土木建筑外文文献翻译中英文：地下建筑结构

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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。

土木工程钢筋混凝土结构中英文对照外文翻译文献

中英文翻译原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and the stress of steel bars will increase . When the steel approaches the yielding stress ƒy , the deflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃ when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large crosssections .As concrete has high modulus of elasticity, reinforced concrete structures are usually stiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures arecheaper. 1.37kn/m6m 200 400(a)plain concrete beam 9.31kn/m6m 200 400(b)Reinfoced concrete beam2φ16(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforced concrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressedconcrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid development and is subjected to revision according to new findings from research. In China, the design code undergoes major revision in about every fifteen years and with minor revision in between. This book is based on the latest current code in China “Code for Design of Concrete Structures”(GB50010-2002). The studentsmust keep in mind that this course can not give them the knowledge which is universally valid regardless of time and place, but the basic principles on which the current design method in the country is established.The desk calculator has made calculations to a high degree of precision possible and easy. Students must not forget that concrete is a man-made material and a 10% consistency in quality is remarkably good. Reinforcing bad=rs are rolled in factory, yet variation is=n strength may be as high as 5%. Besides, the position of bars in the formwork may deviate from their design positions. In fact two figure accuracy is adequate for almost all the cases, rather than carrying the calculations to meaningless precision. The time and effort of the designer are better spent to find out where the tension may occur to resist it by placing reinforcement there.中文译文：钢筋混凝土结构设计一、钢筋混凝土基本概念和特点混凝土是指由水泥胶凝的水、细致聚合体、粗聚合物（碎石或沙砾）、空气、以及其他混合物的坚硬混合物。

土木工程混凝土结构中英文对照外文翻译文献

中英文翻译Concrete structure reinforcement designAbstract：structure in the long-term natural environment and under the use environment's function, its function is weaken inevitably gradually, our structural engineering's duty not just must finish the building earlier period the project work, but must be able the science appraisal structure damage objective law and the degree, and adopts the effective method guarantee structure the security use, that the structure reinforcement will become an important work. What may foresee will be the 21st century, the human building also by the concrete structure, the steel structure, the bricking-up structure and so on primarily, the present stage I will think us in the structure reinforcement this aspect research should also take this as the main breakthrough direction.Key word：Concrete structure reinforcement bricking-up structure reinforcement steel structure reinforcement1 Concrete structure reinforcementConcrete structure's reinforcement divides into the directreinforcement and reinforces two kinds indirectly, when the design may act according to the actual condition and the operation requirements choice being suitable method and the necessary technology.1.1the direct reinforcement's general method1）Enlarges the section reinforcement lawAdds the concretes cast-in-place level in the reinforced concrete member in bending compression zone, may increase the section effective height, the expansion cross sectional area, thus enhances the component right section anti-curved, the oblique section anti-cuts ability and the section rigidity, plays the reinforcement reinforcement the role.In the suitable muscle scope, the concretes change curved the component right section supporting capacity increase along with the area of reinforcement and the intensity enhance. In the original component right section ratio of reinforcement not too high situation, increases the main reinforcement area to be possible to propose the plateau component right section anti-curved supporting capacity effectively. Is pulled in the section the area to add the cast-in-place concrete jacket to increase the component section, through new Canada partial and original component joint work, but enhances the componentsupporting capacity effectively, improvement normal operational performance.Enlarges the section reinforcement law construction craft simply, compatible, and has the mature design and the construction experience; Is suitable in Liang, the board, the column, the wall and the general structure concretes reinforcement; But scene construction's wet operating time is long, to produces has certain influence with the life, and after reinforcing the building clearance has certain reduction.2) Replacement concretes reinforcement lawThis law's merit with enlarges the method of sections to be close, and after reinforcing, does not affect building's clearance, but similar existence construction wet operating time long shortcoming; Is suitable somewhat low or has concretes carrier's and so on serious defect Liang, column in the compression zone concretes intensity reinforcement. 3) the caking outsourcing section reinforcement lawOutside the Baotou Steel Factory reinforcement is wraps in the section or the steel plate is reinforced component's outside, outside the Baotou Steel Factory reinforces reinforced concrete Liang to use the wet outsourcing law generally, namely uses the epoxy resinification to be in themilk and so on methods with to reinforce the section the construction commission to cake a whole, after the reinforcement component, because is pulled with the compressed steel cross sectional area large scale enhancement, therefore right section supporting capacity and section rigidity large scale enhancement.This law also said that the wet outside Baotou Steel Factory reinforcement law, the stress is reliable, the construction is simple, the scene work load is small, but is big with the steel quantity, and uses in above not suitably 600C in the non-protection's situation the high temperature place; Is suitable does not allow in the use obviously to increase the original component section size, but requests to sharpen its bearing capacity large scale the concrete structure reinforcement.4) Sticks the steel reinforcement lawOutside the reinforced concrete member in bending sticks the steel reinforcement is (right section is pulled in the component supporting capacity insufficient sector area, right section compression zone or oblique section) the superficial glue steel plate, like this may enhance is reinforcedcomponent's supporting capacity, and constructs conveniently.This law construction is fast, the scene not wet work or only has the plastering and so on few wet works, to producesis small with the life influence, and after reinforcing, is not remarkable to the original structure outward appearance and the original clearance affects, but the reinforcement effect is decided to a great extent by the gummy craft and the operational level; Is suitable in the withstanding static function, and isin the normal humidity environment to bend or the tension member reinforcement.5) Glue fibre reinforcement plastic reinforcement lawOutside pastes the textile fiber reinforcement is pastes with the cementing material the fibre reinforcement compound materials in is reinforced the component to pull the region, causes it with to reinforce the section joint work, achieves sharpens the component bearing capacity the goal. Besides has glues the steel plate similar merit, but also has anticorrosive muddy, bears moistly, does not increase the self-weight of structure nearly, durably, the maintenance cost low status merit, but needs special fire protection processing, is suitable in each kind of stress nature concrete structure component and the general construction.This law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.6) Reeling lawThis law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.7) Fang bolt anchor lawThis law is suitable in the concretes intensity rank is the C20~C60 concretes load-bearing member transformation, the reinforcement; It is not suitable for already the above structure which and the light quality structure makes decent seriously.1.2The indirect reinforcement's general method1)Pre-stressed reinforcement law(1)Thepre-stressed horizontal tension bar reinforces concretes member in bending,because the pre-stressed and increases the exterior load the combined action, in the tensionbar has the axial tension, this strength eccentric transmits on the component through the pole end anchor (, when tension bar and Liang board bottom surface close fitting, tension bar can look for tune together with component, this fashion has partial pressures to transmit directly for component bottom surface), has the eccentric compression function in the component, this function has overcome the bending moment which outside the part the load produces, reduced outside the load effect, thus sharpened component's anti-curved ability. At the same time, because the tension bar passes to component's pressure function, the component crack development can alleviate, the control, the oblique section anti-to cut the supporting capacity also along with it enhancement.As a result of the horizontal lifting stem's function, the original component's section stress characteristic by received bends turned the eccentric compression, therefore, after the reinforcement, component's supporting capacity was mainly decided in bends under the condition the original component's supporting capacity 。

土木工程高层建筑中英文对照外文翻译文献

中英文资料翻译1外文资料The Tall Office Building Artistically ConsideredThe architects of this land and generation are now brought face to face with something new under the sun namely, that evolution and integration of social conditions, that special grouping of them, that results in a demand for the erection of tall office buildings.It is not my purpose to discuss the social conditions; I accept them as the fact, and say at once that the design of the tall office building must be recognized and confronted at the outset as a problem to be solved a vital problem, pressing for a true solution.Let us state the conditions in the plainest manner. Briefly, they are these: offices are necessary for the transaction of business; the invention and perfection of the high speed elevators make vertical travel, that was once tedious and painful, now easy and comfortable; development of steel manufacture has shown the way to safe, rigid, economical constructions rising to a great height; continued growth of population in the great cities, consequent congestion of centers and rise in value of ground, stimulate an increase in number of stories; these successfully piled one upon another, react on ground values and so on, byaction and reaction, interaction and inter reaction. Thus has come about that form of lofty construction called the "modern office building". It has come in answer to a call, for in it a new grouping of social conditions has found a habitation and a name.Up to this point all in evidence is materialistic, an exhibition of force, of resolution, of brains in the keen sense of the word. It is the joint product of the speculator, the engineer, the builder.Problem: How shall we impart to this sterile pile, this crude, harsh, brutal agglomeration, this stark, staring exclamation of eternal strife, the graciousness of these higher forms of sensibility and culture that rest on the lower and fiercer passions? How shall we proclaim from the dizzy height of this strange, weird, modern housetop the peaceful evangel of sentiment, of beauty, the cult of a higher life?This is the problem; and we must seek the solution of it in a process analogous to its own evolution indeed, a continuation of it namely, by proceeding step by step from general to special aspects, from coarser to finer considerations.It is my belief that it is of the very essence of every problem that is contains and suggests its own solution. This I believe to be natural law. Let us examine, then, carefully the elements, let us search out this contained suggestion, this essence of the problem.The practical conditions are, broadly speaking, these:Wanted 1st, a story below ground, containing boiler, engines of various sorts, etc. in short, the plant for power, heating, lighting, etc. 2nd, a ground floor, so called, devoted to stores, banks, or other establishments requiring large area, ample spacing, ample light, and great freedom of access, 3rd, a second story readily accessible by stairways this space usually in large subdivisions, with corresponding liberality in structural spacing and expanse of glass and breadth of external openings, 4th, above this an indefinite number of stories of offices piled tier upon tier, one tier just like another tier, one office just like all the other offices an office being similar to a cell in honey comb, merely a compartment, nothing more, 5th, and last, at the top of this pile is placed a space or story that, as related to the life and usefulness of the structure, is purely physiological in its nature namely, the attic. In this the circulatory system completes itself and makes it grand turn, ascending and descending. The space is filled with tanks, pipes, valves, sheaves, and mechanical etcetera that supplement and complement the force originating plant hidden below ground in the cellar. Finally, or at the beginning rather, there must be on the ground floor a main aperture or entrance common to all the occupants or patrons of the building.This tabulation is, in the main, characteristic of every tall office building in the country. As to the necessary arrangements for light courts, these are not germane to the problem, and as will become soon evident, I trust need not be considered here. These things, and such others as the arrangement of elevators, for example, have to do strictly with the economics of the building, and I assumethem to have been fully considered and disposed of to the satisfaction of purely utilitarian and pecuniary demands. Only in rare instances does the plan or floor arrangement of the tall office building take on an aesthetic value, and thus usually when the lighting court is external or becomes an internal feature of great importance.As I am here seeking not for an individual or special solution, but for a true normal type, the attention must be confined to those conditions that, in the main, are constant in all tall office buildings, and every mere incidental and accidental variation eliminated from the consideration, as harmful to the clearness of the main inquiry.The practical horizontal and vertical division or office unit is naturally based on a room of comfortable area and height, and the size of this standard office room as naturally predetermines the standard structural unit, and, approximately, the size of window openings. In turn, these purely arbitrary units of structure form in an equally natural way the true basis of the artistic development of the exterior. Of course the structural spacings and openings in the first or mercantile story are required to be the largest of all; those in the second or quasi mercantile story are of a some what similar nature. The spacings and openings in the attic are of no importance whatsoever the windows have no actual value, for light may be taken from the top, and no recognition of a cellular division is necessary in the structural spacing.Hence it follow inevitably, and in the simplest possible way, that if wefollow our natural instincts without thought of books, rules, precedents, or any such educational impediments to a spontaneous and "sensible" result, we will in the following manner design the exterior of our tall office building to wit: Beginning with the first story, we give this a min entrance that attracts the eye to it location, and the remainder of the story we treat in a more or less liberal, expansive, sumptuous way a way based exactly on the practical necessities, but expressed with a sentiment of largeness and freedom. The second story we treat in a similar way, but usually with milder pretension. Above this, throughout the indefinite number of typical office tiers, we take our cue from the individual cell, which requires a window with its separating pier, its still and lintel, and we, without more ado, make them look all alike because they are all alike. This brings us to the attic, which having no division into office cells, and no special requirement for lighting, gives us the power to show by means of its broad expanse of wall, and its dominating weight and character, that which is the fact namely, that the series of office tiers has come definitely to an end.This may perhaps seem a bald result and a heartless, pessimistic way of stating it, but even so we certainly have advanced a most characteristic stage beyond the imagined sinister building of the speculator engineer builder combination. For the hand of the architect is now definitely felt in the decisive position at once taken, and the suggestion of a thoroughly sound, logical, coherent expression of the conditions is becoming apparent.When I say the hand of the architect, I do not mean necessarily theaccomplished and trained architect. I mean only a man with a strong, natural liking for buildings, and a disposition to shape them in what seems to his unaffected nature a direct and simple way. He will probably tread an innocent path from his problem to its solution, and therein he will show an enviable gift of logic. If we have some gift for form in detail, some feeling for form purely and simply as form, some love for that, his result in addition to it simple straightforward naturalness and completeness in general statement, will have something of temperament and interest.However, thus far the results are only partial and tentative at best relatively true, they are but superficial. We are doubtless right in our instinct but we must seek a fuller justification, a finer sanction, for it.I assume now that in the study of our problem we have passed through the various stages of inquiry, as follows: 1st, the social basis of the demand for tall buildings; 2nd, its literal material satisfaction; 3rd, the elevation of the question from considerations of literal planning, construction, and equipment, to the plane of elementary architecture as a direct outgrowth of sound, sensible building; 4th, the question again elevated from an elementary architecture to the beginnings of true architectural expression, through the addition of a certain quality and quantity of sentiment.But our building may have all these in a considerable degree and yet be far from that adequate solution of the problem I am attempting to define. We must now heed quality and quantity of sentiment.It demands of us, what is the chief characteristic of the tall office building? And at once we answer, it is lofty. This loftiness is to the artist nature its thrilling aspect. It is the very open organ tone in its appeal. It must be in turn the dominant chard in his expression of it, the true excitant of his imagination. It must be tall, every inch of it tall. The force and power of altitude must be in it, the glory and pride of exaltation must be in it. It must be every inch a proud and soaring thing, rising in sheer exultation that from bottom to top it is a unit without a single dissenting line that it is the new, the unexpected, the eloquent peroration of most bald, most sinister, most forbidding conditions.The man who designs in the spirit and with the sense of responsibility to the generation he lives in must be no coward, no denier, no bookworm, no dilettante. He must live of his life and for his life in the fullest, most consummate sense. He must realize at once and with the grasp of inspiration that the problem of the tall office building is one of the most stupendous, one of the most magnificent opportunities that the Lord of Nature in His beneficence has ever offered to the proud spirit of man.That this has not been perceived indeed has been flatly denied is an exhibition of human perversity that must give us pause.One more consideration. Let us now lift this question into the region of calm, philosophic observation. Let us seek a comprehensive, a final solution: let the problem indeed dissolve.Certain critics, and very thoughtful ones, have advanced the theory that thetrue prototype of the tall office building is the classical column, consisting of base, shaft and capital the molded base of the column typical of the lower stories of our building, the plain or fluted shaft suggesting the monotonous, uninterrupted series of office tiers, and the capital the completing power and luxuriance of the attic.Other theorizers, assuming a mystical symbolism as a guide, quite the many trinities in nature and art, and the beauty and conclusiveness of such trinity in unity. They aver the beauty of prime numbers, the mysticism of the number three, the beauty of all things that are in three parts to wit, the day, subdividing into morning, noon, and night; the limbs, the thorax, and the head, constituting the body. So they say, should the building be in three parts vertically, substantially as before, but for different motives.Others, of purely intellectual temperament, hold that such a design should be in the nature of a logical statement; it should have a beginning, a middle, and an ending, each clearly defined therefore again a building, as above, in three parts vertically.2中文翻译高层办公建筑艺术思考这个时代该领域的建筑师开始正视一些新的由于社会条件变革和整合以及它们特殊组合导致的对高层办公建筑的立面要求。

