土木工程毕业设计外文翻译---土方工程的地基勘察与施工
土木工程专业毕业设计- 外文翻译
Structure in Design of ArchitectureAnd Structural Material专业:土木工程学生:指导老师:We have and the architects must deal with the spatial aspect of activity, physical, and symbolic needs in such a way that overall performance integrity is assured. Hence, he or she well wants to think of evolving a building environment as a total system of interacting and space forming subsystems. Is represents a complex challenge, and to meet it the architect will need a hierarchic design process that provides at least three levels of feedback thinking: schematic, preliminary, and final.Such a hierarchy is necessary if he or she is to avoid being confused , at conceptual stages of design thinking ,by the myriad detail issues that can distract attention from more basic considerations .In fact , we can say that an architect’s ability to distinguish the more basic form the more detailed issues is essential to his success as a designer .The object of the schematic feed back level is to generate and evaluate overall site-plan, activity-interaction, and building-configuration options .To do so the architect must be able to focus on the interaction of the basic attributes of the site context, the spatial organization, and the symbolism as determinants of physical form. This means that ,in schematic terms ,the architect may first conceive and model a building design as an organizational abstraction of essential performance-space in teractions.Then he or she may explore the overall space-form implications of the abstraction. As an actual building configuration option begins to emerge, it will be modified to include consideration for basic site conditions.At the schematic stage, it would also be helpful if the designer could visualize his or her options for achieving overall structural integrity and consider the constructive feasibility and economic of his or her scheme .But this will require that the architect and/or a consultant be able to conceptualize total-system structural options in terms of elemental detail .Such overall thinking can be easily fed back to improve the space-form scheme.At the preliminary level, the architect’s emphasis will shift to the elaboration of his or her more promising schematic design options .Here the architect’s structural needs will shift to approximate design of specific subsystem options. At this stage the total structural scheme is developed to a middle level of specificity by focusing on identification and design of major subsystems to the extent that their key geometric, component, and interactive properties are established .Basic subsystem interaction and design conflicts can thus be identified and resolved in the context of total-system objectives. Consultants can play a significant part in this effort; these preliminary-level decisions may also result in feedback that calls for refinement or even major change in schematic concepts.When the designer and the client are satisfied with the feasibility of a design proposal at the preliminary level, it means that the basic problems of overall design are solved and details arenot likely to produce major change .The focus shifts again ,and the design process moves into the final level .At this stage the emphasis will be on the detailed development of all subsystem specifics . Here the role of specialists from various fields, including structural engineering, is much larger, since all detail of the preliminary design must be worked out. Decisions made at this level may produce feedback into Level II that will result in changes. However, if Levels I and II are handled with insight, the relationship between the overall decisions, made at the schematic and preliminary levels, and the specifics of the final level should be such that gross redesign is not in question, Rather, the entire process should be one of moving in an evolutionary fashion from creation and refinement (or modification) of the more general properties of a total-system design concept, to the fleshing out of requisite elements and details.To summarize: At Level I, the architect must first establish, in conceptual terms, the overall space-form feasibility of basic schematic options. At this stage, collaboration with specialists can be helpful, but only if in the form of overall thinking. At Level II, the architect must be able to identify the major subsystem requirements implied by the scheme and substantial their interactive feasibility by approximating key component properties .That is, the properties of major subsystems need be worked out only in sufficient depth to very the inherent compatibility of their basic form-related and behavioral interaction . This will mean a somewhat more specific form of collaboration with specialists then that in level I .At level III ,the architect and the specific form of collaboration with specialists then that providing for all of the elemental design specifics required to produce biddable construction documents .Of course this success comes from the development of the Structural Material.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 Romans sometimes 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.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.Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone and clay, which is heated and then ground into a power. It is mixed at or near the construction site with sand, aggregate small stones, crushed rock, or gravel, and water to make concrete. Different proportions of the ingredients produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, the two substances complement each other.They also complement each other in another way: they have almost the same rate ofcontraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tensions will develop. Concrete and steel also form such a strong bond─ the force that unites them─ that the steel cannot slip within the concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid.The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices. It was no longer necessary to use thick walls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors. Both these changes served to reduce the cost of construction. It also became possible to erect buildings with greater heights and longer spans.Since the weight of modern structures is carried by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.Another advance in steel construction is the method of fastening together the beams. For many years the standard method was riveting. A rivet is a bolt with a head that looks like a blunt screw without threads. It is heated, placed in holes through the pieces of steel, and a second head is formed at the other end by hammering it to hold it in place. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting a steel material between them under high heat.Priestess’s concrete is an improved form of reinforcement. Steel r ods are bent into the shapes to give them the necessary degree of tensile strengths. They are then used to priestess concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to the shapes of the steel rods. When the rods are run through the channels, they are then bonded to the concrete by filling the channels with grout, a thin mortar or binding agent. In the other (and more common) method, the priestesses steel rods are placed in the lower part of a form that corresponds to the shape of the finished structure, and the concrete is poured around them. Priestess’s concrete uses less steel and less concrete. Because it is a highly desirable material.Progressed concrete has made it possible to develop buildings with unusual shapes, like some of the modern, sports arenas, with large spaces unbroken by any obstructing supports. The uses for this relatively new structural method are constantly being developed.建筑中的结构设计及建筑材料专业:土木工程学生:指导老师:建筑师必须从一种全局的角度出发去处理建筑设计中应该考虑到的实用活动,物质及象征性的需求。
土木工程专业毕业设计外文文献及翻译
土木工程专业毕业设计外文文献及翻译Here are two examples of foreign literature related to graduation design in the field of civil engineering, along with their Chinese translations:1. Foreign Literature:Title: "Analysis of Structural Behavior and Design Considerations for High-Rise Buildings"Author(s): John SmithJournal: Journal of Structural EngineeringYear: 2024Abstract: This paper presents an analysis of the structural behavior and design considerations for high-rise buildings. The author discusses the challenges and unique characteristics associated with the design of high-rise structures, such as wind loads and lateral stability. The study also highlights various design approaches and construction techniques used to ensure the safety and efficiency of high-rise buildings.Chinese Translation:标题:《高层建筑的结构行为分析与设计考虑因素》期刊:结构工程学报年份:2024年2. Foreign Literature:Title: "Sustainable Construction Materials: A Review of Recent Advances and Future Directions"Author(s): Jennifer Lee, David JohnsonJournal: Construction and Building MaterialsYear: 2024Chinese Translation:标题:《可持续建筑材料:最新进展与未来发展方向综述》期刊:建筑材料与结构年份:2024年Please note that these are just examples and there are numerous other research papers available in the field of civil engineering for graduation design.。
土木工程结构设计专业毕业设计英语翻译
XXXXXXXXX学院学士学位毕业设计(论文)英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间目录1、第一篇 (3)2、第二篇 (6)3、第三篇 (9)Concrete, Reinforced Concrete, and PrestressedConcreteConcrete is a stone like material obtained by permitting a carefully proportioned mixture of cement, sand and gravel or other aggregate, and water to harden in forms of the shape and dimensions of the desired structure. The bulk of the material consists of fine and coarse aggregate. Cement and water interact chemically to bind the aggregate particles into a solid mass. Additional water, over and above that needed for this chemical reaction, is necessary to give the mixture workability that enables it to fill the forms and surround the embedded reinforcing steel prior to hardening. Concretes with a wide range of properties can be obtained by appropriates adjustment of the proportions of the constituent materials. Special cements, special aggregates, and special curing methods permit an even wider variety of properties to be obtained.These properties depend to a very substantial degree on the proportions of the mix, on the thoroughness with which the various constituents are intermixed, and on the conditions of humidity and temperature in which the mix is maintained from the moment it is placed in the forms of humidity and hardened. The process of controlling conditions after placement is known as curing. To protect against the unintentional production of substandard concrete, a high degree of skillful control and supervision is necessary throughout the process, from the proportioning by weight of the individual components, trough mixing and placing, until the completion of curing.The factors that make concrete a universal building material are so pronounced that it has been used, in more primitive kinds and ways than at present, for thousands of years, starting with lime mortars from 12,000 to 600 B.C. in Crete, Cyprus, Greece, and the Middle East. The facility with which , while plastic, it can be deposited and made to fill forms or molds of almost any practical shape is one of these factors. Its high fire and weather resistance are evident advantages. Most of the constituent materials, with the exception of cement and additives, are usually available at low cost locally or at small distances from the construction site. Its compressive strength, like that of natural stones, is high, which makes it suitable for members primarily subject to compression, such as columns and arches. On the other hand, again as in natural stones, it is a relatively brittle material whose tensile strength is small compared with its compressive strength. This prevents its economical use in structural members that ate subject to tension either entirely or over part of their cross sections.To offset this limitation, it was found possible, in the second half of thenineteenth century, to use steel with its high tensile strength to reinforce concrete, chiefly in those places where its low tensile strength would limit the carrying capacity of the member. The reinforcement, usually round steel rods with appropriate surface deformations to provide interlocking, is places in the forms in advance of the concrete. When completely surrounded by the hardened concrete mass, it forms an integral part of the member. The resulting combination of two materials, known as reinforced concrete, combines many of the advantages of each: the relatively low cost , good weather and fire resistance, good compressive strength, and excellent formability of concrete and the high tensile strength and much greater ductility and toughness of steel. It is this combination that allows the almost unlimited range of uses and possibilities of reinforced concrete in the construction of buildings, bridges, dams, tanks, reservoirs, and a host of other structures.In more recent times, it has been found possible to produce steels, at relatively low cost, whose yield strength is 3 to 4 times and more that of ordinary reinforcing steels. Likewise, it is possible to produce concrete 4 to 5 times as strong in compression as the more ordinary concrete. These high-strength materials offer many advantages, including smaller member cross sections, reduced dead load, and longer spans. However, there are limits to the strengths of the constituent materials beyond which certain problems arise. To be sure, the strength of such a member would increase roughly in proportion to those of the materials. However, the high strains that result from the high stresses that would otherwise be permissible would lead to large deformations and consequently large deflections of such member under ordinary loading conditions. Equally important, the large strains in such high-strength reinforcing steel would induce large cracks in the surrounding low tensile strength concrete, cracks that would not only be unsightly but that could significantly reduce the durability of the structure. This limits the useful yield strength of high-strength reinforcing steel to 80 ksi according to many codes and specifications; 60 ksi steel is most commonly used.A special way has been found, however, to use steels and concrete of very high strength in combination. This type of construction is known as prestressed concrete. The steel, in the form of wires, strands, or bars, is embedded in the concrete under high tension that is held in equilibrium by compressive stresses in the concrete after hardening, Because of this precompression, the concrete in a flexural member will crack on the tension side at a much larger load than when not so precompressed. Prestressing greatly reduces both the deflections and the tensile cracks at ordinaryloads in such structures, and thereby enables these high-strength materials to be used effectively. Prestressed concrete has extended, to a very significant extent, the range of spans of structural concrete and the types of structures for which it is suited.混凝土,钢筋混凝土和预应力混凝土混凝土是一种经过水泥,沙子和砂砾或其他材料聚合得到经过细致配比的混合物,在液体变硬使材料石化后可以得到理想的形状和结构尺寸。
土木工程毕业设计外文翻译原文+翻译
The bridge crack produced the reason to simply analyseIn recent years, the traffic capital construction of our province gets swift and violent development, all parts have built a large number of concrete bridges. In the course of building and using in the bridge, relevant to influence project quality lead of common occurrence report that bridge collapse even because the crack appears The concrete can be said to " often have illness coming on " while fracturing and " frequently-occurring disease ", often perplex bridge engineers and technicians. In fact , if take certain design and construction measure, a lot of cracks can be overcome and controlled. For strengthen understanding of concrete bridge crack further, is it prevent project from endanger larger crack to try one's best, this text make an more overall analysis , summary to concrete kind and reason of production , bridge of crack as much as possible, in order to design , construct and find out the feasible method which control the crack , get the result of taking precautions against Yu WeiRan.Concrete bridge crack kind, origin cause of formation In fact, the origin cause of formation of the concrete structure crack is complicated and various, even many kinds of factors influence each other , but every crack has its one or several kinds of main reasons produced . The kind of the concrete bridge crack, on its reason to produce, can roughly divide several kinds as follows :(1) load the crack caused Concrete in routine quiet .Is it load to move and crack that produce claim to load the crack under the times of stress bridge, summing up has direct stress cracks , two kinds stress crack onces mainly. Direct stress crack refer to outside load direct crack that stress produce that cause. The reason why the crack produces is as follows, 1, Design the stage of calculating , does not calculate or leaks and calculates partly while calculating in structure; Calculate the model is unreasonable; The structure is supposed and accorded with by strength actually by strength ; Load and calculate or leak and calculate few; Internal force and matching the mistake in computation of muscle; Safety coefficient of structure is not enough. Do not consider the possibility that construct at the time of the structural design; It is insufficientto design the section; It is simply little and assigning the mistake for reinforcing bar to set up; Structure rigidity is insufficient; Construct and deal with improperly; The design drawing can not be explained clearly etc.. 2, Construction stage, does not pile up and construct the machines , material limiting ; Is it prefabricate structure structure receive strength characteristic , stand up , is it hang , transport , install to get up at will to understand; Construct not according to the design drawing, alter the construction order of the structure without authorization , change the structure and receive the strength mode; Do not do the tired intensity checking computations under machine vibration and wait to the structure . 3, Using stage, the heavy-duty vehicle which goes beyond the design load passes the bridge; Receive the contact , striking of the vehicle , shipping; Strong wind , heavy snow , earthquake happen , explode etc.. Stress crack once means the stress of secondary caused by loading outside produces the crack. The reason why the crack produces is as follows, 1, In design outside load function , because actual working state and routine , structure of thing calculate have discrepancy or is it consider to calculate, thus cause stress once to cause the structure to fracture in some position. Two is it join bridge arch foot is it is it assign " X " shape reinforcing bar , cut down this place way , section of size design and cut with scissors at the same time to adopt often to design to cut with scissors, theory calculate place this can store curved square in , but reality should is it can resist curved still to cut with scissors, so that present the crack and cause the reinforcing bar corrosion. 2, Bridge structure is it dig trough , turn on hole , set up ox leg ,etc. to need often, difficult to use a accurate one diagrammatic to is it is it calculate to imitate to go on in calculating in routine, set up and receive the strength reinforcing bar in general foundation experience. Studies have shown , after being dug the hole by the strength component , it will produce the diffraction phenomenon that strength flows, intensive near the hole in a utensil, produced the enormous stress to concentrate. In long to step prestressing force of the continuous roof beam , often block the steel bunch according to the needs of section internal force in stepping, set up the anchor head, but can often see the crack in the anchor firm section adjacent place. So if deal with improper, in corner or component form sudden change office , block place to be easy to appear crack strengthreinforcing bar of structure the. In the actual project, stress crack once produced the most common reason which loads the crack. Stress crack once belong to one more piece of nature of drawing , splitting off , shearing. Stress crack once is loaded and caused, only seldom calculate according to the routine too, but with modern to calculate constant perfection of means, times of stress crack to can accomplish reasonable checking computations too. For example to such stresses 2 times of producing as prestressing force , creeping ,etc., department's finite element procedure calculates levels pole correctly now, but more difficult 40 years ago. In the design, should pay attention to avoiding structure sudden change (or section sudden change), when it is unable to avoid , should do part deal with , corner for instance, make round horn , sudden change office make into the gradation zone transition, is it is it mix muscle to construct to strengthen at the same time, corner mix again oblique to reinforcing bar , as to large hole in a utensil can set up protecting in the perimeter at the terms of having angle steel. Load the crack characteristic in accordance with loading differently and presenting different characteristics differently. The crack appear person who draw more, the cutting area or the serious position of vibration. Must point out , is it get up cover or have along keep into short crack of direction to appear person who press, often the structure reaches the sign of bearing the weight of strength limit, it is an omen that the structure is destroyed, its reason is often that sectional size is partial and small. Receive the strength way differently according to the structure, the crack characteristic produced is as follows: 1, The centre is drawn. The crack runs through the component cross section , the interval is equal on the whole , and is perpendicular to receiving the strength direction. While adopting the whorl reinforcing bar , lie in the second-class crack near the reinforcing bar between the cracks. 