribution analysis should be made for a line of girders at a floor level.7.2.2 Two-Cycle Moment Distribution [7.2].This is a concise form of moment distribution for estimating girder moments in a continuous multibay span. It is more accurate than the formulas in Table 7.1, especially for cases of unequal spans and unequal loading in different spans.The following is assumed for the analysis:1. A counterclockwise restraining moment on the end of a girder is positive anda clockwise moment is negative.2. The ends of the columns at the floors above and below the considered girder are fixed.3. In the absence of known member sizes, distribution factors at each joint aretaken equal to 1 /n, where n is the number of members framing into the joint in the plane of the frame.Two-Cycle Moment Distribution—Worked Example. The method is demonstrated by a worked example. In Fig, 7.4, a four-span girder AE from a rigid-frame bent is shown with its loading. The fixed-end moments in each span are calculated for dead loading and total loading using the formulas given in Fig, 7.5. The moments are summarized in Table 7.2.The purpose of the moment distribution is to estimate for each support the maximum girder moments that can occur as a result of dead loading and pattern live loading.A different load combination must be considered for the maximum moment at each support, and a distribution made for each combination.The five distributions are presented separately in Table 7.3, and in a combined form in Table 7.4. Distributions a in Table 7.3 are for the exterior supports A andE. For the maximum hogging moment at A, total loading is applied to span AB with dead loading only on BC. The fixed-end moments are written in rows 1 and 2. In this distribution only .the resulting moment at A is of interest. For the first cycle, joint B is balanced with a correcting moment of- (-867 + 315)/4 = - U/4 assigned to M BA where U is the unbalanced moment. This is not recorded, but half of it, ( - U/4)/2, is carried over to M AB. This is recorded in row 3 and then added to the fixed-end moment and the result recorded in row 4.The second cycle involves the release and balance of joint A. The unbalanced moment of 936 is balanced by adding-U/3 = -936/3 = -312 to M BA (row 5), implicitly adding the same moment to the two column ends at A. This completes the second cycle of the distribution. The resulting maximum moment at A is then given by the addition of rows 4 and 5, 936 - 312 = 624. The distribution for the maximum moment at E follows a similar procedure.Distribution b in Table 7.3 is for the maximum moment at B. The most severe loading pattern for this is with total loading on spans AB and BC and dead load only on CD. The operations are similar to those in Distribution a, except that the T first cycle involves balancing the two adjacent joints A and C while recording only their carryover moments to B. In the second cycle, B is balanced by adding - (-1012 + 782)/4 = 58 to each side of B. The addition of rows 4 and 5 then gives the maximum hogging moments at B. Distributions c and d, for the moments at joints C and D, follow patterns similar to Distribution b.The complete set of operations can be combined as in Table 7.4 by initially recording at each joint the fixed-end moments for both dead and total loading. Then the joint, or joints, adjacent to the one under consideration are balanced for the appropriate combination of loading, and carryover moments assigned .to the considered joint and recorded. The joint is then balanced to complete the distribution for that support.Maximum Mid-Span Moments. The most severe loading condition for a maximum mid-span sagging moment is when the considered span and alternate other spans and total loading. A concise method of obtaining these values may be included in the combined two-cycle distribution, as shown in Table 7.5. Adopting the convention that sagging moments at mid-span are positive, a mid-span total; loading moment is calculated for the fixed-end condition of each span and entered in the mid-span column of row 2. These mid-span moments must now be corrected to allow for rotation of the joints. This is achieved by multiplying the carryover moment, row 3, at the left-hand end of the span by (1 + 0.5 D.F. )/2, and the carryover moment at the right-hand end by -(1 + 0.5 D.F.)/2, where D.F. is the appropriate distribution factor, and recording the results in the middle column. For example, the carryover to the mid-span of AB from A = [(1 + 0.5/3)/2] x 69 = 40 and from B = -[(1+ 0.5/4)/2] x (-145) = 82. These correction moments are then added to the fixed-end mid-span moment to give the maximum mid-span sagging moment, that is, 733 + 40 + 82 = 855.7.2.3 Column ForcesThe gravity load axial force in a column is estimated from the accumulated tributary dead and live floor loading above that level, with reductions in live loading as permitted by the local Code of Practice. The gravity load maximum column moment is estimated by taking the maximum difference of the end moments in the connected girders and allocating it equally between the column ends just above and below the joint. To this should be added any unbalanced moment due to eccentricity of the girderconnections from the centroid of the column, also allocated equally between the column ends above and below the joint.第七章框架结构高层框架结构一般由平行或正交布置的梁柱结构组成，梁柱结构是由带有能承担弯矩作用节点的梁、柱组成。
土木项目工程外文文献及翻译
本科毕业设计外文文献及译文文献、资料题目：Designing Against Fire Of Building 文献、资料来源：国道数据库文献、资料发表（出版）日期：2008.3.25院（部）：土木工程学院专业：土木工程班级：土木辅修091姓名：武建伟学号：2008121008 指导教师：周学军、李相云翻译日期：20012.6.1外文文献:Designing Against Fire Of BulidingJohn Lynch ABSTRACT:This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electrical systems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are considered in the context of current regulatoryrequirements. The principles and assumptions associ- ated with various approaches are discussed.1 INTRODUCTIONOther papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the case of fire. Rather, it is building regulations such as the Building Code of Australia (BCA) that directly specify most of the requirements for fire safety of buildings with reference being made to Standards such as AS3600 or AS4100 for methods for determining the fire resistance of structural elements.The purpose of this paper is to consider the design of buildings for fire safety from an engineering perspective (as is currently done for other loads such as wind or earthquakes), whilst at the same time,putting such approaches in the context of the current regulatory requirements.At the outset,it needs to be noted that designing a building for fire safety is far more than simply considering the building structure and whether it has sufficient structural adequacy.This is because fires can have a direct influence on occupants via smoke and heat and can grow in size and severity unlike other effects imposed on the building. Notwithstanding these comments, the focus of this paper will be largely on design issues associated with the building structure.Two situations associated with a building are used for the purpose of discussion. The multi-storey office building shown in Figure 1 is supported by atransfer structure that spans over a set of railway tracks. It is assumed that a wide range of rail traffic utilises these tracks including freight and diesel locomotives. The first situation to be considered from a fire safety perspective is the transfer structure.This is termed Situation 1 and the key questions are: what level of fire resistance is required for this transfer structure and how can this be determined? This situation has been chosen since it clearly falls outside the normal regulatory scope of most build- ing regulations. An engineering solution, rather than a prescriptive one is required. The second fire situation (termed Situation 2) corresponds to a fire within the office levels of the building and is covered by building regulations. This situation is chosen because it will enable a discussion of engineering approaches and how these interface with the building regulations–since both engineering and prescriptive solutions are possible.2 UNIQUENESS OF FIRE2.1 IntroductionWind and earthquakes can be considered to be “natural”phenomena over which designers have no control except perhaps to choose the location of buildings more carefully on the basis of historical records and to design building to resist sufficiently high loads or accelerations for the particular location. Dead and live loads in buildings are the result of gravity. All of these loads are variable and it is possible (although generally unlikely) that the loads may exceed the resistance of the critical structural members resulting in structural failure.The nature and influence of fires in buildings are quite different to those associated with other“loads”to which a building may be subjected to. The essential differences are described in the following sections.2.2 Origin of FireIn most situations (ignoring bush fires), fire originates from human activities within the building or the malfunction of equipment placed within the building to provide a serviceable environment. It follows therefore that it is possible to influence the rate of fire starts by influencing human behaviour, limiting and monitoring human behaviour and improving the design of equipment and its maintenance. This is not the case for the usual loads applied to a building.2.3 Ability to InfluenceSince wind and earthquake are directly functions of nature, it is not possible to influence such events to any extent. One has to anticipate them and design accordingly. It may be possible to influence the level of live load in a building by conducting audits and placing restrictions on contents. However, in the case of a fire start, there are many factors that can be brought to bear to influence the ultimate size of the fire and its effect within the building. It is known that occupants within a building will often detect a fire and deal with it before it reaches a sig- nificant size. It is estimated that less than one fire in five (Favre, 1996) results in a call to the fire brigade and for fires reported to the fire brigade, the majority will be limited to the room of fire origin. In oc- cupied spaces, olfactory cues (smell) provide powerful evidence of the presence of even a small fire. The addition of a functional smoke detection system will further improve the likelihoodof detection and of action being taken by the occupants.Fire fighting equipment, such as extinguishers and hose reels, is generally provided within buildings for the use of occupants and many organisations provide training for staff in respect of the use of such equipment.The growth of a fire can also be limited by automatic extinguishing systems such as sprinklers, which can be designed to have high levels of effectiveness.Fires can also be limited by the fire brigade depending on the size and location of the fire at the time of arrival.2.4 Effects of FireThe structural elements in the vicinity of the fire will experience the effects of heat. The temperatures within the structural elements will increase with time of exposure to the fire, the rate of temperature rise being dictated by the thermal resistance of the structural element and the severity of the fire. The increase in temperatures within a member will result in both thermal expansion and,eventually,a reduction in the structural resistance of the member. Differential thermal expansion will lead to bowing of a member. Significant axial expansion will be accommodated in steel members by either overall or local buckling or yielding of local- ised regions. These effects will be detrimental for columns but for beams forming part of a floor system may assist in the development of other load resisting mechanisms (see Section 4.3.5).With the exception of the development of forces due to restraint of thermal expansion, fire does not impose loads on the structure but rather reduces stiffness and strength. Such effects are not instantaneous but are a function of time and thisis different to the effects of loads such as earthquake and wind that are more or less instantaneous.Heating effects associated with a fire will not be significant or the rate of loss of capacity will be slowed if:(a) the fire is extinguished (e.g. an effective sprinkler system)(b) the fire is of insufficient severity –insufficient fuel, and/or(c)the structural elements have sufficient thermal mass and/or insulation to slow the rise in internal temperatureFire protection measures such as providing sufficient axis distance and dimensions for concrete elements, and sufficient insulation thickness for steel elements are examples of (c). These are illustrated in Figure 2.The two situations described in the introduction are now considered.3 FIRE WITHIN BUILDINGS3.1 Fire Safety ConsiderationsThe implications of fire within the occupied parts of the office building (Figure 1) (Situation 2) are now considered. Fire statistics for office buildings show thatabout one fatality is expected in an office building for every 1000 fires reported to the fire brigade. This is an order of magnitude less than the fatality rate associated with apartment buildings. More than two thirds of fires occur during occupied hours and this is due to the greater human activity and the greater use of services within the building. It is twice as likely that a fire that commences out of normal working hours will extend beyond the enclosure of fire origin.A relatively small fire can generate large quantities of smoke within the floor of fire origin. If the floor is of open-plan construction with few partitions, the presence of a fire during normal occupied hours is almost certain to be detected through the observation of smoke on the floor. The presence of full height partitions across the floor will slow the spread of smoke and possibly also the speed at which the occupants detect the fire. Any measures aimed at improving housekeeping, fire awareness and fire response will be beneficial in reducing the likelihood of major fires during occupied hours.For multi-storey buildings, smoke detection systems and alarms are often provided to give “automatic”detection and warning to the occupants. An alarm signal is also transmitted to the fire brigade.Should the fire not be able to be controlled by the occupants on the fire floor, they will need to leave the floor of fire origin via the stairs. Stair enclosures may be designed to be fire-resistant but this may not be sufficient to keep the smoke out of the stairs. Many buildings incorporate stair pressurisation systems whereby positive airflow is introduced into the stairs upon detection of smoke within the building. However, this increases the forces required to openthe stair doors and makes it increasingly difficult to access the stairs. It is quite likely that excessive door opening forces will exist(Fazio et al,2006) From a fire perspective, it is common to consider that a building consists of enclosures formed by the presence of walls and floors.An enclosure that has sufficiently fire-resistant boundaries (i.e. walls and floors) is considered to constitute a fire compartment and to be capable of limiting the spread of fire to an adjacent compartment. However, the ability of such boundaries to restrict the spread of fire can be severely limited by the need to provide natural lighting (windows)and access openings between the adjacent compartments (doors and stairs). Fire spread via the external openings (windows) is a distinct possibility given a fully developed fire. Limit- ing the window sizes and geometry can reduce but not eliminate the possibility of vertical fire spread.By far the most effective measure in limiting fire spread, other than the presence of occupants, is an effective sprinkler system that delivers water to a growing fire rapidly reducing the heat being generated and virtually extinguishing