土木工程专业英语课文原文及对照翻译

土木工程专业英语课文原文及对照翻译Civil EngineeringCivil engineering, the oldest of the engineering specialties, is the planning, design, construction, and management of the built environment. This environment includes all structures built according to scientific principles, from irrigation and drainage systems to rocket-launching facilities.土木工程学作为最老的工程技术学科，是指规划，设计，施工及对建筑环境的管理。

此处的环境包括建筑符合科学规范的所有结构，从灌溉和排水系统到火箭发射设施。

Civil engineers build roads, bridges, tunnels, dams, harbors, power plants, water and sewage systems, hospitals, schools, mass transit, and other public facilities essential to modern society and large population concentrations. They also build privately owned facilities such as airports, railroads, pipelines, skyscrapers, and other large structures designed for industrial, commercial, or residential use. In addition, civil engineers plan, design, and build complete cities and towns, and more recently have been planning and designing space platforms to house self-contained communities.土木工程师建造道路，桥梁，管道，大坝，海港，发电厂，给排水系统，医院，学校，公共交通和其他现代社会和大量人口集中地区的基础公共设施。

土木工程英文文献及翻译

Civil engineeringCivil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like bridges, roads, canals, dams, and buildings.[1][2][3] Civil engineering is the oldest engineering discipline after military engineering,[4] and it was defined to distinguish non-military engineering from military engineering.[5] It is traditionally broken into several sub-disciplines including environmental engineering, geotechnical engineering, structural engineering, transportation engineering, municipal or urban engineering, water resources engineering, materials engineering, coastal engineering,[4] surveying, and construction engineering.[6] Civil engineering takes place on all levels: in the public sector from municipal through to national governments, and in the private sector from individual homeowners through to international companies.History of the civil engineering professionSee also: History of structural engineeringEngineering has been an aspect of life since the beginnings of human existence. The earliest practices of Civil engineering may have commenced between 4000 and 2000 BC in Ancient Egypt and Mesopotamia (Ancient Iraq) when humans started to abandon a nomadic existence, thus causing a need for the construction of shelter. During this time, transportation became increasingly important leading to the development of the wheel and sailing.Until modern times there was no clear distinction between civil engineering and architecture, and the term engineer and architect were mainly geographical variations referring to the same person, often used interchangeably.[7]The construction of Pyramids in Egypt (circa 2700-2500 BC) might be considered the first instances of large structure constructions. Other ancient historic civil engineering constructions include the Parthenon by Iktinos in Ancient Greece (447-438 BC), theAppian Way by Roman engineers (c. 312 BC), the Great Wall of China by General Meng T'ien under orders from Ch'in Emperor Shih Huang Ti (c. 220 BC)[6] and the stupas constructed in ancient Sri Lanka like the Jetavanaramaya and the extensive irrigation works in Anuradhapura. The Romans developed civil structures throughout their empire, including especially aqueducts, insulae, harbours, bridges, dams and roads.In the 18th century, the term civil engineering was coined to incorporate all things civilian as opposed to military engineering.[5]The first self-proclaimed civil engineer was John Smeaton who constructed the Eddystone Lighthouse.[4][6]In 1771 Smeaton and some of his colleagues formed the Smeatonian Society of Civil Engineers, a group of leaders of the profession who met informally over dinner. Though there was evidence of some technical meetings, it was little more than a social society.In 1818 the Institution of Civil Engineers was founded in London, and in 1820 the eminent engineer Thomas Telford became its first president. The institution received a Royal Charter in 1828, formally recognising civil engineering as a profession. Its charter defined civil engineering as:the art of directing the great sources of power in nature for the use and convenience of man, as the means of production and of traffic in states, both for external and internal trade, as applied in the construction of roads, bridges, aqueducts, canals, river navigation and docks for internal intercourse and exchange, and in the construction of ports, harbours, moles, breakwaters and lighthouses, and in the art of navigation by artificial power for the purposes of commerce, and in the construction and application of machinery, and in the drainage of cities and towns.[8] The first private college to teach Civil Engineering in the United States was Norwich University founded in 1819 by Captain Alden Partridge.[9] The first degree in Civil Engineering in the United States was awarded by Rensselaer Polytechnic Institute in 1835.[10] The first such degree to be awarded to a woman was granted by Cornell University to Nora Stanton Blatchin 1905.History of civil engineeringCivil engineering is the application of physical and scientific principles, and its history is intricately linked to advances in understanding of physics and mathematics throughout history. Because civil engineering is a wide ranging profession, including several separate specialized sub-disciplines, its history is linked to knowledge of structures, materials science, geography, geology, soils, hydrology, environment, mechanics and other fields.Throughout ancient and medieval history most architectural design and construction was carried out by artisans, such as stone masons and carpenters, rising to the role of master builder. Knowledge was retained in guilds and seldom supplanted by advances. Structures, roads and infrastructure that existed were repetitive, and increases in scale were incremental.[12]One of the earliest examples of a scientific approach to physical and mathematical problems applicable to civil engineering is the work of Archimedes in the 3rd century BC, including Archimedes Principle, which underpins our understanding of buoyancy, and practical solutions such as Archimedes' screw. Brahmagupta, an Indian mathematician, used arithmetic in the 7th century AD, based on Hindu-Arabic numerals, for excavation (volume) computations.[13]Civil engineers typically possess an academic degree with a major in civil engineering. The length of study for such a degree is usually three to five years and the completed degree is usually designated as a Bachelor of Engineering, though some universities designate the degree as a Bachelor of Science. The degree generally includes units covering physics, mathematics, project management, design and specific topics in civil engineering. Initially such topics cover most, if not all, of thesub-disciplines of civil engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.[14]While anUndergraduate (BEng/BSc) Degree will normally provide successful students with industry accredited qualification, some universities offer postgraduate engineering awards (MEng/MSc) which allow students to further specialize in their particular area of interest within engineering.[15]In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience and exam requirements) before being certified. Once certified, the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa), Chartered Engineer (in most Commonwealth countries), Chartered Professional Engineer (in Australia and New Zealand), or European Engineer (in much of the European Union). There are international engineering agreements between relevant professional bodies which are designed to allow engineers to practice across international borders.The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may prepare, sign and seal, and submit engineering plans and drawings to a public authority for approval, or seal engineering work for public and private clients.".[16]This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.[17]In other countries, no such legislation exists. In Australia, state licensing of engineers is limited to the state of Queensland. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.[18] In this way, these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, thecharge of criminal negligence.[citation needed] An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.CareersThere is no one typical career path for civil engineers. Most people who graduate with civil engineering degrees start with jobs that require a low level of responsibility, and as the new engineers prove their competence, they are trusted with tasks that have larger consequences and require a higher level of responsibility. However, within each branch of civil engineering career path options vary. In some fields and firms, entry-level engineers are put to work primarily monitoring construction in the field, serving as the "eyes and ears" of senior design engineers; while in other areas, entry-level engineers perform the more routine tasks of analysis or design and interpretation. Experienced engineers generally do more complex analysis or design work, or management of more complex design projects, or management of other engineers, or into specialized consulting, including forensic engineering.In general, civil engineering is concerned with the overall interface of human created fixed projects with the greater world. General civil engineers work closely with surveyors and specialized civil engineers to fit and serve fixed projects within their given site, community and terrain by designing grading, drainage, pavement, water supply, sewer service, electric and communications supply, and land divisions. General engineers spend much of their time visiting project sites, developing community consensus, and preparing construction plans. General civil engineering is also referred to as site engineering, a branch of civil engineering that primarily focuses on converting a tract of land from one usage to another. Civil engineers typically apply the principles of geotechnical engineering, structural engineering, environmental engineering, transportation engineering and construction engineering toresidential, commercial, industrial and public works projects of all sizes and levels of construction翻译：土木工程土木工程是一个专业的工程学科，包括设计，施工和维护与环境的改造，涉及了像桥梁，道路，河渠，堤坝和建筑物工程交易土木工程是最古老的军事工程后，工程学科，它被定义为区分军事工程非军事工程的学科它传统分解成若干子学科包括环境工程，岩土工程，结构工程，交通工程，市或城市工程，水资源工程，材料工程，海岸工程，勘测和施工工程等土木工程的范围涉及所有层次：从市政府到国家，从私人部门到国际公司。