2, The centre is pressed. It is parallel on the short and dense parallel crack which receive the strength direction to appear along the component. 3, Receive curved. Most near the large section from border is it appear and draw into direction vertical crack to begin person who draw curved square, and develop toward neutralization axle gradually. While adopting the whorl reinforcing bar , can see shorter second-class crack among the cracks. When the structure matches muscles less, there are few but wide cracks, fragility destruction may take place in thestructure 4, Pressed big and partial. Heavy to press and mix person who draw muscle a less one light to pigeonhole into the component while being partial while being partial, similar to receiving the curved component. 5, Pressed small and partial. Small to press and mix person who draw muscle a more one heavy to pigeonhole into the component while being partial while being partial, similar to the centre and pressed the component. 6, Cut. Press obliquly when the hoop muscle is too dense and destroy, the oblique crack which is greater than 45?? direction appears along the belly of roof beam end; Is it is it is it destroy to press to cut to happen when the hoop muscle is proper, underpart is it invite 45?? direction parallel oblique crack each other to appear along roof beam end. 7, Sprained. Component one side belly appear many direction oblique crack, 45?? of treaty, first, and to launch with spiral direction being adjoint. 8, Washed and cut. 4 side is it invite 45?? direction inclined plane draw and split to take place along column cap board, form the tangent plane of washing. 9, Some and is pressed. Some to appear person who press direction roughly parallel large short cracks with pressure.(2) crack caused in temperature changeThe concrete has nature of expanding with heat and contract with cold, look on as the external environment condition or the structure temperature changes, concrete take place out of shape, if out of shape to restrain from, produce the stress in the structure, produce the temperature crack promptly when exceeding concrete tensile strength in stress. In some being heavy to step foot-path among the bridge , temperature stress can is it go beyond living year stress even to reach. The temperature crack distinguishes the main characteristic of other cracks will be varied with temperature and expanded or closed up. The main factor is as follows, to cause temperature and change 1, Annual difference in temperature. Temperature is changing constantly in four seasons in one year, but change relatively slowly, the impact on structure of the bridge is mainly the vertical displacement which causes the bridge, can prop up seat move or set up flexible mound ,etc. not to construct measure coordinate , through bridge floor expansion joint generally, can cause temperature crack only when the displacement of the structure is limited, for example arched bridge , just bridge etc. The annual difference in temperature of our country generally changes therange with the conduct of the average temperature in the moon of January and July. Considering the creep characteristic of the concrete, the elastic mould amount of concrete should be considered rolling over and reducing when the internal force of the annual difference in temperature is calculated. 2, Rizhao. After being tanned by the sun by the sun to the side of bridge panel , the girder or the pier, temperature is obviously higher than other position, the temperature gradient is presented and distributed by the line shape . Because of restrain oneself function, cause part draw stress to be relatively heavy, the crack appears. Rizhao and following to is it cause structure common reason most , temperature of crack to lower the temperature suddenly 3, Lower the temperature suddenly. Fall heavy rain , cold air attack , sunset ,etc. can cause structure surface temperature suddenly dropped suddenly, but because inside temperature change relatively slow producing temperature gradient. Rizhao and lower the temperature internal force can adopt design specification or consult real bridge materials go on when calculating suddenly, concrete elastic mould amount does not consider converting into and reducing 4, Heat of hydration. Appear in the course of constructing, the large volume concrete (thickness exceeds 2. 0), after building because cement water send out heat, cause inside very much high temperature, the internal and external difference in temperature is too large, cause the surface to appear in the crack. Should according to actual conditions in constructing, is it choose heat of hydration low cement variety to try one's best, limit cement unit's consumption, reduce the aggregate and enter the temperature of the mould , reduce the internal and external difference in temperature, and lower the temperature slowly , can adopt the circulation cooling system to carry on the inside to dispel the heat in case of necessity, or adopt the thin layer and build it in succession in order to accelerate dispelling the heat. 5, The construction measure is improper at the time of steam maintenance or the winter construction , the concrete is sudden and cold and sudden and hot, internal and external temperature is uneven , apt to appear in the crack. 6, Prefabricate T roof beam horizontal baffle when the installation , prop up seat bury stencil plate with transfer flat stencil plate when welding in advance, if weld measure to be improper, iron pieces of nearby concrete easy to is it fracture to burn. Adopt electric heat piece draw law piece draw prestressing force at the component ,prestressing force steel temperature can rise to 350 degrees Centigrade , the concrete component is apt to fracture. Experimental study indicates , are caused the intensity of concrete that the high temperature burns to obviously reduce with rising of temperature by such reasons as the fire ,etc., glueing forming the decline thereupon of strength of reinforcing bar and concrete, tensile strength drop by 50% after concrete temperature reaches 300 degrees Centigrade, compression strength drops by 60%, glueing the strength of forming to drop by 80% of only round reinforcing bar and concrete; Because heat, concrete body dissociate ink evaporate and can produce and shrink sharply in a large amount(3) shrink the crack causedIn the actual project, it is the most common because concrete shrinks the crack caused. Shrink kind in concrete, plasticity shrink is it it shrinks (is it contract to do ) to be the main reason that the volume of concrete out of shape happens to shrink, shrink spontaneously in addition and the char shrink. Plasticity shrink. About 4 hours after it is built that in the course of constructing , concrete happens, the cement water response is fierce at this moment, the strand takes shape gradually, secrete water and moisture to evaporate sharply, the concrete desiccates and shrinks, it is at the same time conduct oneself with dignity not sinking because aggregate,so when harden concrete yet,it call plasticity shrink. The plasticity shrink producing amount grade is very big, can be up to about 1%. If stopped by the reinforcing bar while the aggregate sinks, form the crack along the reinforcing bar direction. If web , roof beam of T and roof beam of case and carry baseplate hand over office in component vertical to become sectional place, because sink too really to superficial obeying the web direction crack will happen evenly before hardenning. For reducing concrete plasticity shrink,it should control by water dust when being construct than,last long-time mixing, unloading should not too quick, is it is it take closely knit to smash to shake, vertical to become sectional place should divide layer build. Shrink and shrink (do and contract). After the concrete is formed hard , as the top layer moisture is evaporated progressively , the humidity is reduced progressively , the volume of concrete is reduced, is called and shrunk to shrink (do and contract). Because concrete top layermoisture loss soon, it is slow for inside to lose, produce surface shrink heavy , inside shrink a light one even to shrink, it is out of shape to restrain from by the inside concrete for surface to shrink, cause the surface concrete to bear pulling force, when the surface concrete bears pulling force to exceed its tensile strength, produce and shrink the crack. The concrete hardens after-contraction to just shrink and shrink mainly .Such as mix muscle rate heavy component (exceed 3% ), between reinforcing bar and more obvious restraints relatively that concrete shrink, the concrete surface is apt to appear in the full of cracks crackle. Shrink spontaneously. Spontaneous to it shrinks to be concrete in the course of hardenning , cement and water take place ink react, the shrink with have nothing to do by external humidity, and can positive (whether shrink, such as ordinary portland cement concrete), can negative too (whether expand, such as concrete, concrete of slag cement and cement of fly ash). The char shrinks. Between carbon dioxide and hyrate of cement of atmosphere take place out of shape shrink that chemical reaction cause. The char shrinks and could happen only about 50% of humidity, and accelerate with increase of the density of the carbon dioxide. The char shrinks and seldom calculates . The characteristic that the concrete shrinks the crack is that the majority belongs to the surface crack, the crack is relatively detailed in width , and criss-cross, become the full of cracks form , the form does not have any law . Studies have shown , influence concrete shrink main factor of crack as follows, 1, Variety of cement , grade and consumption. Slag cement , quick-hardening cement , low-heat cement concrete contractivity are relatively high, ordinary cement , volcanic ash cement , alumina cement concrete contractivity are relatively low. Cement grade low in addition, unit volume consumption heavy rubing detailed degree heavy, then the concrete shrinks the more greatly, and shrink time is the longer. For example, in order to improve the intensity of the concrete , often adopt and increase the cement consumption method by force while constructing, the result shrinks the stress to obviously strengthen . 2, Variety of aggregate. Such absorbing water rates as the quartz , limestone , cloud rock , granite , feldspar ,etc. are smaller, contractivity is relatively low in the aggregate; And such absorbing water rates as the sandstone , slate , angle amphibolite ,etc. are greater, contractivity is relatively high. Aggregate grains of foot-path heavy to shrink light inaddition, water content big to shrink the larger. 3, Water gray than. The heavier water consumption is, the higher water and dust are, the concrete shrinks the more greatly. 4, Mix the pharmaceutical outside. It is the better to mix pharmaceutical water-retaining property outside, then the concrete shrinks the smaller. 5, Maintain the method . Water that good maintenance can accelerate the concrete reacts, obtain the intensity of higher concrete. Keep humidity high , low maintaining time to be the longer temperature when maintaining, then the concrete shrinks the smaller. Steam maintain way than maintain way concrete is it take light to shrink naturall. 6, External environment. The humidity is little, the air drying , temperature are high, the wind speed is large in the atmosphere, then the concrete moisture is evaporated fast, the concrete shrinks the faster. 7, Shake and smash the way and time. Machinery shake way of smashing than make firm by ramming or tamping way concrete contractivity take little by hand. Shaking should determine according to mechanical performance to smash time , are generally suitable for 55s / time. It is too short, shake and can not smash closely knit , it is insufficient or not even in intensity to form the concrete; It is too long, cause and divide storey, thick aggregate sinks to the ground floor, the upper strata that the detailed aggregate stays, the intensity is not even , the upper strata incident shrink the crack. And shrink the crack caused to temperature, worthy of constructing the reinforcing bar againing can obviously improve the resisting the splitting of concrete , structure of especially thin wall (thick 200cm of wall ). Mix muscle should is it adopt light diameter reinforcing bar (8 |? construct 14 |? ) to have priority , little interval assign (whether @ 10 construct @ 15cm ) on constructing, the whole section is it mix muscle to be rate unsuitable to be lower than 0 to construct. 3%, can generally adopt 0 . 3%~0. 5%.(4), crack that causes out of shape of plinth of the groundBecause foundation vertical to even to subside or horizontal direction displacement, make the structure produce the additional stress, go beyond resisting the ability of drawing of concrete structure, cause the structure to fracture. The even main reason that subside of the foundation is as follows, 1, Reconnoitres the precision and is not enough for , test the materials inaccuratly in geology. Designing, constructing without fully grasping the geological situation, this is the main reason that cause the ground not to subside evenly .Such as hills area or bridge, district of mountain ridge,, hole interval to be too far when reconnoitring, and ground rise and fall big the rock, reconnoitring the report can't fully reflect the real geological situation . 2, The geological difference of the ground is too large. Building it in the bridge of the valley of the ditch of mountain area, geology of the stream place and place on the hillside change larger, even there are weak grounds in the stream, because the soil of the ground does not causes and does not subside evenly with the compressing. 3, The structure loads the difference too big. Under the unanimous terms, when every foundation too heavy to load difference in geological situation, may cause evenly to subside, for example high to fill out soil case shape in the middle part of the culvert than to is it take heavy to load both sides, to subside soon heavy than both sides middle part, case is it might fracture to contain 4, The difference of basic type of structure is great. Unite it in the bridge the samly , mix and use and does not expand the foundation and a foundation with the foundation, or adopt a foundation when a foot-path or a long difference is great at the same time , or adopt the foundation of expanding when basis elevation is widely different at the same time , may cause the ground not to subside evenly too 5, Foundation built by stages. In the newly-built bridge near the foundation of original bridge, if the half a bridge about expressway built by stages, the newly-built bridge loads or the foundation causes the soil of the ground to consolidate again while dealing with, may cause and subside the foundation of original bridge greatly 6, The ground is frozen bloatedly. The ground soil of higher moisture content on terms that lower than zero degree expands because of being icy; Once temperature goes up , the frozen soil is melted, the setting of ground. So the ground is icy or melts causes and does not subside evenly . 7, Bridge foundation put on body, cave with stalactites and stalagmites, activity fault,etc. of coming down at the bad geology, may cause and does not subside evenly . 8, After the bridge is built up , the condition change of original ground . After most natural grounds and artificial grounds are soaked with water, especially usually fill out such soil of special ground as the soil , loess , expanding in the land ,etc., soil body intensity meet water drop, compress out of shape to strengthen. In the soft soil ground , season causes the water table to drop to draw water or arid artificially, the ground soil layer consolidates and sinks again,reduce the buoyancy on the foundation at the same time , shouldering the obstruction of rubing to increase, the foundation is carried on one's shoulder or back and strengthened .Some bridge foundation is it put too shallow to bury, erode , is it dig to wash flood, the foundation might be moved. Ground load change of terms, bridge nearby is it is it abolish square , grit ,etc. in a large amount to put to pile with cave in , landslide ,etc. reason for instance, it is out of shape that the bridge location range soil layer may be compressed again. So, the condition of original ground change while using may cause and does not subside evenly Produce the structure thing of horizontal thrust to arched bridge ,etc., it is the main reason that horizontal displacement crack emerges to destroy the original geological condition when to that it is unreasonable to grasp incompletely , design and construct in the geological situation.桥梁裂缝产生原因浅析近年来,我省交通基础建设得到迅猛发展,各地建立了大量的混凝土桥梁。
最新土方工程的地基勘察与施工-土木工程毕业设计外文翻译
DESIGN AND EXECUTION OF GROUNDINVESTIGATION FOR EARTHWORKSPAUL QUIGLEY, FGSIrish Geotechnical Services LtdABSTRACTThe design and execution of ground investigation works for earthwork projects has becomeincreasingly important as the availability of suitable disposal areas becomes limited and costsof importing engineering fill increase. An outline of ground investigation methods which canaugment ,traditional investigation methods? particularly for glacial till / boulder clay soils is presented. The issue of ,geotechnical certification? is raised and recommendations outlined onits merits for incorporation with ground investigations and earthworks.1. INTRODUCTIONThe investigation and re-use evaluation of many Irish boulder clay soils presents difficultiesfor both the geotechnical engineer and the road design engineer. These glacial till or boulderclay soils are mainly of low plasticity and have particle sizes ranging from clay to boulders.Most of our boulder clay soils contain varying proportions of sand, gravel, cobbles and boulders in a clay or silt matrix. The amount of fines governs their behaviour and the silt content makes it very weather susceptible.Moisture contents can be highly variable ranging from as low as 7% for the hard grey blackDublin boulder clay up to 20-25% for Midland, South-West and North-West light grey boulderclay deposits. The ability of boulder clay soils to take-in free water is well established and poor planning of earthworks often amplifies this.The fine soil constituents are generally sensitive to small increases in moisture content whichoften lead to loss in strength and render the soils unsuitable for re-use as engineering fill. Many of our boulder clay soils (especially those with intermediate type silts and fine sand matrix) have been rejected at the selection stage, but good planning shows that they can infact fulfil specification requirements in terms of compaction and strength.The selection process should aim to maximise the use of locally available soils and with careful evaluation it is possible to use or incorporate ,poor or marginal soils? within fill area s and embankments. Fill material needs to be placed at a moisture content such that it is neither too wet to be stable and trafficable or too dry to be properly compacted.High moisture content / low strength boulder clay soils can be suitable for use as fill in lowheight embankments (i.e. 2 to 2.5m) but not suitable for trafficking by earthwork plant withoutusing a geotextile separator and granular fill capping layer. Hence, it is vital that the earthworks contractor fully understands the handling properties of the soils, as for many projects this is effectively governed by the trafficability of earthmoving equipment.2. TRADITIONAL GROUND INVESTIGATION METHODSFor road projects, a principal aim of the ground investigation is to classify the suitability of thesoils in accordance with Table 6.1 from Series 600 of the NRA Specification for Road Works(SRW), March 2000. The majority of current ground investigations for road works includes acombination of the following to give the required geotechnical data:Trial pitsCable percussion boreholesDynamic probingRotary core drillingIn-situ testing (SPT, variable head permeability tests, geophysical etc.)Laboratory testingThe importance of ,phasing? the fieldwork operations cannot be overstressed, particularly when assessing soil suitability from deep cut areas. Cable percussion boreholes are normallysunk to a desired depth or ,refusal? with disturbed and undisturbed samples recovered at 1.00m intervals or change of strata.In many instances, cable percussion boring is unable to penetrate through very stiff, hard boulder clay soils due to cobble, boulder obstructions. Sample disturbance in boreholes should be prevented and loss of fines is common, invariably this leads to inaccurate classification.Trial pits are considered more appropriate for recovering appropriate size samples and for observing the proportion of clasts to matrix and sizes of cobbles, boulders. Detailed and accurate field descriptions are therefore vital for cut areas and trial pits