it.3.2 Estimating Fire SeverityIn the absence of measures to extinguish developing fires, or should such systems fail; severe fires can develop within buildings.In fire engineering literature, the term “fire load”refers to the quantity of combustibles within an enclosure and not the loads (forces) applied to the structure during a fire. Similarly, fire load density refers to the quantity of fuel per unit area. It is normally expressed in terms of MJ/m2or kg/m2 of wood equivalent.Surveys of combustibles for various occupancies (i.e offices, retail, hospitals, warehouses, etc)have been undertaken and a good summary of the available data is given in FCRC (1999). As would be expected, the fire load density is highly variable. Publications such as the International Fire Engineering Guidelines (2005) give fire load data in terms of the mean and 80th percentile.The latter level of fire load density is sometimes taken as the characteristic fire load density and is sometimes taken as being distributed according to a Gumbel distribution (Schleich et al, 1999).The rate at which heat is released within an enclosure is termed the heat release rate (HRR) and normally expressed in megawatts (MW). The application of sufficient heat to a combustible material results in the generation of gases some of which are combustible. This process is called pyrolisation.Upon coming into contact with sufficient oxygen these gases ignite generating heat. The rate of burning(and therefore of heat generation) is therefore dependent on the flow of air to the gases generated by the pyrolising fuel.This flow is influenced by the shape of the enclosure (aspect ratio), and the position and size of any potential openings. It is found from experiments with single openings in approximately cubic enclosures that the rate of burning is directly proportional to A h where A is the area of the opening and h is the opening height. It is known that for deep enclosures with single openings that burning will occur initially closest to the opening moving back into the enclosure once the fuel closest to the opening is consumed (Thomas et al, 2005). Significant temperature variations throughout such enclosures can be expected.The use of the word ‘opening’in relation to real building enclosures refers to any openings present around the walls including doors that are left open and any windows containing non fire-resistant glass.It is presumed that such glass breaks in the event of development of a significant fire. If the windows could be prevented from breaking and other sources of air to the enclosure limited, then the fire would be prevented from becoming a severe fire.Various methods have been developed for determining the potential severity of a fire within an enclosure.These are described in SFPE (2004). The predictions of these methods are variable and are mostly based on estimating a representative heat release rate (HRR) and the proportion of total fuel ςlikely to be consumed during the primary burning stage (Figure 4). Further studies of enclosure fires are required to assist with the development of improved models, as the behaviour is very complex.3.3 Role of the Building StructureIf the design objectives are to provide an adequate level of safety for the occupants and protection of adjacent properties from damage, then the structural adequacy of the building in fire need only be sufficient to allow the occupants to exit the building and for the building to ultimately deform in a way that does not lead to damage or fire spread to a building located on an adjacent site.These objectives are those associated with most building regulations including the Building Code of Australia (BCA). There could be other objectives including protection of the building against significant damage. In considering these various objectives, the following should be taken into account when considering the fireresistance of the building structure.3.3.1 Non-Structural ConsequencesSince fire can produce smoke and flame, it is important to ask whether these outcomes will threaten life safety within other parts of the building before the building is compromised by a loss of structural adequacy? Is search and rescue by the fire brigade not feasible given the likely extent of smoke? Will the loss of use of the building due to a severe fire result in major property and income loss? If the answer to these questions is in the affirmative, then it may be necessary to minimise the occurrence of a significant fire rather than simply assuming that the building structure needs to be designed for high levels of fire resistance. A low-rise shopping centre with levels interconnected by large voids is an example of such a situation.3.3.2 Other Fire Safety SystemsThe presence of other systems (e.g. sprinklers) within the building to minimise the occurrence of a serious fire can greatly reduce the need for the structural elements to have high levels of fire resistance. In this regard, the uncertainties of all fire-safety systems need to be considered. Irrespective of whether the fire safety system is the sprinkler system, stair pressurisation, compartmentation or the system giving the structure a fire-resistance level (e.g. concrete cover), there is an uncertainty of performance. Uncertainty data is available for sprinkler systems(because it is relatively easy to collect) but is not readily available for the other fire safety systems. This sometimes results in the designers and building regulators considering that only sprinkler systems are subject to uncertainty. Inreality, it would appear that sprinklers systems have a high level of performance and can be designed to have very high levels of reliability.3.3.3 Height of BuildingIt takes longer for a tall building to be evacuated than a short building and therefore the structure of a tall building may need to have a higher level of fire resistance. The implications of collapse of tall buildings on adjacent properties are also greater than for buildings of only several storeys.3.3.4 Limited Extent of BurningIf the likely extent of burning is small in comparison with the plan area of the building, then the fire cannot have a significant impact on the overall stability of the building structure. Examples of situations where this is the case are open-deck carparks and very large area building such as shopping complexes where the fire-effected part is likely to be small in relation to area of the building floor plan.3.3.5 Behaviour of Floor ElementsThe effect of real fires on composite and concrete floors continues to be a subject of much research.Experimental testing at Cardington demonstrated that when parts of a composite floor are subject to heating, large displacement behaviour can develop that greatly assists the load carrying capacity of the floor beyond that which would predicted by considering only the behaviour of the beams and slabs in isolation.These situations have been analysed by both yield line methods that take into account the effects of membrane forces (Bailey, 2004) and finite element techniques. In essence, the methods illustrate that it is notnecessary to insulate all structural steel elements in a composite floor to achieve high levels of fire resistance.This work also demonstrated that exposure of a composite floor having unprotected steel beams, to a localised fire, will not result in failure of the floor.A similar real fire test on a multistory reinforced concrete building demonstrated that the real structural behaviour in fire was significantly different to that expected using small displacement theory as for normal tempera- ture design (Bailey, 2002) with the performance being superior than that predicted by considering isolated member behaviour.3.4 Prescriptive Approach to DesignThe building regulations of most countries provide prescriptive requirements for the design of buildings for fire.These requirements are generally not subject to interpretation and compliance with them makes for simpler design approval–although not necessarily the most cost-effective designs.These provisions are often termed deemed-to-satisfy (DTS) provisions. All aspects of designing buildings for fire safety are covered–the provision of emergency exits, spacings between buildings, occupant fire fighting measures, detection and alarms, measures for automatic fire suppression, air and smoke handling requirements and last, but not least, requirements for compartmentation and fire resistance levels for structural members. However, there is little evidence that the requirements have been developed from a systematic evaluation of fire safety. Rather it would appear that many of the requirements have been added one to another to deal with another fire incident or to incorporate a new form of technology. There does not appear to have been any real attempt to determinewhich provision have the most significant influence on fire safety and whether some of the former provisions could be modified.The FRL requirements specified in the DTS provisions are traditionally considered to result in member resistances that will only rarely experience failure in the event of a fire.This is why it is acceptable to use the above arbitrary point in time load combination for assessing members in fire. There have been attempts to evaluate the various deemed-to-satisfy provisions (particularly the fire- resistance requirements)from a fire-engineering perspective taking into account the possible variations in enclosure geometry, opening sizes and fire load (see FCRC, 1999).One of the outcomes of this evaluation was the recognition that deemed-to- satisfy provisions necessarily cover the broad range of buildings and thus must, on average, be quite onerous because of the magnitude of the above variations.It should be noted that the DTS provisions assume that compartmentation works and that fire is limited to a single compartment. This means that fire is normally only considered to exist at one level. Thus floors are assumed to be heated from below and columns only over one storey height.3.5 Performance-Based DesignAn approach that offers substantial benefits for individual buildings is the move towards performance-based regulations. This is permitted by regulations such as the BCA which state that a designer must demonstrate that the particular building will achieve the relevant performance requirements. The prescriptive provisions (i.e. the DTS provisions) are presumed to achieve these requirements. It is necessary to show that any building that does not conform to the DTS provisionswill achieve the performance requirements.But what are the performance requirements? Most often the specified performance is simply a set of performance statements (such as with the Building Code of Australia)with no quantitative level given. Therefore, although these statements remind the designer of the key elements of design, they do not, in themselves, provide any measure against which to determine whether the design is adequately safe.Possible acceptance criteria are now considered.3.5.1 Acceptance CriteriaSome guidance as to the basis for acceptable designs is given in regulations such as the BCA. These and other possible bases are now considered in principle.(i)compare the levels of safety (with respect to achieving each of the design objectives) of the proposed alternative solution with those asso- ciated with a corresponding DTS solution for the building.This comparison may be done on either a qualitative or qualitative risk basis or perhaps a combination. In this case, the basis for comparison is an acceptable DTS solution. Such an approach requires a “holistic”approach to safety whereby all aspects relevant to safety, including the structure, are considered. This is, by far, the most common basis for acceptance.(ii)undertake a probabilistic risk assessment and show that the risk associated with the proposed design is less than that associated with common societal activities such as using pub lic transport. Undertaking a full probabilistic risk assessment can be very difficult for all but the simplest situations.Assuming that such an assessment is undertaken it will be necessary for the stakeholders toaccept the nominated level of acceptable risk. Again, this requires a “holistic”approach to fire safety.(iii) a design is presented where it is demonstrated that all reasonable measures have been adopted to manage the risks and that any possible measures that have not been adopted will have negligible effect on the risk of not achieving the design objectives.(iv) as far as the building structure is concerned,benchmark the acceptable probability of failure in fire against that for normal temperature design. This is similar to the approach used when considering Building Situation 1 but only considers the building structure and not the effects of flame or smoke spread. It is not a holistic approach to fire safety.Finally, the questions of arson and terrorism must be considered. Deliberate acts of fire initiation range from relatively minor incidents to acts of mass destruction.Acts of arson are well within the accepted range of fire events experienced by build- ings(e.g. 8% of fire starts in offices are deemed "suspicious"). The simplest act is to use a small heat source to start a fire. The resulting fire will develop slowly in one location within the building and will most probably be controlled by the various fire- safety systems within the building. The outcome is likely to be the same even if an accelerant is used to assist fire spread.An important illustration of this occurred during the race riots in Los Angeles in 1992 (Hart 1992) when fires were started in many buildings often at multiple locations. In the case of buildings with sprinkler systems,the damage was limited and the fires significantly controlled.Although the intent was todestroy the buildings,the fire-safety systems were able to limit the resulting fires. Security measures are provided with systems such as sprinkler systems and include:- locking of valves- anti-tamper monitoring- location of valves in secure locationsFurthermore, access to significant buildings is often restricted by security measures.The very fact that the above steps have been taken demonstrates that acts of destruction within buildings are considered although most acts of arson do not involve any attempt to disable the fire-safety systems.At the one end of the spectrum is "simple" arson and at the other end, extremely rare acts where attempts are made to destroy the fire-safety systems along with substantial parts of the building.This can be only achieved through massive impact or the use of explosives. The latter may be achieved through explosives being introduced into the building or from outside by missile attack.The former could result from missile attack or from the collision of a large aircraft. The greater the destructiveness of the act,the greater the means and knowledge required. Conversely, the more extreme the act, the less confidence there can be in designing against such an act. This is because the more extreme the event, the harder it is to predict precisely and the less understood will be its effects. The important point to recognise is that if sufficient means can be assembled, then it will always be possible to overcome a particular building design.Thus these acts are completely different to the other loadings to which a。
土木工程专业外文文献及翻译
英文原文：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem， this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering， and aim at concrete the circumstance put forward some prevention， processing measure。
Keyword:Concrete crack prevention processing ForewordConcrete's is 1 kind is anticipate by the freestone bone， cement， water and other mixture but formation of the in addition material of quality brittleness not and all material。
Because the concrete construction transform with oneself，control etc。