土木类外文翻译建筑的组成(译文和英文)

中文3295字Components of A Building and Tall Buildings1. AbstractMaterials and structural forms are combined to make up the various parts of a building, including the load-carrying frame, skin, floors, and partitions. The building also has mechanical and electrical systems, such as elevators, heating and cooling systems, and lighting systems. The superstructure is that part of a building above ground, and the substructure and foundation is that part of a building below ground.The skyscraper owes its existence to two developments of the 19th century: steel skeleton construction and the passenger elevator. Steel as a construction material dates from the introduction of the Bessemer converter in 1885.Gustave Eiffel (1832-1932) introduced steel construction in France. His designs for the Galerie des Machines and the Tower for the Paris Exposition of 1889 expressed the lightness of the steel framework. The Eiffel Tower, 984 feet (300 meters) high, was the tallest structure built by man and was not surpassed u ntil 40 years later by a series of American skyscrapers.Elisha Otis installed the first elevator in a department store in New York in 1857.In 1889, Eiffel installed the first elevators on a grand scale in the Eiffel Tower, whose hydraulic elevators could transport 2,350 passengers to the summit every hour.2. Load-Carrying FrameUntil the late 19th century, the exterior walls of a building were used as bearing walls to support the floors. This construction is essentially a post and lintel type, and it is still used in frame construction for houses. Bearing-wall construction limited the height of building because of the enormous wall thickness required；for instance, the 16-story Monadnock Building built in the 1880’s in Chicago had walls 5 feet (1.5 meters) thick at the lower floors. In 1883, William Le Baron Jenney (1832-1907) supported floors on cast-iron columns to form a cage-like construction. Skeleton construction, consisting of steel beams and columns, was first used in 1889. As a consequence of skelet on construction, the enclosing walls become a “curtain wall” rather than serving a supporting function. Masonry was the curtain wall material until the 1930’s, when light metal and glass curtainwalls were used. After the introduction of buildings continued to increase rapidly.All tall buildings were built with a skeleton of steel until World War Ⅱ. After the war, the shortage of steel and the improved quality of concrete led to tall building being built of reinforced concrete. Marina Tower (1962) in Chicago is the tallest concrete building in the United States；its height—588 feet (179 meters)—is exceeded by the 650-foot (198-meter) Post Office Tower in London and by other towers.A change in attitude about skyscraper construction has brought a return to the use of the bearing wall. In New York City, the Columbia Broadcasting System Building, designed by Eero Saarinen in 1962,has a perimeter wall consisting of 5-foot (1.5meter) wide concrete columns spaced 10 feet (3 meters) from column center to center. This perimeter wall, in effect, constitutes a bearing wall. One reason for this trend is that stiffness against the action of wind can be economically obtained by using the walls of the building as a tube；the World Trade Center building is another example of this tube approach. In contrast, rigid frames or vertical trusses are usually provided to give lateral stability.3. SkinThe skin of a building consists of both transparent elements (windows) and opaque elements (walls). Windows are traditionally glass, although plastics are being used, especially in schools where breakage creates a maintenance problem. The wall elements, which are used to cover the structure and are supported by it, are built of a variety of materials: brick, precast concrete, stone, opaque glass, plastics, steel, and aluminum. Wood is used mainly in house construction；it is not generally used for commercial, industrial, or public building because of the fire hazard.4. FloorsThe construction of the floors in a building depends on the basic structural frame that is used. In steel skeleton construction, floors are either slabs of concrete resting on steel beams or a deck consisting of corrugated steel with a concrete topping. In concrete construction, the floors are either slabs of concrete on concrete beams or a series of closely spaced concrete beams (ribs) in two directions topped with a thin concrete slab, giving the appearance of a waffle on its underside. The kind of floor that is used depends on the span between supporting columns or walls and the function of the space. In an apartment building, for instance, where walls and columns are spaced at 12 to 18 feet (3.7 to 5.5 meters), the most popular construction is a solid concrete slab with no beams. The underside of the slab serves as the ceiling for the space below it. Corrugated steel decks are often used in office buildings because the corrugations, when enclosed by another sheet of metal, form ducts for telephone and electrical lines.5. Mechanical and Electrical SystemsA modern building not only contains the space for which it is intended (office, classroom, apartment) but also contains ancillary space for mechanical and electrical systems that help toprovide a comfortable environment. These ancillary spaces in a skyscraper office building may constitute 25% of the total building area. The importance of heating, ventilating, electrical, and plumbing systems in an office building is shown by the fact that 40% of the construction budget is allocated to them. Because of the increased use of sealed building with windows that cannot be opened, elaborate mechanical systems are provided for ventilation and air conditioning. Ducts and pipes carry fresh air from central fan rooms and air conditioning machinery. The ceiling, which is suspended below the upper floor construction, conceals the ductwork and contains the lighting units. Electrical wiring for power and for telephone communication may also be located in this ceiling space or may be buried in the floor construction in pipes or co nduits.There have been attempts to incorporate the mechanical and electrical systems into the architecture of building by frankly expressing them；for example, the American Republic Insurance Company Building(1965) in Des Moines, Iowa, exposes both the ducts and the floor structure in an organized and elegant pattern and dispenses with the suspended ceiling. This type of approach makes it possible to reduce the cost of the building and permits innovations, such as in the span of the structure.6. Soils and FoundationsAll building are supported on the ground, and therefore the nature of the soil becomes an extremely important consideration in the design of any building. The design of a foundation depends on many soil factors, such as type of soil, soil stratification, thickness of soil lavers and their compaction, and groundwater conditions. Soils rarely have a single composition；they generally are mixtures in layers of varying thickness. For evaluation, soils are graded according to particle size, which increases from silt to clay to sand to gravel to rock. In general, the larger particle soils will support heavier loads than the smaller ones. The hardest rock can support loads up to 100 tons per square foot(976.5 metric tons/sq meter), but the softest silt can support a load of only 0.25 ton per square foot(2.44 metric tons/sq meter). All soils beneath the surface are in a state of compaction；that is, they are under a pressure that is equal to the weight of the soil column above it. Many soils (except for most sands and gavels) exhibit elastic properties—they deform when compressed under load and rebound when the load is removed. The elasticity of soils is often time-dependent, that is, deformations of the soil occur over a length of time which may vary fr om minutes to years after a load is imposed. Over a period of time, a building may settle if it imposes a load on the soil greater than the natural compaction weight of the soil. Conversely, a building may heave if it imposes loads on the soil smaller than the natural compaction weight. The soil may also flow under the weight of a building；that is, it tends to be squeezed out.Due to both the compaction and flow effects, buildings tend settle. Uneven settlements, exemplified by the leaning towers in Pisa and Bologna, can have damaging effects—the building may lean, walls and partitions may crack, windows and doors may become inoperative, and, in theextreme, a building may collapse. Uniform settlements are not so serious, although extreme conditions, such as those in Mexico City, can have serious consequences. Over the past 100 years, a change in the groundwater level there has caused some buildings to settle more than 10 feet (3 meters). Because such movements can occur during and after construction, carefu l analysis of the behavior of soils under a building is vital.The great variability of soils has led to a variety of solutions to the foundation problem. Where firm soil exists close to the surface, the simplest solution is to rest columns on a small sla b of concrete(spread footing). Where the soil is softer, it is necessary to spread the column load over a greater area；in this case, a continuous slab of concrete(raft or mat) under the whole building is used. In cases where the soil near the surface is unable to support the weight of the building, piles of wood, steel, or concrete are driven down to firm soil.The construction of a building proceeds naturally from the foundation up to the superstructure. The design process, however, proceeds from the roof down to the foundation (in the direction of gravity). In the past, the foundation was not subject to systematic investigation. A scientific approach to the design of foundations has been developed in the 20th century. Karl Terzaghi of the United States pioneered studies that made it possible to make accurate predictions of the behavior of foundations, using the science of soil mechanics coupled with exploration and testing procedures. Foundation failures of the past, such as the classical example of the le aning tower in Pisa, have become almost nonexistent. Foundations still are a hidden but costly part of many buildings.Although there have been many advancements in building construction technology in general, spectacular achievements have been made in the design and construction of ultrahigh-rise buildings.The early development of high-rise buildings began with structural steel framing. Reinforced concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes. The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structural systems.Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit. Excessive lateral sway may cause serious recurring damage to partitions, ceilings, and other architectural details. In additi on, excessive sway may cause discomfort to the occupants of the building because of their perception of such motion. Structural systems of reinforced concrete, as well as steel, take full advantage of the inherent potential stiffness of the total building and therefore do not require additional stiffening to limit the sway.In a steel structure, for example, the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building. Curve A in Fig.1 represents t he average unit weight of a conventional frame with increasing numbers of stories. Curve B represents theaverage steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame. Structural engineers have developed structural systems with a view to eliminating this premium.7. Tube in tubeAnother system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system (Fig.2), known as the tube-in-tube system, made it possible to design the world’s present tallest (714 ft or 218 m) lightweight concrete building (the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.Systems combining both concrete and steel have also been developed, an example of which is the composite system developed by Skidmore, Owings & Merrill in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The story One Shell Square Building in New Orleans is based on this system.建筑的组成部分1 摘要材料和结构类型是构成建筑物各方面的组成部分，包括承重结构、围护结构、楼地面和隔墙。