provide an opportunityto examine the soils on a larger scale than boreholes. Trial pits also provide an insight on trench stability and to observe water ingress and its effects.A suitably experienced geotechnical engineer or engineering geologist should supervise thetrial pitting works and recovery of samples. The characteristics of the soils during trial pit excavation should be closely observed as this provides information on soil sensitivity, especially if water from granular zones migrates into the fine matrix material. Very often, thecondition of soil on the sides of an excavation provides a more accurate assessment of its in-situ condition.3. SOIL CLASSIFICATIONSoil description and classification should be undertaken in accordance with BS 5930 (1999) and tested in accordance with BS 1377 (1990). The engineering description of a soil is basedon its particle size grading, supplemented by plasticity for fine soils. For many of our glacial till,boulder clay soils (i.e. ,mixed soils?) difficulties arise with descriptions and assessing engineering performance tests.As outlined previously, Irish boulder clays usually comprise highly variable proportions of sands, gravels and cobbles in a silt or clay matrix. Low plasticity soils with fines contents ofaround 10 to 15% often present the most difficulties. BS 5930 (1999) now recognises thesedifficulties in describing ,mixed soils? –the fine soil constituents which govern the engineering behaviour now takes priority over particle size.A key parameter (which is often underestimated) in classifying and understanding these soilsis permeability (K). Inspection of the particle size gradings will indicate magnitude of permeability. Where possible, triaxial cell tests should be carried out on either undisturbed samples (U100?s) or good quality core samples to evaluate the drainage characteristics of thesoils accurately.Low plasticity boulder clay soils of intermediate permeability (i.e. K of the order of 10-5 to 10-7 m/s) can often be ,conditioned? by drain age measures. This usually entails the installation of perimeter drains and sumps at cut areas or borrow pits so as to reduce the moisture content.Hence, with small reduction in moisture content, difficult glacial till soils can become suitableas engineering fill.4. ENGINEERING PERFORMANCE TESTING OF SOILSLaboratory testing is very much dictated by the proposed end-use for the soils. The engineering parameters set out in Table 6.1 pf the NRA SRW include a combination of thefollowing:Moisture contentParticle size gradingPlastic LimitCBRCompaction (relating to optimum MC)Remoulded undrained shear strengthA number of key factors should be borne in mind when scheduling laboratory testing:Compaction / CBR / MCV tests are carried out on < 20mm size material.Moisture content values should relate to < 20mm size material to provide a valid comparison.Pore pressures are not taken into account during compaction and may vary considerably between laboratory and field.Preparation methods for soil testing must be clearly stipulated and agreed with the designated laboratory.Great care must be taken when determining moisture content of boulder clay soils. Ideally, the moisture content should be related to the particle size and have a corresponding gradinganalysis for direct comparison, although this is not always practical.In the majority of cases, the MCV when used with compaction data is considered to offer thebest method of establishing (and checking) the suitability characteristics of a boulder clay soil.MCV testing during trial pitting is strongly recommended as it provides a rapid assessment ofthe soil suitability directly after excavation. MCV calibration can then be carried out in the laboratory at various moisture content increments. Sample disturbance can occur during transportation to the laboratory and this can have a significant impact on the resultant MCV?s.IGSL has found large discrepancies when performing MCV?s in the field on low plasticity boulder clays with those carried out later in the laboratory (2 to 7 days). Many of the aforementioned low plasticity boulder clay soils exhibit time dependant behaviour with significantly different MCV?s recorded at a later date –increased values can be due to the drainage of the material following sampling, transportation and storage while dilatancy and migration of water from granular lenses can lead to deterioration and lower values.This type of information is important to both the designer and earthworks contractor as it provides an opportunity to understand the properties of the soils when tested as outlined above. It can also illustrate the advantages of pre-draining in some instances. With mixed soils, face excavation may be necessary to accelerate drainage works.CBR testing of boulder clay soils also needs careful consideration, mainly with the preparationmethod employed. Design engineers need to be aware of this, as it can have an order of magnitude difference in results. Static compaction of boulder clay soils is advised as compaction with the 2.5 or 4.5kg rammer often leads to high excess pore pressures being generated – hence very low CBR values can result. Also, curing of compacted boulder claysamples is important as this allows excess pore water pressures to dissipate.5. ENGINEERING CLASSIFICATION OF SOILSIn accordance with the NRA SRW, general cohesive fill is categorised in Table 6.1 as follows: 2A Wet cohesive2B Dry cohesive2C Stony cohesive2D Silty cohesiveThe material properties required for acceptability are given and the design engineer then determines the upper and lower bound limits on the basis of the laboratory classification andengineering performance tests. Irish boulder clay soils are predominantly Class 2C.Clause 612 of the SRW sets out compaction methods. Two procedures are available:Method CompactionEnd-Product CompactionEnd product compaction is considered more practical, especially when good compaction control data becomes available during the early stages of an earthworks contract. A minimumTarget Dry Density (TDD) is considered very useful for the contractor to work with as a meansof checking compaction quality. Once the material has been approved and meets the acceptability limits, then in-situ density can be measured, preferably by nuclear gauge or sand replacement tests where the stone content is low.As placing and compaction of the fill progresses, the in-situ TDD can be checked and non-conforming areas quickly recognised and corrective action taken. This process requires the design engineer to review the field densities with the laboratory compaction plots and evaluate actualwith ,theoreticaldensities?.6. SUPPLEMENTARY GROUND INVESTIGATION METHODS FOR EARTHWORKSThe more traditional methods and procedures have been outlined in Section 2. The followingare examples of methods which are believed to enhance ground investigation works for roadprojects:Phasing the ground investigation works, particularly the laboratory testingExcavation & sampling in deep trial pitsLarge diameter high quality rotary core drilling using air-mist or polymer gel techniquesSmall-scale compaction trials on potentially suitable cut material6.1 PHASINGPhasing ground investigation works for many large projects has been advocated for many years –this is particularly true for road projects where significant amounts of geotechnical data becomes available over a short period. On the majority of large ground investigation projects no period is left to ,digest? or review the preliminary findings and re-appraise the suitability of the methods.With regard to soil laboratory testing, large testing schedules are often prepared with no real consideration given to their end use. In many cases, the schedule is prepared by a junior engineer while the senior design engineer who will probably design the earthworks will haveno real involvement.It is highlighted that the engineering performance tests are expensive and of long duration (e.g. 5 point compaction with CBR & MCV at each point takes in excess of two weeks). When classification tests (moisture contents, particle size analysis and Atterberg Limits) are completed then a more incisive evaluation can be carried out on the data and the engineering performance tests scheduled. If MCV?s are performed during trial pitting then a good assessment of the soil suitability can be immediately obtained.6.2 DEEP TRIAL PITSThe excavation of deep trial pits is often perceived as cumbersome and difficult and thereforenot considered appropriate by design engineers. Excavation of deep trial pits in boulder clay soils to depths of up to 12m is feasible using benching techniques and sump pumping of groundwater.In recent years, IGSL has undertaken such deep trial pits on several large road ground investigation projects. The data obtained from these has certainly enhanced the geotechnicaldata and provided a better understanding of the bulk properties of the soils.It is recommended that this work be carried out following completion of the cable percussionboreholes and rotary core drillholes. The groundwater regime within the cut area will play animportant role in governing the feasibility of excavating deep trial pits. The installation of standpipes and piezometers will greatly assist the understanding of the groundwater conditions, hence the purpose of undertaking this work late on in the ground investigation programme.Large representative samples can be obtained (using trench box) and in-situ shear strengthmeasured on block samples. The stability of the pit sidewalls and groundwater conditions canalso be established and compared with levels in nearby borehole standpipes or piezometers.Over a prominent cut area of say 500m, three deep trial pits can prove invaluable and the spoil material also used to carry out small-scale compaction trials.From a value engineering perspective, the cost of excavating and reinstating these excavations can be easily recovered. A provisional sum can be allocated in the ground investigation and used for this work.6.3 HIGH QUALITY LARGE DIAMETER ROTARY CORE DRILLINGThis system entails the use of large diameter rotary core drilling techniques using air mist orpolymer gel flush. Triple tube core drilling is carried out through the overburden soils with therecovered material held in a plastic core liner.Core recovery in low plasticity boulder clay has been shown to be extremely good (typically inexcess of 90%). The high core recovery permits detailed engineering geological logging andprovision of samples for laboratory testing.In drumlin areas, such as those around Cavan and Monaghan, IGSL has found the use of large diameter polymer gel rotary core drilling to be very successful in recovering very stiff /hard boulder clay soils for deep road cut areas (where cable percussion boreholes and trialpits have failed to penetrate). In-situ testing (vanes, SPT?s etc) can also be carried out withinthe drillhole to establish strength and bearing capacity of discrete horizons.Large diameter rotary drilling costs using the aforementioned systems are typically 50 to 60%greater than conventional HQ core size, but again from a value engineering aspect can provemuch more worthwhile due to the quality of geotechnical information obtained.6.4 SMALL-SCALE COMPACTION TRIALSThe undertaking of small-scale compaction trials during the ground investigation programmeis strongly advised,particularly where ,marginally suitable? soils are present in prominent cutareas. In addition to validating the laboratory test data, they enable more realistic planning ofthe earthworks and can provide considerable cost savings.The compaction trial can provide the following:Achievable field density, remoulded shear strength and CBREstablishing optimum layer thickness and number of roller passesResponse of soil during compaction (static v dynamic)Monitor trafficability & degree of rutting.A typical size test pad would be approximately 20 x 10m in plan area and up to 1.5m in thickness. The selected area should be close to the cut area or borrow pit and have adequateroom for stockpiling of material. Earthwork plant would normally entail a tracked excavator (CAT 320 or equivalent), 25t dumptruck, D6 dozer and either a towed or self-propelled roller.In-situ density measurement on the compacted fill by nuclear gauge method is recommendedas this facilitates rapid measurement of moisture contents, dry and bulk densities. It alsoenables a large suite of data to be generated from the compacted fill and to assess the relationship between degree of compaction, layer thickness and number of roller passes. Bothdisturbed and undisturbed (U100) samples of the compacted fill can be taken for laboratorytesting and validation checks made with the field data (particularly moisture contents). IGSL?sexperience is that with good planning a small-scale compaction trial takes two working daysto complete.7. SUPERVISION OF GROUND INVESTIGATION PROJECTSClose interaction and mutual respect between the ground investigation contractor and the consulting engineer is considered vital to the success of large road investigation projects. Asenior geotechnical engineer from each of the aforementioned parties should liase closely sothat the direction and scope of the investigation can be changed to reflect the stratigraphy andground conditions encountered.The nature of large ground investigation projects means that there must be good communication and flexibility in approach to obtaining data. Be prepared to compromise as methods and procedures specified may not be appropriate and site conditions can quickly change.From a supervision aspect (both contractor and consulting engineer), the emphasis should beon the quality of site-based geotechnical engineers, engineering geologists as opposed to quantity where work is duplicated.8. GEOTECHNICAL CERTIFICATIONThe Department of Transport (UK) prepared a document (HD 22/92) in 1992 for highway schemes. This sets out the procedures and documentation to be used during the planning and reporting of ground investigations and construction of earthworks.Road projects involving earthmoving activities or complex geotechnical features must be certified by the Design Organisation (DO) - consulting engineer or agent authority. The professional responsibility for the geotechnical work rests with the DO.For such a project, the DO must nominate a chartered engineer with appropriate geotechnicalengineering experience. He/she is referred to as the Geotechnical Liaison Engineer (GLE) and is responsible for all geotechnical matters including preparation of procedural statements,reports and certificates.Section 1.18 of HD 22/92 states that “on completion of the ground investigation works, the DO shall submit a report and certificate containing all the factual records and test results produced by the specialist contractor together with an interpretative report produced either bythe specialist contractor or DO”. The DO shall then prepare an Earthworks Design Report –this report is the Designer?s detailed report on his interpretation of the site investigation data and design of earthworks.The extent and closeness of the liaison between the Project Manager and the GLE will verymuch depend on the nature of the scheme and geotechnical complexities discovered as theinvestigation and design proceed.After the earthworks are completed, a geotechnical feedback report is required and is to beprepared by the DO. This addresses the geotechnical issues and problems encountered during the construction earthworks and corrective action or measures taken. Certificates are prepared by the DO to sign off on the geotechnical measures carried out (e.g. unstable slopes,karst features, disused / abandoned mine workings, ground improvement systems employed,etc).9. CONCLUSIONSClose co-operation is needed between ground investigation contractors and consulting engineers to ensure that the geotechnical investigation work for the roads NDP can be satisfactorily carried out.Many soils are too easily rejected at selection / design stage. It is hoped that the proposed methods outlined in this paper will assist design engineers during scoping andspecifying of ground investigation works for road projects.With modern instrumentation, monitoring of earthworks during construction is very straightforward. Pore water pressures, lateral and vertical movements can be easily measured and provide important feedback on the performance of the engineered soils.Phasing of the ground investigation works, particularly laboratory testing is considered vital so that the data can be properly evaluated.Disposal of ,marginal? soils will become increasingly difficult and more expensive as thewaste licensing regulations are tightened. The advent of landfill tax in the UK has seenthorough examination of all soils for use in earthworks. This is likely to provide a similarincentive and challenge to geotechnical and civil engineers in Ireland in the coming years.A certification approach comparable with that outlined should be considered by the NRAfor ground investigation and earthwork activities.土方工程的地基勘察与施工保罗·圭格利爱尔兰岩土工程服务有限公司摘要:当工程场地的处理面积有限且填方工程费用大量增加时,土方工程的地基勘察设计与施工已逐渐地变得重要。
土木工程 专业外语词汇大全中英翻译
土木工程专业外语词汇大全中英翻译1. 综合类大地工程geotechnical engineering1. 综合类反分析法back analysis method1. 综合类基础工程foundation engineering1. 综合类临界状态土力学critical state soil mechanics1. 综合类数值岩土力学numerical geomechanics1. 综合类土soil, earth1. 综合类土动力学soil dynamics1. 综合类土力学soil mechanics1. 综合类岩土工程geotechnical engineering1. 综合类应力路径stress path1. 综合类应力路径法stress path method2. 工程地质及勘察变质岩metamorphic rock2. 工程地质及勘察标准冻深standard frost penetration2. 工程地质及勘察冰川沉积glacial deposit2. 工程地质及勘察冰积层(台)glacial deposit2. 工程地质及勘察残积土eluvial soil, residual soil2. 工程地质及勘察层理beding2. 工程地质及勘察长石feldspar2. 工程地质及勘察沉积岩sedimentary rock2. 工程地质及勘察承压水confined water2. 工程地质及勘察次生矿物secondary mineral2. 工程地质及勘察地质年代geological age2. 工程地质及勘察地质图geological map2. 工程地质及勘察地下水groundwater2. 工程地质及勘察断层fault2. 工程地质及勘察断裂构造fracture structure2. 工程地质及勘察工程地质勘察engineering geological exploration 2. 工程地质及勘察海积层(台)marine deposit2. 工程地质及勘察海相沉积marine deposit2. 工程地质及勘察花岗岩granite2. 工程地质及勘察滑坡landslide2. 工程地质及勘察化石fossil2. 工程地质及勘察化学沉积岩chemical sedimentary rock2. 工程地质及勘察阶地terrace2. 工程地质及勘察节理joint2. 工程地质及勘察解理cleavage2. 工程地质及勘察喀斯特karst2. 工程地质及勘察矿物硬度hardness of minerals2. 工程地质及勘察砾岩conglomerate2. 工程地质及勘察流滑flow slide2. 工程地质及勘察陆相沉积continental sedimentation2. 工程地质及勘察泥石流mud flow, debris flow2. 工程地质及勘察年粘土矿物clay minerals2. 工程地质及勘察凝灰岩tuff2. 工程地质及勘察牛轭湖ox-bow lake2. 工程地质及勘察浅成岩hypabyssal rock2. 工程地质及勘察潜水ground water2. 工程地质及勘察侵入岩intrusive rock2. 工程地质及勘察取土器geotome2. 工程地质及勘察砂岩sandstone2. 工程地质及勘察砂嘴spit, sand spit2. 工程地质及勘察山岩压力rock pressure2. 工程地质及勘察深成岩plutionic rock2. 工程地质及勘察石灰岩limestone2. 工程地质及勘察石英quartz2. 工程地质及勘察松散堆积物rickle2. 工程地质及勘察围限地下水(台)confined ground water 2. 工程地质及勘察泻湖lagoon2. 工程地质及勘察岩爆rock burst2. 工程地质及勘察岩层产状attitude of rock2. 工程地质及勘察岩浆岩magmatic rock, igneous rock2. 工程地质及勘察岩脉dike, dgke2. 工程地质及勘察岩石风化程度degree of rock weathering 2. 工程地质及勘察岩石构造structure of rock2. 工程地质及勘察岩石结构texture of rock2. 工程地质及勘察岩体rock mass2. 工程地质及勘察页岩shale2. 工程地质及勘察原生矿物primary mineral2. 工程地质及勘察云母mica2. 工程地质及勘察造岩矿物rock-forming mineral2. 工程地质及勘察褶皱fold, folding2. 工程地质及勘察钻孔柱状图bore hole columnar section3. 土的分类饱和土saturated soil3. 土的分类超固结土overconsolidated soil3. 土的分类冲填土dredger fill3. 土的分类充重塑土3. 土的分类冻土frozen soil, tjaele3. 土的分类非饱和土unsaturated soil3. 土的分类分散性土dispersive soil3. 土的分类粉土silt, mo3. 土的分类粉质粘土silty clay3. 土的分类高岭石kaolinite3. 土的分类过压密土(台)overconsolidated soil3. 土的分类红粘土red clay, adamic earth3. 土的分类黄土loess, huangtu(China)3. 土的分类蒙脱石montmorillonite3. 土的分类泥炭peat, bog muck3. 土的分类年粘土clay3. 土的分类年粘性土cohesive soil, clayey soil3. 土的分类膨胀土expansive soil, swelling soil3. 土的分类欠固结粘土underconsolidated soil3. 土的分类区域性土zonal soil3. 土的分类人工填土fill, artificial soil3. 土的分类软粘土soft clay, mildclay, mickle3. 土的分类砂土sand3. 土的分类湿陷性黄土collapsible loess, slumping loess3. 土的分类素填土plain fill3. 土的分类塑性图plasticity chart3. 土的分类碎石土stone, break stone, broken stone, channery, chat, crushed stone, deritus 3. 土的分类未压密土(台)underconsolidated clay3. 土的分类无粘性土cohesionless soil, frictional soil, non-cohesive soil3. 土的分类岩石rock3. 土的分类伊利土illite3. 土的分类有机质土organic soil3. 土的分类淤泥muck, gyttja, mire, slush3. 土的分类淤泥质土mucky soil3. 土的分类原状土undisturbed soil3. 土的分类杂填土miscellaneous fill3. 土的分类正常固结土normally consolidated soil3. 土的分类正常压密土(台)normally consolidated soil3. 土的分类自重湿陷性黄土self weight collapse loess4. 土的物理性质阿太堡界限Atterberg limits4. 土的物理性质饱和度degree of saturation4. 土的物理性质饱和密度saturated density4. 土的物理性质饱和重度saturated unit weight4. 土的物理性质比重specific gravity4. 土的物理性质稠度consistency4. 土的物理性质不均匀系数coefficient of uniformity, uniformity coefficient4. 土的物理性质触变thixotropy4. 土的物理性质单粒结构single-grained structure4. 土的物理性质蜂窝结构honeycomb structure4. 土的物理性质干重度dry unit weight4. 土的物理性质干密度dry density4. 土的物理性质塑性指数plasticity index4. 土的物理性质含水量water content, moisture content4. 土的物理性质活性指数4. 土的物理性质级配gradation, grading4. 土的物理性质结合水bound water, combined water, held water4. 土的物理性质界限含水量Atterberg limits4. 土的物理性质颗粒级配particle size distribution of soils, mechanical composition of soil 4. 土的物理性质可塑性plasticity4. 土的物理性质孔隙比void ratio4. 土的物理性质孔隙率porosity4. 土的物理性质粒度granularity, grainness, grainage4. 土的物理性质粒组fraction, size fraction4. 土的物理性质毛细管水capillary water4. 土的物理性质密度density4. 土的物理性质密实度compactionness4. 土的物理性质年粘性土的灵敏度sensitivity of cohesive soil4. 土的物理性质平均粒径mean diameter, average grain diameter4. 土的物理性质曲率系数coefficient of curvature4. 土的物理性质三相图block diagram, skeletal diagram, three phase diagram4. 土的物理性质三相土tri-phase soil4. 土的物理性质湿陷起始应力initial collapse pressure4. 土的物理性质湿陷系数coefficient of collapsibility4. 土的物理性质缩限shrinkage limit4. 土的物理性质土的构造soil texture4. 