a series problem， harden model of in the concrete existence numerous tiny hole， spirit cave and tiny crack， is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality。
建筑抗震设计中英文对照外文翻译文献
中英文对照外文翻译The frame structure anti- earthquake concept design The disaster has an earthquake dashing forward sending out nature, may forecast nature very low so far, bring about loss for human society is that the natural disaster of all kinds is hit by one of the gravest disaster gravely. In the light of now available our country science level and economy condition, correct the target building seismic resistance having brought forward "three standards " fortification, be that generally, the what be spoken "small earthquake shocks does not but constructs in the dirty trick, big earthquakes do not fall ". That generally, what be talked small shocks in the earthquake, big earthquakes refer to respectively is intensity exceed probability in 50 fortifying for 3%'s 63% , 10% , 2 ~ being more is caught in an earthquake, earthquake , rare Yu earthquake.Since building the astigmatic design complexity, in actual project, anti-knock conceptual design appears especially important right away. It includes the following content mainly: Architectural design should pay attention to the architectural systematic ness; Choose rational building structure system; the tensile resisting inclining force structure and the component is designed.That the ability designs law is the main content that the structure denasality designs includes standard our country internal force adjustment and structure two aspect. It is twenty centuries seventies later stage , reinforced concrete structure brought forward by famous New Zealand scholar T.Paulay and Park has sufficient tonsillitis method under the force designing an earthquake chooses value is prejudiced low situationW.hose core thought is: "The beam cuts organization " or "the beam column cuts organization " by the fact that "the strong weak post beam " guidesstructure to take form; Avoid structure by "strong weak scissors turn " before reach estimate that shearing happened in the denasality in the ability front destroy; Turn an ability and consume an ability by the fact that necessary structure measure makes the location may form the plasticity hinge have the necessary plasticity. Make structure have the necessary tonsillitis from all above three aspect guarantee. That framed structure is the common structure form, whose senility certainly designs that, is to embody from about this three aspect also mainly.1, Strong pillar weak beamDriving force reaction analysis indicates structure; architectural deformability is connected with to destroying mechanism. Common have three kinds model’s c onsume energy organization ", beam hinge organization ““, post hinge organization ““, beam column hinge organization "."Beam hinge organization " and "beam column hinge organization " Lang Xian knuckle under , may let the entire frame have distribution and energy consumption heavierthan big internal forces ability, limit tier displacement is big , plasticity hinge quantity is many , the hinge does not lose efficacy but the structure entirety does not lose efficacy because of individual plasticity. The as a result anti-knock function is easy to be that the armored concrete is ideal consume energy organization. Being that our country norm adopts allows a pillar , the shearing force wall puts up the hinge beam column hinge scheme, taking place adopting "strong relative weak post beam " measure , postponing a pillar cuts time. Weak tier of post hinge organization possibility appear on unable complete trouble shooting but , require that the axis pressure restricting a pillar compares as a result, architectural weakness prevents necessary time from appearing tier by the fact that Cheng analysis law judges now and then, post hinge organization.Are that V. I. P. is to enhance the pillar bending resistance , guidance holds in the beam appear first, the plasticity cuts our "strong common weak post beam " adjustment measure. Before plasticity hinge appearing on structure, structure component Yin La District concrete dehiscence and pressure area concrete mistake elasticity character, every component stiffness reduces a reinforced bar will do with the cementation degeneration between the concrete. That stiffness reduces a beam isrelatively graver than accepting the pillar pressing on , structure enhances from initial shearing type deformation to curved scissors shape deformation transition , curved post inner regulation proportion really more curved than beam; The at the same time architectural period is lengthened, size affecting the participation modulus shaking a type respectively to structure's; Change happened in the earthquake force modulus , lead to the part pillar bend regulation enhancing, feasible beam reality knuckles under intensity rise , the post inner bends regulation when plasticity hinge appearing on thereby feasible beam enhancing since structure cause and the people who designs the middle reinforced bar's are to enhance.. And after plasticity hinge appearing on structure, same existence having above-mentioned cause, structure knuckles under mistake elasticity in the day after tomorrow process being that process , post that the earthquake enhances strenuously further bend regulation enhancing with earthquake force but enhance. The force arouses an earthquake overturn force moment having changed the actual post inner axis force. We knuckle under the ability lessening than axis pressure in standardizing being limited to be able to ensure that the pillar also can lead to a pillar in big the bias voltage range inner , axis force diminution like value. The anti-knock norm is stipulated: Except that the frame top storey and post axis pressure are compared to the strut beam and frame pillar being smaller than 0.15 person and frame, post holds curved regulation designing that value should accord with difference being，that first order takes 1.4 , the two stage takes 1.2 , grade-three takes 1.1. 9 degree and one step of framed structure stillresponds to coincidence, ，intensity standard value ascertains that according to matching reinforced bar area and material really. The bottom post axis is strenuously big, the ability that the plasticity rotates dispatches, be that pressure collapses after avoiding a foot stall producing a hinge, one, two, three steps of framed structure bottom, post holds cross section constituting curved regulation designing that value takes advantage of that 1.5, 1.25 compose in reply 1.15 in order to enhancing a modulus respectively. Combination of the corner post adjustment queen bends regulation still should take advantage of that not to be smallerthan 1.10's modular. Curved regulation designs that value carries out adjustment to one-level anti-knock grade shearing force wall limb cross section combination , force the plasticity hinge to appear to reinforce location in the wall limb bottom, the bottom reinforces location and all above layer of curved regulation designing that value takes wall limb bottom cross section constituting curved regulation designing value , other location multiplies 1.2's by to enhance a modulus. Prop up anti-knock wall structure to part frame, bottom-end , whose curved combination regulation design value respond to one, two steps of frame pillars post upper end and bottom post take advantage of that 1.5 composes in reply 1.25 in order to enhancing a modulus respectively. All above "strong weak post beam” adjustment measure, reaction analysis indicates , big satisfied fundamental earthquakes demand no upside down course nonlinearity driving force. Reinforced bar spending area, the beam in 7 is controlled from gravity load, the post reinforced ba r matches’ tendon rates basically from the minimum under the control of. Have enhanced post Liana Xiang all round resisting the curved ability. At the same time, 7 degree of area exactly curved regulation plasticity hinge appears on disaster very much, plays arrive at advantageous role to fighting against big earthquakes. In 9 degree of area, adopt reality to match reinforced bar area and material bending regulation within intensity standard value calculation post, structural beam reinforced bar enhancing same lead to enhancing bending regulation within post designing value, under importing in many waves, the beam holds the plasticity hinge rotating developing greatly, more sufficient, post holds the plasticity hinge developing insufficiency, rotate less. Design demand with the beam. Reaction and 9 degree are about the same to 8 degree of area , whose big earthquake displacement , that post holds the plasticity hinge is bigger than rotating 9 degree much but, the beam holds the plasticity hinge appearing sufficient but rotate small, as a result "strong weak post beam " effect is not obvious , curved regulation enhances a modulus ought to take 1.35 , this waits for improving and perfecting going a step further when the grade suggesting that 8 degree of two stage is anti-knock in connection with the expert.2, Strong shear weak curved"Strong weak scissors turn” is that the plasticity cuts cross section for guarantee on reach anticipate that shearing happened in the mistake elastic-deformation prior to destroy. As far as common structure be concerned, main behaviors holds in the beam, post holds, the shearing force wall bottom reinforces area , shearing force wall entrance to a cave company beam tools , beam column node core area. Show mainly with being not that seismic resistance is compared with each other, strengthening measure in improving the effect shearing force; Aspect adjusting a shear bearing the weight of two forces.1)effect shearing forceOne, two, three-level frame beam and anti-knock wall middle stride over high ratio greater than 2.5 company beam, shearing force design value among them, first order choose 1.3, two stage choose 1.2, three-level choose 1.1, first order framed structure and 9 Due Shan respond to coincidence. Coincidence one, two, three steps of frame post and frame pillar , shearing force being designed being worth taking 1.4 among them, one step , taking 1.2, three steps of take 1.1 , one-level framed structure and 9 Due Shank two steps responding to. One, two, three steps of anti-knock walls bottom reinforces location the shearing force designs that value is among them, first order takes 1.6 , the two stage takes 1.4 , grade-three takes 1.2, 9 Dud Shank respond to coincidence. The node core area seismic resistance the beam column node , one, two steps of anti-knock grades are carried out is born the weight of force checking calculation by the scissors , should accord with anti-knock structure measure about 3 step, correct 9 degree of fortify and one-level anti-knock grade framed structure, think to the beam end the plasticity hinge already appears , the node shearing force holds reality completely from the beam knuckling under curved regulation decision , hold reality according to the beam matching reinforced bar covering an area of the growing modulus that intensity standard value calculation,takes advantage of that at the same time with 1.15 with material. Other first order holds curved regulation according to the beamdesigning that value secretly schemes against , the shearing force enhances a modulus being 1.35 , the two stage is 1.2.2) Shear formulaThe continuous beam of armored concrete and the cantilever beam are born the weight of at home and abroad under low repeated cycle load effect by the scissors the force experiment indicates the main cause pooling efforts and reducing even if tendon dowel force lessening is that the beam is born the weight of a force by the scissors, concrete scissors pressure area lessening shearing an intensity, tilted rift room aggregate bite. Scissors bear the weight of a norm to the concrete accepting descending strenuously being 60% be not anti-knock, the reinforced bar item does not reduce. By the same token, the experiment indicates to insisting to intimidate post with that the force is born the weight of by the scissors, loading makes post the force be born the weight of by the scissors reducing 10% ~ again and again 30%, the item arouses , adopts practice identical with the beam mainly from the concrete. The experiment is indicated to shearing force wall, whose repeated loading breaks the subtraction modulus up than monotony increases be loaded with force lessening is born the weight of by the scissors 15% ~ 20%, adopts to be not that seismic resistance is born the weight of by the scissors energy times 0.8's. Two parts accept the pressure pole strenuously tilted from the concrete is born the weight of by the scissors and horizontal stirrup of beam column node seismic resistance cutting the expert who bears the weight of force composition , is connected with have given a relevance out formula.Tilted for preventing the beam , post , company beam , shearing force wall , node from happening pressure is destroyed, we have stipulated upper limits force upper limit to be born the weight of by the scissors , have stipulated to match hoop rate’s namely to accepting scissors cross section.Reaction analysis indicates strong weak curved scissors requests; all above measure satisfies basically by mistake elasticity driving force. The plasticity rotates because ofanti-knock grade of two stage beam column under big earthquakes still very big , suggest that the shearing force enhances a modulus is bigger than having there is difference between one step unsuitably in connection with the expert, to the beam choose 1.25 is fairly good , ought to take 1.3 ~ to post 1.35. It's the rationality taking value remains to be improved and perfected in going a step further.Require that explanatory being , the beam column node accept a force very complicated , need to ensure that beam column reinforced bar reliability in the node is anchoring , hold occurrence bending resistance at the same time in the beam column destroying front, shearing happened in the node destroy, whose essence should belong to "strong weak curved scissors" categories. The node carries out adjustment on one, two steps of anti-knock grades shearing force and, only, the person enhances a modulus be are minor than post, ratio post also holds structure measure a little weak. As a result ", more strong node “statement, is not worth it encourage.3) Structure measureStructure measure is a beam, post, the shearing force wall plasticity cuts the guarantee that area asks to reach the plasticity that reality needs turning ability and consuming ability. Its "strong with "strong weak scissors turn ", weak post beam " correlates, a architectural denasality of guarantee.”Strong weak scissors turn " is a prerequisite for ensuring that the plasticity hinge turns an ability and consumes an ability; Strict "strong weak post beam " degree, the measure affecting corresponding structure, if put strict "strong weak post beam " into practice, ensure that the pillar does not appear than the plasticity hinge, corresponding axis pressure waiting for structure measure to should be a little loose right away except the bottom. Our country adopts "the strong relative weak post beam”, delays a pillar going beyond the hinge time, therefore needing to adopt stricter structure measure.