土木工程专业Reinforced-Concrete钢筋混凝土大学毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土文献、资料英文题目：Reinforced Concrete文献、资料来源： __________________________ 文献、资料发表（出版）日期： _____________________ 院（部）:专业：_________________________________________ 班级：_________________________________________ 姓名：_________________________________________ 学号：_________________________________________ 指导教师：翻译日期：2017.02.14外文文献翻译Reinforced ConcreteCon crete and rein forced con crete are used as build ing materials in every coun try. In many, in clud ing the Un ited States and Can ada, rein forced con crete is a dominant structural material in engin eered con structi on.The uni versal n ature of rein forced con crete con structi on stems from the wide availability of rei nforci ng bars and the con stitue nts of con crete, gravel, sand, and cement, the relatively simple skills required in con crete con structi on, and the economy of rein forced con crete compared to other forms of con structi on. Con crete and rein forced con crete are used in bridges, build ings of all sorts un dergro und structures, water tan ks, televisi on towers, offshore oil explorati on and product ion structures, dams, and eve n in ships.Rein forced con crete structures may be cast-i n-place con crete, con structed in their fin al locatio n, or they may be precast con crete produced in a factory and erected at the con structi on site. Con crete structures maybe severe and functional in design, or the shape and layout and be whimsical and artistic. Few other buildi ng materials off the architect and engin eer such versatility and scope.Con crete is stro ng in compressi on but weak in tension. As a result, cracks develop whe never loads, or restrai ned shri nkage of temperature changes, give rise to tensile stresses in excess of the tensile strengthof the con crete. In a pla in con crete beam, the mome nts about the n eutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beamfails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the con crete in such a way that the tension forces n eeded for mome nt equilibrium after the con crete cracks can be developed in the bars.The con structi on of a rein forced con crete member invo Ives build ing a from of mold in the shape of the member being built. The form must be strong eno ugh to support both the weight and hydrostatic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies,wind, and so on. The reinforcement is placed in this form and held in place duri ng the con cret ing operati on. After the con crete has harde ned, the forms are removed. As the forms are removed, props of shores are in stalled to support the weight of the con crete un til it has reached sufficie nt stre ngth to support the loadsby itself.The designer must proportion a concrete memberfor adequate strengthto resist the loads and adequate stiffness to prevent excessive deflecti ons. In beam must be proporti oned sothat it can be con structed.For example, the reinforcement must be detailed so that it can beassembled in the field, and since the con crete is placed in the form after the rei nforceme nt is inplace, the con crete must be ableto flow around,between, andpast the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions.The choice of structural system is made by thearchitect of engineer early in the design, based on the followingcon siderati ons:1. Economy. Freque ntly, the foremost con sideratio n is the overall const of the structure. This is, of course, a fun cti on of the costs ofthe materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall con structi on time since the con tractor and owner must borrow or otherwise allocate money to carry out the con struct ion and will not receive a retur n on this investment until the building is ready for occupancy. In a typical large apartme nt of commercial project, the cost of con struct ion financing willbe a significant fraction of the total cost. As a result, financial savings due to rapid con structi on may more tha n offset in creased material costs. For this reas on, any measures the desig ner can take to sta ndardize the desig n and forming will gen erally pay off in reduced overall costs.In many cases the Ion g-term economy of the structure may be more importa nt tha n the first cost. As a result, maintenance and durability are importa nt con siderati on.2. Suitability of material for architectural and structural function.A rein forced con crete system freque ntly allows the desig ner to comb ine the architectural and structural functions. Con crete has the adva ntage that it is placed in a plastic con diti on and is give n the desired shapeand texture by meansof the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearingelements while providing the finished floor and / or ceiling surfaces. Similarly, rein forced con crete walls can providearchitecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Fin ally, the choice of size of shape is governed by the designer and not by the availability of standard manu factured members.3. Fire resista nee. The structure in a buildi ng must withsta nd theeffects of a fire and rema in sta nding while the build ing is evacuated and the fire is exti nguished. A con crete buildi ng in here ntly has a 1- to 3-hour fire rat ing without special fireproofi ng or other details. Structural steel or timber build ings must be fireproofed to atta in similar fire ratin gs.4. Low maintenan ce. Con crete members in here ntly require less maintenance than do structural steel or timber members. This is particularly true if den se, air-e ntrained con crete has bee n used forsurfaces exposed to the atmosphere, and if care has bee n take n in the desig n to provide adequate drain age off and away from the structure. Special precauti ons must be take n for con crete exposed to salts such as deici ng chemicals.5. Availability of materials. Sand, gravel, ceme nt, and con cretemixi ng facilities are very widely available, and rein forci ng steel canbe tran sported to most job sites more easily tha n can structural steel. As a result, re in forced con crete is freque ntly used in remote areas.On the other hand, there are a nu mber of factors that may cause one to selecta material other tha n rein forced con crete. These in clude:1. Low tensile strength. The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to crack ing. In structural uses this is overcome by using rei nforceme nt to carry ten sile forces and limit crack widths to with in acceptable values. Un less care is take n in desig n and con struct ion, however, these cracks maybe unsightly or mayallow penetration of water. Wherthis occurs, water or chemicals such as road deicing salts may cause deterioration or stai ning of the con crete. Special desig n details are required in such cases. In the case of water-retai ning structures, special details and /of prestress ing are required to preve nt leakage.2. Forms and shori ng. The con structi on of a cast-i n-place structureinvo Ives three steps not encoun tered in the con struct ion of steel or timberstructures. These are ( a ) the con struct ion of the forms, ( b ) the removal of these forms, and (c) propp ing or shori ng the new con crete to support its weight until itsstrength is adequate. Each of these steps invoIves labor and / or materials, which are not necessary with other forms of con structi on.3. Relatively low strength per unit of weight for volume. Thecompressive strength of concrete is roughly 5 to 10%that of steel, while its unit den sity is roughly 30% that of steel. As a result, a con cretestructure requires a larger volume and a greater weight of material than does acomparable steel structure. As a result, Iong-span structures are ofte n built from steel.4. Time-depe ndent volume cha nges. Both con crete and steelundergo-approximately the same amount of thermal expansionandcon tracti on. Because there is less mass of steel to be heated or cooled, andbecause steel is a better con crete, a steel structure is gen erallyaffected by temperature cha nges to a greater exte nt tha n is a con crete structure.On the other hand, con crete un dergoes fryi ng shri nkage, which, if restrained, may cause deflections or cracking. Furthermore, deflecti ons will tend to in crease with time, possibly doubli ng, due to creep of the con crete un der susta ined loads.In almost every branch of civil extensiveuse is made of reinforced foundations.Engineers and architects reinforced con crete desig n throughout theirprofessi onal careers. Muchof this text is directly concerned with the behavior and proporti oningof components that makeup typical reinforced concrete structures-beams, colu mns, and slabs. Once the behavior of these in dividual eleme nts is un derstood, the desig ner will have the backgro und to an alyze and desig n a wide range of complex structures, such as foun datio ns, buildi ngs, and bridges, composed of these eleme nts.Si nee rei nforced concrete is a no homogeneous material that creeps, shri nks,and cracks, its stresses cannot be accurately predicted by the traditi onal equati ons derived in a course in stre ngth of materials forhomoge neous elastic materials. Much of rein forced con crete desig n in thereforeempirical, i.e., design equations and design methods are based on experime ntal and engineering and architecture con crete for structures and requires basic knowledge oftime-proved results in stead of being derived exclusively from theoretical formulati ons.A thorough un dersta nding of the behavior of rein forced con crete will allow the desig ner to con vert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete ' s desirable characteristics, its high compressive stre ngth, its fire resista nee, and its durability.Concrete, a stone like material, is madeby mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives (that modify properties ) into a workable mixture. In its un harde ned or plastic state, concrete can be placed in forms to produce a large variety of structural eleme nts. Although the harde ned con crete by itself, i.e., without any rein forceme nt, is stro ng in compressi on, it lacks ten sile stre ngth and therefore cracks easily. Because unrein forced con crete is brittle, it cannot undergo large deformations under load and fails sudde nly-without warni ng. The additi on fo steel rein forceme nt to the con crete reduces the n egative effects of its two prin cipal in here nt weaknesses, its susceptibility to cracking and its brittleness. Whenthe rein forceme nt is stro ngly bon ded to the con crete, a strong, stiff, and ductile con struct ion material is produced. This material, calledrei nforced con crete, is used exte nsively to con struct foun dati ons,structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Twoother characteristics of concrete that are present even when concrete is rein forced are shri nkage and creep, but the n egative effects of these properties can be mitigated by careful desig n.A code is a set tech ni cal specificati ons and sta ndards that con trol importa nt details of desig n and con struct ion. The purpose of codes it produce structures so that the public will be protected from poor of in adequate and con struct ion.Two types f coeds exist. One type, called a structural code, is orig in ated and con trolled by specialists whoare concerned with the proper use of a specific material or who are invo Ived with the safe desig n of a particular class of structures.The sec ond type of code, called a build ing code, is established to cover con struct ion in a give n region, ofte n a city or a state. The objective of a build ing code is also to protect the public by acco un ti ng for the in flue nee of the local en vir onmen tal con diti ons on con structi on. For example, local authorities may specifyadditional provisions toaccount for such regional conditions as earthquake, heavy snow, ortorn ados. Nati onal structural codes gen rally are in corporated into local build ing codes.The America n Con crete In stitute ( ACI ) Buildi ng Code coveri ng the desig n of rein forced con crete build in gs. It contains provisi ons coveri ngall aspects of re in forced con crete manu facture, desig n, and con structi on. It includes specifications on quality of materials, details on mixing andplacing concrete, design assumptions for the analysis of continuous structures, and equati ons for proporti oning members for desig n forces.All structures must be proporti oned so they will not fail or deform excessively un der any possible con diti on of service. Therefore it is important that an engineer use great care in anticipating all the probable loads to which a structure will be subjected duri ng its lifetime.Although the desig n of most members is con trolled typically by dead and live load acting simultaneously, consideration must also be given tothe forces produced by wind, impact, shrinkage, temperature change, creep and support settleme nts, earthquake, and so forth.The load associated with the weight of the structure itself and its perma nent comp onents is called the dead load. The dead load of con crete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately un til members have bee n sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the memberssized, and architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initial estimate of its value ( or slightly less ), the design is complete,but if a significant differenee exists between the computed and estimated values of dead weight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly importa nt whe n spa ns are long, say over 75 ft ( 22.9 m ),because dead load con stitutes a major porti on of the desig n load.Live loads associated with building use are specific items of equipme nt and occupa nts in a certa in area of a build ing, buildi ng codes specify values of un iform live for which members are to be desig ned.After the structure has bee n sized for vertical load, it is checkedfor wi nd in comb in ati on with dead and live load as specified in the code. Windloads do not usually con trol the size of members in buildi ng lessthan 16 to 18 stories, but for tall buildings wind loads becomesignificant and cause large forces to develop in the structures. Under these conditions economycan be achieved only by selecting a structural system that is able to tran sfer horiz on tal loads into the ground efficie ntly.钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。

土木工程专业英语课文_翻译_考试必备

土木工程专业英语课文_翻译_考试必备土木工程专业英语课文翻译The principal construction materials of earlier times were wood and masonry brick, stone, or tile, and similar materials. The courses or layers were bound together with mortar or bitumen, a tar like substance, or some other binding agent. The Greeks and Romanssometimes used iron rods or claps to strengthen their building. The columns of the Parthenon in Athens, for example, have holes drilled in them for iron bars that have now rusted away. The Romans also used a natural cement called puzzling, made from volcanic ash, that became as hard as stone under water.早期时代的主要施工材料，木材和砌体砖，石，或瓷砖，和类似的材料。

这些课程或层密切联系在一起，用砂浆或沥青，焦油一个样物质，或其他一些有约束力的代理人。

希腊人和罗马人有时用铁棍或拍手以加强其建设。

在雅典的帕台农神庙列，例如，在他们的铁钻的酒吧现在已经生锈了孔。

罗马人还使用了天然水泥称为令人费解的，由火山灰制成，变得像石头一样坚硬在水中。

Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. Steel, basically an alloy of iron and a small amount of carbon had been made up to that time by a laborious process that restricted it to such special uses as sword blades. After the invention of the Bessemer process in 1856, steel was available in large quantities at low prices. The enormous advantage of steel is its tensile force which, as we have seen,tends to pull apart many materials. New alloys have further, which is a tendency for it to weaken as a result of continual changes in stress.钢铁和水泥，两个最重要的现代建筑材料，介绍了在十九世纪。

土木工程建筑外文翻译外文文献英文文献钢筋混凝土及土方工程简介[策划]