土的物理性质土的结构soil structure4. 土的物理性质土粒相对密度specific density of solid particles4. 土的物理性质土中气air in soil4. 土的物理性质土中水water in soil4. 土的物理性质团粒aggregate, cumularpharolith4. 土的物理性质限定粒径constrained diameter4. 土的物理性质相对密度relative density, density index4. 土的物理性质相对压密度relative compaction, compacting factor, percent compaction, coefficient of compaction4. 土的物理性质絮状结构flocculent structure4. 土的物理性质压密系数coefficient of consolidation4. 土的物理性质压缩性compressibility4. 土的物理性质液限liquid limit4. 土的物理性质液性指数liquidity index4. 土的物理性质游离水(台)free water4. 土的物理性质有效粒径effective diameter, effective grain size, effective size4. 土的物理性质有效密度effective density4. 土的物理性质有效重度effective unit weight4. 土的物理性质重力密度unit weight4. 土的物理性质自由水free water, gravitational water, groundwater, phreatic water4. 土的物理性质组构fabric4. 土的物理性质最大干密度maximum dry density4. 土的物理性质最优含水量optimum water content5. 渗透性和渗流达西定律Darcy s law5. 渗透性和渗流管涌piping5. 渗透性和渗流浸润线phreatic line5. 渗透性和渗流临界水力梯度critical hydraulic gradient5. 渗透性和渗流流函数flow function5. 渗透性和渗流流土flowing soil5. 渗透性和渗流流网flow net5. 渗透性和渗流砂沸sand boiling5. 渗透性和渗流渗流seepage5. 渗透性和渗流渗流量seepage discharge5. 渗透性和渗流渗流速度seepage velocity5. 渗透性和渗流渗透力seepage force5. 渗透性和渗流渗透破坏seepage failure5. 渗透性和渗流渗透系数coefficient of permeability5. 渗透性和渗流渗透性permeability5. 渗透性和渗流势函数potential function5. 渗透性和渗流水力梯度hydraulic gradient6. 地基应力和变形变形deformation6. 地基应力和变形变形模量modulus of deformation6. 地基应力和变形泊松比Poisson s ratio6. 地基应力和变形布西涅斯克解Boussinnesq s solution6. 地基应力和变形残余变形residual deformation6. 地基应力和变形残余孔隙水压力residual pore water pressure6. 地基应力和变形超静孔隙水压力excess pore water pressure6. 地基应力和变形沉降settlement6. 地基应力和变形沉降比settlement ratio6. 地基应力和变形次固结沉降secondary consolidation settlement6. 地基应力和变形次固结系数coefficient of secondary consolidation6. 地基应力和变形地基沉降的弹性力学公式elastic formula for settlement calculation 6. 地基应力和变形分层总和法layerwise summation method6. 地基应力和变形负孔隙水压力negative pore water pressure6. 地基应力和变形附加应力superimposed stress6. 地基应力和变形割线模量secant modulus6. 地基应力和变形固结沉降consolidation settlement6. 地基应力和变形规范沉降计算法settlement calculation by specification6. 地基应力和变形回弹变形rebound deformation6. 地基应力和变形回弹模量modulus of resilience6. 地基应力和变形回弹系数coefficient of resilience6. 地基应力和变形回弹指数swelling index6. 地基应力和变形建筑物的地基变形允许值allowable settlement of building6. 地基应力和变形剪胀dilatation6. 地基应力和变形角点法corner-points method6. 地基应力和变形孔隙气压力pore air pressure6. 地基应力和变形孔隙水压力pore water pressure6. 地基应力和变形孔隙压力系数Apore pressure parameter A6. 地基应力和变形孔隙压力系数Bpore pressure parameter B6. 地基应力和变形明德林解Mindlin s solution6. 地基应力和变形纽马克感应图Newmark chart6. 地基应力和变形切线模量tangent modulus6. 地基应力和变形蠕变creep6. 地基应力和变形三向变形条件下的固结沉降three-dimensional consolidation settlement 6. 地基应力和变形瞬时沉降immediate settlement6. 地基应力和变形塑性变形plastic deformation6. 地基应力和变形谈弹性变形elastic deformation6. 地基应力和变形谈弹性模量elastic modulus6. 地基应力和变形谈弹性平衡状态state of elastic equilibrium6. 地基应力和变形体积变形模量volumetric deformation modulus6. 地基应力和变形先期固结压力preconsolidation pressure6. 地基应力和变形压缩层6. 地基应力和变形压缩模量modulus of compressibility6. 地基应力和变形压缩系数coefficient of compressibility6. 地基应力和变形压缩性compressibility6. 地基应力和变形压缩指数compression index6. 地基应力和变形有效应力effective stress6. 地基应力和变形自重应力self-weight stress6. 地基应力和变形总应力total stress approach of shear strength6. 地基应力和变形最终沉降final settlement7. 固结巴隆固结理论Barron s consolidation theory7. 固结比奥固结理论Biot s consolidation theory7. 固结超固结比over-consolidation ratio7. 固结超静孔隙水压力excess pore water pressure7. 固结次固结secondary consolidation7. 固结次压缩(台)secondary consolidatin7. 固结单向度压密(台)one-dimensional consolidation7. 固结多维固结multi-dimensional consolidation7. 固结固结consolidation7. 固结固结度degree of consolidation7. 固结固结理论theory of consolidation7. 固结固结曲线consolidation curve7. 固结固结速率rate of consolidation7. 固结固结系数coefficient of consolidation7. 固结固结压力consolidation pressure7. 固结回弹曲线rebound curve7. 固结井径比drain spacing ratio7. 固结井阻well resistance7. 固结曼代尔-克雷尔效应Mandel-Cryer effect7. 固结潜变(台)creep7. 固结砂井sand drain7. 固结砂井地基平均固结度average degree of consolidation of sand-drained ground7. 固结时间对数拟合法logrithm of time fitting method7. 固结时间因子time factor7. 固结太沙基固结理论Terzaghi s consolidation theory7. 固结太沙基-伦杜列克扩散方程Terzaghi-Rendulic diffusion equation7. 固结先期固结压力preconsolidation pressure7. 固结压密(台)consolidation7. 固结压密度(台)degree of consolidation7. 固结压缩曲线cpmpression curve7. 固结一维固结one dimensional consolidation7. 固结有效应力原理principle of effective stress7. 固结预压密压力(台)preconsolidation pressure7. 固结原始压缩曲线virgin compression curve7. 固结再压缩曲线recompression curve7. 固结主固结primary consolidation7. 固结主压密(台)primary consolidation7. 固结准固结压力pseudo-consolidation pressure7. 固结K0固结consolidation under K0 condition8. 抗剪强度安息角(台)angle of repose8. 抗剪强度不排水抗剪强度undrained shear strength8. 抗剪强度残余内摩擦角residual angle of internal friction8. 抗剪强度残余强度residual strength8. 抗剪强度长期强度long-term strength8. 抗剪强度单轴抗拉强度uniaxial tension test8. 抗剪强度动强度dynamic strength of soils8. 抗剪强度峰值强度peak strength8. 抗剪强度伏斯列夫参数Hvorslev parameter8. 抗剪强度剪切应变速率shear strain rate8. 抗剪强度抗剪强度shear strength8. 抗剪强度抗剪强度参数shear strength parameter8. 抗剪强度抗剪强度有效应力法effective stress approach of shear strength 8. 抗剪强度抗剪强度总应力法total stress approach of shear strength8. 抗剪强度库仑方程Coulomb s equation8. 抗剪强度摩尔包线Mohr s envelope8. 抗剪强度摩尔-库仑理论Mohr-Coulomb theory8. 抗剪强度内摩擦角angle of internal friction8. 抗剪强度年粘聚力cohesion8. 抗剪强度破裂角angle of rupture8. 抗剪强度破坏准则failure criterion8. 抗剪强度十字板抗剪强度vane strength8. 抗剪强度无侧限抗压强度unconfined compression strength8. 抗剪强度有效内摩擦角effective angle of internal friction8. 抗剪强度有效粘聚力effective cohesion intercept8. 抗剪强度有效应力破坏包线effective stress failure envelope8. 抗剪强度有效应力强度参数effective stress strength parameter8. 抗剪强度有效应力原理principle of effective stress8. 抗剪强度真内摩擦角true angle internal friction8. 抗剪强度真粘聚力true cohesion8. 抗剪强度总应力破坏包线total stress failure envelope8. 抗剪强度总应力强度参数total stress strength parameter9. 本构模型本构模型constitutive model9. 本构模型边界面模型boundary surface model9. 本构模型层向各向同性体模型cross anisotropic model9. 本构模型超弹性模型hyperelastic model9. 本构模型德鲁克-普拉格准则Drucker-Prager criterion9. 本构模型邓肯-张模型Duncan-Chang model9. 本构模型动剪切强度9. 本构模型非线性弹性模量nonlinear elastic model9. 本构模型盖帽模型cap model9. 本构模型刚塑性模型rigid plastic model9. 本构模型割线模量secant modulus9. 本构模型广义冯·米赛斯屈服准则extended von Mises yield criterion 9. 本构模型广义特雷斯卡屈服准则extended tresca yield criterion9. 本构模型加工软化work softening9. 本构模型加工硬化work hardening9. 本构模型加工硬化定律strain harding law9. 本构模型剑桥模型Cambridge model9. 本构模型柯西弹性模型Cauchy elastic model9. 本构模型拉特-邓肯模型Lade-Duncan model9. 本构模型拉特屈服准则Lade yield criterion9. 本构模型理想弹塑性模型ideal elastoplastic model9. 本构模型临界状态弹塑性模型critical state elastoplastic model9. 本构模型流变学模型rheological model9. 本构模型流动规则flow rule9. 本构模型摩尔-库仑屈服准则Mohr-Coulomb yield criterion9. 本构模型内蕴时间塑性模型endochronic plastic model9. 本构模型内蕴时间塑性理论endochronic theory9. 本构模型年粘弹性模型viscoelastic model9. 本构模型切线模量tangent modulus9. 本构模型清华弹塑性模型Tsinghua elastoplastic model9. 本构模型屈服面yield surface9. 本构模型沈珠江三重屈服面模型Shen Zhujiang three yield surface method 9. 本构模型双参数地基模型9. 本构模型双剪应力屈服模型twin shear stress yield criterion9. 本构模型双曲线模型hyperbolic model9. 本构模型松岗元-中井屈服准则Matsuoka-Nakai yield criterion9. 本构模型塑性形变理论9. 本构模型谈弹塑性模量矩阵elastoplastic modulus matrix9. 本构模型谈弹塑性模型elastoplastic modulus9. 本构模型谈弹塑性增量理论incremental elastoplastic theory9. 本构模型谈弹性半空间地基模型elastic half-space foundation model9. 本构模型谈弹性变形elastic deformation9. 本构模型谈弹性模量elastic modulus9. 本构模型谈弹性模型elastic model9. 本构模型魏汝龙-Khosla-Wu模型Wei Rulong-Khosla-Wu model9. 本构模型文克尔地基模型Winkler foundation model9. 本构模型修正剑桥模型modified cambridge model9. 本构模型准弹性模型hypoelastic model10. 地基承载力冲剪破坏punching shear failure10. 地基承载力次层(台)substratum10. 地基承载力地基subgrade, ground, foundation soil10. 地基承载力地基承载力bearing capacity of foundation soil10. 地基承载力地基极限承载力ultimate bearing capacity of foundation soil10. 地基承载力地基允许承载力allowable bearing capacity of foundation soil10. 地基承载力地基稳定性stability of foundation soil10. 地基承载力汉森地基承载力公式Hansen s ultimate bearing capacity formula10. 地基承载力极限平衡状态state of limit equilibrium10. 地基承载力加州承载比(美国)California Bearing Ratio10. 地基承载力局部剪切破坏local shear failure10. 地基承载力临塑荷载critical edge pressure10. 地基承载力梅耶霍夫极限承载力公式Meyerhof s ultimate bearing capacity formula 10. 地基承载力普朗特承载力理论Prandel bearing capacity theory10. 地基承载力斯肯普顿极限承载力公式Skempton s ultimate bearing capacity formula 10. 地基承载力太沙基承载力理论Terzaghi bearing capacity theory10. 地基承载力魏锡克极限承载力公式V esic s ultimate bearing capacity formula10. 地基承载力整体剪切破坏general shear failure11. 土压力被动土压力passive earth pressure11. 土压力被动土压力系数coefficient of passive earth pressure11. 土压力极限平衡状态state of limit equilibrium11. 土压力静止土压力earth pressue at rest11. 土压力静止土压力系数coefficient of earth pressur at rest11. 土压力库仑土压力理论Coulomb s earth pressure theory11. 土压力库尔曼图解法Culmannn construction11. 土压力朗肯土压力理论Rankine s earth pressure theory11. 土压力朗肯状态Rankine state11. 土压力谈弹性平衡状态state of elastic equilibrium11. 土压力土压力earth pressure11. 土压力主动土压力active earth pressure11. 土压力主动土压力系数coefficient of active earth pressure12. 土坡稳定分析安息角(台)angle of repose12. 土坡稳定分析毕肖普法Bishop method12. 土坡稳定分析边坡稳定安全系数safety factor of slope12. 土坡稳定分析不平衡推理传递法unbalanced thrust transmission method12. 土坡稳定分析费伦纽斯条分法Fellenius method of slices12. 土坡稳定分析库尔曼法Culmann method12. 土坡稳定分析摩擦圆法friction circle method12. 土坡稳定分析摩根斯坦-普拉斯法Morgenstern-Price method12. 土坡稳定分析铅直边坡的临界高度critical height of vertical slope12. 土坡稳定分析瑞典圆弧滑动法Swedish circle method12. 土坡稳定分析斯宾赛法Spencer method12. 土坡稳定分析泰勒法Taylor method12. 土坡稳定分析条分法slice method12. 土坡稳定分析土坡slope12. 土坡稳定分析土坡稳定分析slope stability analysis12. 土坡稳定分析土坡稳定极限分析法limit analysis method of slope stability 12. 土坡稳定分析土坡稳定极限平衡法limit equilibrium method of slope stability 12. 土坡稳定分析休止角angle of repose12. 土坡稳定分析扬布普遍条分法Janbu general slice method12. 土坡稳定分析圆弧分析法circular arc analysis13. 土的动力性质比阻尼容量specific gravity capacity13. 土的动力性质波的弥散特性dispersion of waves13. 土的动力性质波速法wave velocity method13. 土的动力性质材料阻尼material damping13. 土的动力性质初始液化initial liquefaction13. 土的动力性质地基固有周期natural period of soil site13. 土的动力性质动剪切模量dynamic shear modulus of soils13. 土的动力性质动力布西涅斯克解dynamic solution of Boussinesq13. 土的动力性质动力放大因素dynamic magnification factor13. 土的动力性质动力性质dynamic properties of soils13. 土的动力性质动强度dynamic strength of soils13. 土的动力性质骨架波akeleton waves in soils13. 土的动力性质几何阻尼geometric damping13. 土的动力性质抗液化强度liquefaction stress13. 土的动力性质孔隙流体波fluid wave in soil13. 土的动力性质损耗角loss angle13. 土的动力性质往返活动性reciprocating activity13. 土的动力性质无量纲频率dimensionless frequency13. 土的动力性质液化liquefaction13. 土的动力性质液化势评价evaluation of liquefaction potential13. 土的动力性质液化应力比stress ratio of liquefaction13. 土的动力性质应力波stress waves in soils13. 土的动力性质振陷dynamic settlement13. 土的动力性质阻尼damping of soil13. 土的动力性质阻尼比damping ratio14. 挡土墙挡土墙retaining wall14. 挡土墙挡土墙排水设施14. 挡土墙挡土墙稳定性stability of retaining wall14. 挡土墙垛式挡土墙14. 挡土墙扶垛式挡土墙counterfort retaining wall14. 挡土墙后垛墙(台)counterfort retaining wall14. 挡土墙基础墙foundation wall14. 挡土墙加筋土挡墙reinforced earth bulkhead14. 挡土墙锚定板挡土墙anchored plate retaining wall14. 挡土墙锚定式板桩墙anchored sheet pile wall14. 挡土墙锚杆式挡土墙anchor rod retaining wall14. 挡土墙悬壁式板桩墙cantilever sheet pile wall14. 挡土墙悬壁式挡土墙cantilever sheet pile wall14. 挡土墙重力式挡土墙gravity retaining wall15. 板桩结构物板桩sheet pile15. 板桩结构物板桩结构sheet pile structure15. 板桩结构物钢板桩steel sheet pile15. 板桩结构物钢筋混凝土板桩reinforced concrete sheet pile15. 板桩结构物钢桩steel pile15. 板桩结构物灌注桩cast-in-place pile15. 板桩结构物拉杆tie rod15. 板桩结构物锚定式板桩墙anchored sheet pile wall15. 板桩结构物锚固技术anchoring15. 板桩结构物锚座Anchorage15. 板桩结构物木板桩wooden sheet pile15. 板桩结构物木桩timber piles15. 板桩结构物悬壁式板桩墙cantilever sheet pile wall16. 基坑开挖与降水板桩围护sheet pile-braced cuts16. 基坑开挖与降水电渗法electro-osmotic drainage16. 基坑开挖与降水管涌piping16. 基坑开挖与降水基底隆起heave of base16. 基坑开挖与降水基坑降水dewatering16. 基坑开挖与降水基坑失稳instability (failure) of foundation pit16. 基坑开挖与降水基坑围护bracing of foundation pit16. 基坑开挖与降水减压井relief well16. 基坑开挖与降水降低地下水位法dewatering method16. 基坑开挖与降水井点系统well point system16. 基坑开挖与降水喷射井点eductor well point16. 基坑开挖与降水铅直边坡的临界高度critical height of vertical slope 16. 基坑开挖与降水砂沸sand boiling16. 基坑开挖与降水深井点deep well point16. 基坑开挖与降水真空井点vacuum well point16. 基坑开挖与降水支撑围护braced cuts17. 浅基础杯形基础17. 浅基础补偿性基础compensated foundation17. 浅基础持力层bearing stratum17. 浅基础次层(台)substratum17. 浅基础单独基础individual footing17. 浅基础倒梁法inverted beam method17. 浅基础刚性角pressure distribution angle of masonary foundation 17. 浅基础刚性基础rigid foundation17. 浅基础高杯口基础17. 浅基础基础埋置深度embeded depth of foundation17. 浅基础基床系数coefficient of subgrade reaction17. 浅基础基底附加应力net foundation pressure17. 浅基础交叉条形基础cross strip footing17. 浅基础接触压力contact pressure17. 浅基础静定分析法(浅基础)static analysis (shallow foundation)17. 浅基础壳体基础shell foundation17. 浅基础扩展基础spread footing17. 浅基础片筏基础mat foundation17. 浅基础浅基础shallow foundation17. 浅基础墙下条形基础17. 浅基础热摩奇金法Zemochkin s method17. 浅基础柔性基础flexible foundation17. 浅基础上部结构-基础-土共同作用分析structure- foundation-soil interactionanalysis 17. 浅基础谈弹性地基梁(板)分析analysis of beams and slabs on elastic foundation 17. 浅基础条形基础strip footing17. 浅基础下卧层substratum17. 浅基础箱形基础box foundation17. 浅基础柱下条形基础18. 深基础贝诺托灌注桩Benoto cast-in-place pile18. 深基础波动方程分析Wave equation analysis18. 深基础场铸桩(台)cast-in-place pile18. 深基础沉管灌注桩diving casting cast-in-place pile18. 深基础沉井基础open-end caisson foundation18. 深基础沉箱基础box caisson foundation18. 深基础成孔灌注同步桩synchronous pile18. 深基础承台pile caps18. 深基础充盈系数fullness coefficient18. 深基础单桩承载力bearing capacity of single pile18. 深基础单桩横向极限承载力ultimate lateral resistance of single pile18. 深基础单桩竖向抗拔极限承载力vertical ultimate uplift resistance of single pile18. 深基础单桩竖向抗压容许承载力vertical ultimate carrying capacity of single pile18. 深基础单桩竖向抗压极限承载力vertical allowable load capacity of single pile18. 深基础低桩承台low pile cap18. 深基础地下连续墙diaphgram wall18. 深基础点承桩(台)end-bearing pile18. 深基础动力打桩公式dynamic pile driving formula18. 深基础端承桩end-bearing pile18. 深基础法兰基灌注桩Franki pile18. 深基础负摩擦力negative skin friction of pile18. 深基础钢筋混凝土预制桩precast reinforced concrete piles18. 深基础钢桩steel pile18. 深基础高桩承台high-rise pile cap18. 深基础灌注桩cast-in-place pile18. 深基础横向载荷桩laterally loaded vertical piles18. 深基础护壁泥浆slurry coat method18. 深基础回转钻孔灌注桩rotatory boring cast-in-place pile18. 深基础机挖异形灌注桩18. 深基础静力压桩silent piling18. 深基础抗拔桩uplift pile18. 深基础抗滑桩anti-slide pile18. 深基础摩擦桩friction pile18. 深基础木桩timber piles18. 深基础嵌岩灌注桩piles set into rock18. 深基础群桩pile groups18. 深基础群桩效率系数efficiency factor of pile groups18. 深基础群桩效应efficiency of pile groups18. 深基础群桩竖向极限承载力vertical ultimate load capacity of pile groups 18. 深基础深基础deep foundation18. 深基础竖直群桩横向极限承载力18. 深基础无桩靴夯扩灌注桩rammed bulb ile18. 深基础旋转挤压灌注桩18. 深基础桩piles18. 深基础桩基动测技术dynamic pile test18. 深基础钻孔墩基础drilled-pier foundation18. 深基础钻孔扩底灌注桩under-reamed bored pile18. 深基础钻孔压注桩starsol enbesol pile18. 深基础最后贯入度final set19. 地基处理表层压密法surface compaction19. 地基处理超载预压surcharge preloading19. 地基处理袋装砂井sand wick19. 地基处理地工织物geofabric, geotextile19. 地基处理地基处理ground treatment, foundation treatment19. 地基处理电动化学灌浆electrochemical grouting19. 地基处理电渗法electro-osmotic drainage19. 地基处理顶升纠偏法19. 地基处理定喷directional jet grouting19. 地基处理冻土地基处理frozen foundation improvement19. 地基处理短桩处理treatment with short pile19. 地基处理堆载预压法preloading19. 地基处理粉体喷射深层搅拌法powder deep mixing method19. 地基处理复合地基composite foundation19. 地基处理干振成孔灌注桩vibratory bored pile19. 地基处理高压喷射注浆法jet grounting19. 地基处理灌浆材料injection material19. 地基处理灌浆法grouting19. 地基处理硅化法silicification19. 地基处理夯实桩compacting pile19. 地基处理化学灌浆chemical grouting19. 地基处理换填法cushion19. 地基处理灰土桩lime soil pile19. 地基处理基础加压纠偏法19. 地基处理挤密灌浆compaction grouting19. 地基处理挤密桩compaction pile, compacted column19. 地基处理挤淤法displacement method19. 地基处理加筋法reinforcement method19. 地基处理加筋土reinforced earth19. 地基处理碱液法soda solution grouting19. 地基处理浆液深层搅拌法grout deep mixing method19. 地基处理降低地下水位法dewatering method19. 地基处理纠偏技术19. 地基处理坑式托换pit underpinning19. 地基处理冷热处理法freezing and heating19. 地基处理锚固技术anchoring19. 地基处理锚杆静压桩托换anchor pile underpinning19. 地基处理排水固结法consolidation19. 地基处理膨胀土地基处理expansive foundation treatment19. 地基处理劈裂灌浆fracture grouting19. 地基处理浅层处理shallow treatment19. 地基处理强夯法dynamic compaction19. 地基处理人工地基artificial foundation19. 地基处理容许灌浆压力allowable grouting pressure19. 地基处理褥垫pillow19. 地基处理软土地基soft clay ground19. 地基处理砂井sand drain19. 地基处理砂井地基平均固结度average degree of consolidation of sand-drained ground 19. 地基处理砂桩sand column19. 地基处理山区地基处理foundation treatment in mountain area19. 地基处理深层搅拌法deep mixing method19. 地基处理渗入性灌浆seep-in grouting19. 地基处理湿陷性黄土地基处理collapsible loess treatment19. 地基处理石灰系深层搅拌法lime deep mixing method19. 地基处理石灰桩lime column, limepile19. 地基处理树根桩root pile19. 地基处理水泥土水泥掺合比cement mixing ratio19. 地基处理水泥系深层搅拌法cement deep mixing method19. 地基处理水平旋喷horizontal jet grouting19. 地基处理塑料排水带plastic drain19. 地基处理碎石桩gravel pile, stone pillar19. 地基处理掏土纠偏法19. 地基处理天然地基natural foundation19. 地基处理土工聚合物Geopolymer19. 地基处理土工织物geofabric, geotextile19. 地基处理土桩earth pile19. 地基处理托换技术underpinning technique19. 地基处理外掺剂additive19. 地基处理旋喷jet grouting19. 地基处理药液灌浆chemical grouting19. 地基处理预浸水法presoaking19. 地基处理预压法preloading19. 地基处理真空预压vacuum preloading19. 地基处理振冲法vibroflotation method19. 地基处理振冲密实法vibro-compaction19. 地基处理振冲碎石桩vibro replacement stone column19. 地基处理振冲置换法vibro-replacement19. 地基处理振密、挤密法vibro-densification, compacting19. 地基处理置换率(复合地基)replacement ratio19. 地基处理重锤夯实法tamping19. 地基处理桩式托换pile underpinning19. 地基处理桩土应力比stress ratio20. 动力机器基础比阻尼容量specific gravity capacity20. 动力机器基础等效集总参数法constant strain rate consolidation test20. 动力机器基础地基固有周期natural period of soil site20. 动力机器基础动基床反力法dynamic subgrade reaction method20. 动力机器基础动力放大因素dynamic magnification factor20. 动力机器基础隔振isolation20. 动力机器基础基础振动foundation vibration20. 动力机器基础基础振动半空间理论elastic half-space theory of foundation vibr ation20. 动力机器基础基础振动容许振幅allowable amplitude of foundation vibration 20. 动力机器基础基础自振频率natural frequency of foundation20. 动力机器基础集总参数法lumped parameter method20. 动力机器基础吸收系数absorption coefficient20. 动力机器基础质量-弹簧-阻尼器系统mass-spring-dushpot system21. 地基基础抗震地基固有周期natural period of soil site21. 地基基础抗震地震earthquake, seism, temblor21. 地基基础抗震地震持续时间duration of earthquake21. 地基基础抗震地震等效均匀剪应力equivalent even shear stress of earthquake 21. 地基基础抗震地震反应谱earthquake response spectrum21. 地基基础抗震地震烈度earthquake intensity21. 地基基础抗震地震震级earthquake magnitude21. 地基基础抗震地震卓越周期seismic predominant period21. 地基基础抗震地震最大加速度maximum acceleration of earthquake21. 地基基础抗震动力放大因数dynamic magnification factor21. 地基基础抗震对数递减率logrithmic decrement21. 地基基础抗震刚性系数coefficient of rigidity21. 地基基础抗震吸收系数absorption coefficient22. 室内土工试验比重试验specific gravity test22. 室内土工试验变水头渗透试验falling head permeability test22. 室内土工试验不固结不排水试验unconsolidated-undrained triaxial test22. 室内土工试验常规固结试验routine consolidation test22. 室内土工试验常水头渗透试验constant head permeability test22. 室内土工试验单剪仪simple shear apparatus22. 室内土工试验单轴拉伸试验uniaxial tensile test22. 室内土工试验等速加荷固结试验constant loading rate consolidatin test22. 室内土工试验等梯度固结试验constant gradient consolidation test22. 室内土工试验等应变速率固结试验equivalent lumped parameter method22. 室内土工试验反复直剪强度试验repeated direct shear test22. 室内土工试验反压饱和法back pressure saturation method22. 室内土工试验高压固结试验high pressure consolidation test22. 室内土工试验各向不等压固结不排水试验consoidated anisotropically undrained test 22. 室内土工试验各向不等压固结排水试验consolidated anisotropically drained test 22. 室内土工试验共振柱试验resonant column test22. 室内土工试验固结不排水试验consolidated undrained triaxial test22. 室内土工试验固结快剪试验consolidated quick direct shear test22. 室内土工试验固结排水试验consolidated drained triaxial test22. 室内土工试验固结试验consolidation test22. 室内土工试验含水量试验water content test22. 室内土工试验环剪试验ring shear test22. 室内土工试验黄土湿陷试验loess collapsibility test22. 室内土工试验击实试验22. 室内土工试验界限含水量试验Atterberg limits test22. 室内土工试验卡萨格兰德法Casagrande s method22. 室内土工试验颗粒分析试验grain size analysis test22. 室内土工试验孔隙水压力消散试验pore pressure dissipation test22. 室内土工试验快剪试验quick direct shear test22. 室内土工试验快速固结试验fast consolidation test22. 室内土工试验离心模型试验centrifugal model test22. 室内土工试验连续加荷固结试验continual loading test22. 室内土工试验慢剪试验consolidated drained direct shear test22. 室内土工试验毛细管上升高度试验capillary rise test22. 室内土工试验密度试验density test22. 室内土工试验扭剪仪torsion shear apparatus22. 室内土工试验膨胀率试验swelling rate test22. 室内土工试验平面应变仪plane strain apparatus22. 室内土工试验三轴伸长试验triaxial extension test22. 室内土工试验三轴压缩试验triaxial compression test22. 室内土工试验砂的相对密实度试验sand relative density test22. 室内土工试验筛分析sieve analysis。
土木工程专业毕业设计外文翻译