①the beam structure measure beam plasticity hinge cross section senility and many factors match tendon rates and the rise knuckling under an intensity but reduce in connection with cross section tensile, with the reinforced bar being pulled; The reinforced bar matches tendon rates and concrete intensity rise but improve with being pressed on, width enhances but enhances with cross section; Plasticity hinge areastirrup can guard against the pressure injustice releasing a tendon , improve concrete limit pressure strain , arrest tilted rift carrying out , fight against a shearing force , plasticity hinge deformation and consume an ability bring into full play, That deck-molding is stridden over is smaller than exceeding , shearing deformation proportion is increasingly big, the gentility destroying , using the tilted rift easy to happen reduces. The beam has led low even if the tendon matches hoop, the reinforced bar may knuckle under after Lang Kai cracks break up by pulling even. As a result, the norm matches tendon rates to the beam even if the tendon maximum matches tendon rates and minimum , the stirrup encryption District length , maximal spacing , minimal diameter , maximal limb lead all have strict regulations from when, volume matches hoop. Being bending regulation , the guarantee cross section denasality , holding to the beam possibly for the end fighting against a beam to pull the pressure reinforced bar area ratio make restrict. Stride over height at the same time, to minimal beam width, than, aspect ratio has done regulation.② the post structure measureFor post bending a type accepting the force component, axis pressure than to the denasality and consuming to be able to, nature effect is bigger. Destroy axis pressure than big bias voltages happened in the pillar hour, component deformation is big , gentility energy nature easy to only consume, reduces; Nature is growing with axis pressure than enhancing , consuming an energy, but the gentility sudden drop, moreover the stirrup diminishes to the gentility help. Readjust oneself to a certain extent to adopt the pillar, main guarantee it's tonsillitis that the low earthquake designs strenuously, but consuming energy sex to second. The pressure ratio has made a norm to the axis restricting, can ensure that within big bias voltages range in general. Stirrup same get the strain arriving at big roles, restraining the longitudinal tendon, improving concrete pressure, deter the tilted rift from developing also to the denasality. Be to match tendon symmetrically like post, the person leads feeling bigger , as big , becoming deformed when the pillar knuckles under more even if the tendon matches tendon , the tensile finishes exceeding. As a result, the tendon minimum matches tendon rates, the stirrup encryption District length, maximalspacing, minimal diameter, maximal limb lead having made strict regulations out from when, and volume matches hoop to the pillar jumping. At the same time, aspect ratio , scissors to the pillar have stridden over a ratio , minimal altitude of cross section , width have done out regulation, to improve the anti-knock function.③ Node structure measureThe node is anchoring beam column reinforced bar area, effect is very big to structure function. Be under swear to act on earthquake and the vertical stroke to load, area provides necessary constraint to node core when node core area cuts pressure low than slanting, keep the node fundamental shear ability under disadvantageous condition, make a beam column anchoring even if the tendon is reliable, match hoop rates to node core area maximal spacing of stirrup, minimal diameter, volume having done out regulation. The beam column is main node structure measure content even if tendon reliability in the node is anchoring. Have standardized to beam tendon being hit by the node diameter; Release the anchoring length of tendon to the beam column; anchoring way all has detailed regulation.To sum up ,; Framed structure is to pass "the design plan calculating and coming realize structure measure the ability running after beam hinge organization" mainly thereby, realize "the small earth—quake shocks does not but constructs in the dirty trick, big earthquakes do not fall " three standards to-en fortifying target's. References.框架结构抗震设计地震灾害具有突发性，至今可预报性很低，给人类社会造成的损失严重，是各类自然灾中最严重的灾害之一。
土木工程毕业设计中英文摘要和目录
摘要建筑名称：博文图书馆位置：青岛市经济技术开发区结构类型：钢筋混凝土框架结构层数：四层总建筑面积：7629.4m2本设计建筑名称为博文图书馆。
图书馆不仅仅是一个阅读的场所，它更是市民交流的平台。
作为城市地标，拟建建筑物要考虑与临边建筑风格相协调，同时也要突出自己的建筑风格。
本图书馆建筑建筑总高度25.875米，共4层，层高5.1米，采用现浇钢筋混凝土框架结构，抗震等级为三级，抗震设防烈度为7度，整个设计包括建筑设计和结构设计两部分。
建筑设计部分，首先根据建筑的使用功能确定建筑的初步布局，包括建筑体形及室内空间布置等，然后结合使用的材料、做法进一步确定具体尺寸和平、立面风格等。
具体来说，主要包括总平面设计、建筑平面设计（功能布局及布置思路、房间的布置、卫生间的设计、楼梯布置、柱网布置等）、立面设计、剖面设计（层数层高确定及楼梯设计）、建筑材料设计（屋面做法、楼面做法）、防火设计，并对主要设计规范、尺寸单位、荷载及钢筋混凝土作了附加说明。
结构设计部分，首先根据建筑设计、工艺使用要求、材料供应情况以及场地地质条件等确定结构布置方案，然后选取一榀典型框架进行设计计算。
在明确计算简图的前提下，进一步确定框架承受的荷载，包括恒载、屋（楼）面活载和风荷载，在此基础上进行框架内力计算（采用D值法计算风荷载作用下的内力，采用弯矩二次分配法计算竖向荷载作用下的内力）、内力组合、梁、柱和基础等构件的配筋计算以及风荷载作用下的侧移验算。
除此之外，还进行了楼梯设计（梯段板设计、平台板设计及平台梁设计）、雨篷的设计与计算等。
为进一步验证手算结果的精确度，采用PKPM 2005行业软件进行了电算，比较分析表明手算结果是可靠的。
最后用AutoCAD进行绘图。
关键词：钢筋混凝土框架结构；图书馆建筑；建筑设计；结构设计AbstractBuilding Name：Bo Wen LibraryLocation：Economic and Technological Development Zone of Qingdao Struture System：R.C.frameNumber of Stories：4 storiesTotal floor area：7629.4m2The building name of the design is Bo Wen Library. It is not only a reading place but a platform for communication. As a landmark of the city, The proposed building should be considered to be in accordance with the style of surrounding architecture, and also highlight its own style.The present project is a 4-storey library with the floor height 5.1m and the total height 25.875m. The four-layer building is adopted the cast-in-place reinforced concrete frame structure, and the seismic fortification intensity is 7 with the anti-seismic level 3. The entire graduation project divides into two parts, that is, the architectural design part and the structural design part.In the architectural design part, the general layout is first determined according to the building function, including conformation and indoor spatial setting; then the dimension, plane style and elevation style are chosen considering the engineering materials and constructional details. Make it more specific,it includes the total plane design, architectural graphic design (the function layout and layout thinking, the room arrangement and the design of toilet, stair layout, column, etc), the facade design layout, section design(the number and the height of layers identity and stair design), building materials design (roofing approach, the floor practice) and fire prevention design. In addition, instructions for the main design norms and dimensions, load and reinforced concrete is given.In the structural design part, the array of structure is first determined according to architectural design, process demand, material supply and geological conditions; then a typical transverse frame is taken to be computed. After the extract of computation sketch, the external loads such as the dead load, living load on the roof (floor) and the wind load are calculated; then the internal force in the structure is obtained through the moment distribution method under verticalloading and the modified knick point method under horizontal loads. In the following, the combination of internal force is performed. On the above basis, the design of structural components such as beams, columns and foundations are respectively carried out, and at the same time the checking computation of the slidesway under wind load is done. In addition, the design of the stair (ladder period of board design, smooth bedplate design and platform beam design), the canopy and other accessory components are also completed..To verify the accuracy of above results, numerical tests are performed with the software PKPM 2005, and the comparisons prove that the original results are reliable. Finally, the construction documents are completed using the software AutoCAD 2004.Keywords: Reinforced concrete frame; Multi-storey library building; Architectural design; Structural design.目录1 建筑设计 (1)1.1设计资料 (1)1.1.1建筑环境和地点 (1)1.1.2建筑设计要求 (2)1.2 总平面设计 (3)1.2.1总平面设计要求 (3)1.2.2总图设计 (4)1.2.3方案特点 (5)1.2.4基地环境分析 (6)1.2.5交通组织 (7)1.2.6绿化景观设计 (8)1.2.7 变形缝的设计 (8)1.3 建筑平面设计 (9)1.3.1设计指导思想及本方案平面特点 (10)1.3.2功能分区 (12)1.3.3房间的布置 (14)1.3.4卫生间的设计 (16)1.3.5人流组织说明 (17)1.3.6防火疏散组织与楼梯的布置 (17)1.3.7柱网的布置 (19)1.4 立面设计 (20)1.4.1立面设计要求 (21)1.4.2方案造型设计 (22)1.5 剖面设计 (25)1.5.1剖面设计基本要求 (25)1.5.2屋面、楼面做法 (28)1.5.3楼梯选择 (29)1.6细部构造总说明 (31)1.6.1勒脚 (31)1.6.2散水 (31)1.6.3楼地面工程 (32)1.6.4屋面工程 (32)1.6.5门窗工程 (32)1.6.6基础工程 (33)1.7防火设计 (34)1.8其它说明 (35)2.结构设计 (36)2.1 板的设计 (36)2.1.1 设计资料 (36)2.1.2 楼盖的结构平面布置 (36)2.1.3单向板计算 (37)2.1.4 双向板计算 (40)2.2 次梁计算 (47)2.3框架设计 (50)2.3.1 设计资料 (50)2.3.2 结构布置及结构计算简图 (52)2.3.3 荷载统计 (54)2.3.4 内力计算 (66)2.3.5 内力组合 (94)2.3.6截面设计 (102)2.4 基础设计 (114)2.4.1基础资料 (114)2.4.2荷载统计 (115)2.4.3地基承载力验算 (117)2.4.4配筋计算 (126)2.4.5联合基础设计 (134)2.5 楼梯设计 (138)2.5.1 设计资料 (138)2.5.2 梯段板设计 (139)2.5.3 平台板设计 (140)2.5.4 平台梁设计 (141)2.6 雨篷设计 (143)2.6.1 设计资料 (143)2.6.2 雨篷板抗弯强度计算 (143)2.6.3 雨篷梁计算 (145)参考文献 (150)致谢 (152)附录博文图书馆图纸目录表 (153)。
土木工程专业毕业设计外文文献及翻译
英文原文：Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP compositesAhmed Khalifa a,* , Antonio Nanni ba Department of Structural Engineering, University of Alexandria, Alexandria 21544, Egyptb Department of Civil Engineering, University of Missouri at Rolla, Rolla, MO 65409, USAReceived 28 April 1999; received in revised form 30 October 2001; accepted 10 January 2002AbstractThe present study examines the shear performance and modes of failure of rectangular simply supported reinforced concrete(RC) beams designed with shear deficiencies. These members were strengthened with externally bonded carbon fiber reinforced polymer (CFRP) sheets and evaluated in the laboratory. The experimental program consisted of twelve full-scale RC beams tested to fail in shear. The variables investigated within this program included steel stirrups, and the shear span-to-effective depth ratio, as well as amount and distribution of CFRP. The experimental results indicated that the contribution of externally bonded CFRP to the shear capacity was significant. The shear capacity was also shown to be dependent upon the variables investigated. Test results were used to validate a shear design approach, which showed conservative and acceptable predictions.○C 2002 Elsevier Science Ltd. All rights reserved.Keywords: Rehabilitation; Shear; Carbon fiber reinforced polymer 1. IntroductionFiber reinforced polymer (FRP) composite systems, composed offibers embedded in a polymeric matrix, can be used for shear strengthening of reinforced con-crete (RC) members [1–7]. Many existing RC beams are deficient and in need of strengthening. The shear failure of an RC beam is clearly different from its flexural failure. In shear, the beam fails suddenly without sufficient warning and diagonal shear cracks are consid-erably wider than the flexural cracks [8].The objectives of this program were to:1. Investigate performance and mode of failure of simply supported rectangular RC beams with shear deficien-cies after strengthening with externally bonded CFRP sheets.2. Address the factors that influence shear capacity of strengthened beams such as: steel stirrups, shear span-to-effective depth ratio (a/d ratio), and amount and distribution of CFRP.3. Increase the experimental database on shear strength-ening with externally bonded FRP reinforcement.4. Validate the design approach previously proposed by the authors [9].For these objectives, 12 full-scale, RC beams designed to fail in shear were strengthened with different CFRP schemes. These members were tested as simple beams using a four-point loading configuration with two different a/d ratios.2. Experimental program2.1. Test specimens and materialsTwelve full-scale beam specimens with a total span of 3050 mm. and a rectangular cross-section of 150-mm-wide and 305-mm-deep were tested. The specimens were grouped into two main series designated SW and SO depending on the presence of steel stirrups in the shear span of interest.Series SW consisted of four specimens. The details and dimensionsof the specimens designated series SW are illustrated in Fig. 1a. In this series, four 32-mm steel bars were used as longitudinal reinforcement with two at top and two at bottom face of the cross-section to induce a shear failure. The specimens were reinforced with 10-mm steel stirrups throughout their entire span. The stirrups spacing in the shear span of interest, right half, was selected to allow failure in that span.Series SO consisted of eight beam specimens, which had the same cross-section dimension and longitudinal steel reinforcement as for series SW. No stirrups were provided in the test half span as illustrated.Each main series (i.e. series SW and SO) was subdivided into two subgroups according to shear span-to-effective depth ratio. This was selected to be a/d = 3 and 4, resulting in the following four subgroups: SW3;SW4; SO3; and SO4.The mechanical properties of the materials used for manufacturing the test specimens are listed in Table 1.Fabrication of the specimens including surface preparation and CFRP installation is described elsewhere [10].2.2. Strengthening schemesOne specimen from each series (SW3-1, SW4-1, SO3-1 and SO4-1) was left without strengthening as a control specimen, whereas eight beam specimens were strengthened with externally bonded CFRP sheets following three different schemes as illustrated in Fig. 2.In series SW3, specimen SW3-2 was strengthened with two CFRP plies having perpendicular fiber directions (90°/0°). The first ply was attached in the form of continuous U-wrap with the fiber direction oriented perpendicular to the longitudinal axis of the specimen (90°). The second ply was bonded on the two sides of thespecimen with the fiber direction parallel to the beam axis（0°）.This ply [i.e. 0°ply] was selected to investigate the impact of additional horizontal restraint on shear strength.In series SW4, specimen SW4-2 was strengthened with two CFRP plies having perpendicular fiber direction (90°/0°) as for specimen SW3-2.Four beam specimens were strengthened in series SO3. Specimen SO3-2 was strengthened with one-ply CFRP strips in the form of U-wrap with 90°-fiber orientation. The strip width was 50 mm with center-to-center spacing of 125 mm. Specimen SO3-3 was strengthened in a manner similar to that of specimen SO3-2, but with strip width equal to 75 mm. Specimen SO3-4 was strengthened with one-ply continuous U-wrap (90°). Specimen SO3-5 was strengthened with twoCFRP plies (90°/0°) similar to specimens SW3-2 and SW4-2.In series SO4, two beam specimens were strengthened. Specimen SO4-2 was strengthened with one-ply CFRP strips in the form of U-wrap similar to specimen SO3-2. Specimen SO4-3 was strengthened with one-ply continuous U-wrap (90°) similar to SO3-4.2.3. Test set-up and instrumentationAll specimens were tested as simple span beams subjected to a four-point load as illustrated in Fig. 3. A universal testing machine with 1800 KN capacity was used in order to apply a concentrated load on a steel distribution beam used to generate the two concentrated loads. The load was applied progressively in cycles, usually one cycle before cracking followed by three cycles with the last one up to ultimate. The applied load vs. deflection curves shown in this paper are the envelopes of these load cycles.Four linear variable differential transformers (LVDTs) were usedfor each test to monitor vertical displacements at various locations as shown in Fig. 3. Two LVDTs were located at mid-span on each side of the specimen. The other two were located at the specimen supports to record support settlement.For each specimen of series SW, six strain gauges were attached to three stirrups to monitor the stirrup strain during loading as illustrated in Fig. 1a. Three strain gauges were attached directly to the FRP sheet on the sides of each strengthened beam to monitor strain variation in the FRP. The strain gauges were oriented in the vertical direction and located at the section mid-height with distances of 175, 300 and 425 mm, respectively, from the support for series SW3 and SO3. For beam specimens of series SW4 and SO4, the strain gauges were located at distance of 375, 500 and 625 mm, respectively, from the support.3. Results and discussionIn the following discussion, reference is always made to weak shear span or span of interest.3.1. Series SW3Shear cracks in the control specimen SW3-1 were observed