土木工程建筑外文翻译外文文献英文文献钢筋混凝土及土方工程简介[策划]2 外文翻译Introduction to reinforced concrete and earthworks:Abstract As a designer must first clear the building structureitself was designed and intensity levels, as well as related issues in-depth discussion and research, this paper describes on the reinforced concrete, earthwork engineering knowledge, let more in-depth understanding of this Discusses the key, and the rational application of knowledge to help us design more excellent buildingKeywords: concrete, earthwork, structural safety2.1 Reinforced ConcretePlain concrete is formed from a hardened mixture ofcement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections hasto be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible becauseconcrete can easily be given any desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned, the finished product becomes strong, durable, and, in combination with the reinforcing bars, adaptable for use as main members of any structural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean, a wall, a slab, a foundation. a mass columns, or an extension of previously placed and hardened concrete. For beams, columns, and walls, the forms should be well oiled after cleaning them, and the reinforcement should be cleared of rust and other harmful materials. In foundations, the earth should be compacted and thoroughly moistened to about 6 in. in depth to avoid absorption of the moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type, as the case requires, unless it is placed by pumping.It must be kept in mind, however, that over vibration can be harmful since it could causesegregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures above 50?F. It is necessary to maintain such a condition in order that the chemical hydration reaction can take place. If drying is too rapid, surface cracking takes place. This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydration.It is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element, such as geometrical width, depth, area of reinforcement, steel strain, concrete strain,steel stress, and so on. Consequently, trial and adjustment is necessary in the choice of concrete sections, with assumptions based on conditions at site, availability of the constituent materials, particular demands of the owners, architectural and headroom requirements, the applicable codes, and environmental reinforced concrete is often a site-constructed composite, in contrast to the standard mill-fabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive at the required section, the first design input step generates intoa series of trial-and-adjustment analyses.The trial-and –adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design. Hence every design is an analysis once a trial section is chosen. The availability of handbooks, charts, and personal computers and programs supports this approach as a more efficient, compact, and speedy instructional method compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design.2.2 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering, this is a field where there are real opportunities for the enthusiast. In 1935 most of the methods now in use for carrying and excavating earth with rubber-tyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab, though they are still widely used are only a few of the many current methods. To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines. Generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmoving means cutting into ground where itssurface is too high ( cuts ), and dumping the earth in other places where the surface is too low ( fills). Toreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts andwherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness. From the available maps ahd levels, the engineering must tryto reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork. On the site when further information becomes available he can make changes in jis sections and layout,but the drawing lffice work will not have been lost. It will have helped him to reach the best solution in the shortest time.The cheapest way of moving earth is to take it directly out of thecut and drop it as fill with the same machine. This is not always possible, but when it canbe done it is ideal, being both quick and cheap. Draglines, bulldozers and face shovels an dothis. The largest radius is obtained with the dragline,and thelargest tonnage of earth is moved by the bulldozer, though only overshort distances.The disadvantages of the dragline are that it must dig below itself, it cannot dig with force into compacted material, itcannot dig on steep slopws, and its dumping and digging are not accurate.Face shovels are between bulldozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anleto dig into a vertical cliff face in a way which would be dangerous tora bulldozer operator and impossible for a dragline. Each piece of equipment should be level of their tracks and for deep digs in compactmaterial a backacter is most useful, but its dumping radius is considerably less than that of the same escavator fitted with a face shovel.Rubber-tyred bowl scrapers are indispensable for fairly leveldigging where the distance of transport is too much tor a dragline or face shovel. They can dig the material deeply ( but only below themselves ) to a fairly flat surface, carry it hundreds of meters if need be, then drop it and level it roughly during the dumping. For hard digging it is often found economical to keep a pusher tractor ( wheeled or tracked ) on the digging site, to push each scraper as it returns to dig. As soon as the scraper is full,the pusher tractor returns to the beginning of the dig to heop to help the nest scraper.Bowl scrapers are often extremely powerful machines;many makersbuild scrapers of 8 cubic meters struck capacity, which carry 10 m ? heaped. The largest self-propelled scrapers are of 19 m ? struck capacity ( 25 m ? heaped )and they are driven by a tractor engine of 430 horse-powers.Dumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials. Dumpers have the earth container over the front axle on large rubber-tyred wheels, and the container tips forwards on most types, though in articulated dumpers the direction of tip can be widely varied. The smallest dumpers have a capacity of about 0.5 m ?, and the largest standard types are of about 4.5 m ?. Special types include the self-loading dumper of up to 4 m ? and the articulated type of about 0.5 m ?. The distinction between dumpers and dump trucks must beremembered .dumpers tip forwards and the driver sits behind the load. Dump trucks are heavy,strengthened tipping lorries, the driver travels in front lf theload and the load is dumped behind him, so they are sometimes called rear-dump trucks.2.3 Safety of StructuresThe principal scope of specifications is to provide generalprinciples and computational methods in order to verify safety of structures. The “ safety factor ”, which according to modern trends is independent of the nature and combination of the materials used, can usually be defined as the ratio between the conditions. This ratio is also proportional to the inverse of the probability ( risk ) of failure of the structure.Failure has to be considered not only as overall collapse of the structure but also as unserviceability or, according to a more precise. Common definition. As the reaching of a “ limit state ” which causes the construction not to accomplish the task it was designed for. There are two categories of limit state :(1)Ultimate limit sate, which corresponds to the highest value ofthe load-bearing capacity. Examples include local buckling or global instability of the structure; failure of some sections and subsequent transformation of the structure into a mechanism; failure by fatigue;elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure; and sensitivity of the structure to alternating loads, to fire and to explosions.(2)Service limit states, which are functions of the use anddurability of the structure. Examples include excessive deformations and displacements without instability; early or excessive cracks; large vibrations; and corrosion.Computational methods used to verify structures with respect to the different safety conditions can be separated into:(1)Deterministic methods, in which the main parameters are considered as nonrandom parameters.(2)Probabilistic methods, in which the main parameters are considered as random parameters.Alternatively, with respect to the different use of factors of safety, computational methods can be separated into:(1)Allowable stress method, in which the stresses computed under maximumloads are compared with the strength of the material reduced bygiven safety factors.(2)Limit states method, in which the structure may be proportionedon the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ).The stresses corresponding to working ( service ) conditions with unfactored live and dead loads are compared with prescribed values( service limit state ) . From the four possible combinations of thefirst two and second two methods, we can obtain some usefulcomputational methods. Generally, two combinations prevail:(1)deterministic methods, which make use of allowable stresses.(2)Probabilistic methods, which make use of limit states.The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then combined to define the safety factor. probabilistic approaches depend upon :(1) Random distribution of strength of materials with respect to the conditions of fabrication and erection ( scatter of the values of mechanical properties through out the structure );(2) Uncertainty of the geometry of the cross-section sand of the structure ( faults and imperfections due to fabrication and erection of the structure );(3) Uncertainty of the predicted live loads and dead loads acting on the structure;(4)Uncertainty related to the approximation of the computational method used ( deviation of the actual stresses from computed stresses ).Furthermore, probabilistic theories mean that the allowable risk can be based on several factors, such as :(1) Importance of the construction and gravity of the damage by its failure;(2)Number of human lives which can be threatened by this failure;(3)Possibility and/or likelihood of repairing the structure;(4) Predicted life of the structure.All these factors are related to economic and social considerations such as:(1) Initial cost of the construction;(2) Amortization funds for the duration of the construction;(3) Cost of physical and material damage due to the failure of the construction;(4) Adverse impact on society;(5) Moral and psychological views.The definition of all these parameters, for a given safety factor, allows construction at the optimum cost. However, the difficulty of carrying out a complete probabilistic analysis has to be taken into account. For such an analysis the laws of the distribution of the live load and its induced stresses, of the scatter of mechanical properties of materials, and of the geometry of the cross-sections and the structure have to be known. Furthermore, it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material, on the cross-sections and upon the load acting on the structure. These practical difficulties can be overcome in two ways. The first is toapply different safety factors to the material and to the loads, without necessarily adopting the probabilistic criterion. The second is an approximate probabilistic method which introduces some simplifying assumptions ( semi-probabilistic methods ) .References:1. Hanjing Yun. Building decoration materials and their application. China Building Industry Press .2000.2. Xia Yan eds. Civil engineering materials. Wuhan UniversityPress .2009.3. From before the king, Huoman Lin. Building materials (first edition). Lanzhou University Press .19974. Zhang Xiong editor. Building functional materials. China Building Industry Press .2000.5. Yanhan Dong, Qian Xiao Qian ed. New Building Materials tutorial. China Building Materials Industry Press .2005.6. Zhang Fen Qin, Zhao Man ed. Building decoration materials. Chongqing University Press, .2007.7. Xuyou Hui ed. Building materials and learning. Southwest Jiaotong University Press .2007.1 中文翻译钢筋混凝土及土方工程简介摘要:作为设计人员首先必须明确自身设计的建筑构筑物得等级和强度，以及对相关问题进行深入的讨论和研究，本文主要叙述了关于钢筋混凝土，土方工程方面的相关知识，让我们更加深入的了解这方面的主要关键论述，以及合理应用知识来帮助我们设计更加优良的建筑。