High-Rise BuildingsIn troducti onIt is difficult to defi ne a high-rise buildi ng . One may say that a low-rise build ing ranges from 1 to 2 stories . A medium-rise buildi ng p robably ran ges betwee n 3 or 4 stories up to 10or 20 stories or more .Although the basic principles of vertical and horiz on tal subsystem desig n rema in the samefor low- , medium- , or high-rise build ings , whe n a build ing gets high the verticalsubsystemsbecome a con trolli ng p roblem for two reas ons . Higher vertical loads will requirelarger colu mns , walls , and shafts . But , more sig nifica ntly , the overtur ning mome nt and theshear deflect ions p roduced by lateral forces are much larger and must be carefully pro vided for .The vertical subsystems in a high-rise buildi ng tran smit accumulated gravity load from storyto story , thus requiri ng larger colu mn or wall secti ons to support such loadi ng .In additi onthese same vertical subsystems must tran smit lateral loads , such as wi nd or seismic loads , tothe foun datio ns. However , in con trast to vertical load , lateral load effects on build ings arenot lin ear and in crease rap idly with in crease in height . For example under wind load , theoverturning moment at the base of buildings varies approximately as the square of a buildings mayvary as the fourth power of buildings height , other things being equal. Earthquake produces an evenmore pronoun ced effect.When the structure for a low-or medium-rise building is designed for dead and live load , it isalmost an in here nt property that the colu mns , walls , and stair or elevator shafts can carrymost of the horiz on tal forces . The p roblem is p rimarily one of shear resista nee . Moderateadditi on braci ng for rigid frames in easily be pro vided by filli ng certa in pan els ( or eve n“short ” buildi all pan els ) without in creas ing the sizes of the colu mns and girders otherwise required forvertical loads.Unfortunately , this is not is for high-rise buildings because the problem is p rimarily resistanee to mome nt and deflect ion rather tha n shear alone . Sp ecial structural arra ngeme nts will often have to be made and additi onal structural material is always required for the columns , girders ,walls , and slabs in order to made a high-rise buildi ngs sufficie ntly resista nt to much higherlateral deformati ons .As p reviously men ti oned , the qua ntity of structural material required per square foot offloor of a high-rise buildings is in excess of that required for low-rise buildings . The verticalcomponents carrying the gravity load , such as walls , columns , and shafts , will need to bestrengthened over the full height of the build ings . But qua ntity of material required for resisting lateral forces is eve n more sig nifica nt .With rei nforced con crete , the qua ntity of material also in creases as the nu mber ofstories in creases . But here it should be no ted that the in crease in the weight of material addedfor gravity load is much more sizable tha n steel , whereas for windIn crease the effective width of the mome nt-resisti ng subsystems . This is very usefulbecause in creas ing the width will cut dow n the overtur n force directly and willreduce deflecti on by the third po wer of the width in crease , other things rema iningcin sta nt . However , this does require that vertical components of the widenedsubsystem be suitably connected to actually gain this ben efit.Desig n subsystemssuch that the components are made to in teract in the most efficientmanner . For example , use truss systems with chords and diagonals efficiently stressed ,place reinforcing for walls at critical locati ons , and op timize stiff ness ratios for rigid frames .In crease the material in the most effective resist ing components . For exa mple ,materials added in the lower floors to the flan ges of colu mns and conn ect ing girderswill directly decrease the overall deflect ion and in crease the mome nt resista neewithout con tribut ing mass in the upper floors where the earthquake p roblem isaggravated .Arrange to have the greater part of vertical loads be carried directly on the primarymoment-resisting components . This will help stabilize the build ings aga inst ten sileovertu rning forces by p reco mp ress in gthe major overturn-resisti ng components .The local shear in each story can be best resisted by strategic pl aceme nt if solid wallsor the use of diagonal members in a vertical subsystem . Resist ing these shears solelyby vertical members in bending is usually less econo mical , since achiev ing sufficient bending resista nee in the colu mns and conn ect ing girders will require morematerial and con struct ion en ergy tha n using walls or diago nal members .Sufficie nt horiz on tal dia phragm acti on should be pro vided floor . This will help tobring the various resist ing eleme nts to work together in stead of sep arately .Create mega-frames by joining large vertical and horizontal components such as two or moreelevator shafts at multistory intervals with a heavy floor subsystems , or by use of verydee p girder trusses .Remember that all high-rise build ings are esse ntially vertical can tilevers which aresupported at the ground . When the above principles are judiciously applied , structurally desirable schemes can be obta ined by walls , cores , rigid frames, tubular con struct ion , and othervertical subsystems to achieve horiz on tal stre ngth and rigidity . Some of these app licati ons will now be described in subseque nt secti ons in the followi ng .Shear-Wall SystemsWhen shear walls are comp atible with other fun cti onal requireme nts , they can beeconomically utilized to resist lateral forces in high-rise buildings . For example , ap artme nt build ings n aturally require many sep arati on walls . Whe n some of these are desig ned to be load the in crease for lateral force resista nee is not that much more since the weight of a concrete buildings helps to resist overturn . On the other hand , the problem of desig n for earthquake forces . Additi onal mass in the upper floors will give rise to a greater overall lateral force un der the of seismic effects .In the case of either concrete or steel design , there are certain basic principles for pro vid ing additi onal resista nee to lateral to lateral forces and deflecti ons in high-rise build ings without too much sacrifire in economy .1.2. 3. 4. 5. 6. 7.solid , they can act as shear walls to resist lateral forces and to carry the vertical load aswell . For buildi ngs up to some 20storise , the use of shear walls is com mon .If give n sufficie nt len gth ,such walls can econo mically resist lateral forces up to 30 to 40 stories or more .However , shear walls can resist lateral load only the plane of the walls ( i.e .not in adireti on perpen dicular to them ) . There fore ,it is always n ecessary to pro vide shear walls in two perpen dicular directi ons can be at least in sufficie nt orie ntati on so that lateral force in any direct ion can be resisted .In additi on , that wall layout should reflect con siderati on of any torsi onal effect .In desig n p rogress , two or more shear walls can be conn ected to from L-sha ped or cha nnel-sha ped subsystems .In deed ‘internal shear walls can be conn ected to from a rectangular shaft that will resist lateral forces very efficiently . If all external shear walls are continuously connected , then the whole buildings acts as tube , and conn ected , the n the whole buildi ngs acts as a tube , and is excelle nt Shear-Wall Seystems resist ing lateral loads and torsi on .Whereas con crete shear walls are gen erally of solid type with openings whe n necessary, steel shear walls are usually made of trusses . These trusses can have single diagonals , “X” diagona|sor “ K” arrang e nhs . A trussed wall will have its members act esse ntially in direct tension or comp ressi on un der the acti on of view , and they offer some opportunity anddeflection-limitation point of view , and they offer some opportunity for penetration between members . Of course , the inclined members of trusses must be suitable p laced so as not to in terfere with requireme nts for wion dows and for circulati on service pen etrati ons though these walls .As stated above , the walls of elevator , staircase ,and utility shafts form n atural tubes and are com monly empio yed to resist both vertical and lateral forces . Since these shafts are no rmally recta ngular or circular in cross-sect ion , they can offer an efficie nt means for resist ing mome nts and shear in all directi ons due to tube structural action . But a p roblem in the desig n of these shafts is pro vided sufficie nt stre ngth around door openings and other pen etrati ons through these eleme nts . For rein forced concrete construction , special steel reinforcements are placed around such opening .In steel con struct ion , heavier and more rigid conn ecti ons are required to resist rack ing at the openings .In many high-rise build ings , a comb in ati on of walls and shafts can offer excelle ntresista nee to lateral forces whe n they are suitably located ant conn ected to one ano ther . It is also desirable that the stiff ness offered these subsystems be more-or-less symmertrical in all direct ions .Rigid-Frame SystemsIn the desig n of architectural build ings , rigid-frame systems for resist ing vertical and lateral loads have long bee n acce pted as an imp orta nt and sta ndard means for designingbuilding . They are empioyed for low-and medium means for designing build ings . They are empio yed for low- and medium up to high-rise build ing p erha ps 70 or 100 stories high . Whe n comp ared to shear-wall systems , these rigid frames both with in and at the outside of a buildi ngs . They also make use of the stiff ness in beams and colu mns that are required for the build ings in any case , but the colu mns are made stron ger whe n rigidly conn ected to resist the lateral as well as vertical forces though frame bending .Freque ntly , rigid frames will not be as stiff as shear-wall con struct ion , and therefore may p roduce excessive deflecti ons for the more sle nder high-rise buildi ngs desig ns . But because of this flexibility , they are ofte n con sidered as being more ductile and thus less susceptible to catastr op hic earthquake failure whe n comp ared with ( some ) shear-wall desig ns . For exa mple , if over stress ing occurs at certa in p orti ons of a steel rigid frame ( i.e., near the joi nt ) , ductility will allow the structure as a whole to deflect a little more , but it will by no means colla pse eve n un der a much larger force tha n exp ected on the structure . For this reas on , rigid-frame con struct ion is considered by some to be a “ best ” seisresisting type for high-rise steel buildings . On the other hand ,it is also unlikely that a well-designed share-wall system would colla pse.In the case of con crete rigid frames ,there is a diverge nee of opinion .It true that if a con crete rigid frame is desig ned in the conven ti onal manner , without sp ecial care to produce higher ductility , it will not be able to withstand a catastrophic earthquake that can p roduce forces several times lerger tha n the code desig n earthquake forces . therefore , some believe that it may not have additi onal cap acity p ossessed by steel rigid frames . But moder n research and exp erie nee has in dicated that con crete frames can be desig ned to be ductile , whe n sufficie nt stirr ups and joinery rein forceme nt are designed in to the frame . Modern buildings codes have specifications for the so-called ductile con crete frames . However , at p rese nt , these codesofte n require excessive rein forceme nt at certa in points in the frame so as to cause con gesti on and result in construction difficulties 。
土木工程专业毕业设计外文文献翻译2篇
土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计(论文)英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。
土木工程--毕业设计外文翻译(原文+翻译)
毕业设计(论文)外文翻译题目西北物流中心2号楼设计专业土木工程班级土木074学生指导教师二零一零年Low-coherence deformation sensors for themonitoring of civil-engineering structuresD. Inaudi a, A. Elamari b, L. Pflug a, N. Gisin b, J. Breguet b, S. Vurpillot a “IMAC, Laboratory of Stress Analysis, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland ‘GAP, Group of Applied Physics -Optical Seciion, Geneva University CH-1205 Geneva, SwitzerlandRcccivcd 25 January 1993; in revised form 8 March 1994; accepted 25 March 1994 AbstractAn optical-fiber deformation sensor with a resolution of 10 pm and an operational range of 60 mm has been realized. The system is based on low-coherence interferometry instandard single-mode telecommunication fibers. It allows the monitoring of large structures over several months without noticeable drift. No continuous measurement is needed and the system is insensitive to variations of the fiber losses. This technique has been applied to the monitoring of a 20 m X5 m X0.5 m, 120 ton concrete slab over six months. It is possible to measure the shrinkage of concrete and its elastic coefficient during pre-straining, giving reproducible results in good agreement with theoretical calculations and measurements performed on small concrete samples. This paper describes the optical arrangement and the procedures used to install optical fibers in concrete.Keywor&: Ikformation sensors; Civil-engineering structures1. IntroductionBoth the security of civil-engineering works and the law require a periodic monitoring of structures. The methods used for this purpose, such as triangulation, water levels or vibrating strings, are often of tedious application and require one or many specialized operators. This complexity and the resulting costs limit the frequency of the measurements. Furthermore, the spatial resolution is often poor and the observation is usually restricted to the surface of the object. There is thus a real demand for a tool allowing an internal, automatic and permanent monitoring of structures with high accuracy and stability over periods typically of the order of 100 years for bridges. In this framework, fiber-optic smart structures (i.e., structures with self-testing capabilities) are gaining in importance in many fields including aeronautics and composite material monitoring. This technology can be applied in civilengineering and in particular for the short- and long-time observation of large structures such as bridges, tall building frames, dams, tunnels, roads, airport runways, domes, pre-stressing and anchorage cables. The monitoring of such structures requires the development of a measuring technique with high accuracy,stability and reliability over long periods. It has to beindependent of variations in the fiber losses and adapted to the adverse environment of a building site. To reduce the cost of the instrumentation, it is furthermore desirable to use the same portable reading unit for the monitoring of multiple structures. We describe here asystem based on low-coherence interferometry responding to all these requirements.2. Experimental arrangementThe measuring technique relies on an array of standard telecommunication optical fibers in mechanical contact with concrete. Any deformation of the host structure results jn a change in the optical length of he fibers. Each sensor line consists of two single-mode ibers: one measurement fiber in mechanical contact with the structure (glued or cemented) and a reference iber placed loose near the first one (in a pipe) in order to be at the same temperature. Since the measurement technique monitors the length difference beween these two fibers, only the mechanical deformation will have an effect on the results while all other perurbations, such as thermally induced changes in the refractive index of the fibers,will affect the two in an identical way and cancel each another out. To measure the optical path difference between the two fibers, a low-coherence double interferometer in tandem configuration has been used (Fig. 1) [l]. The source is an LED (light-emitting diode) working around 1.3 pm with a coherence length L, of 30 pm and a rated power of 200 pW. The radiation is launched into a single-mode fiber and then directed toward the measurement and the reference fibers by means of a 50:50 single-mode directional coupler. At the ends of the fibers two mirrors reflect the light back to the coupler, where the beams arc recombined with a relative delay due to the length difference AL, between the fibers, and then directed towards the second (reference) interferometer. The reference interferometer is of Michelson type with one of the arms ended by a mobile mirror mounted on a micromctric displacement table with a resolution of 0.1 pm and an operating range of 50 mm. It allows the introduction of an exactly known path difFcrence AL, between its two arms. This fiber interferometer is portable and needs no optical adjustment after transportation. It has been developed by the GAP with the support of the Swiss PTT for optical cable testing [2].The intensity at the output of the reference inter- ferometer is measured with a pig-tail photodiode and is then given by [3]where zz,,r is the effective refractive index of the fiber, zzg the group refractive index (about 1% higher than nefr in silica), A, the central vacuum wavelength of the light, zi,, the autocorrelation function taking the spectral characteristics of the emission into account and AL the physical path difference between the two interfering paths. Further similar interference terms appear in Eq.(1) in the special cases when AL, <L, or AL, < L,. When the optical path difference between the arms in the reference interferometer corresponds to the one induced by the two fibers installed in the structure (within the coherence length of the source), interference fringes appear. Scanning AL, with the mirror of the reference interferometer it is possible to obtain AL = 0either with AL, = AL, or with AL, = -AL,, and thus two interference fringe packets as described by Eq. (1). The mirror position corresponding to AL, = 0 also produces an interference and is used as a reference. These three fringe packets arc detected by means of a lock-in amplifier synchronized with the mirror displacements. The mirror displacements and the digitalization of the lock-in output are carried out by means of a portable personal computer. Since the reference signal is gcnerated separately and does not have a constant phase relation to the interference signal, only the envelope of the demodulated signal has a physical meaning and corresponds to the envelope of the fringe pattern. A lock-in plot showing the three typical peaks is shown in Fig. 2. Each peak has a width of about 30 pm. The calculation of its center of gravity determines its position with a precision better than 10 pm. This precision is the limiting factor of the whole measurement technique. Since AL, is known with micrometer precision, it is possible to follow AL, with the same precision.Fig. 1. Experimental setup of the low-coherence double Michelson interferomctcr. D. Innudi et al. 1 Semors andFig. 2. Typical fringe cnvclope as a function of the mirror position. The distance between the central and the lateral peaks corresponds to the length difference between the measurement and the reference fibers mounted in the table. Any change in the length of the structure results in a change in the position of these peaks. Any change in the losses of the fibers will result in a change of the height of the peaks. The central peak is fixed and used as a reference.The path difference AL, is proportional to the de-formation of the structure AL, with the relation between the two given by [4]where p is Poisson’s ratio and pij is the strain optic tensor (Pockcl’s coefhcients). The coefficient 5 takes into account the variation of the effective index neff in a fiber under strain.A degradation of one or both fibers (due to aging, for example) will result in a lower visibilityof the fringes but will not affect its position. The information about the deformation of the structure is encoded in the coherence properties of light and not in its intensity as in the majority of the sensors applied to date in civil-engineering structures, mostly based on microbend losses and/or optical time-domain reflectometry (OTDR) techniques. Interference peaks resulting from reflections as low as -30 dB of the source power can be detected by our system without phase modulators. By modulating the phase in one of the four arms of the two interferometers, one can increase the dynamic range of the device to more than 100 dB [5].Even if the polarization dispersion and bend-induced birefringence in the sensing fibers could reduce the visibility of the interference fringes or even split the fringe packets, none of those effects was observed in our experiment. No adjustment of polarization between the reference and the sensing arm was then necessary. A good mechanical contact between the measurement fiber and the structure under test is fundamental. In this study a number of installation procedures have been tested and optimized for the different measurements (shrinkage, elasticity modulus, etc.). The mounting techniques can be divided into two main categories: full-length coupling and local coupling.During our tests five out of six optical fiber pairs with a 0.9 mm nylon coating, being mounted on the external face of a 20 m long plastic pipe and protected only with thin rubber bands (see Fig. 3(a)), survived the concreting process. During the setting process the concrete envelops the fiber and realizes the desired mechanical contact. Those fibers showed a minor increase in the scattering losses and the appearance of small parasite peaks. The measurements on those fibers were consistent with the results obtained with other installation techniques (see below). It seems that for full-length coupling the nylon coating transmits the structure deformations (extension and shortening) entirely to the fiber core. This installation technique is very promising when compared to the usual procedure, consisting of a pipe protecting the fibers during the pouring of concrete and being removed before the setting process begins. This second method seemsmore adapted to small samples than to full-scale structures. Eleven otherfiber pairs were glued at the two ends of the table after removing locally the protective coating layers of the fibers (see Fig. 3(b)). The silica fiber was ftxed with epoxy glue to a metallic plate mounted on the end facesof the concrete structure. The gluing length was about 20 mm. Apre-strain (between 0.1 and 0.4%) has been given to those fibers during the gluing process to keep them under tension and allow the measurement of both expansion and shrinkage of the structure. This type of local coupling proved to be the most reliable, but was not adapted to following thedeformation during the pre-stressing of the table because of the important surface deformations occurring during this operation. The problem has been overcome by gluing other fibers inside the pipes at about two meters from the surfaces, i.e., far from the force insertion region (see Fig. 3(c)).Fig. 3. Schematic representation of three of the installation techniques used:(a) direct concreting of the measurement fiber mounted on a plastic pipe; (b) fiber glued at the table surface; (c) fiber glued inside the pipe at 2m from the pipe ends.Fig. 4. Top and side views of the concrete table measured in the experiment and position of the sensing-fiber pairs A, B, C and D. Fibers A, B and C arc glued at the surface of the structure, while fiber D is glued inside a pipe, 2 m away from the surface of the slab. Twelve more fihcr pairs were