close to the middle of the shear span when the load reached approximately 90 kN. As the load increased, additional shear cracks formed throughout, widening and propagating up to final failure at a load of 253 kNIn specimen SW3-2 strengthened with CFRP (90°/0°), no cracks were visible on the sides or bottom of the test specimen due to the FRP wrapping. However，a longitudinal splitting crack initiated on the top surface of the beam at a high load of approximately 320 kN. The crack initiated at the location of applied load and extended towards the support. The specimen failed by concrete splitting at total load of 354 kN. This was an increase of 40% in ultimatecapacity compared to the control specimen SW3-1. The splitting failure was due to the relatively high longitudinal compressive stress developed at top of the specimen, which created a transverse tension, led to the splitting failure. In addition, the relatively large amount of longitudinal steel reinforcement combined with over-strengthening for shear by CFRP wrap probably caused this mode of failure. The load vs. mid-span deflection curves for specimens SW3-1 and SW3-2 are illustrated , to show the additional capacity gained by CFRP.The maximum CFRP vertical strain measured at failure in specimen SW3-2 was approximately 0.0023 mm/mm, which corresponded to 14% of the reported CFRP ultimate strain. This value is not an absolute because it greatly depends on the location of the strain gauges with respect to a crack. However, the recorded strain indicates that if the splitting did not occur, the shear capacity could have reached higher load.Comparison between measured local stirrup strains in specimens SW3-1 and SW3-2 are shown in Fig. 6. The stirrups 1, 2 and 3 were located at distance of 175, 300 and 425 mm from the support, respectively. The results showed that the stirrups 2 and 3 did not yield at ultimate for both specimens. The strains (and the forces) in the stirrups of specimen SW3-2 were, in general, smaller than those of specimen SW3-1 at the same level of loading due to the effect of CFRP.3.2. Series SW4In specimen SW4-1, the first diagonal crack was formed in the member at a total applied load of 75 kN. As the load increased, additional shear cracks appeared throughout the shear span. Failure of the beam occurred when the total applied load reached 200 kN. This was a decrease of 20% in shear capacity compared tothe specimen SW3-1In specimen SW4-2, the failure was controlled by concrete splitting similar to test specimen SW3-2. The total applied load at ultimate was 361 kN with an 80% increase in shear capacity compared to the control specimen SW4-1. In addition, the measured strains in the stirrups for specimen SW4-2 were less than those of specimen SW4-1. The applied load vs. mid-span deflection curves for beams SW4-1 and SW4-2 are illustrated . It may be noted that specimen SW4-2 resulted in greater deflection when compared to specimen SW4-1.When comparing the test results of series SW3 specimens to that of series SW4, the ultimate failure load of specimen SW3-2 and SW4-2 was almost the same. However, the enhanced capacity of specimen SW3-2 (a/d=3) due to the addition of the CFRP reinforcement was 101 kN, while specimen SW4-2 (a/d=4) was 161 kN. This indicates that the contribution of external CFRP reinforcement may be influenced by the ayd ratio and appears to decrease with a decreasing a/d ratio. Further, for both strengthened specimens (SW3-2 and SW4-2), CFRP sheets did not fracture or debond from the concrete surface at ultimate and this indicates that CFRP could provide additional strength if the beams did not failed by splitting.3.3. Series SO3Fig. 8 illustrates the failure modes for series SO3 specimens. That details the applied load vs. mid-span deflection for the specimens. The failure mode of control specimen SO3-1 was shear compression. Failure of the specimen occurred at a total applied load of 154 kN. This load was a decrease of shear capacity by 54.5 kN compared to the specimen SW3-1 due to the absent of the steel stirrups. In addition, the crack pattern in specimen SW3-1 was different from of specimen SO3-1. In specimen SW3-1, the presenceof stirrups provided a better distribution of diagonal cracks throughout the shear span.In specimen SO3-2, strengthened with 50-mm CFRP strips spaced at 125 mm, the first diagonal shear crack was observed at an applied load of 100 kN. The crack propagated as the load increased in a similar manner to that of specimen SO3-1. Sudden failure occurred due to debonding of the CFRP strips over the diagonal shear crack, with spalled concrete attached to the CFRP strips. The total ultimate load was 262 kN with a 70% increase in shear capacity over the control specimen SO3-1. The maximum local CFRP vertical strain measured at failure in specimen SO3-2 was 0.0047 mm/mm (i.e. 28% of the ultimate strain), which indicated that the CFRP did not reach its ultimate.Specimen SO3-3, strengthened with 75-mm CFRP strips failed as a result of CFRP debonding at a total applied load of 266 kN. No significant increase in shear capacity was noted compared to specimen SO3-2. The maximum-recorded vertical CFRP strain at failure was 0.0052 mmymm (i.e. 31% of the ultimate strain). Specimen SO3-4, which was strengthened with a continuous CFRP U-wrap (908), failed as a result of CFRP debonding at an applied load of 289 kN. Results show that specimen SO3-4 exhibited increase in shear capacity of 87, 10 and 8.5% over specimens SO3-1,SO3-2 and SO3-3, respectively. Applied load vs. vertical CFRP strain for specimen SO3-4 is illustrated in Fig. 10 in which strain gauges sg1, sg2 and sg3 were located at mid-height with distances of 175, 300 and 425 mm from the support, respectively. Fig. 10 shows that the CFRP strain was zero prior to diagonal crack formation, then increased slowly until the specimen reached a load in the neighborhood of the ultimate strength of the control specimen. At this point, the CFRP strain increased significantly until failure. Themaximum local CFRP vertical strain measured at failure was approxi- mately 0.0045 mm/mm.When comparing the results of beams SO3-4 and SO3-2, the CFRP amount used to strengthen specimen SO3-4 was 250% of that used for specimen SO3-2. Only a 10% increase in shear capacity was achieved for the additional amount of CFRP used. This means that if an end anchor to control FRP debonding is not used, there is an optimum FRP quantity, beyond which the strengthening effect is questionable. A previous study [11] showed that by using an end anchor system, the failure mode of FRP debonding could be avoided. Reported findings are consistent with those of other research [7], which was based on a review of the experimental results available in the literature, and indicated that the contribution of FRP to the shear capacity increases almost linearly, with FRP axial rigidity expressed by f f E ρ(f ρ is the FRP area fraction and f E is the FRP elastic modulus) up to approximately 0.4 GPa. Beyond this value, the effectiveness of FRP ceases to be positive.In specimen SO3-5, the use of a horizontal ply over the continuous U-wrap (i.e. 90°/0°) resulted in a concrete splitting failure rather than a CFRP debonding failure. The failure occurred at total applied load of 339 kN with a 120% increase in the shear capacity compared to the control specimen SO3-1. The strengthening with two perpendicular plies (i.e. 90°/0°) resulted in a 17% increase in shear capacity compared to the specimen with only one CFRP ply in 90° orientation (i.e. specimen SO3-4). The maximum local CFRP vertical strain measured at failure was 0.0043 mm/mm.By comparing the test results of specimens SW3-2 and SO3-5, having the same a/d ratio and strengthening schemes but with different steel shear reinforcement, the shear strength (i.e. 177 and 169.5 kN for specimens SW3-2 and SO3-5, respectively), and the ductility arealmost identical. One may conclude that the contribution of CFRP benefits the beam capacity to a greater degree for beams without steel shear reinforcement than for beams with adequate shear reinforcement.3.4. Series SO4Series SO4 exhibited the largest increase in shear capacity compared to the other series investigated with this research study. The experimental results in terms of applied load vs mid-span deflection for this series is illustrated in Fig. 11.The control specimen SO4-1 failed as a result of shear compression at a total applied load of 130 kN. Specimen SO4-2, strengthened with CFRP strips, the failure was controlled by CFRP debonding at a total load of 255 kN with 96% increase in shear capacity over the control specimen SO4-1. The maximum local CFRP vertical strain measured at failure was 0.0062mmymm.When comparing the test results of specimen SO4-2 to that of specimen SO3-2, the enhanced shear capacity of specimen SO4-2 (a/d=4) due to addition of CFRP strips was 62.5 kN, while specimen SO3-2 (a/d=3) resulted in added shear capacity of 54 kN. As expected, the contribution of CFRP reinforcement to resist the shear appeared to decrease with decreasing a/d ratio. Specimen SO4-3, strengthened with continuous U- wrap, failed as a result of concrete splitting at an applied load of 310 kN with a 138% increase in shear capacity compared to that of specimen SO4-1. The maximum local CFRP vertical strain measured at failure was 0.0037 mm/mm.4. Design approachThe design approach for computing the shear capacity of RC beams strengthened with externally bonded CFRP reinforcement,expressed in ACI design code [12] format, was proposed and published in 1998 [13]. The design model described two possible failure mechanisms of CFRP reinforcement namely: CFRP fracture; and CFRP debonding. Furthermore, two limits on the contribution of CFRP shear were proposed. The first limit was set to control the shear crack width and loss of aggregate interlock, and the second was to preclude web crushing. Also, the concrete strength and CFRP wrap- ping schemes were incorporated as design parameters. In recent study [9,10], modifications were proposed to the 1998 design approach to include results of a new study on bond mechanism between CFRP sheets and concrete surface [14]. In addition, the model was extended to provide the shear design equations in Eurocode as well as ACI format. Comparing with all test results available in the literature to date, 76 tests, the design approach showed acceptable and conservative estimates [10,13]. In this section, the summary of the design approach is presented. The comparison between experimental results and the calculated factored shear strength demonstrates the ability of the design approach to predict the shear capacity of the strengthened beams. demonstrates the ability of the design approach to predict the shear capacity of the strengthened beams.4.1. Summary of the shear design approach — ACI formatIn traditional shear design (including the ACI Code), the nominal shear strength of an RC section is the sum of the nominal shear strengths of concrete and steel shear reinforcement. For beams strengthened with externally bonded FRP reinforcement, the shear strength may be computed by the addition of a third term to account of the FRP contribution. This is expressed as follows:The design shear strength,n V , is obtained by multiplying thenominal shear strength by a strength reduction factor for shear,φ. It was suggested that the reduction factor φ=0.85 given in ACI [12] be main-tained for the concrete and steel terms. However, a more stringent strength reduction factor of 0.7 for the CFRP contribution was suggested w10x. This is due to the relative novelty of this repair technique. Thus, the design shear strength is expressed as follows.4.2. Contribution of CFRP reinforcement to the shear capacityThe expression used to compute shear contribution of CFRP reinforcement is given in Eq. (3). This equation is similar to that for shear contribution of steel stirrups and consistent with the ACI format.The area of CFRP shear reinforcement,f A , is the total thickness of the sheet (usually f t 2or sheets on both sides of the beam) times the width of the CFRP strip f ω. The dimensions used to define the areaof CFRP in addition to the spacingf s and the effective depth of CFRP,f d ， are shown in Fig. 12. Note that for continuous verticalshear reinforcement, the spacing of the strip,f s , and the width of the strip, f ω, are equal.In Eq. (3), an effective average CFRP stressfe f , smaller than its ultimate strength,fu f , was used to replace the yield stress of steel. At the ultimate limit state for the member in shear, it is not possible to attain the full strength of the FRP [7,13]. Failure is governed by either fracture of the FRP sheet at average stress levels well belowFRP ultimate capacity due to stress concentrations, debonding of the FRP sheet from the concrete surface, or a significant decrease in the post- cracking concrete shear strength from a loss of aggregate interlock. Thus, the effective average CFRP stress is computed by applying a reduction coefficient, R, to the CFRP ultimate strength as expressed in Eq. (4).The reduction coefficient depends on the possible failure modes (either CFRP fracture or CFRP debonding). In either case, an upper limit for the reduction coefficient is established in order to control shear crack width and loss of aggregate interlock. 4.3. Reduction coefficient based on CFRP sheet fracture failureThe proposed reduction coefficient was calibrated on all available test results to date, 22 tests with failure controlled by CFRP fracture [10，13]. The reduction coefficient was established as a function of f f E ρ (where f ρis the area fraction of CFRP) andexpressed in Eq.(5) for ≤f f E ρ0.7 GPa.4.4. Reduction coefficient based on CFRP debonding failureThe shear capacity governed by CFRP debonding from the concrete surface was presented [9,10]as a function of CFRP axial rigidity, concrete strength, effective depth of CFRP reinforcement, and bonded surface configurations. In determining the reduction coefficient for bond, the effective bond length, e L , has to be determined first. Based on analytical and experimental data from bond tests, Miller [14] showed that the effective bond length slightly increases as CFRP axial rigidity,f f E t , increases. However, he suggested a constant conservative value e L for equal to 75 mm. The value may be modified when more bond tests data becomesavailable.After a shear crack develops, only that portion of the width of CFRP extending past the crack by the effective bonded length is assumed to be capable of carrying shear.[13] The effective width, fe W , based on the shear crack angle of 45°, and the wrapping scheme is expressed in Eqs. (6a) and (6b);if the sheet in the form of a U-wrap (6a)if the sheet is bonded only to the sides of the beam.