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。

土木工程外文文献及翻译

1 IntroductionThe corrosion of steel reinforcement is a major cause of the deterioration of reinforced concrete structures throughout the world. In uncorroded structures the bond between the steel reinforcement and the concrete ensures that reinforced concrete acts in a composite manner. However, when corrosion of the steel occurs this composite performance is adversely affected. This is due to the formation of corrosion products on the steel surface, which affect the bond between the steel and the concrete.The deterioration of reinforced concrete is characterized by a general or localized loss of section on the reinforcing bars and the formation of expansive corrosion products. This deterioration can affect structures in a number of ways; the production of expansive products creates tensile stresses within the concrete, which can result in cracking and spalling of the concrete cover. This cracking can lead to accelerated ingress of the aggressive agents causing further corrosion. It can also result in a loss of strength and stiffness of the concrete cover. The corrosion products can also affect the bond strength between the concrete and the reinforcing steel. Finally the corrosion reduces the cross section of the reinforcing steel, which can affect the ductility of the steel and the load bearing capacity, which can ultimately impact upon the serviceability of the structure and the structural capacity [12, 25].Previous research has investigated the impact of corrosion on bond [2–5, 7, 12, 20, 23–25, 27, 29], with a number of models being proposed [4, 6, 9, 10, 18, 19, 24, 29]. The majority of this research has focused on the relationship between the level of corrosion (mass loss of steel) or the current density degree(corrosion current applied in accelerated testing) and crack width, or on the relationship between bond strength and level of corrosion. Other research has investigated the mechanical behaviour of corroded steel [1, 11] and the friction characteristics [13]. However, little research has focused on the relationship between crack width and bond [23, 26, 28], a parameter that can be measured with relative ease on actual structures.The corrosion of the reinforcing steel results in the formation of iron oxides which occupy a larger volume than that of the parent metal. This expansion creates tensile stresses within the surrounding concrete, eventually leading to cracking of the cover concrete. Once cracking occurs there is a loss of confining force from the concrete. This suggests that the loss of bond capacity could be related to the longitudinal crack width [12]. However, the use of confinement within the concrete can counteract this loss of bond capacity to a certain degree. Research to date has primarily involved specimens with confinement. This paper reports a study comparing the loss of bond of specimens with and without confinement.2 Experimental investigation2.1 SpecimensBeam end specimens [28] were selected for this study. This type of eccentr ic pullout or ‘beam end’ type specimen uses a bonded length representative of the anchorage zone of a typical simply supported beam. Specimens of rectangular cross section were cast with a longitudinal reinforcing bar in each corner, Fig. 1. An 80 mm plastic tube was provided at the bar underneath the transverse reaction to ensure that the bond strength was not enhanced due to a (transverse) compressive force acting on the bar over this length.Fig. 1 Beam end specimenDeformed rebar of 12 and 16 mm diameter with cover of three times bar diameter were investigated. Duplicate sets of confined and unconfined specimens were tested. The confined specimens had three sets of 6 mm stainless steel stirrups equally spaced from the plastic tube, at 75 mm centres.This represents four groups of specimens with a combination of different bar diameter and with/without confinement. The specimens were selected in order to investigate the influence of bar size, confinement and crack width on bond strength.2.2 MaterialsThe mix design is shown, Table 1. The cement was Type I Portland cement, the aggregate was basalt with specific gravity 2.99. The coarse and fine aggregate were prepared in accordance with AS 1141-2000. Mixing was undertaken in accordance with AS 1012.2-1994. Specimens were cured for28 days under wet hessian before testing.Table 1 Concrete mix designMateri al Cement w/c Sand10 mmwashedaggregate7 mmwashedaggregateSalt SlumpQuantit y 381 kg/m30.49517 kg/m3463 kg/m3463 kg/m318.84 kg/m3140 ± 25 mmIn order to compare bond strength for the different concrete compressive strengths, Eq. 1 is used to normalize bond strength for non-corroded specimens as has been used by other researcher [8].(1)where is the bond strength for grade 40 concrete, τ exptl is the experimental bond strength and f c is the experimental compressive strength.The tensile strength of the Φ12 and Φ16 mm steel bars was nominally500 MPa, which equates to a failure load of 56.5 and 100.5 kN, respectively. 2.3 Experiment methodologyAccelerated corrosion has been used by a number of authors to replicate the corrosion of the reinforcing steel happening in the natural environment [2, 3, 5, 6, 10, 18, 20, 24, 27, 28, 30]. These have involved experiments using impressed currents or artificial weathering with wet/dry cycles and elevated temperatures to reduce the time until corrosion, while maintaining deterioration mechanisms representative of natural exposure. Studies using impressed currents have used current densities between 100 μA/cm2 and 500 mA/cm2 [20]. Research has suggested that current densities up to 200 μA/cm2 result in similar stresses during the early stages of corrosion when compared to 100 μA/cm2 [21]. As such an applied current density of 200 μA/cm2 was selected for this study—representative of the lower end of the spectrum of such current densities adopted in previous research. However, caution should be applied when accelerating the corrosion using impressed current as the acceleration process does not exactly replicate the mechanisms involved in actual structures. In accelerated tests the pits are not allowed to progress naturally, and there may be a more uniform corrosion on the surface. Also the rate of corrosion may impact on the corrosion products, such that different oxidation state products may be formed, which could impact on bond.The steel bars served as the anode and four mild steel metal plates were fixed on the surface to serve as cathodes. Sponges (sprayed with salt water)were placed between the metal plates and concrete to provide an adequate contact, Fig. 2.Fig. 2 Accelerated corrosion systemWhen the required crack width was achieved for a particular bar, the impressed current was discontinued for that bar. The specimen was removed for pullout testing when all four locations exhibited the target crack width. Average surface crack widths of 0.05, 0.5, 1 and 1.5 mm were adopted as the target crack widths. The surface crack width was measured at 20 mm intervals along the length of the bar, beginning 20 mm from the end of the (plastic tube) bond breaker using an optical microscope. The level of accuracy in the measurements was ±0.02 mm. Measurements of crack width were taken on the surface normal to the bar direction regardless of the actual crack orientation at that location.Bond strength tests were conducted by means of a hand operated hydraulic jack and a custom-built test rig as shown in Fig. 3. The loading scheme is illustrated in Fig. 4. A plastic tube of length 80 mm was provided at the end of the concrete section underneath the transverse reaction to ensure that the bond strength was not enhanced by the reactive (compressive) force (acting normal to the bar). The specimen was positioned so that an axial force was applied to thebar being tested. The restraints were sufficiently rigid to ensure minimal rotation or twisting of the specimen during loading.Fig. 3 Pull-out test, 16 mm bar unconfinedFig. 4 Schematic of loading. Note: only test bar shown for clarity3 Experimental results and discussion3.1 Visual inspectionFollowing the accelerated corrosion phase each specimen was visually inspected for the location of cracks, mean crack width and maximum crack width (Sect. 2.3).While each specimen had a mean target crack width for each bar, variations in this crack width were observed prior to pull out testing. This is due to corrosion and cracking being a dynamic process with cracks propagating at different rates. Thus, while individual bars were disconnected, once the target crack width had been achieved, corrosion and crack propagation continued (to some extent) until all bars had achieved the target crack width and pull out tests conducted. This resulted in a range of data for the maximum and mean crack widths for the pull out tests.The visual inspection of the specimens showed three stages to the cracking process. The initial cracks occurred in a very short period, usually generated within a few days. After that, most cracks grew at a constant rate until they reached 1 mm, 3–4 weeks after first cracking. After cracks had reached 1 mm they then grew very slowly, with some cracks not increasing at all. For the confined and unconfined specimens the surface cracks tended to occur on the side of the specimens (as opposed to the top or bottom) and to follow the line of the bars. In the case of the unconfined specimens in general these were the only crack while it was common in the cases of confined specimens to observe cracks that were aligned vertically down the side—adjacent to one of the links, Fig. 5.Fig. 5 Typical crack patternsDuring the pull-out testing the most common failure mode for both confined and unconfined was splitting failure—with the initial (pre-test) cracks caused by the corrosion enlarging under load and ultimately leading to the section failing exhibiting spalling of the top corner/edge, Fig. 6. However for several of the confined specimens, a second mode of failure also occurred with diagonal (shear like) cracks appearing in the side walls, Fig. 7. The appearance of these cracks did not appear to be related to the presence of vertical cracks observed (in specimens with stirrups) during the corrosion phase as reported above.Fig. 6 Longitudinal cracking after pull-outFig. 7 Diagonal cracking after pull-outThe bars were initially (precasting) cleaned with a 12% hydrochloric acid solution, then washed in distilled water and neutralized by a calcium hydroxide solution before being washed in distilled water again. Following the pull-out tests, the corroded bars were cleaned in the same way and weighed again.The corrosion degree was determined using the following equationwhere G 0 is the initial weight of the steel bar before corrosion, G is the final weight of the steel bar after removal of the post-test corrosion products, g 0 is the weight per unit length of the steel bar (0.888 and 1.58 g/mm for Φ12 and Φ16 mm bars, respectively), l is the embedded bond length.Figures 8 and 9 show steel bars with varying degree of corrosion. The majority exhibited visible pitting, similar to that observed on reinforcement in actual structures, Fig. 9. However, a small number of others exhibitedsignificant overall section loss, with a more uniform level of corrosion, Fig. 8, which may be a function of the acceleration methodology.Fig. 8 Corroded 12 mm bar with approximately 30% mass lossFig. 9 Corroded 16 mm bar with approximately 15% mass loss3.2 Bond stress and crack widthFigure 10 shows the variation of bond stress with mean crack width for16 mm bars and Fig. 11 for the 12 mm bars. Figures 12 and 13 show the data for the maximum crack width.Fig. 10 Mean crack width versus bond stress for 16 mm barsFig. 11 Mean crack width versus bond stress for 12 mm bars Fig. 12 Maximum crack width versus bond stress for 16 mm bars Fig. 13 Maximum crack width versus bond stress for 12 mm barsThe data show an initial increase in bond strength for the 12 mm specimens with stirrups, followed by a significant decrease in bond, which is in agreement with other authors [12, 15]. For the 16 mm specimens an increase on the control bond stress was observed for specimens with 0.28 and 0.35 mm mean crack widths, however, a decrease in bond stress was observed for at the mean crack width of 0.05 mm.The 12 mm bars with stirrups displayed an increase in bond stress of approximately 25% from the control values to the maximum bond stress. An increase of approximately 14% was observed for the 16 mm specimens. Other researchers [17, 24, 25] have reported enhancements of bond stress of between 10 and 60% due to confinement, slightly higher to that observed in these experiment. However the loading techniques and cover depths have not all been the same. Variations in experimental techniques include a shorter embedded length and a lower cover. The variation on the proposed empirical relationship between bond strength, degree of corrosion, bar size, cover, link details and tensile strength predicted by Rodriguez [24] has been discussed in detail in Tang et al. [28]. The analysis demonstrates that there would be an expected enhancement of bond strength due to confinement of approximately 25%—corresponding to a change of bond strength of approximately 0.75 MPa for the 16 mm bars (assessed at a 2% section loss). For the 12 mm bars the corresponding effect of confinement is found to be approximately 35% corresponding to a 1.0 MPa difference in bond stress. The experimental results (14 and 25%, above) are 60–70% of these values.Both sets of data indicate a relationship showing decreasing bond strength with (visible surface) crack width. A regression analysis of the bond strengthdata reveals a better linear relationship with the maximum crack width as opposed to the mean crack width (excluding the uncracked confined specimens), Table 2.Table 2 Best fit parameters, crack width versus bond strengthThere was also a significantly better fit for the unconfined specimens than the confined specimens. This is consistent with the observation that in the unconfined specimens the bond strength will be related to the bond between the bars and the concrete, which will be affected by the level of corrosion present, which itself will influence the crack width. In confined specimens the confining steel will impact upon both the bond and the cracking.3.3 Corrosion degree and bond stressIt is apparent that (Fig. 14) for corrosion degrees less than 5% the bond stress correlated well. However, as the degree of corrosion increased there was no observable correlation at all. This contrasts with the relationship between the observed crack width and bond stress, which gives a reasonable correlation, even as crack widths increase to 2 and 2.5 mm. A possible explanation for this variation is that in the initial stages of corrosion virtually all the dissolved iron ions react to form expansive corrosion products. This reaction impacts on both the bond stress and the formation of cracks. However, once cracks have been formed it is possible for the iron ions to be transported along the crack and out of the concrete. As the bond has already been effectively lost at the crack any iron ions dissolving at the crack and being directly transported out of the concrete will cause an increase in the degree of corrosion, but not affect the surface crack width. The location, orientation and chemistry within the crack will control the relationship between bond stress and degree of corrosion, which will vary from specimen to specimen. Hence the large variations in corrosion degree and bond stress for high levels of corrosion.Fig. 14 Bond stress versus corrosion degree, 12 mm bars, unconfined specimenSignificantly larger crack widths were observed for the unconfined specimens, compared to the confined specimens with similar levels of corrosion and mass lost. The largest observed crack for unconfined specimens was2.5 mm compared to 1.4 mm for the confined specimens. This is as expected and is a direct result of the confinement which limits the degree of cracking.3.4 Effect of confinementThe unconfined specimens for both 16 and 12 mm bars did not display the initial increase in bond strength observed for the confined bars. Indeed the unconfined specimens with cracks all displayed a reduced bond stress compared to the control specimens. This is in agreement with other authors [16, 24] findings for cracked specimens. In cracked corroded specimens Fang observed a substantial reduction in bond strength for deformed bars without stirrups, while Rodriguez observed bond strengths of highly corroded cracked specimens without stirrups were close to zero, while highly corroded cracked specimens with stirrups retained bond strengths of between 3 and 4 MPa. In uncorroded specimens Chana noted an increase in bond strength due to stirrups of between 10 and 20% [14]. However Rodriguez and Fang observed no variation due to the presence of confinement in uncorroded bars.The data is perhaps unexpected as it could be anticipated that the corrosion products would lead to an increase in bond due to the increase in internal pressures, caused by the corrosion products increasing the confinement and mechanical interlocking around the bar, coupled with increased roughness of the bar resulting in a greater friction between the bar and the surrounding concrete. However, these pressures would then relieved by the subsequent cracking of the concrete, which would contribute to the decrease in the bond strength as crackwidths increase. A possible hypothesis is that due to the level of cover, three times bar diameter, the effect of confinement by the stirrups is reduced, such that it has little impact on the bond stress in uncracked concrete. However, once cracking has taken place the confinement does have a beneficial effect on the bond.It may also be that the compressive strength of the concrete combined with the cover will have an effect on the bond stresses for uncorroded specimens. The data presented here has a cover of three times bar diameter and a strength of 40 MPa, other research ranges from 1.5 to four times cover with compressive strengths from 40 to 77 MPa.3.5 Comparison of 12 and 16 mm rebarThe maximum bond stress for 16 mm unconfined bars was measured at 8.06 MPa and for the 12 mm bars it was 8.43 MPa. These both corresponded to the control specimens with no corrosion. The unconfined specimens for both the 12 and 16 mm bars showed no increase in bond stress due to corrosion. For the confined specimens the maximum bond stress for the control specimens were 7.29 MPa for the 12 mm bars and 6.34 MPa for the 16 mm bars. The maximum bond stress for both sets of confined specimens corresponded to point of the initial cracking. The maximum bond stresses were observed at a mean crack width of 0.01 mm for the 12 mm bars and 0.28 mm for the 16 mm bars. The corresponding bond stresses were, 8.45 and 7.20 MPa. Overall the 12 mm bars displayed higher bond stresses compared to the 16 mm bars at all crack widths. This is attributed to a different failure mode. The 16 mm specimens demonstrate splitting failure while the 12 mm bars bond failure.3.6 Effect of casting positionThere was no significant difference of bond strength due to the position of the bar (top or bottom cast) once cracking was observed, Fig. 15. For control specimens, with no corrosion, however, the bottom cast bars had a slightly higher bond stress than the top cast bars. These observations are in agreement with other authors [4, 11, 15, 22]. It is generally accepted that uncorroded bottom cast bars have significantly improved bond compared to top cast bars due to the corrosion products filling the voids that are often present under top cast bars as the corrosion progresses [14]. The corrosion also act s as an ‘anchor’, similar to the ribs on deformed bars, to increase the bond. Overall, the mean value of bond stress for all bars (corroded and uncorroded) located in the top were within 1% of the mean bond stress of all bars located in the bottom of the section—for both unconfined and confined bars. This is probably due to the level of cover. The results reported previously are on specimens with one times cover [14]. However, at three times cover it would be anticipated that greater compaction would be achieved around the top cast bars. Thus the area of voids would be reduced and thus the effect of the corrosion product filling these voids and increasing the bond strength would be reduced.Fig. 15 Bond stress versus mean crack width for 12 mm bars, top and bottom cast positions,confined specimen4 ConclusionsA relationship was observed between crack width and bond stress. The correlation was better for maximum crack width and bond stress than for mean crack width and bond stress.Confined bars displayed a higher bond stress at the point of initial cracking than where no corrosion had occurred. As crack width increase the bond stress reduced significantly.Unconfined bars displayed a decrease in bond stress at initial cracking, followed by a further decrease as cracking increased.Top cast bars displayed a higher bond stress in specimens with no corrosion. Once cracking had occurred no variation between top and bottom cast bars was observed.The 12 mm bars displayed higher bond stress values than 16 mm with no corrosion, control specimens, and at similar crack widths.A good correlation was observed between bond stress and degree of corrosion was observed at low levels of corrosion (less than 5%). However, at higher levels of corrosion no correlation was discerned.Overall the results indicated a potential relationship between the maximum crack width and the bond. Results shown herein should be interpreted with caution as this variation may be not only due to variations between accelerated corrosion and natural corrosion but also due to the complexity of the cracking mechanism in reality.中文译文：约束和无约束的钢筋对裂缝宽度的影响收稿日期：2010年1月14 纳稿日期：2010年12月14日线上发表时间：2010年1月23日摘要本报告公布了局限约束和自由的变形对粘结强度12、16毫米钢筋的表面腐蚀程度和裂纹影响的比较结果。