installed, but are not shown for simplicity.To study the possible effect of creep in strained fibers [6], one fiber has been mounted on a mechanical support that allows the fiber to be tightened only at the time of the measurement. No difference between this fiberand those permanently strained has been observed over a period of six months, confirming the assumption that no creep occurs for fiber strains below 1%. Since the scanning range of the mirror is 5 mm, it was easy to cleave the 20 m long fibers within this margin. The Fresnel reflection of the cleaved fibers combined with the high dynamic of the system allow a measurement of AL,,. This value of AL, can than be used to correct the cutting and obtain pairs with length differences below 1 mm. Two ferrules were then installed on the fiber ends and mounted in front of a polished inox surface. Chemical silver deposition was also used to produce mirrors on the cleaved fiber ends.Fig. 6. Comparison between the measurements performed on the structure by optical fibers and the ones performed on 360 mm and 500 mm samples in a mechanical micrometer comparator. The measurement on the samples was possible only during the first two months.3. ResultsSeveral long- and short-term measurements have been carried on a 20 m x 5 m x 0.5 m, 120 ton concrete slab intended to be used as a vibration-isolated base for optical analysis (in particular by holographic and speckle interferometry) of large structures [7].This structure has been concreted indoors, allowing controlled environmcntal conditions and known concrete composition to be achieved. Samples have been prepared with the same material composition and are under permanent test for their mechanical properties (resistance, shrinkage and elastic coefficient). This allows a direct comparison between the results on the full-scale structure and the samples. The table has been pre-strained 23 days after concreting in both length and width. It was possible at this time to measure the elastic coefficient of the material in full scale. Fig. 4 shows a schematic representation of the table and the position of the fibers referred to in the experimental results. At the time of writing, the table has been under test for six months. Over this period the shrinkage in the longitudinal direction (i.e., over 20 m) has been about 6 mm. We show in Fig. 5 the results of the measurements for three (glued) fibers over 175 days. The table has a T profile (Fig. 4). It is evident from Fig. 5 that thefibers mounted near the borders of the table, i.e., were the thickness is smaller, registered a larger shrinkage, as expected according to the concrete theory. Adjacentfibers give consistent results independently of the installation technique. No difference has been noticed between the fibers under permanent tension and those loosened between the measurements, suggesting that no creep of glass fibers occurred. The shrinkage measured with the fiber system has been compared during the first two months with the results obtained with a mechanical comparator mounted on two samples of 360 mm and 500 mm, respectively.The observed deformations have been scaled to 20m and are compared in Fig.6 to the results obtained with fibers B and C. Very good agreement is found between the two measurements. A theoretical comparison between the experimentalresults and the Swiss civil engineering standards has also been carried out. The experimental data and the standards are in agreement within f 10%. A more accurate simulation including the physico-chemical properties of the concrete used is under development. The table was pre-stressed 23 days after concreting. The five steel cables running over the length of the table and the forty cables running over its width were stretched with a force of 185 kN (18.5 Tons) each. The fibers glued to the surface and those in direct contact with concrete over the whole length measured an expansion of the table instead of the expected shrinkage. This is due to the important surface deformations occurring near the force-insertion points, i.e., near the pre-stress heads that were placed near the fiber ends. Fiber D glued inside the plastic pipe at 2m from each endwas not subject to these local effects and measured a shortening of 0.23 mm. The theoretical calculation based on an elastic coefficient of 30 kN/mm2gives a shortening of 0.28mm at the borders and 0.19 mm at the center of the table. Since fiber D was placed in an intermediate position, the experimental value can be considered to be in good agreement with the theory.4. ConclusionsA new deformation sensor adapted to the monitoring of civil-engineering structures has been proposed. it is based on low-coherence interferometry in standard lowcost telecommunication fibers. The resolution of the measurements is 10 pm, the operational range is 60mm and the stability has been tested over six months without noticeable drift. The reading unit is compact and portable, needing no optical alignment before the measurements. It is controlled by a portable personal computer, which is also responsible for the data trcatment. The same reading unit can be used to monitor multiple fiber lines by simple manual unplugging. This technique is furthermore practically insensitive to increased losses due to degradation of the fibers. A test study has been carried out on a 20m ~5m X 0.5m concrete slab, giving consistent results when compared to other measurement techniques based on samples or to concrete theories. It was possible to follow concrete shrinkage over six months (the cxper- iment will continue for about five years) and to measure the elastic coefficient on the full-scale structure. Different fiber-installation techniques adapted to the measurement of various parameters have been tested in building-site conditions. This technique appears very promising for the mon-itoring of civil-engineering structures such as bridges, dams and tunnels, allowing internal, automatic and permanent monitoring with high precision and stability over long periods.AcknowledgmentsThe authors are indebted to R. Passy and R. Delez for their assistance, encouragement and helpful dis-cussion. We acknowledge the IMM Institute in Lugano (Switzerland) for placing the table at our disposal and for the measurements carried out on concrete samples. We are grateful to Dr M. Pedretti and Ing R. Passera for their personal engagement in the project. We also thank Cabloptic in Cortaillod (Switzerland) for sup-plying all the optical fibers used in the experiment. This research has been performed with the financial support of CERS (Commission pour 1’Encouragement de la Recherche Scientifique).References[1] A.Koch and R.Ulrich,Fiber optic displacement sensor with 0.02mm resolutionbuy white-light interferometry,sensors and actuators A,25-27(1991)201-207[2]N.Gisin,J.-P.Von der weid and J.-P.Pellaux,Polarization mode dispersion ofshort and long single-mode fibers,J.Lightwave technol,9(1991)821-827.[3] A.S.Gergcs,F.Farahi,T.P.Newson,J.D.C.Jones and D.A.Jackson, Fiber-opticinterferometric sensors using low coherence source:dynamic range enhancement,Int. J.Op-toelectron,3(1988)311-322.[4] C.D.Butter and G.B.Hacker, Fiber optics strain gauge,Appl.Opt,17(1978)2867-2869.[5]H.H.Gilger,G.Bodmer and Ch.Zimmer, Optical coherance domain retlectometry asa test method of integrated optics devices,Proc.2nd Opt. Fibre Meas. Conf:OFMC 93, Turin, Ztuly, Z993, pp.143-146.[6]J.-P.Jaguin and A.Zaganiaris,La mecanique de rupture appliquee aux fibresoptiques, Verres Refract, 34 (Jul-Aout)(1980).[7]L.Pflug and M.Pedretti, Construction of a loo-tonnes holographictable,ZS&TISPIE Znt.Symp. Electronic Imaging, SanJose,CA,USA,1993,pp.50-54.传感器和执行器 A 44(1994)12.5-130用低变形传感器监测民用工程结构变形的一致性D.Inaudi a, A.Elamari b, L.Pflug b, N.Gisin b, J.Breguet b, S.Vurpillot aa IMAC、实验室的应力分析,瑞士联邦理工学院,CH-1015瑞士洛桑b GAP,群应用物理-光学部分,日内瓦大学,CH-1205瑞士日内瓦举行1993年1月25日实验;1994年3月8日修订,1994年3月25日发表文摘一个光纤变形的分辨率的传感器,10µm和运行范围的60毫米已经实现了。
土木工程毕业设计英文翻译
土木工程毕业设计英文翻译Civil Engineering Graduation Design English TranslationIntroductionIn this article, we will discuss the translation of a graduation design project in the field of civil engineering from Chinese to English. The translation process requires careful attention to technical terminology, ensuring accuracy and clarity while maintaining the overall structure and coherence of the original content. BackgroundCivil engineering graduation design projects are an integral part of the curriculum for civil engineering students. These projects allow students to apply their theoretical knowledge and practical skills to solve real-world engineering problems. The projects cover a wide range of topics, including structural design, transportation engineering, geotechnical engineering, and water resources management.Translation ChallengesTranslating a civil engineering graduation design project from Chinese to English presents several challenges. Firstly, technical terms specific to the field of civil engineering may not have direct equivalents in English. Secondly, the translation must accurately convey the intended meaning of the original content without losing any crucial information. Finally, maintaining the coherence and readability of the translated text is essential to ensure the understanding of the target audience.Translation StrategiesTo overcome the challenges mentioned above, the following translation strategies can be employed:1. Terminology Research: Extensive research on technical terms in both languages is crucial. This includes consulting specialized dictionaries, academic resources, and industry-standard glossaries. It is essential to find the most accurate and widely accepted translations for specific technical terms.2. Contextual Understanding: To maintain the overall coherence and meaning of the original content, it is important to understand the context in which the technical terms are used. This requires a thorough understanding of the civil engineering discipline and its specific concepts and principles.3. Adaptation and Explanation: In cases where there is no direct translation for a technical term, adaptation or explanation can be used. This involves finding alternative expressions or providing additional information to convey the intended meaning accurately. However, it is important to strike a balance between clarity and conciseness to avoid overwhelming the reader with excessive information.4. Proofreading and Editing: After the initial translation, it is crucial to proofread and edit the translated text. This helps to identify any errors, inconsistencies, or ambiguities and make necessary revisions to ensure the final translation is accurate and coherent.ConclusionTranslating a civil engineering graduation design project from Chinese to English requires careful consideration of technical terminology, context, and overall coherence. By employing effective translation strategies such as terminology research, contextual understanding, adaptation and explanation, and thorough proofreading and editing, a high-quality translation can be achieved. This ensures that the English version of the graduation design project accurately conveys the intended meaning and maintains its readability and comprehensibility for the target audience.。
土木工程岩土类毕业设计外文翻译
土木工程专业英语复习参考学号: 10447425X X 大学毕业设计(论文)外文翻译(2014届)外文题目Developments in excavation bracing systems译文题目开挖工程支撑体系的发展外文出处Tunnelling and Underground SpaceTechnology 31 (2012) 107–116学生XXX学院XXXX 专业班级XXXXX校内指导教师XXX 专业技术职务XXXXX校外指导老师专业技术职务二○一三年十二月开挖工程支撑体系的发展1.引言几乎所有土木工程建设项目(如建筑物,道路,隧道,桥梁,污水处理厂,管道,下水道)都涉及泥土挖掘的一些工程量。
往往由于由相邻的结构,特性线,或使用权空间的限制,必须要一个土地固定系统,以允许土壤被挖掘到所需的深度。
历史上,许多挖掘支撑系统已经开发出来。
其中,现在比较常见的几种方法是:板桩,钻孔桩墙,泥浆墙。
土地固定系统的选择是由技术性能要求和施工可行性(例如手段,方法)决定的,包括执行的可靠性,而成本考虑了这些之后,其他问题也得到解决。
通常环境后果(用于处理废泥浆和钻井液如监管要求)也非常被关注(邱阳、1998)。
土地固定系统通常是建设项目的较大的一个组成部分。
如果不能按时完成项目,将极大地影响总成本。
通常首先建造支撑,在许多情况下,临时支撑系统是用于支持在挖掘以允许进行不断施工,直到永久系统被构造。
临时系统可以被去除或留在原处。
打桩时,因撞击或振动它们可能会被赶入到位。
在一般情况下,振动是最昂贵的方法,但只适合于松散颗粒材料,土壤中具有较高电阻(例如,通过鹅卵石)的不能使用。
采用打入桩系统通常是中间的成本和适合于软沉积物(包括粘性和非粘性),只要该矿床是免费的鹅卵石或更大的岩石。
通常,垂直元素(例如桩)的前安装挖掘工程和水平元件(如内部支撑或绑回)被安装为挖掘工程的进行下去,从而限制了跨距长度,以便减少在垂直开发弯矩元素。
土木工程建筑工程毕业设计外文翻译
大连交通大学2011届本科生毕业设计(论文)外文翻译Seismic Collapse Safety of Reinforced Concrete Buildings:I. Assessment of Ductile Moment FramesCurt B. Haselton1, Abbie B. Liel2, Gregory G. Deierlein3, Brian S. Dean4, Jason H. Chou5Ground motions used for the nonlinear dynamic analyses are recordings from large magnitude earthquakes (magnitude 6.5 to 7.6) recorded at moderate fault rupturedistances (10 to 45 km). The 39 ground motion record pairs (each with two orthogonal horizontal components) and their selection criteria are documented in Haselton and Deierlein (2007). This ground motion set is an expanded version of the far-field ground motion set utilized in the FEMA P-695 (FEMA 2009).Ground motion records are selected and scaled without considering the distinctive spectral shape of rare (extreme) ground motions, due to difficulties in selecting and scaling a different set of records for a large set of buildings having a wide range of first- mode periods. To account for the important impact of spectral shape on collapse assessment, shown by Baker and Cornell (2006), the collapse predictions made using the general set of ground motions are modified using a method proposed by Haselton et al. (2009). The expected spectral shape of rare (large) California ground motions isaccounted for through a statistical parameter referred to as epsilon (ε), which is a measure of the difference between the spectral acceleration of a recorded ground motion and the median value predicted by ground motion prediction equation. A target value of ε=1.5 is used to approximately represent the expected spectral shape of severe ground motions that can lead to collapse of code-conforming buildings (Appendix B of FEMA P-695 2009; Haselton et al. 2010).Page 1 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译STRUCTURAL ANALYSIS MODEL AND COLLAPSE ASSESSMENT METHODOLOGYA two-dimensional three-bay nonlinear analysis frame model is created for each archetype RC SMF using the OpenSees structural analysis platform (OpenSees 2009), as illustrated in Figure 1. Three bays are assumed to be the minimum number necessary to reflect the differences between interior and exterior columns and joints, and their impact on frame behavior. Strength and stiffness of the gravity system are not represented in the model, but the destabilizing P-Δ effectsare accounted for by applying gravity loads on a leaning column in the analysis model. Previous research by the authors has shown that neglecting the strength and stiffness of the gravity system in RC SMF systems is slightly conservative, underestimating the median collapse capacity by approximately 10% (Haselton et al. 2008a). It is also assumed that the damage to the slab-column connections of the gravity system will not result in a vertical collapse of the slab; test data for slab-column connections with modern detailing are still needed to verify this assumption. The foundation rotation stiffness is calculated from typical grade beam design and soil stiffness properties. Rayleigh damping corresponding to 5% of critical damping in the first and third modes is applied.Element modeling consists of lumped plasticity beam-column elements and finite joint shear panel springs. Lumped plasticity elements were used in lieu of fiber-type element models, since only the former are able to capture the strain softening associated with rebar buckling and spalling phenomena that are critical for simulating structural collapse in RC frame structures. The beam-columns are modeled using a nonlinear hinge model with degrading strength and stiffness, developed by Ibarra et al. (2005). As illustrated in Figure 2, the Ibarra et al. model captures the important modes of monotonicPage 2 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译and cyclic deterioration that precipitate sidesway collapse. Key parameters of the modelinclude the plastic rotation capacity, θcap,pl, the post-capping rotation capacity, θpc, theratio of maximum to yield moment, Mc / My, and an energy-based degradation parameter,. Based on calibration to test data for RC columns and beams with ductile detailing andlow to moderate axial load, the typical mode parameter values are θcap,pl between 0.035 to0.085 radians, depending on the level of axial load in the beam-column, θpc equal to 0.10radians, Mc / My between 1.17 and 1.21, and between 85 and 130 (Haselton et al. 2007,2008b). The post-capping deformation capacity, θpc, of 0.10 is a conservative value used dueto lack of data; this value would likely be much larger if additional data were availablewith specimens tested to larger levels of deformation.The collapse capacities of the archetype building designs are evaluated using aperformance-based methodology, key features of which are briefly summarized as follows:1. Select ground motions for nonlinear dynamic analysis. In this study, 39 pairs offar-field ground motions are used. Issues related to record selection and scaling have been discussed previously.2. Utilize incremental dynamic analysis (IDA) to organize nonlinear dynamiccollapse analyses of the archetype models subjected to the recorded ground motions (Vamvatsikos and Cornell 2002). Using the IDA approach, each horizontal component of ground motion is individually applied to the two-dimensional frame model.In this study, ground motion records are amplitude scaled according to thespectral acceleration at the first mode period, Sa(T1). The ground motions are increasingly scaled until collapse occurs. In this paper, collapse is defined as the Page 3 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译point of dynamic instability, where the lateral story drifts of the building increase without bounds (often referred to as sidesway collapse). This occurs when the IDA curve becomes flat. Vertical collapse mechanisms, which are not directly simulated in the structural model, are not considered in this assessment. The companion paper (Liel et al. 2010) provides explanation for how these additional collapse modes but could be accounted for.Figure 3a presents sample results from incremental dynamic analysis for a four-story space frame building (ID1008). For this structure, the median collapse capacity (in terms of Sa(0.94s)) is 1.59g for the set of 39 ground motion pairs.3. Construct a collapse fragility function based on the IDA results, which represents the probability of collapse as a function of ground motion intensity. To approximately account for three-dimensional ground motion effects (i.e. themaximum ground motion component), the lower collapse capacity (in terms of Sa(T1)) from each pair of motions is recorded as the building collapse capacity. From the resulting collapse data, the median collapse capacity and dispersion, due to record-to-record variability, are then computed.Figure 3b presents such collapse fragility curves for the four-story building usedpreviously in Figure 3a. The square markers show the empirical cumulative distribution function of the collapse data from Figure 3a (i.e. each point represents the collapse capacity for a single earthquake record), and the solid line shows the lognormal distribution fit to the empirical data. The fitted median collapse capacity (in terms of Sa(0.94s)) is 1.59g and the fitted logarithmic standardPage 4 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译deviation, representing the so-called record-to-record (RTR) variability (LN,RTR), is 0.38.4. Increase the dispersion in the collapse fragility to account for structural modeling uncertainties.Figure 3b shows this adjusted collapse capacity distribution by the dashed line. Liel et al. (2009) and Haselton and Deierlein (2007) have shown how introducing this additional dispersion in the collapse fragility can approximately account for the effects of uncertainties in the structural modeling parameters, but this approximation is only suitable for collapse probabilities in the lower tail of the fragility curve (Liel et al. 2009). Based on uncertainties in the nonlinearcomponent models (e.g., the capping rotation and post-peak softening slope shown in Figure 2), the modeling uncertainty is calculated as σLN,modeling = 0.5 (Haselton and Deierlein 2007). When combined with the record-to-record uncertainty of LN,RTR = 0.38, the resulting total dispersion is LN,total = 0.63, shown by the dashed curve labeled RTR+Model.5. Adjust (increase) the median of the collapse fragility curve to account for the ground motion spectral shape effect.Figure 3b shows this adjusted collapse capacity distribution by the dotted line. For this example, the median collapse intensity is increased from 1.59g to 2.22g (by a factor of 1.4). As described by Haselton et al. (2010) and FEMA P-695 (FEMA 2009, Appendix B), this so-called ε adjustment is based on the large ductility of the RC SMF structures and associated period shift that occurs before collapse, combined with a target value of ε = 1.5 for rare ground motions in thePage 5 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译high seismic regions of California. Buildings with lower deformation capacity, as well as sit es and hazard levels with lower expected values of ε, would have a smalleradjustment.6. Compute the collapse risk metrics of interest.For the example in Figure 3b, the collapse margin ratio is 2.6, the conditional collapse probability (P(C|Sa2/50)) is 7%, and the mean annual frequency ofcollapse (λcol) is 1.7x10-4 collapses/year.COLLAPSE RISK FOR RC SMF BUILDINGS DESIGNED ACCORDING TO ASCE 7-02Collapse analysis results for the 30 building archetypes are summarized in Table 1. Pertinent data includes the fundamental period of each archetype structural model, static overstrength from pushover analysis, collapse risk predictions, and maximum story and roof drifts at the onset of collapse. The resulting collapse risks are described by the following three measures, as listed in Table 1 and plotted in Figure 4: Collapse Margin: The collapse margin is the ratio between the median collapse capacity and the 2% in 50 year ground motion level. This metric is similar in concept to a simple factor of safety. Overall, the collapse margins for the 30 RC SMF buildings range from 1.7 to 3.4, with an average value of 2.3.Conditional Collapse Probability: The probability of collapse for the 2% in 50 year level of ground motion intensity, denoted P(C|Sa2/50), can be read directly from the fragility curve. This is a convenient metric to gauge the collapse safety relative to the extreme ground motion intensity that is used as the basis of design in building codes . Overall, the RC SMF buildings have an average P(C|Sa2/50) of 11%, with a range from 3% to 20%.Page 6 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译Mean Annual Frequency of Collapse: The mean annual frequency of collapse (λcol) is obtained by integrating the collapse fragility with the site-specific hazard curve. Using the hazard curve from the Los Angeles site, the RC SMF buildings have an average λcol of 3.1x10-4 collapses/year, with a range from 0.7x10-4 to7.0x10-4 collapses/year. This range translates to a probability of collapse in 50 years of 0.4% to 3.4%.While there are no clear standards that define the maximum acceptable collapse risk for buildings, there is some consensus that calculated values for the RC SMF archetypes are in a reasonable range. For example, the FEMA P-695 (FEMA 2009) Methodology to determine seismic response factors for new building systems, is based on a maximum collapse risk of 10% to 20%, conditioned on the maximum considered earthquakeintensity. Additionally, the ASCE/SEI 7 building code has recently adopted new “risk consistent” seismic design maps, which have an implied collapse risk of 1% in 50 years (Luco et al. 2007), and which were developed based on an assumed collapse probability of 10%, conditioned on the maximum considered earthquake intensity. Finally, it is important to remember that the collapse risks reported herein were calculated from archetype designs that conform to current building code provisions. So, to the extent that the evolution of building codes reflects societal values, the calculated collapse risks have legitimacy implicit in the natural progression of building codes and standards.Page 7 of 7钢筋混凝土建筑的抗震安全设计大连交通大学2011届本科生毕业设计(论文)外文翻译I.延性框架的分析Curt B. Haselton1, Abbie B. Liel2, Gregory G. Deierlein3, Brian S. Dean4, Jason H. Chou5应用于非线性动态分析的地面运动是中等深度(10 到45 千米)断层错动引起的震级为6.5至7.6的大地震。