(6b)The final expression for the reduction coefficient, R, for the mode of failure controlled by CFRP debonding is expressed in Eq. (8)Eq. (7) is applicable for CFRP axial rigidity, f f E t , ranging from 20 to 90 mm-GPa (kN/mm). Research into quantifying the bond characteristics for axial rigidities above 90 mm ·GPa is being conducted at the University of Missouri, Rolla (UMR).4.5. Upper limit of the reduction coefficientIn order to control the shear crack width and loss of aggregate interlock, an upper limit of reduction coefficient, R, was suggested and calibrated with all of the available test results [10] to be equal to fu ε/006.0where fu εis the ultimate tensile CFRP strain. This limit is such that the average effective strain in CFRP materials at ultimate can not be greater than 0.006 mm/mm (without the strengthening reduction factor,φ).4.6. Controlling reduction coefficientThe final controlling reduction coefficient for the CFRP system is taken as the lowest value determined from the two possible modes of failure and the upper limit. Note that if the sheet is wrappedentirely around the beam or an effective end anchor is used, the failure mode of CFRP debonding is not to be considered. The reduction coefficient is only controlled by FRP fracture and the upper limit.4.7. CFRP spacing requirementsSimilar to steel shear reinforcement, and consistent with ACI provision for the stirrups spacing [12], the spacing of FRP strips should not be so wide as to allow the formation of a diagonal crack without intercepting a strip. For this reason, if strips are used, they should not be spaced by more than the maximum given in Eq. (8).4.8. Limit on total shear reinforcement ACI 318M-95 [12] 11.5.6.7 and 11.5.6.8 set a limit on the total shear strength that may be provided by more than one type of shear reinforcement to preclude the web crushing. FRP shear reinforcement should be included in this limit. A modification to ACI 318M-95 Section 11.5.6.8 was suggested as follows:4.9. Shear capacity of a CFRP strengthened section — Eurocode formatThe proposed design equation wEq. (3)x for computing the contribution of externally bonded CFRP reinforcement may be rewritten in Eurocode (EC2 1992) [15] format as Eq. (10).In this equation, the partial safety factor for CFRP materials,f ,was suggested equal to 1.3 [10].5. Conclusions and further recommendation An experimental investigation was conducted to study the shearbehavior and the modes of failure of simply supported rectangular section RC beams with shear deficiencies, strengthened with CFRP sheets. The parameters investigated in this program were existence of steel shear reinforcement, shear span-to-effective depth ratio (ayd ratio), and CFRP amount and distribution.The results confirm that the strengthening technique using CFRP sheets can be used to increase significantly shear capacity, with efficiency that varies depending on the tested variables. For the beams tested in this program, increases in shear strength of 40–138% were achieved.Conclusions that emerged from this study may be summarized as follows:●The contribution of externally CFRP reinforcement to the shearcapacity is influenced by the a/d ratio.●Increasing the amount of CFRP may not result in a proportionalincrease in the shear strength. The CFRP amount used to strengthen specimen SO3-4 was 250% of that used in specimen SO3-2, which resulted in a minimal (10%) increase in shear capacity. An end anchor is recommended if FRP debonding is to be avoided.●The test results indicated that contribution of CFRP benefits theshear capacity at a greater degree for beams without shear reinforcement than for beams with adequate shear reinforcement.●The results of series SO3 indicated that the 0° ply improved theshear capacity by providing horizontal restraint.●The shear design algorithms provided acceptable andconservative estimates for the strengthened beams.Recommendations for future research are as follows:●Experimental and analytical investigations are required to linkthe shear contribution of FRP with the load condition. These studies have to consider both the longitudinal steel reinforcement ratio and the concrete strength as parameters. Laboratory specimens should maintain practical dimensions.● The strengthening effectiveness of FRP has to be addressed in thecases of short and very short shear spans in which arch action governs failure.● The interaction between the contribution of external FRP andinternal steel shear reinforcement has to be investigated.● To optimize design algorithms, additional specimens need to betested with different CFRP amount and configurations to create a large database of information.● Shear design algorithms need to be expanded to includestrengthening with aramid FRP and glass FRP sheets in addition to CFRP.6. NomenclatureA: Shear spanf A :Area of CFRP shear reinforcements=2t f w fw b : Width of the beam cross-sectionD: Depth from the top of the section to the tension steel reinforcement centroidf d :Effective depth of the CFRP shear reinforcement (usually equal to d for rectangular sections and dyts for T-sections)f E :Elastic modulus of FRP (GPa)'c f :Nominal concrete compressive strength (MPa)fef :Effective tensile stress in the FRP sheet in the direction of the principal fibers (stress level in the FRP at failure)fu f :Ultimate tensile strength of the FRP sheet in the direction of the。
土木工程外文文献及翻译
本科毕业设计外文文献及译文文献、资料题目：Designing Against Fire Of Building 文献、资料来源：国道数据库文献、资料发表（出版）日期：2008.3.25院（部）：土木工程学院专业：土木工程班级：土木辅修091姓名：xxxx外文文献:Designing Against Fire Of BulidingxxxABSTRACT:This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electrical systems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are considered in the context of current regulatory requirements. The principles and assumptions associ- ated with various approaches are discussed.1 INTRODUCTIONOther papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the case of fire. Rather, it is building regulations such as the Building Code of Australia (BCA) that directly specify most of the requirements for fire safety of buildings with reference being made to Standards such as AS3600 or AS4100 for methods for determining the fire resistance of structural elements.The purpose of this paper is to consider the design of buildings for fire safety from an engineering perspective (as is currently done for other loads such as wind or earthquakes), whilst at the same time,putting such approaches in the context of the current regulatory requirements.At the outset,it needs to be noted that designing a building for fire safety is far morethan simply considering the building structure and whether it has sufficient structural adequacy.This is because fires can have a direct influence on occupants via smoke and heat and can grow in size and severity unlike other effects imposed on the building. Notwithstanding these comments, the focus of this paper will be largely on design issues associated with the building structure.Two situations associated with a building are used for the purpose of discussion. The multi-storey office building shown in Figure 1 is supported by a transfer structure that spans over a set of railway tracks. It is assumed that a wide range of rail traffic utilises these tracks including freight and diesel locomotives. The first situation to be considered from a fire safety perspective is the transfer structure.This is termed Situation 1 and the key questions are: what level of fire resistance is required for this transfer structure and how can this be determined? This situation has been chosen since it clearly falls outside the normal regulatory scope of most build- ing regulations. An engineering solution, rather than a prescriptive one is required. The second fire situation (termed Situation 2) corresponds to a fire within the office levels of the building and is covered by building regulations. This situation is chosen because it will enable a discussion of engineering approaches and how these interface with the building regulations–since both engineering and prescriptive solutions are possible.2 UNIQUENESS OF FIRE2.1 IntroductionWind and earthquakes can be considered to b e “natural” phenomena over which designers have no control except perhaps to choose the location of buildings more carefully on the basis of historical records and to design building to resist sufficiently high loads or accelerations for the particular location. Dead and live loads in buildings are the result of gravity. All of these loads are variable and it is possible (although generally unlikely) that the loads may exceed the resistance of the critical structural members resulting in structural failure.The nature and influence of fires in buildings are quite different to those associated with other“loads” to which a building may be subjected to. The essential differences are described in the following sections.2.2 Origin of FireIn most situations (ignoring bush fires), fire originates from human activities within the building or the malfunction of equipment placed within the building to provide a serviceable environment. It follows therefore that it is possible to influence the rate of fire starts by influencing human behaviour, limiting and monitoring human behaviour and improving thedesign of equipment and its maintenance. This is not the case for the usual loads applied to a building.2.3 Ability to InfluenceSince wind and earthquake are directly functions of nature, it is not possible to influence such events to any extent. One has to anticipate them and design accordingly. It may be possible to influence the level of live load in a building by conducting audits and placing restrictions on contents. However, in the case of a fire start, there are many factors that can be brought to bear to influence the ultimate size of the fire and its effect within the building. It is known that occupants within a building will often detect a fire and deal with it before it reaches a sig- nificant size. It is estimated that less than one fire in five (Favre, 1996) results in a call to the fire brigade and for fires reported to the fire brigade, the majority will be limited to the room of fire origin. In oc- cupied spaces, olfactory cues (smell) provide powerful evidence of the presence of even a small fire. The addition of a functional smoke detection system will further improve the likelihood of detection and of action being taken by the occupants.Fire fighting equipment, such as extinguishers and hose reels, is generally provided within buildings for the use of occupants and many organisations provide training for staff in respect of the use of such equipment.The growth of a fire can also be limited by automatic extinguishing systems such as sprinklers, which can be designed to have high levels of effectiveness.Fires can also be limited by the fire brigade depending on the size and location of the fire at the time of arrival. 2.4 Effects of FireThe structural elements in the vicinity of the fire will experience the effects of heat. The temperatures within the structural elements will increase with time of exposure to the fire, the rate of temperature rise being dictated by the thermal resistance of the structural element and the severity of the fire. The increase in temperatures within a member will result in both thermal expansion and,eventually,a reduction in the structural resistance of the member. Differential thermal expansion will lead to bowing of a member. Significant axial expansion will be accommodated in steel members by either overall or local buckling or yielding of local- ised regions. These effects will be detrimental for columns but for beams forming part of a floor system may assist in the development of other load resisting mechanisms (see Section 4.3.5).With the exception of the development of forces due to restraint of thermal expansion, fire does not impose loads on the structure but rather reduces stiffness and strength. Such effects are not instantaneous but are a function of time and this is different to the effects of loads such as earthquake and wind that are more or less instantaneous.Heating effects associated with a fire will not be significant or the rate of loss of capacity will be slowed if:(a) the fire is extinguished (e.g. an effective sprinkler system)(b) the fire is of insufficient severity – insufficient fuel, and/or(c)the structural elements have sufficient thermal mass and/or insulation to slow the rise in internal temperatureFire protection measures such as providing sufficient axis distance and dimensions for concrete elements, and sufficient insulation thickness for steel elements are examples of (c). These are illustrated in Figure 2.The two situations described in the introduction are now considered.3 FIRE WITHIN BUILDINGS3.1 Fire Safety ConsiderationsThe implications of fire within the occupied parts of the office building (Figure 1) (Situation 2) are now considered. Fire statistics for office buildings show that about one fatality is expected in an office building for every 1000 fires reported to the fire brigade. This is an order of magnitude less than the fatality rate associated with apartment buildings. More than two thirds of fires occur during occupied hours and this is due to the greater human activity and the greater use of services within the building. It is twice as likely that a fire that commences out of normal working hours will extend beyond the enclosure of fire origin.A relatively small fire can generate large quantities of smoke within the floor of fire origin. If the floor is of open-plan construction with few partitions, the presence of a fire during normal occupied hours is almost certain to be detected through the observation of smoke on the floor. The presence of full height partitions across the floor will slow the spread of smoke and possibly also the speed at which the occupants detect the fire. Any measures aimed at improving housekeeping, fire awareness and fire response will be beneficial in reducing thelikelihood of major fires during occupied hours.For multi-storey buildings, smoke detection systems and alarms are often provided to give “automatic” detection and warning to the occupants. An alarm signal is also transmitted to the fire brigade.Should the fire not be able to be controlled by the occupants on the fire floor, they will need to leave the floor of fire origin via the stairs. Stair enclosures may be designed to be fire-resistant but this may not be sufficient to keep the smoke out of the stairs. Many buildings incorporate stair pressurisation systems whereby positive airflow is introduced into the stairs upon detection of smoke within the building. However, this increases the forces required to open the stair doors and makes it increasingly difficult to access the stairs. It is quite likely that excessive door opening forces will exist(Fazio et al,2006)From a fire perspective, it is common to consider that a building consists of enclosures formed by the presence of walls and floors.An enclosure that has sufficiently fire-resistant boundaries (i.e. walls and floors) is considered to constitute a fire compartment and to be capable of limiting the spread of fire to an adjacent compartment. However, the ability of such boundaries to restrict the spread of fire can be severely limited by the need to provide natural lighting (windows)and access openings between the adjacent compartments (doors and stairs). Fire spread via the external openings (windows) is a distinct possibility given a fully developed fire. Limit- ing the window sizes and geometry can reduce but not eliminate the possibility of vertical fire spread.By far the most effective measure in limiting fire spread, other than the presence of occupants, is an effective sprinkler system that delivers water to a growing fire rapidly reducing the heat being generated and virtually extinguishing it.3.2 Estimating Fire SeverityIn the absence of measures to extinguish developing fires, or should such systems fail; severe fires can develop within buildings.In fire en gineering literature, the term “fire load” refers to the quantity of combustibles within an enclosure and not the loads (forces) applied to the structure during a fire. Similarly, fire load density refers to the quantity of fuel per unit area. It is normally expressed in terms of MJ/m2 or kg/m2 of wood equivalent. Surveys of combustibles for various occupancies (i.e offices, retail, hospitals, warehouses, etc)have been undertaken and a good summary of the available data is given in FCRC (1999). As would be expected, the fire load density is highly variable. Publications such as the International Fire Engineering Guidelines (2005) give fire load data in terms of the mean and 80th percentile.The latter level of fire load density is sometimes taken asthe characteristic fire load density and is sometimes taken as being distributed according to a Gumbel distribution (Schleich et al, 1999).The rate at which heat is released within an enclosure is termed the heat release rate (HRR) and normally expressed in megawatts (MW). The application of sufficient heat to a combustible material results in the generation of gases some of which are combustible. This process is called pyrolisation.Upon coming into contact with sufficient oxygen these gases ignite generating heat. The rate of burning(and therefore of heat generation) is therefore dependent on the flow of air to the gases generated by the pyrolising fuel.This flow is influenced by the shape of the enclosure (aspect ratio), and the position and size of any potential openings. It is found from experiments with single openings in approximately cubic enclosures that the rate of burning is directly proportional to A h where A is the area of the opening and h is the opening height. It is known that for deep enclosures with single openings that burning will occur initially closest to the opening moving back into the enclosure once the fuel closest to the opening is consumed (Thomas et al, 2005). Significant temperature variations throughout such enclosures can be expected.The use of the word ‘opening’ in relation to real building enclosures refers to any openings present around the walls including doors that are left open and any windows containing non fire-resistant glass.It is presumed that such glass breaks in the event of development of a significant fire. If the windows could be prevented from breaking and other sources of air to the enclosure limited, then the fire would be prevented from becoming a severe fire.Various methods have been developed for determining the potential severity of a fire within an enclosure.These are described in SFPE (2004). The predictions of these methods are variable and are mostly based on estimating a representative heat release rate (HRR) and the proportion of total fuel ςlikely to be consumed during the primary burning stage (Figure 4). Further studies of enclosure fires are required to assist with the development of improved models, as the behaviour is very complex.3.3 Role of the Building StructureIf the design objectives are to provide an adequate level of safety for the occupants and protection of adjacent properties from damage, then the structural adequacy of the building in fire need only be sufficient to allow the occupants to exit the building and for the building to ultimately deform in a way that does not lead to damage or fire spread to a building located on an adjacent site.These objectives are those associated with most building regulations includingthe Building Code of Australia (BCA). There could be other objectives including protection of the building against significant damage. In considering these various objectives, the following should be taken into account when considering the fire resistance of the building structure.3.3.1 Non-Structural ConsequencesSince fire can produce smoke and flame, it is important to ask whether these outcomes will threaten life safety within other parts of the building before the building is compromised by a loss of structural adequacy? Is search and rescue by the fire brigade not feasible given the likely extent of smoke? Will the loss of use of the building due to a severe fire result in major property and income loss? If the answer to these questions is in the affirmative, then it may be necessary to minimise the occurrence of a significant fire rather than simply assuming that the building structure needs to be designed for high levels of fire resistance. A low-rise shopping centre with levels interconnected by large voids is an example of such a situation.3.3.2 Other Fire Safety SystemsThe presence of other systems (e.g. sprinklers) within the building to minimise the occurrence of a serious fire can greatly reduce the need for the structural elements to have high levels of fire resistance. In this regard, the uncertainties of all fire-safety systems need to be considered. Irrespective of whether the fire safety system is the sprinkler system, stair pressurisation, compartmentation or the system giving the structure a fire-resistance level (e.g. concrete cover), there is an uncertainty of performance. Uncertainty data is available for sprinkler systems(because it is relatively easy to collect) but is not readily available for the other fire safety systems. This sometimes results in the designers and building regulators considering that only sprinkler systems are subject to uncertainty. In reality, it would appear that sprinklers systems have a high level of performance and can be designed to have very high levels of reliability.3.3.3 Height of BuildingIt takes longer for a tall building to be evacuated than a short building and therefore the structure of a tall building may need to have a higher level of fire resistance. The implications of collapse of tall buildings on adjacent properties are also greater than for buildings of only several storeys.3.3.4 Limited Extent of BurningIf the likely extent of burning is small in comparison with the plan area of the building, then the fire cannot have a significant impact on the overall stability of the building structure. Examples of situations where this is the case are open-deck carparks and very large area building such as shopping complexes where the fire-effected part is likely to be small in relation to area of the building floor plan.3.3.5 Behaviour of Floor ElementsThe effect of real fires on composite and concrete floors continues to be a subject of much research.Experimental testing at Cardington demonstrated that when parts of a composite floor are subject to heating, large displacement behaviour can develop that greatly assists the load carrying capacity of the floor beyond that which would predicted by considering only the behaviour of the beams and slabs in isolation.These situations have been analysed by both yield line methods that take into account the effects of membrane forces (Bailey, 2004) and finite element techniques. In essence, the methods illustrate that it is not necessary to insulate all structural steel elements in a composite floor to achieve high levels of fire resistance.This work also demonstrated that exposure of a composite floor having unprotected steel beams, to a localised fire, will not result in failure of the floor.A similar real fire test on a multistory reinforced concrete building demonstrated that the real structural behaviour in fire was significantly different to that expected using small displacement theory as for normal tempera- ture design (Bailey, 2002) with the performance being superior than that predicted by considering isolated member behaviour.3.4 Prescriptive Approach to DesignThe building regulations of most countries provide prescriptive requirements for the design of buildings for fire.These requirements are generally not subject to interpretation and compliance with them makes for simpler design approval–although not necessarily the most cost-effective designs.These provisions are often termed deemed-to-satisfy (DTS) provisions. All aspects of designing buildings for fire safety are covered–the provision of emergency exits, spacings between buildings, occupant fire fighting measures, detection and alarms, measures for automatic fire suppression, air and smoke handling requirements and last, but not least, requirements for compartmentation and fire resistance levels for structural members. However, there is little evidence that the requirements have been developed from a systematic evaluation of fire safety. Rather it would appear that many of the requirements have been added one to another to deal with another fire incident or to incorporate a new form of technology. There does not appear to have been any real attempt to determine which provision have the most significant influence on fire safety and whether some of the former provisions could be modified.The FRL requirements specified in the DTS provisions are traditionally considered to result in member resistances that will only rarely experience failure in the event of a fire.This is why it is acceptable to use the above arbitrary point in time load combination for assessing members in fire. There have been attempts to evaluate the various deemed-to-satisfy provisions (particularly the fire- resistance requirements)from a fire-engineering perspective taking intoaccount the possible variations in enclosure geometry, opening sizes and fire load (see FCRC, 1999).One of the outcomes of this evaluation was the recognition that deemed-to- satisfy provisions necessarily cover the broad range of buildings and thus must, on average, be quite onerous because of the magnitude of the above variations.It should be noted that the DTS provisions assume that compartmentation works and that fire is limited to a single compartment. This means that fire is normally only considered to exist at one level. Thus floors are assumed to be heated from below and columns only over one storey height.3.5 Performance-Based DesignAn approach that offers substantial benefits for individual buildings is the move towards performance-based regulations. This is permitted by regulations such as the BCA which state that a designer must demonstrate that the particular building will achieve the relevant performance requirements. The prescriptive provisions (i.e. the DTS provisions) are presumed to achieve these requirements. It is necessary to show that any building that does not conform to the DTS provisions will achieve the performance requirements.But what are the performance requirements? Most often the specified performance is simply a set of performance statements (such as with the Building Code of Australia)with no quantitative level given. Therefore, although these statements remind the designer of the key elements of design, they do not, in themselves, provide any measure against which to determine whether the design is adequately safe.Possible acceptance criteria are now considered.3.5.1 Acceptance CriteriaSome guidance as to the basis for acceptable designs is given in regulations such as the BCA. These and other possible bases are now considered in principle.(i)compare the levels of safety (with respect to achieving each of the design objectives) of the proposed alternative solution with those asso- ciated with a corresponding DTS solution for the building.This comparison may be done on either a qualitative or qualitative risk basis or perhaps a combination. In this case, the basis for comparison is an acceptable DTS solution. Such an approach requires a “holistic” approach to safety whereby all aspects relevant to safety, including the structure, are considered. This is, by far, the most common basis for acceptance.(ii)undertake a probabilistic risk assessment and show that the risk associated with the proposed design is less than that associated with common societal activities such as using pub lic transport. Undertaking a full probabilistic risk assessment can be very difficult for all but the simplest situations.Assuming that such an assessment is undertaken it will be necessary for the stakeholders to accept the nominated level of acceptable risk. Again, this requires a “holistic”approach to fire safety.(iii) a design is presented where it is demonstrated that all reasonable measures have been adopted to manage the risks and that any possible measures that have not been adopted will have negligible effect on the risk of not achieving the design objectives.(iv) as far as the building structure is concerned,benchmark the acceptable probability of failure in fire against that for normal temperature design. This is similar to the approach used when considering Building Situation 1 but only considers the building structure and not the effects of flame or smoke spread. It is not a holistic approach to fire safety.Finally, the questions of arson and terrorism must be considered. Deliberate acts of fire initiation range from relatively minor incidents to acts of mass destruction.Acts of arson are well within the accepted range of fire events experienced by build- ings(e.g. 8% of fire starts in offices are deemed "suspicious"). The simplest act is to use a small heat source to start a fire. The resulting fire will develop slowly in one location within the building and will most probably be controlled by the various fire- safety systems within the building. The outcome is likely to be the same even if an accelerant is used to assist fire spread.An important illustration of this occurred during the race riots in Los Angeles in 1992 (Hart 1992) when fires were started in many buildings often at multiple locations. In the case of buildings with sprinkler systems,the damage was limited and the fires significantly controlled.Although the intent was to destroy the buildings,the fire-safety systems were able to limit the resulting fires. Security measures are provided with systems such as sprinkler systems and include:- locking of valves- anti-tamper monitoring- location of valves in secure locationsFurthermore, access to significant buildings is often restricted by security measures.The very fact that the above steps have been taken demonstrates that acts of destruction within buildings are considered although most acts of arson do not involve any attempt to disable the fire-safety systems.At the one end of the spectrum is "simple" arson and at the other end, extremely rare acts where attempts are made to destroy the fire-safety systems along with substantial parts of the building.This can be only achieved through massive impact or the use of explosives. The latter may be achieved through explosives being introduced into the building or from outside by missile attack.The former could result from missile attack or from the collision of a large aircraft. The greater the destructiveness of the act,the greater the means and knowledge required. Conversely, the more extreme the act, the less confidence there can be in designing against suchan act. This is because the more extreme the event, the harder it is to predict precisely and the less understood will be its effects. The important point to recognise is that if sufficient means can be assembled, then it will always be possible to overcome a particular building design.Thus these acts are completely different to the other loadings to which a building is subjected such as wind,earthquake and gravity loading. This is because such acts of destruction are the work of intelligent beings and take into account the characteristics of the target.Should high-rise buildings be designed for given terrorist activities,then terrorists will simply use greater means to achieve the end result.For example, if buildings were designed to resist the impact effects from a certain size aircraft, then the use of a larger aircraft or more than one aircraft could still achieve destruction of the building. An appropriate strategy is therefore to minimise the likelihood of means of mass destruction getting into the hands of persons intent on such acts. This is not an engineering solution associated with the building structure.It should not be assumed that structural solutions are always the most appropriate, or indeed, possible.In the same way, aircrafts are not designed to survive a major fire or a crash landing but steps are taken to minimise the likelihood of either occurrence.The mobilization of large quantities of fire load (the normal combustibles on the floors) simultaneously on numerous levels throughout a building is well outside fire situations envisaged by current fire test standards and prescriptive regulations. Risk management measures to avoid such a possibility must be considered.4 CONCLUSIONSFire differs significantly from other “loads” such as wind, live load and earthquakes i n respect of its origin and its effects.Due to the fact that fire originates from human activities or equipment installed within buildings, it is possible to directly influence the potential effects on the building by reducing the rate of fire starts and providing measures to directly limit fire severity.The design of buildings for fire safety is mostly achieved by following the prescriptive requirements of building codes such as the BCA. For situations that fall outside of the scope of such regulations, or where proposed designs are not in accordance with the prescriptive requirements, it is possible to undertake performance-based fire engineering designs.However, there are no design codes or standards or detailed methodologies available for undertaking such designs.Building regulations require that such alternative designs satisfy performance requirements and give some guidance as to the basis for acceptance of these designs (i.e. acceptance criteria).This paper presents a number of possible acceptance criteria, all of which use the measure of risk level as the basis for comparison.Strictly, when considering the risks。