土木工程混凝土论文中英文资料外文翻译文献

土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。

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。

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。

地下工程结构英文文献综述范文

地下工程结构英文文献综述范文A Review of Underground Engineering Structures in the Literature.Abstract: Underground engineering structures have played a pivotal role in the development of cities worldwide. This review article explores the key research and advancements in the field of underground engineering, focusing on various structural designs, construction techniques, and challenges encountered. The objective is to provide a comprehensive overview of the current state-of-the-art in underground engineering and identify potential areas for further research.Introduction:With the increasing urbanization and the need for space-efficient infrastructure, underground engineering structures have become a crucial aspect of modern-day construction. These structures range from subway systems,underground parking lots, to large-scale utility tunnels. The design and construction of these structures involve complex engineering principles and challenges that require meticulous planning and execution.Structural Designs:The structural design of underground engineering is crucial, as it needs to withstand both vertical and horizontal loads while considering factors like soil conditions, groundwater levels, and seismic activities. The most common structural systems include cast-in-place concrete, segmental lining, and soil nailing. Concrete linings offer high durability and strength, while segmental linings provide flexibility in curved sections. Soilnailing is often used in soil stabilization and slope reinforcement.Construction Techniques:The construction of underground structures involves various techniques, such as excavation methods, shoringsystems, and groundwater control. Excavation methods range from open-cut methods to trenchless techniques like auger casting and microtunneling. Shoring systems, including sheet piling and bracing, are essential for maintaining stability during excavation. Groundwater control is crucial to prevent flooding and ensure the integrity of the structure.Challenges and Mitigation Strategies:Underground engineering faces several challenges, including soil stability, groundwater infiltration, and seismic activity. Soil stability can be addressed through soil reinforcement techniques like soil nailing and grouting. Groundwater infiltration requires effective dewatering systems and waterproofing materials. In seismic regions, special considerations are made for earthquake-resistant design, including the use of flexible joints and seismic isolation systems.Future Research Directions:With the evolving technology and increasing complexity of underground projects, there are several areas that require further research. These include innovative materials for underground construction, such as high-performance concrete and polymer-based composites. Advanced numerical modeling techniques can help in predicting the behavior of underground structures under various loading conditions. Furthermore, the integration of smart sensors and monitoring systems can enhance the safety andefficiency of underground construction.Conclusion:Underground engineering structures are a crucial component of modern urban infrastructure. This review article has provided an overview of the key research and advancements in the field, focusing on structural designs, construction techniques, and challenges encountered. Future research directions have been identified to further advance the field of underground engineering and meet the demands of sustainable and efficient urban development.。