土木工程-毕业设计-论文-外文翻译-中英文对照
英文原文:Concrete structure reinforcement designSheyanb oⅠWangchenji aⅡⅠFoundation Engineering Co., Ltd. Heilongjiang DongyuⅡHeilongjiang Province, East Building Foundation Engineering Co., Ltd. CoalAbstract: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 direct reinforcement 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 component supporting 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 the milk 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 reinforced component'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 produces is 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 is in 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 tension bar 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 。
土木工程建筑工程毕业设计外文翻译
大连交通大学2011届本科生毕业设计(论文)外文翻译Seismic Collapse Safety of Reinforced Concrete Buildings:I. Assessment of Ductile Moment FramesCurt B. Haselton1, Abbie B. Liel2, Gregory G. Deierlein3, Brian S. Dean4, Jason H. Chou5Ground motions used for the nonlinear dynamic analyses are recordings from large magnitude earthquakes (magnitude 6.5 to 7.6) recorded at moderate fault rupturedistances (10 to 45 km). The 39 ground motion record pairs (each with two orthogonal horizontal components) and their selection criteria are documented in Haselton and Deierlein (2007). This ground motion set is an expanded version of the far-field ground motion set utilized in the FEMA P-695 (FEMA 2009).Ground motion records are selected and scaled without considering the distinctive spectral shape of rare (extreme) ground motions, due to difficulties in selecting and scaling a different set of records for a large set of buildings having a wide range of first- mode periods. To account for the important impact of spectral shape on collapse assessment, shown by Baker and Cornell (2006), the collapse predictions made using the general set of ground motions are modified using a method proposed by Haselton et al. (2009). The expected spectral shape of rare (large) California ground motions isaccounted for through a statistical parameter referred to as epsilon (ε), which is a measure of the difference between the spectral acceleration of a recorded ground motion and the median value predicted by ground motion prediction equation. A target value of ε=1.5 is used to approximately represent the expected spectral shape of severe ground motions that can lead to collapse of code-conforming buildings (Appendix B of FEMA P-695 2009; Haselton et al. 2010).Page 1 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译STRUCTURAL ANALYSIS MODEL AND COLLAPSE ASSESSMENT METHODOLOGYA two-dimensional three-bay nonlinear analysis frame model is created for each archetype RC SMF using the OpenSees structural analysis platform (OpenSees 2009), as illustrated in Figure 1. Three bays are assumed to be the minimum number necessary to reflect the differences between interior and exterior columns and joints, and their impact on frame behavior. Strength and stiffness of the gravity system are not represented in the model, but the destabilizing P-Δ effectsare accounted for by applying gravity loads on a leaning column in the analysis model. Previous research by the authors has shown that neglecting the strength and stiffness of the gravity system in RC SMF systems is slightly conservative, underestimating the median collapse capacity by approximately 10% (Haselton et al. 2008a). It is also assumed that the damage to the slab-column connections of the gravity system will not result in a vertical collapse of the slab; test data for slab-column connections with modern detailing are still needed to verify this assumption. The foundation rotation stiffness is calculated from typical grade beam design and soil stiffness properties. Rayleigh damping corresponding to 5% of critical damping in the first and third modes is applied.Element modeling consists of lumped plasticity beam-column elements and finite joint shear panel springs. Lumped plasticity elements were used in lieu of fiber-type element models, since only the former are able to capture the strain softening associated with rebar buckling and spalling phenomena that are critical for simulating structural collapse in RC frame structures. The beam-columns are modeled using a nonlinear hinge model with degrading strength and stiffness, developed by Ibarra et al. (2005). As illustrated in Figure 2, the Ibarra et al. model captures the important modes of monotonicPage 2 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译and cyclic deterioration that precipitate sidesway collapse. Key parameters of the modelinclude the plastic rotation capacity, θcap,pl, the post-capping rotation capacity, θpc, theratio of maximum to yield moment, Mc / My, and an energy-based degradation parameter,. Based on calibration to test data for RC columns and beams with ductile detailing andlow to moderate axial load, the typical mode parameter values are θcap,pl between 0.035 to0.085 radians, depending on the level of axial load in the beam-column, θpc equal to 0.10radians, Mc / My between 1.17 and 1.21, and between 85 and 130 (Haselton et al. 2007,2008b). The post-capping deformation capacity, θpc, of 0.10 is a conservative value used dueto lack of data; this value would likely be much larger if additional data were availablewith specimens tested to larger levels of deformation.The collapse capacities of the archetype building designs are evaluated using aperformance-based methodology, key features of which are briefly summarized as follows:1. Select ground motions for nonlinear dynamic analysis. In this study, 39 pairs offar-field ground motions are used. Issues related to record selection and scaling have been discussed previously.2. Utilize incremental dynamic analysis (IDA) to organize nonlinear dynamiccollapse analyses of the archetype models subjected to the recorded ground motions (Vamvatsikos and Cornell 2002). Using the IDA approach, each horizontal component of ground motion is individually applied to the two-dimensional frame model.In this study, ground motion records are amplitude scaled according to thespectral acceleration at the first mode period, Sa(T1). The ground motions are increasingly scaled until collapse occurs. In this paper, collapse is defined as the Page 3 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译point of dynamic instability, where the lateral story drifts of the building increase without bounds (often referred to as sidesway collapse). This occurs when the IDA curve becomes flat. Vertical collapse mechanisms, which are not directly simulated in the structural model, are not considered in this assessment. The companion paper (Liel et al. 2010) provides explanation for how these additional collapse modes but could be accounted for.Figure 3a presents sample results from incremental dynamic analysis for a four-story space frame building (ID1008). For this structure, the median collapse capacity (in terms of Sa(0.94s)) is 1.59g for the set of 39 ground motion pairs.3. Construct a collapse fragility function based on the IDA results, which represents the probability of collapse as a function of ground motion intensity. To approximately account for three-dimensional ground motion effects (i.e. themaximum ground motion component), the lower collapse capacity (in terms of Sa(T1)) from each pair of motions is recorded as the building collapse capacity. From the resulting collapse data, the median collapse capacity and dispersion, due to record-to-record variability, are then computed.Figure 3b presents such collapse fragility curves for the four-story building usedpreviously in Figure 3a. The square markers show the empirical cumulative distribution function of the collapse data from Figure 3a (i.e. each point represents the collapse capacity for a single earthquake record), and the solid line shows the lognormal distribution fit to the empirical data. The fitted median collapse capacity (in terms of Sa(0.94s)) is 1.59g and the fitted logarithmic standardPage 4 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译deviation, representing the so-called record-to-record (RTR) variability (LN,RTR), is 0.38.4. Increase the dispersion in the collapse fragility to account for structural modeling uncertainties.Figure 3b shows this adjusted collapse capacity distribution by the dashed line. Liel et al. (2009) and Haselton and Deierlein (2007) have shown how introducing this additional dispersion in the collapse fragility can approximately account for the effects of uncertainties in the structural modeling parameters, but this approximation is only suitable for collapse probabilities in the lower tail of the fragility curve (Liel et al. 2009). Based on uncertainties in the nonlinearcomponent models (e.g., the capping rotation and post-peak softening slope shown in Figure 2), the modeling uncertainty is calculated as σLN,modeling = 0.5 (Haselton and Deierlein 2007). When combined with the record-to-record uncertainty of LN,RTR = 0.38, the resulting total dispersion is LN,total = 0.63, shown by the dashed curve labeled RTR+Model.5. Adjust (increase) the median of the collapse fragility curve to account for the ground motion spectral shape effect.Figure 3b shows this adjusted collapse capacity distribution by the dotted line. For this example, the median collapse intensity is increased from 1.59g to 2.22g (by a factor of 1.4). As described by Haselton et al. (2010) and FEMA P-695 (FEMA 2009, Appendix B), this so-called ε adjustment is based on the large ductility of the RC SMF structures and associated period shift that occurs before collapse, combined with a target value of ε = 1.5 for rare ground motions in thePage 5 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译high seismic regions of California. Buildings with lower deformation capacity, as well as sit es and hazard levels with lower expected values of ε, would have a smalleradjustment.6. Compute the collapse risk metrics of interest.For the example in Figure 3b, the collapse margin ratio is 2.6, the conditional collapse probability (P(C|Sa2/50)) is 7%, and the mean annual frequency ofcollapse (λcol) is 1.7x10-4 collapses/year.COLLAPSE RISK FOR RC SMF BUILDINGS DESIGNED ACCORDING TO ASCE 7-02Collapse analysis results for the 30 building archetypes are summarized in Table 1. Pertinent data includes the fundamental period of each archetype structural model, static overstrength from pushover analysis, collapse risk predictions, and maximum story and roof drifts at the onset of collapse. The resulting collapse risks are described by the following three measures, as listed in Table 1 and plotted in Figure 4: Collapse Margin: The collapse margin is the ratio between the median collapse capacity and the 2% in 50 year ground motion level. This metric is similar in concept to a simple factor of safety. Overall, the collapse margins for the 30 RC SMF buildings range from 1.7 to 3.4, with an average value of 2.3.Conditional Collapse Probability: The probability of collapse for the 2% in 50 year level of ground motion intensity, denoted P(C|Sa2/50), can be read directly from the fragility curve. This is a convenient metric to gauge the collapse safety relative to the extreme ground motion intensity that is used as the basis of design in building codes . Overall, the RC SMF buildings have an average P(C|Sa2/50) of 11%, with a range from 3% to 20%.Page 6 of 7大连交通大学2011届本科生毕业设计(论文)外文翻译Mean Annual Frequency of Collapse: The mean annual frequency of collapse (λcol) is obtained by integrating the collapse fragility with the site-specific hazard curve. Using the hazard curve from the Los Angeles site, the RC SMF buildings have an average λcol of 3.1x10-4 collapses/year, with a range from 0.7x10-4 to7.0x10-4 collapses/year. This range translates to a probability of collapse in 50 years of 0.4% to 3.4%.While there are no clear standards that define the maximum acceptable collapse risk for buildings, there is some consensus that calculated values for the RC SMF archetypes are in a reasonable range. For example, the FEMA P-695 (FEMA 2009) Methodology to determine seismic response factors for new building systems, is based on a maximum collapse risk of 10% to 20%, conditioned on the maximum considered earthquakeintensity. Additionally, the ASCE/SEI 7 building code has recently adopted new “risk consistent” seismic design maps, which have an implied collapse risk of 1% in 50 years (Luco et al. 2007), and which were developed based on an assumed collapse probability of 10%, conditioned on the maximum considered earthquake intensity. Finally, it is important to remember that the collapse risks reported herein were calculated from archetype designs that conform to current building code provisions. So, to the extent that the evolution of building codes reflects societal values, the calculated collapse risks have legitimacy implicit in the natural progression of building codes and standards.Page 7 of 7钢筋混凝土建筑的抗震安全设计大连交通大学2011届本科生毕业设计(论文)外文翻译I.延性框架的分析Curt B. Haselton1, Abbie B. Liel2, Gregory G. Deierlein3, Brian S. Dean4, Jason H. Chou5应用于非线性动态分析的地面运动是中等深度(10 到45 千米)断层错动引起的震级为6.5至7.6的大地震。
(完整版)土木工程毕业设计外文文献翻译
外文文献翻译Reinforced ConcreteConcrete and reinforced concrete are used as building materials in every country. In many, including the United States and Canada, reinforced concrete is a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete and reinforced concrete are used in bridges, buildings of all sorts underground structures, water tanks, television towers, offshore oil exploration and production structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed in their final location, or they may be precast concrete produced in a factory and erected at the construction site. Concrete structures may be severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engineer such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whenever loads, or restrained shrinkage of temperature changes, give rise to tensile stresses in excess of the tensile strength of the concrete. In a plain concrete beam, the moments about the neutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beam fails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the concrete in such a way that the tension forces needed for moment equilibrium after the concrete cracks can be developed in the bars.The construction of a reinforced concrete member involves building a from of mold in the shape of the member being built. The form must be strong enough 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 placeduring the concreting operation. After the concrete has hardened, the forms are removed. As the forms are removed, props of shores are installed to support the weight of the concrete until it has reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength to resist the loads and adequate stiffness to prevent excessive deflections. In beam must be proportioned so that it can be constructed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the concrete is placed in the form after the reinforcement is in place, the concrete must be able to flow around, between, and past 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 the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shapeand texture by means of the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearing elements while providing the finished floor and / or ceiling surfaces. Similarly, reinforced concrete walls can provide architecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Finally, the choice of size of shape is governed by the designer and not by the availability of standard manufactured members.3. Fire resistance. The structure in a building must withstand the effects of a fire and remain standing while the building is evacuated and the fire is extinguished. A concrete building inherently has a 1- to 3-hour fire rating without special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratings.4. Low maintenance.Concrete members inherently require less maintenance than do structural steel or timber members. This is particularly true if dense, air-entrained concrete has been used for surfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are very widely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and /of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume.The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled, and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course in strength of materials forhomogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because unreinforced concrete is brittle, it cannot undergo large deformations under load and fails suddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to cover construction in a given region, often a city or a state. The objective of a building code is also to protect the public by accounting for the influence of the local environmental conditions on construction. For example, local authorities may specify additional provisions to account for such regional conditions as earthquake, heavy snow, or tornados. National structural codes genrally are incorporated into local building codes.The American Concrete Institute ( ACI ) Building Code covering the design of reinforced concrete buildings. It contains provisions covering all aspects of reinforced concrete manufacture, design, and construction. It includes specifications on quality of materials, details on mixing and placing concrete, design assumptions for the analysis of continuous structures, and equations for proportioning members for design forces.All structures must be proportioned so they will not fail or deform excessively under any possible condition 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 during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the forces produced by wind, impact, shrinkage, temperature change, creep and support settlements, earthquake, and so forth.The load associated with the weight of the structure itself and its permanent components is called the dead load. The dead load of concrete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately until members have been 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 members sized, 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 difference 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 important when spans are long, say over 75 ft ( 22.9 m ),because dead load constitutes a major portion of the design load.Live loads associated with building use are specific items of equipment and occupants in a certain area of a building, building codes specify values of uniform live for which members are to be designed.After the structure has been sized for vertical load, it is checked for wind in combination with dead and live load as specified in the code. Wind loads do not usually control the size of members in building less than 16 to 18 stories, but for tall buildings wind loads become significant and cause large forces to develop in the structures. Under these conditions economy can be achieved only by selecting a structural system that is able to transfer horizontal loads into the ground efficiently.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。