土木工程毕业设计英文文献
1. Introduction
The Georgia Department of TransportationG(GDOT) has wellmaintained and timely rehabbed pavements and has enjoyed the reputation as having the best pavements among the fifty states in USA. One of the reasons that GDOT can achieve such high performance standards for its pavements is the utilization of a Pavement Condition Evaluation SystemG (PACES, 1996) to evaluate the pavement conditions annually for the entire highway system in Georgia for the past 15 years. Results of the annual PACES evaluations are then used to develop pavement maintenance and rehabilitation prioritization schedules. The PACES was designed to indicate the extent and types of surface distresses on a flexible pavement at the time of the pavement condition survey. Futhermore, the other advantage of PACES system was that it could link with other vital road characteristic data to make it possible to build the pavement performance database. In the past, the annual maintenance and rehabilitation prioritization scheduling was develop an intelligent prioritization schedule became ever more important for the sake of efficiency and as many of the experienced engineers are retired from GDOT. If the pavement performance prediction model can be developed based on the past PACES data, the remaining service lives for pavements can be forecasted. This would be very useful for schedule for scheduling the rehabilitation and determining the funding level required to
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外文文献翻译Building anti-radar designThe widespread usage of electricity promoted to defend the development of thunder product and be a high pressure power grid to provide motive and illuminate for the thousand 10000, thunder and lightning also a great deal of bane high pressure lose to change to give or get an electric shock an equipments.The high pressure line installs Gao, be apart from long, cross geography complications, is strike by lightning easily medium.The protection scope shortage of the lightning rod with protect up to thousand power lines, so avoid thunder line as to protect high pressure line of new connect a Shan machine to emerge with the tide of the times.After the high pressure line acquire a protection, the hair linked with high pressure line, go together with electricity equipments to be still conduct electricity to press damage, people discover this is because"respond thunder" is play tricks.(Respond the thunder is to respond the metals conductor of neighborhood because of keeping shot thunder to turn on electricity in, respond the thunder can pass 2 kinds to differently respond way incursion conductor, one is an electrostatic induction:When the electric charge in thunder cloud accumulates to gather, neighborhood of the conductor will also respond up the contrary electric charge and be a thunder to turn on electricity, the electric charge in thunder cloud quickly releases, and the conductor Central plains come to is tie up by thunder cloud electric field of the static electricity will also follow conductor fluxion to look for to release passage, will become electricity pulse in the electric circuit. The widespread usage of electricity promoted to defend the development of thunder product and be a high pressure power grid to provide motive and illuminate for the thousand 10000, thunder and lightning also a great deal of bane high pressure lose to change to give or get an electric shock an equipments.First, the building anti-radar classifies the anti-radar building category which pointed out explicitly to the standard, may apply mechanically directly. In the standard to some buildings only pointed out that is bigger than estimate thunder stroke number of times XX/every year, but belongs to two kinds or three kind of anti-radar buildings. Regarding these stipulations, only depends on the direct-viewing feeling and the experience in the design, cannot determine explicitly its building respective anti-radar category, causes to make two kinds anti-radar to make three kinds by mistake, should make three kinds anti-radar, but has not done, the result is to the building which completes creates certain hidden danger. This has the necessity according to the local annual mean thunderstorm day and the building locus geography, the geological soil, the meteorological environment and so on conducts thedetailed research and makes the corresponding computation, determines the anti-radar rank.For example: Under Jinan area Td=26.3 K=2 environment according to formula: N=0.024k · Td1.3 · Ae in the formula: N- building estimate thunder stroke number of times (/year) The K- correction factor (according to newly built building locus's geography, environment decides) Td- annual mean thunderstorm day Ae- and the building truncation receives the same thunder stroke number of times equivalent area (km2)Calculates the length 100 meters, the width 25 meters, above two (H≥9 rice) the provincial level work building must make two kind of anti-radar. If through the computation, this kind of building actual does not make three kinds anti-radar or does not do is possible. From this sees, carries on the overall evaluation to some peculiar circumstance's building and makes the corresponding computation is very essential. the two, anti-radar electric inductions and the thunder electric waves invade the against long jab thunder the measure, the general layout personnel are very explicit. But, along with the technical development, electronic installation's popularization, the anti-radar electric induction and the thunder electric wave invasion must be clear in the design, and consummates gradually forms an anti-radar network. when the 1. thunder and lightning induces - the thunder discharge, has the electrostatic induction and the electromagnetic induction on the nearby conductor, it possibly causes between the metal part to produce the spark. Therefore is protected in building's metal earth, is the anti-radar electric induction key measure. First, completes the equipotential joint. To one, two kind of anti-radar buildings in parallel or overlapping placing metal pipeline, when its clear distance is smaller than 100mm, should use Jin Shuxian to bridge, is prevents the potential difference which the electromagnetic induction creates to be able the small gap breakdown, but produces the electric spark, every other ≤30m completes the earth. the 2. thunder electric wave invasion - as a result of the thunder and lightning to the air line either the metal pipeline's function, the thunder electric wave possibly along these pipeline invasion room, endangers the personal safety or damages the equipment. Therefore, completes the terminal the anti-radar protection, completes the equalizing ring and against flank attack thunder is the anti-radar electric wave invasion key measure. First, two kind of anti-radar construction low pressure coil in entire line uses buries straight said that is built on stilts the line introduces when the indoors many in a 15m section should trade the electric cable (metal armoring electric cable to bury straight, protective covering electric cable puts on steel pipe) the buyer, and is being built on stilts with the electric cable trades meets place completes the lightning protection protection. Two kind of anti-radar constructions work as the air line direct introduction, besides in the residence place addition arrester, and completes the buyer installment iron stock the earth, approaches on building's two telephone pole's iron stock alsoto complete the earth, and the impact earth resistance ≤30Ω, all weak electricity coil in's protection should with the strong electricity coil. The anti-radar building must complete the equalizing ring and against flank attack thunder protection. Equalizing ring from three starts, between link vertical range ≤12m, all downleads, building's metal structure and the hardware reliably connects with the link, the equalizing ring may use in the structure grid's steel bar (steel bar to link up ring circuit). A kind anti-radar constructs above 30m, two kinds anti-radar construct above 45m, three kinds anti-radar construct above 60m, must complete against flank attack thunder protection, makes one week level along the building outer wall to evade the mine belt, between the belt and the belt the vertical range ≤6m, in the outer wall all metal parapet, the windows and doors with evade the mine belt to connect reliably, evade the mine belt to connect reliably again with the downlead. The vertical placing's metal pipeline and the metal peak and the bottom end and the antimine device reliable connection, the goal lies in the equipotential, because and the both sides connection causes it to form the parallel with the downlead, causes the thunder electric current news fast to enter. three, anti-radar electric currents after downlead and when grounding has the high electric potential completes against long jab thunder, the thunder electric wave invasion and the thunder and lightning to the hardware or electrical line counter-attack measure induces, is not a complete anti-radar design. Because, in the building mostly uses together the grounding at present, when thunder long jab in this building antimine device, the supposition flows through approaches the low pressure electric installation place grounding the thunder electric current is 20KA, when impact earth resistance =1Ω, in the grounding the electric potential elevates is 20KV, but the general indoor low pressure installment bears the striking potential most to be high is 8KV. Its result causes the low pressure electric installation insulation to be weak place is possibly penetrated creates the short circuit, has the fire, to damage the equipment, this is very dangerous. Therefore, gives the enough value in the design, realizes omni-directionally, the multi-level anti-radar networks to the anti-radar building, causes the thunder and lightning the influence to reduce to the building is smallest.when building for high-pressured coil, high-pressured, the low pressure side each on supposes the arrester, with protects by the high-pressured coil in thunder and lightning and the operation (circuit breaker movement, throws cuts big electric motor and condenser bank and so on) the overvoltage. The electronic installation are many and the important construction, installs the overvoltage protection again in the low pressure power distribution branch, does for the reserve protection, mainly uses in further suppressing after the pretage protection limit on the surplus overvoltage and the power line the overvoltage which produces by the induction or the coupling.when building for low pressure coil, installs the overvoltage protector in the power source total coil in place. four, about meet dodges tomeet dodges - the direct truncation the lightning rod which is struck by lightning, to evade the mine belt (line), the lightning protection network, as well as serves as the metal roofing which and the steel work meets dodges and so on. In many buildings, the roofing for on person roofing, is high to the artistic request, according to the conventional procedure, clearly spreads the lightning protection network with the garden steel to do meets dodges is artistic on the influence, this standard to two kind of anti-radar buildings in two, three, eight, nine section of building pointed out that with in the reinforced concrete roofing, Liang, column's steel bar achievement meets suitably dodges, in the practical application, may use in the roofing parapet wall the capping steel bar to do meets dodges, is higher than the roofing each kind of iron stock to with the capping steel bar reliable welding (when construction must pay attention to coordination), the capping steel bar with makes in downlead's column four corner postsThe muscle completes the reliable electrical connection. This procedure must have the concretes fragment which regularly to the thunder stroke the possibility creates or withdraw carries on the service. five, earth body - bury in the soil or the concrete foundation does drifts with the conductor about earth body the . In the practical application, the big project uses in the foundation the steel bar to make the earth body generally, and uses the union earth body, the earth resistance value to request slightly ≤1Ω. But in some have the basement, in half basement construction, at the construction uses the waterproofing material to construct the ledger wall to make waterproof processing. At present, uses the waterproofing material has the very good insulating property, therefore, makes the earthed pole directly to this kind of building using the foundation steel bar, had the possibility not to be able to satisfy the project docking earth resistance request, must direct from the column muscle downlead place, one week made in the closed artificial earth body and the foundation along the building slope protection outside the steel bar and uses, like this could achieve the satisfactory earth resistance value.The intelligence mansion is generally and all a type of building, should build up comprehensive connect a ground of system, connect a ground of electric resistance to be no bigger than one Ω .Design in the building crest from avoid thunder to take, lightning rod or mixture constitute of connect a Shan machine, make use of steel pillar or sign the reinforcing bar in the pillar as to defend thunder to lead to log out, and and the foundation reinforcing bar of building, beam reinforcing bar, the metals frame conjunction gets up, become to shut to match good farad cage and construct inside the Shu toward the metals piping should each time all press of the 3 F and turn beam wreath connect with each other, all press wreath should with defend thunder device ad hoc lead to log out connect with each other.When building is more than 30 meters high, in response to 30 meters and the railing on above part ofoutside walls, the metals doors and windows wait a bigger metal direct or through metals doors and windows cover up an iron with defend thunder device a conjunction.The intelligence is various exchanges inside the mansion, the direct current equipments is numerous, the circuit maneuvers interleave, should exchanges work in the building ground, safe protection ground, direct current work ground, defend thunder to connect ground and the cage good conjunction of the building farad, become an etc. electric potential body, avoid connecting the existence potential difference of the of a ground of line, respond to conduct electricity reason of press the creation by cancellation.建筑物防雷设计当人们知道，雷电是一种电力的现象后，向崇拜的雷电与恐惧感逐渐消失，并开始与品味，科学来自新观察自然现象，这魔术，希望使使用或控制雷电活动，以造福人类.超过二百年以来几乎富兰克林为首的小康就技术开始挑战对雷电，他发明的避雷针可能被视为向在最早现阶段维护雷声大的产品和产品名称，今天这几乎由全体人民已知道.事实上，富兰克林发明避雷针是认为金属避雷针的角度谈谈对电力的功能，可合成电荷在积雨云，使积雨云和电场的地球一样低的水平，不能突破的空气中，避免罢工，因此，闪电发生时，当时的避雷针，必须要求尖利.但是事后研究阐述证明：闪电控制棒是发生不可避免的打雷的，因为它可以证明雷声大，是因为建筑物较高，是矗立在签署的避雷针改变了大气电场，使积雨云的一定范围内始终把对电力对闪电棒，也就是说，避雷针只是比它周围其他物体更容易连接山雷电，避雷针是罢工的闪电，但是它可以对其他物体加以保护，这是捍卫建筑物的一种方式，避雷针防雷更加深刻的研究表示，连接避雷针山的功能，几乎有一些建筑物不是很高，但没有形状，可说是避雷针不一定是雷声大，技术的境界，将会知道一起像现在这种类型的防雷装置。