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Construction of rock or soil in the construction. It is a modern city of high-speed product development, the city will again ease the contradictions of the role to improve the living environment, but also opened up new human life. Rational development and utilization of human natural and artificial excavation of the underground space, not only help to ease the development of modern urban contradictions, to improve the living environment, but also to open up a new human life. Because of the large-scale development of underground construction, underground architecture is taking shape, its research includes the history of development of underground construction and development of underground space development and utilization of underground space in urban planning, various types of underground construction planning and design, as well as underground construction and related environmental, physiological, psychological and technical issues.Underground construction has a good protective performance, better thermal stability and confined, as well as an integrated economic, social and environmental benefits. Underground construction in a certain thickness of rock or soil, you can avoid or reduce nuclear weapons, conventional weapons, chemical and biological weapons of destruction, while at the same time more effectively to resist earthquakes, hurricanes and other natural disasters. Underground construction in and around the confined environment of relatively stable existence of the temperature field, temperature, or for creating ultra-clean manufacturing environment and at low temperatures or under high-temperature storage of materials, pollution prevention, especially for energy conservation as well. In the city planned the construction of underground construction, urban land use for savings, lower building density, to improve urban transportation, theexpansion of green space, reduce urban pollution and improve the quality of urban life, etc., can play an important role. Underground construction also has shortcomings, such as construction costs are high, the construction complicated.A Brief History of the development of underground ancient times, humans have been anti-years use of natural caves, and shelter to escape the beast. Zhoukoudian in China found that more than 50 million years ago, Peking Man lived in caves in the natural. According to Yangshao Culture and Longshan Culture found in archaeological sites, to prove that since 7000 ~ 5000 years ago, began living dug caves, from the simple bag-shaped to round or square semi-crypt, above the roof of a simple. Later, the beginning of the construction of housing on the ground, cave gradually ceased to be the main mode of living human beings. However, the ancient tombs on the ground in accordance with the construction method in underground construction. Some grain is also built in the ground, such as the Sui Dynasty in Luoyang warehouse containing Kerry. Northwest China, North China Loess Plateau region, as a result of excavation loess and climate-friendly dry cave tradition continues to this day. Estimated that there are still more than 35 million population live in the cave.After the industrial revolution, as a result of mining and the development of transport, mines, roadways, highways, tunnels, railway tunnels have been built. London, England in 1863 into a city of the world's first underground railway. During World War II, the protection of underground construction in the superiority of attention, some veterans of the important military installations and arms factories, warehouses, etc., built in the ground, and the construction of the air-raid shelter for the residents. Since the late 50s, as a result of economic development and scientific and technological progress, the rapid increase in urban population, the increasingly serious environmental pollution, energy crisisand the existence of the danger of war and other factors, underground construction in Japan, the United States, Sweden, the Federal Republic of Germany , France, Switzerland, Norway, Canada, China, the Soviet Union and many other countries, with high speed and large-scale development. Due to geographical, social development, economic development and strategic direction of the differences in thinking, the development of underground construction and the starting point to solve the different conflicts. At present, the world has more than 80 cities in the construction of an underground railway, as well as many cities are under construction. China, the Soviet Union, Switzerland, Sweden, Finland and other countries from the combat readiness requirements of the construction of a large number of underground civil air defense projects, some in peacetime for the use of various types of public buildings. Japan, the Federal Republic of Germany and France, land of smaller, highly concentrated in big cities, city highlights various contradictions, so the construction of the ground floor of a large number of high-speed transportation network and the Mass Transit Street, the underground commercial center. The United States from the mid-70s to the ground floor of the building as energy-saving measures, the development of a semi-underground soil building, with the exception of the need to stay out of the plane, Chaoyang, housing all the other parts of the soil with a certain thickness of buried or covered combined with the use of solar energy to obtain more than 50% of energy-saving effect. Lack of national energy use of a large number of underground storage of energy as a strategic reserve, such as Sweden, Finland and other countries blocked the construction of the groundwater oil (or gas) are a large-scale database, a single storage capacity has more than one million cubic meters. Sweden, Norway, Italy and other countries rich in water resources, many built in the ground station to increase the water gap.Canada's cold climate, so in large cities, the development of underground commercial center of the city of Montreal has a few underground commercial center even as a construction area of 810,000 square meters, forming an underground city. In addition, industrialized countries also paid attention to the protection of underground construction to play the traditional style of the city to improve the urban environment, urban space, etc. to expand the positive role played by. For example, the city of Nagoya, Japan in conjunction with urban roads alteration, in the ground layout of the commercial street and parking lot, stay out of the ground in addition to the necessary pedestrians, carriageway, in the central part of the park into a large-scale city center. Other factors, such as Tokyo, Osaka and other places are also provided with the underground business street. Another example is the University of the United States a number of historical buildings and structures in order to preserve the unity of style and ease tension in the land, the construction of a number of underground construction, such as library, gymnasium, teaching Museum (Figure 2), achieving good results. These facts reflect the tiefbau increasingly wide range of applications.Underground construction of the type of underground construction can be classified according to the functions of military, civil, air works, industry, transport and communications, storage and other buildings, and underground utilities. For example: in the construction of military fortifications can be used for shooting, observation of construction, shelter construction, etc.), in civil construction, including residential buildings, public buildings, a variety of civil air defense engineering, industrial construction, transportation and communication construction, warehouse construction, as well as the types of underground utilities, such as underground water plant, solid or liquid waste treatment plant, pipeline and other corridors. Several features of both large-scaleunderground construction known as the underground complex. Tiefbau classified according to construction method, there are two types of open excavation and mining. Open excavation completely backfilled after construction, the above did not build any buildings, known as single-built underground construction; above to build other buildings, known as the attached underground construction. Open excavation backfill the latter part of the construction, soil or bulldozers, and as bulldozers building construction or soil. Underground mining construction, usually in the deeper layers of rock or digging into the required space for more than a certain thickness at the top of the natural cover. In addition, China also has a habit of classification methods, into the underground tunnel type, tunnel-type (usually mining), opening ceremony (equivalent to a single open excavation built) and the basement air (that is attached open excavation) . Road tunnel and the main difference is that the relationship between inside and outside the ground elevation, internal than external, as the tunnel, which is lower than the outside as the authentic.Underground construction of the design requirements for the underground architectural design requirements: ①choose engineering geological and hydrogeological conditions of a good place. Underground construction of the planning and design, must be complete and accurate information based on Geological Survey, full use of the favorable geological conditions, to avoid unfavorable factors. Arrangement in the soil in the ground floor of buildings, should be chosen with a certain capacity, and relatively uniform thick soil layer, avoiding the backfill layer, layer of mud, sand and other streaming sites; in the rock should be chosen homogeneous lithology, structure simple, thick stone rock hard to avoid the fault fracture zone, seismic zone and instability, such as the slope. In the plain areas, should pay attention to changes in groundwater leveland its direct impact on the burial depth of underground construction, construction measures and construction methods; in the mountains, rock fissures should be based on the volume of water and gushing location, organization of the underground drainage system construction and attention to surface water flow and the excretion of mountain torrents. ②to ensure the necessary protection. Although the underground construction itself with varying degrees of protection against all kinds of weapons, but the air defense of the military construction and engineering, but also the protection levels in accordance with the provisions of the various effects of different weapons, to conduct a comprehensive protection of the design, layout of the various protection facilities, building structures and protection facilities, as well as a variety of holes, I have the appropriate protection, we should focus on building entrances and exits to ensure the security of the site. ③ the creation of an appropriate internal environment. Underground space in the internal environment, including air temperature, humidity, cleanliness, noise intensity, the illumination lights, interior colors and so on. Appropriate depends mainly on improving the quality of air in the ventilation design to ensure; sound insulation and sound absorption of the appropriate use of measures to control the noise level allowed. Building to deal with such as a complete portfolio of interior space and changes in the unity of the material texture and contrast the rich interior colors and harmonization, have helped to create a good internal environment, the elimination of the underground environment on people's poor physical and psychological effects. ④for structural design and construction to create favorable conditions. Underground construction of the main features of the structural design is a big load, so in the architectural design, from layout, column network options to determine the areas of story should be for the structural design of the economy, create conditionsreasonable. The construction of underground construction is rather complicated, the design should be to simplify the construction and shorten the duration and the use of advanced construction technology to create favorable conditions and minimize the ground during the construction period of the normal activities such as transportation and so on.As the underground construction of the building structure is different from the specificity of the upper part, involving the design, construction technology, environment and soil mechanics, such as technical progress in a series of problems in engineering applications engineers often encounter the following problems:(1) of the underground structures of conventional reinforced concrete structures are mainly ordinary reinforced concrete structural system used in the existence of large-scale underground structure of the high cost, even cross-section structure, and the impact of depth of underground structures, construction progressing at a slow pace, as well as the shortcomings of a waste of construction materials, should the new system, the introduction of construction materials and structural design of underground structures to meet the modern requirements of the development of underground space, with limited resources for better results.(2) as the cause of urban rail transit development, urban towel existing and new buildings and subway lines crisscrossing the upper part of structure is at the top of the subway tunnel, the conventional reinforced concrete structure of care for the larger cross-section of the underground architectural space also have a greater impact. Workers should be the actual situation in innovative technology, choose a reasonable form of structural transformation of the construction and related measures to ensure that the subway project and the safety of the upperstructure and to minimize the impact of the underground space.(3) as an urban development strategy of three-dimensional one, high-rise buildings will continue to challenge the next new height, and construction will continue to increase in the floor, vertical wall structure is not posit the lower part of the greater cross-section, located in Building the lower part of the basement of the building material the use of space caused by an enormous impact; another - aspects of underground construction is the future direction of space, large-span, the vertical component will be an inevitable increase in cross-section. Therefore, the vertical cross-section configuration to optimize materials and even to improve the underground construction of the space is designed to be taken into account.(4) as a result of large-scale development of underground space and underground construction and use of the water requirements of more demanding, long, extra-wide development of the underground construction joints or less, regardless of the trend is sub-slit, regardless of current underground construction joints maximum length of over 800m, long and spacious underground construction specification requirements higher than the conventional approach has solved the structure of super-long concrete shrinkage, temperature, deformation and so on, the ground floor of building large-scale crack the case more and more. On the other hand, in order to prevent occurrence of cracks to increase the floor, roof and side wall of the reinforcement, so that the sharp increase in the basement of steel, it is therefore necessary to seal a device able to reduce power consumption Ultra - contraction of a long side wall and bottom of the internal force and deformation temperature, effectively improve the problem of cracking of underground construction.(5) as a result of underground construction in the fire reached the bottom ofthe lift requirements for the high-level and ultra-high-rise building, fire pit at the end of the lift is often deeper than 2m, the largest reach 3m. Conventional reinforced concrete pile cap by inch: the requirements of anti-punching greater thickness, and then caused by the lift at the end of the partial concave pits and the requirement of the cap to meet the bending, shear, anti-punching conditions, go on local concave The site needs to be integrated with the cap around the basically the same thickness, such as the 3.0m-thick cap, in the partial concave 3.0, the caps into a partial thickness of 6m, the amount of concrete and reinforced caused a significant increase, while the base pit at the bottom of the second excavation deeper than 5m, the safety of the Foundation have been affected.Modern underground structure calculation and analysis of three major aspects: 1) the overall structure of underground construction, including both ground-level structures with basement soil - guitar and pure combination of overall analysis of the soil underground construction - combined with the overall analysis of colorectal; 2 ) underground construction structure steel - concrete composite structure components of the calculation of portfolio analysis; 3) against the practice of underground structure calculation and analysis of the simulation. No matter how kind of an underground structure, the system solve the overall analysis, component analysis and dug up the ground floor of the structure of the three aspects of the problem of the real simulation of underground structures of the structural optimization of a certain significance. Calculation methods and design come to the Conclusion, it can be used as the structural design of underground structures of reference.Most of the use of underground reinforced concrete structures or steel reinforced concrete structure, the current design specifications related to the probabilitytheory are based on limit state design method, the reliability of indicators to measure the reliability of structural components using the design of sub-expressions coefficient design. Limit state can be divided into the carrying capacity limit state and serviceability limit state, for the carrying capacity limit state should be met:Cracks in the ground floor of building structures to deal with prevention and treatment.Analysis:(1) Design factors: emphasis on the general design of underground construction works vertical wall panels of the reinforced structure and intensity, the level of neglect of horizontal reinforcement cracking strength. Cross-section of the wall structure due to the particle stress is non-uniform shrinkage stress and thermal stress of concrete efforts to achieve the ultimate tensile strength, caused by the plastic deformation and fracture;(2) improper selection of materials, such as contraction of cement, and stone size distribution of the poor, with a large quantity of mud; the diameter of fine sand; doped admixtures, such as poor quality. As a result of commodity high-strength grade concrete, cement, and water consumption, and hydration heat caused by high temperature, when the environmental temperature significantly decreased the role of the temperature difference, the new casting of the linear expansion coefficient of concrete! c = 10 × 10-6 / ℃, when the contraction in the cooling caused by tensile stress increases. Concrete wall surface area larger than the shrinkage stress generated internally binding, the formation of shrinkage, shrinkage, temperature difference between the integrated stress, ultimate tensile strength greater than concrete and cracks;(3) The regulations: First, the summer heat without cooling measuresconstruction: concrete mixture into the mold temperature is higher than 35 ℃, when the temperature dropped at night when the temperature both inside and outside the large and prone to fracture; Second, in winter there is no low-temperature thermal insulation during the construction of measures , that is, when the goods after the concrete into the mold, cement hydration heat and the environment significantly increased the temperature at 0 ℃ about, then the outer panel of contraction at low temperatures, resulting in cracks. Third, improper pouring methods, such as pumping to take concrete pouring is not hierarchical, but pouring from one part of the maximum, and then the mobile shop and then pouring a section of pipe; Concrete is a mixture of vertical joints, and pouring speed, vibration trace and uneven, resulting in the concrete wall is not homogeneous, the particle stress is not evenly, resulting in stress cracks Department. Fourth, non-standard installation of reinforced, such as uneven spacing, horizontal transfer has not been reinforced and joint relaxation banding, or the protection of strict control, resulting in a collision so that when pouring concrete reinforced skew, stress is not absorbed, prone to cracks. Especially the "underground engineering specification waterproof" GB50108-2001 of underground water surface reinforced concrete structure to protect the layer thickness is not less than 50 mm since the implementation of the mandatory requirements, long cracks in the basement of the issue of concrete structures have become more prominent.Treatment and prevention measures:(1) underground construction of the vertical cracks in the wall: the contraction is mainly concrete, shrinkage, shrinkage, etc. generated under stress cracks generally do not affect the carrying capacity that can be used to deal with chemical grouting method. The purpose of dealing with the gap closed to preventleakage of water, so that cracks in bonding to restore the original function of the wall and to prevent damage to steel because of cracks and corrosion of passive film role;(2) in the ground outside the building (that is, water surface), a comprehensive inspection of the quality of irrigation joints until cured slurry to eliminate the wall of the swelling on the skin surface, to paste the cracks Department of Polymer waterproofing membrane, a width of about 250 mm. Cracks formed along the first grinding, clean, brush the grass-roots level to deal with agents, chosen with the membrane of qualified matching binder will be a solid material paste;(3) do a good job back to the outskirts of underground construction fill, is the underground construction of the first line of defense against water;(4) the proposed design of the underground construction of the wall panels should be allocated by the hydration of cement can withstand the heat caused by the thermal stress, shrinkage stress, the level of crack control reinforcement, diameter of not less than Ф12, spaced not more than 150mm, joints should be the use of welding, and Cold Drawn Straightening, keep straight after installation, spacing and location of protective layer should be accurate. The addition of reinforced concrete beam and dark columns, enhancing the role of the wall cracking strength, super-long construction of "pouring after sewing" or mixed in concrete ways to UEA expansive agent is effective in reducing measures undertaken Crack. 60d of the late use of concrete strength, can reduce the amount of cement concrete;(5) the quality control of raw materials, timely grasp the construction environment, in strict accordance with the construction norms of construction;(6) the use of thin-layer approach for irrigation, to ensure that the uniformdensity of concrete, to take the conservation of heat storage method, in order to reduce the temperature difference between inside and outside elements, and strictly control the cooling rate of 1.5 ℃ / d, for the concrete conditions of the creation of stress relaxation, is to prevent shrinkage cracks in concrete structures, one of the main measures;(7) Construction of the summer heat must be cooled to control the concrete into the mold temperature shall not exceed 28 ℃; the construction site should be shade measures to reduce the construction of temperature;Winter construction with antifreeze to warm the specific measures, such as the concrete into the mold temperature above 5 ℃, the thermal component to do the work too fast to prevent thermal cracks resulting from shrinkage.Underground construction of the development trend of increasing: ① type and scale. In recent years, some new, emerging types of underground construction. For example, with the growth of use of nuclear energy, nuclear waste handling and storage become a serious problem; in the deep strata (a few hundred meters to 1000 meters) in the construction of an underground nuclear waste repository is to solve this problem a better way to be a wide range of importance. In another example, the primary purpose of energy saving in the underground construction has developed rapidly; At the same time, underground storage of heat, cold energy, mechanical energy (water, compressed air) and other aspects of the ongoing feasibility study and test. Again, in order to improve the urban environment, the ground floor of a large-scale sewage treatment plants have been built in a small number of developed countries, the construction of urban waste disposal in the ground plant also being investigated. ② design and construction and continuously improved. The type of new construction is often higher technical requirements, so that a new process development andimprovement of construction technology. For example, in order to build a database of underground nuclear waste, it is necessary to solve the deep excavation of the post-rock pressure and rock strata in the role of nuclear waste under the stress of high temperature change; order to speed up the construction schedule is necessary to design and manufacture of large-scale mining machinery; in order to reduce project cost, it is necessary to adopt the new structure, high efficiency equipment and high-strength materials. ③ multidisciplinary research. The rapid development of underground construction, so that more and more people in different ways of living in the underground environment, and therefore meet the basic requirements based on the use of underground construction continuously higher quality requirements. From medicine, physiology, psychology and other disciplines, different perspectives, many ways to improve the underground environment of the ways and measures, including some of the more complex issue. For example, the underground environment and its impact on the dose of radioactive elements has been started to conduct research. ④ from individuals to groups, from single to comprehensive development. Urban construction, to a certain stage of development, individual and scattered underground construction can not meet the various needs of urban life, is bound to gradually integrated to the groups and direction. For example, the Mass Transit Railway underground line to increase the formation of high-speed transportation network, the transfer line at different points on the formation of a relatively easy to change stations, car parks and shops, such as the underground complex, which may be expanded to become the underground mall or commercial center . Also, in order to make full use of urban underground space should be to change the city's own utility system and the status of direct-buried pipeline to make it to the layout and use of multi-function integrated pipelinecorridor direction. To this end, calls for unity under the guidance of the overall urban planning, the development of urban underground space development and utilization of comprehensive planning, and the same on the ground to unify urban development planning.地下建筑结构建造在岩层或土层中的建筑。

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