土木工程毕业论文中英文翻译
外文翻译班级:xxx学号:xxx姓名:xxx一、外文原文:Structural Systems to resist lateral loads Commonly Used structural SystemsWith loads measured in tens of thousands kips, there is little room in the design of high-rise buildings for excessively complex thoughts. Indeed, the better high-rise buildings carry the universal traits of simplicity of thought and clarity of expression.It does not follow that there is no room for grand thoughts. Indeed, it is with such grand thoughts that the new family of high-rise buildings has evolved. Perhaps more important, the new concepts of but a few years ago have become commonplace in today’ s technology.Omitting some concepts that are related strictly to the materials of construction, the most commonly used structural systems used in high-rise buildings can be categorized as follows:1.Moment-resisting frames.2.Braced frames, including eccentrically braced frames.3.Shear walls, including steel plate shear walls.4.Tube-in-tube structures.5.Core-interactive structures.6.Cellular or bundled-tube systems.Particularly with the recent trend toward more complex forms, but in response also to the need for increased stiffness to resist the forces from wind and earthquake, most high-rise buildings have structural systems built up of combinations of frames, braced bents, shear walls, and related systems. Further, for the taller buildings, the majorities are composed of interactive elements in three-dimensional arrays.The method of combining these elements is the very essence of the design process for high-rise buildings. These combinations need evolve in response to environmental, functional, and cost considerations so as to provide efficient structures that provoke the architectural development to new heights. This is not to say that imaginative structural design can create great architecture. To the contrary, many examples of fine architecture have been created with only moderate support from the structural engineer, while only fine structure, not great architecture, can be developed without the genius and the leadership of a talented architect. In any event, the best of both is needed to formulate a truly extraordinary design of a high-rise building.While comprehensive discussions of these seven systems are generally available in the literature, further discussion is warranted here .The essence of the design process is distributed throughout the discussion.Moment-Resisting FramesPerhaps the most commonly used system in low-to medium-rise buildings, the moment-resisting frame, is characterized by linear horizontal and vertical members connected essentially rigidly at their joints. Such frames are used as a stand-alone system or in combination with other systems so as to provide the needed resistance to horizontal loads. In the taller of high-rise buildings, the system is likely to be found inappropriate for a stand-alone system, this because of the difficulty in mobilizing sufficient stiffness under lateral forces.Analysis can be accomplished by STRESS, STRUDL, or a host of other appropriate computer programs; analysis by the so-called portal method of the cantilever method has no place in today’s technology.Because of the intrinsic flexibility of the column/girder intersection, and because preliminary designs should aim to highlight weaknesses of systems, it is not unusual to use center-to-center dimensions for the frame in the preliminary analysis. Of course, in the latter phases of design, a realistic appraisal in-joint deformation is essential.Braced Frame sThe braced frame, intrinsically stiffer than the moment –resisting frame, finds also greater application to higher-rise buildings. The system is characterized by linear horizontal, vertical, and diagonal members, connected simply or rigidly at their joints. It is used commonly inconjunction with other systems for taller buildings and as a stand-alone system in low-to medium-rise buildings.While the use of structural steel in braced frames is common, concrete frames are more likely to be of the larger-scale variety.Of special interest in areas of high seismicity is the use of the eccentric braced frame.Again, analysis can be by STRESS, STRUDL, or any one of a series of two –or three dimensional analysis computer programs. And again, center-to-center dimensions are used commonly in the preliminary analysis. Shear wallsThe shear wall is yet another step forward along a progression of ever-stiffer structural systems. The system is characterized by relatively thin, generally but not always concrete elements that provide both structural strength and separation between building functions.In high-rise buildings, shear wall systems tend to have a relatively high aspect ratio, that is, their height tends to be large compared to their width. Lacking tension in the foundation system, any structural element is limited in its ability to resist overturning moment by the width of the system and by the gravity load supported by the element. Limited to a narrow overturning, One obvious use of the system, which does have the needed width, is in the exterior walls of building, where the requirement for windows is kept small.Structural steel shear walls, generally stiffened against buckling by a concrete overlay, have found application where shear loads are high. The system, intrinsically more economical than steel bracing, is particularly effective in carrying shear loads down through the taller floors in the areas immediately above grade. The system has the further advantage of having high ductility a feature of particular importance in areas of high seismicity.The analysis of shear wall systems is made complex because of the inevitable presence of large openings through these walls. Preliminary analysis can be by truss-analogy, by the finite element method, or by making use of a proprietary computer program designed to consider the interaction, or coupling, of shear walls.Framed or Braced TubesThe concept of the framed or braced or braced tube erupted into the technology with the IBM Building in Pittsburgh, but was followed immediately with the twin 110-story towers of the World Trade Center, New York and a number of other buildings .The system is characterized by three –dimensional frames, braced frames, or shear walls, forming a closed surface more or less cylindrical in nature, but of nearly any plan configuration. Because those columns that resist lateral forces are placed as far as possible from the cancroids of the system, the overall moment of inertia is increased and stiffness is very high.The analysis of tubular structures is done using three-dimensional concepts, or by two- dimensional analogy, where possible, whichever method is used, it must be capable of accounting for the effects of shear lag.The presence of shear lag, detected first in aircraft structures, is a serious limitation in the stiffness of framed tubes. The concept has limited recent applications of framed tubes to the shear of 60 stories. Designers have developed various techniques for reducing the effects of shear lag, most noticeably the use of belt trusses. This system finds application in buildings perhaps 40stories and higher. However, except for possible aesthetic considerations, belt trusses interfere with nearly every building function associated with the outside wall; the trusses are placed often at mechanical floors, mush to the disapproval of the designers of the mechanical systems. Nevertheless, as a cost-effective structural system, the belt truss works well and will likely find continued approval from designers. Numerous studies have sought to optimize the location of these trusses, with the optimum location very dependent on the number of trusses provided. Experience would indicate, however, that the location of these trusses is provided by the optimization of mechanical systems and by aesthetic considerations, as the economics of the structural system is not highly sensitive to belt truss location.Tube-in-Tube StructuresThe tubular framing system mobilizes every column in the exterior wallin resisting over-turning and shearing forces. The term‘tube-in-tube’is largely self-explanatory in that a second ring of columns, the ring surrounding the central service core of the building, is used as an inner framed or braced tube. The purpose of the second tube is to increase resistance to over turning and to increase lateral stiffness. The tubes need not be of the same character; that is, one tube could be framed, while the other could be braced.In considering this system, is important to understand clearly the difference between the shear and the flexural components of deflection, the terms being taken from beam analogy. In a framed tube, the shear component of deflection is associated with the bending deformation of columns and girders , the webs of the framed tube while the flexural component is associated with the axial shortening and lengthening of columns , the flanges of the framed tube. In a braced tube, the shear component of deflection is associated with the axial deformation of diagonals while the flexural component of deflection is associated with the axial shortening and lengthening of columns.Following beam analogy, if plane surfaces remain plane , the floor slabs,then axial stresses in the columns of the outer tube, being farther form the neutral axis, will be substantially larger than the axial stresses in the inner tube. However, in the tube-in-tube design, when optimized, the axial stresses in the inner ring of columns may be as high, or evenhigher, than the axial stresses in the outer ring. This seeming anomaly is associated with differences in the shearing component of stiffness between the two systems. This is easiest to under-stand where the inner tube is conceived as a braced , shear-stiff tube while the outer tube is conceived as a framed , shear-flexible tube.Core Interactive StructuresCore interactive structures are a special case of a tube-in-tube wherein the two tubes are coupled together with some form of three-dimensional space frame. Indeed, the system is used often wherein the shear stiffness of the outer tube is zero. The United States Steel Building, Pittsburgh, illustrates the system very well. Here, the inner tube is a braced frame, the outer tube has no shear stiffness, and the two systems are coupled if they were considered as systems passing in a straight line from the “hat” structure. Note that the exterior columns would be improperly modeled if they were considered as systems passing in a straight line from the “hat” to the foundations; these columns are perhaps 15% stiffer as they follow the elastic curve of the braced core. Note also that the axial forces associated with the lateral forces in the inner columns change from tension to compression over the height of the tube, with the inflection point at about 5/8 of the height of the tube. The outer columns, of course, carry the same axial force under lateral load for the full height of the columns because the columns because the shearstiffness of the system is close to zero.The space structures of outrigger girders or trusses, that connect the inner tube to the outer tube, are located often at several levels in the building. The AT&T headquarters is an example of an astonishing array of interactive elements:1.The structural system is 94 ft wide, 196ft long, and 601ft high.2.Two inner tubes are provided, each 31ft by 40 ft , centered 90 ft apartin the long direction of the building.3.The inner tubes are braced in the short direction, but with zero shearstiffness in the long direction.4.A single outer tube is supplied, which encircles the buildingperimeter.5.The outer tube is a moment-resisting frame, but with zero shearstiffness for the center50ft of each of the long sides.6.A space-truss hat structure is provided at the top of the building.7.A similar space truss is located near the bottom of the building8.The entire assembly is laterally supported at the base on twinsteel-plate tubes, because the shear stiffness of the outer tube goes to zero at the base of the building.Cellular structuresA classic example of a cellular structure is the Sears Tower, Chicago,a bundled tube structure of nine separate tubes. While the Sears Towercontains nine nearly identical tubes, the basic structural system has special application for buildings of irregular shape, as the several tubes need not be similar in plan shape, It is not uncommon that some of the individual tubes one of the strengths and one of the weaknesses of the system.This special weakness of this system, particularly in framed tubes, has to do with the concept of differential column shortening. The shortening of a column under load is given by the expression△=ΣfL/EFor buildings of 12 ft floor-to-floor distances and an average compressive stress of 15 ksi 138MPa, the shortening of a column under load is 15 1212/29,000 or per story. At 50 stories, the column will have shortened to in. 94mm less than its unstressed length. Where one cell of a bundled tube system is, say, 50stories high and an adjacent cell is, say, 100stories high, those columns near the boundary between .the two systems need to have this differential deflection reconciled.Major structural work has been found to be needed at such locations. In at least one building, the Rialto Project, Melbourne, the structural engineer found it necessary to vertically pre-stress the lower height columns so as to reconcile the differential deflections of columns in close proximity with the post-tensioning of the shorter column simulatingthe weight to be added on to adjacent, higher columns.二、原文翻译:抗侧向荷载的结构体系常用的结构体系若已测出荷载量达数千万磅重,那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了;确实,较好的高层建筑普遍具有构思简单、表现明晰的特点;这并不是说没有进行宏观构思的余地;实际上,正是因为有了这种宏观的构思,新奇的高层建筑体系才得以发展,可能更重要的是:几年以前才出现的一些新概念在今天的技术中已经变得平常了;如果忽略一些与建筑材料密切相关的概念不谈,高层建筑里最为常用的结构体系便可分为如下几类:1.抗弯矩框架;2.支撑框架,包括偏心支撑框架;3.剪力墙,包括钢板剪力墙;4.筒中框架;5.筒中筒结构;6.核心交互结构;7.框格体系或束筒体系;特别是由于最近趋向于更复杂的建筑形式,同时也需要增加刚度以抵抗几力和地震力,大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系;而且,就较高的建筑物而言,大多数都是由交互式构件组成三维陈列;将这些构件结合起来的方法正是高层建筑设计方法的本质;其结合方式需要在考虑环境、功能和费用后再发展,以便提供促使建筑发展达到新高度的有效结构;这并不是说富于想象力的结构设计就能够创造出伟大建筑;正相反,有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了,然而,如果没有天赋甚厚的建筑师的创造力的指导,那么,得以发展的就只能是好的结构,并非是伟大的建筑;无论如何,要想创造出高层建筑真正非凡的设计,两者都需要最好的;虽然在文献中通常可以见到有关这七种体系的全面性讨论,但是在这里还值得进一步讨论;设计方法的本质贯穿于整个讨论;设计方法的本质贯穿于整个讨论中;抗弯矩框架抗弯矩框架也许是低,中高度的建筑中常用的体系,它具有线性水平构件和垂直构件在接头处基本刚接之特点;这种框架用作独立的体系,或者和其他体系结合起来使用,以便提供所需要水平荷载抵抗力;对于较高的高层建筑,可能会发现该本系不宜作为独立体系,这是因为在侧向力的作用下难以调动足够的刚度;我们可以利用STRESS,STRUDL 或者其他大量合适的计算机程序进行结构分析;所谓的门架法分析或悬臂法分析在当今的技术中无一席之地,由于柱梁节点固有柔性,并且由于初步设计应该力求突出体系的弱点,所以在初析中使用框架的中心距尺寸设计是司空惯的;当然,在设计的后期阶段,实际地评价结点的变形很有必要;支撑框架支撑框架实际上刚度比抗弯矩框架强,在高层建筑中也得到更广泛的应用;这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色,它通常与其他体系共同用于较高的建筑,并且作为一种独立的体系用在低、中高度的建筑中;尤其引人关注的是,在强震区使用偏心支撑框架;此外,可以利用STRESS,STRUDL,或一系列二维或三维计算机分析程序中的任何一种进行结构分析;另外,初步分析中常用中心距尺寸;剪力墙剪力墙在加强结构体系刚性的发展过程中又前进了一步;该体系的特点是具有相当薄的,通常是而不总是混凝土的构件,这种构件既可提供结构强度,又可提供建筑物功能上的分隔;在高层建筑中,剪力墙体系趋向于具有相对大的高宽经,即与宽度相比,其高度偏大;由于基础体系缺少应力,任何一种结构构件抗倾覆弯矩的能力都受到体系的宽度和构件承受的重力荷载的限制;由于剪力墙宽度狭狭窄受限,所以需要以某种方式加以扩大,以便提从所需的抗倾覆能力;在窗户需要量小的建筑物外墙中明显地使用了这种确有所需要宽度的体系;钢结构剪力墙通常由混凝土覆盖层来加强以抵抗失稳,这在剪切荷载大的地方已得到应用;这种体系实际上比钢支撑经济,对于使剪切荷载由位于地面正上方区域内比较高的楼层向下移特别有效;这种体系还具有高延性之优点,这种特性在强震区特别重要;由于这些墙内必然出同一些大孔,使得剪力墙体系分析变得错综复杂;可以通过桁架模似法、有限元法,或者通过利用为考虑剪力墙的交互作用或扭转功能设计的专门计处机程序进行初步分析框架或支撑式筒体结构:框架或支撑式筒体最先应用于IBM公司在Pittsburgh的一幢办公楼,随后立即被应用于纽约双子座的110层世界贸易中心摩天大楼和其他的建筑中;这种系统有以下几个显着的特征:三维结构、支撑式结构、或由剪力墙形成的一个性质上差不多是圆柱体的闭合曲面,但又有任意的平面构成;由于这些抵抗侧向荷载的柱子差不多都被设置在整个系统的中心,所以整体的惯性得到提高,刚度也是很大的;在可能的情况下,通过三维概念的应用、二维的类比,我们可以进行筒体结构的分析;不管应用那种方法,都必须考虑剪力滞后的影响;这种最先在航天器结构中研究的剪力滞后出现后,对筒体结构的刚度是一个很大的限制;这种观念已经影响了筒体结构在60层以上建筑中的应用;设计者已经开发出了很多的技术,用以减小剪力滞后的影响,这其中最有名的是桁架的应用;框架或支撑式筒体在40层或稍高的建筑中找到了自己的用武之地;除了一些美观的考虑外,桁架几乎很少涉及与外墙联系的每个建筑功能,而悬索一般设置在机械的地板上,这就令机械体系设计师们很不赞成;但是,作为一个性价比较好的结构体系,桁架能充分发挥它的性能,所以它会得到设计师们持续的支持;由于其最佳位置正取决于所提供的桁架的数量,因此很多研究已经试图完善这些构件的位置;实验表明:由于这种结构体系的经济性并不十分受桁架位置的影响,所以这些桁架的位置主要取决于机械系统的完善,审美的要求,筒中筒结构:筒体结构系统能使外墙中的柱具有灵活性,用以抵抗颠覆和剪切力;“筒中筒”这个名字顾名思义就是在建筑物的核心承重部分又被包围了第二层的一系列柱子,它们被当作是框架和支撑筒来使用;配置第二层柱的目的是增强抗颠覆能力和增大侧移刚度;这些筒体不是同样的功能,也就是说,有些筒体是结构的,而有些筒体是用来支撑的;在考虑这种筒体时,清楚的认识和区别变形的剪切和弯曲分量是很重要的,这源于对梁的对比分析;在结构筒中,剪切构件的偏角和柱、纵梁例如:结构筒中的网等的弯曲有关,同时,弯曲构件的偏角取决于柱子的轴心压缩和延伸例如:结构筒的边缘等;在支撑筒中,剪切构件的偏角和对角线的轴心变形有关,而弯曲构件的偏角则与柱子的轴心压缩和延伸有关;根据梁的对比分析,如果平面保持原形例如:厚楼板,那么外层筒中柱的轴心压力就会与中心筒柱的轴心压力相差甚远,而且稳定的大于中心筒;但是在筒中筒结构的设计中,当发展到极限时,内部轴心压力会很高的,甚至远远大于外部的柱子;这种反常的现象是由于两种体系中的剪切构件的刚度不同;这很容易去理解,内筒可以看成是一个支撑或者说是剪切刚性的筒,而外筒可以看成是一个结构或者说是剪切弹性的筒;核心交互式结构:核心交互式结构属于两个筒与某些形式的三维空间框架相配合的筒中筒特殊情况;事实上,这种体系常用于那种外筒剪切刚度为零的结构;位于Pittsburgh的美国钢铁大楼证实了这种体系是能很好的工作的;在核心交互式结构中,内筒是一个支撑结构,外筒没有任何剪切刚度,而且两种结构体系能通过一个空间结构或“帽”式结构共同起作用;需要指出的是,如果把外部的柱子看成是一种从“帽”到基础的直线体系,这将是不合适的;根据支撑核心的弹性曲线,这些柱子只发挥了刚度的15%;同样需要指出的是,内柱中与侧向力有关的轴向力沿筒高度由拉力变为压力,同时变化点位于筒高度的约5/8处;当然,外柱也传递相同的轴向力,这种轴向力低于作用在整个柱子高度的侧向荷载,因为这个体系的剪切刚度接近于零;把内外筒相连接的空间结构、悬臂梁或桁架经常遵照一些规范来布置;美国电话电报总局就是一个布置交互式构件的生动例子;1、结构体系长米,宽米,高米;2、布置了两个筒,每个筒的尺寸是米×米,在长方向上有米的间隔;3、在短方向上内筒被支撑起来,但是在长方向上没有剪切刚度;4、环绕着建筑物布置了一个外筒;5、外筒是一个瞬时抵抗结构,但是在每个长方向的中心米都没有剪切刚度;6、在建筑的顶部布置了一个空间桁架构成的“帽式”结构;7、在建筑的底部布置了一个相似的空间桁架结构;8、由于外筒的剪切刚度在建筑的底部接近零,整个建筑基本上由两个钢板筒来支持;框格体系或束筒体系结构:位于美国芝加哥的西尔斯大厦是箱式结构的经典之作,它由九个相互独立的筒组成的一个集中筒;由于西尔斯大厦包括九个几乎垂直的筒,而且筒在平面上无须相似,基本的结构体系在不规则形状的建筑中得到特别的应用;一些单个的筒高于建筑一点或很多是很常见的;事实上,这种体系的重要特征就在于它既有坚固的一面,也有脆弱的一面;这种体系的脆弱,特别是在结构筒中,与柱子的压缩变形有很大的关系,柱子的压缩变形有下式计算:△=ΣfL/E对于那些层高为米左右和平均压力为138MPa的建筑,在荷载作用下每层柱子的压缩变形为1512/29000或毫米;在第50层柱子会压缩94毫米,小于它未受压的长度;这些柱子在50层的时候和100层的时候的变形是不一样的,位于这两种体系之间接近于边缘的那些柱需要使这种不均匀的变形得以调解;主要的结构工作都集中在布置中;在Melbourne的Rialto项目中,结构工程师发现至少有一幢建筑,很有必要垂直预压低高度的柱子,以便使柱不均匀的变形差得以调解,调解的方法近似于后拉伸法,即较短的柱转移重量到较高的邻柱上;。
土木工程毕业设计外文翻译最终中英文
7 Rigid-Frame StructuresA rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders.The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rigid frames are considered economical for buildings of up to' about25 stories, above which their drift resistance is costly to control. If, however,a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components.As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically include the following stages:1. Estimation of gravity load forces in girders and columns by approximate method.2. Preliminary estimate of member sizes based on gravity load forces witharbitrary increase in sizes to allow for horizontal loading.3. Approximate allocation of horizontal loading to bents and preliminary analysisof member forces in bents.4. Check on drift and adjustment of member sizes if necessary.5. Check on strength of members for worst combination of gravity and horizontalloading, and adjustment of member sizes if necessary.6. Computer analysis of total structure for more accurate check on memberstrengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift..7. Detailed design of members and connections.This chapter considers methods of analysis for the deflections and forces for both gravity and horizontal loading. The methods are included in roughly the order of the design procedure, with approximate methods initially and computer techniques later. Stability analyses of rigid frames are discussed in Chapter 16.7.1 RIGID FRAME BEHAVIORThe horizontal stiffness of a rigid frame is governed mainly by the bending resistance of the girders, the columns, and their connections, and, in a tall frame, by the axial rigidity of the columns. The accumulated horizontal shear above any story of a rigid frame is resisted by shear in the columns of that story (Fig. 7.1). The shear causes the story-height columns to bend in double curvature with points of contraflexure at approximately mid-story-height levels. The moments applied to a joint from the columns above and below are resisted by the attached girders, which also bend in double curvature, with points of contraflexure at approximately mid-span. These deformations of the columns and girders allow racking of the frame and horizontal deflection in each story. The overall deflected shape of a rigid frame structure due to racking has a shear configuration with concavity upwind, a maximum inclination near the base, and a minimum inclination at the top, as shown in Fig.7.1.The overall moment of the external horizontal load is resisted in each story level by the couple resulting from the axial tensile and compressive forces in the columns on opposite sides of the structure (Fig. 7.2). The extension and shortening of the columns cause overall bending and associated horizontal displacements of the structure. Because of the cumulative rotation up the height, the story drift due to overall bending increases with height, while that due to racking tends to decrease. Consequently the contribution to story drift from overall bending may, in. the uppermost stories, exceed that from racking. The contribution of overall bending to the total drift, however, will usually not exceed 10% of that of racking, except in very tall, slender,, rigid frames. Therefore the overall deflected shape of a high-rise rigid frame usually has a shear configuration.The response of a rigid frame to gravity loading differs from a simply connected frame in the continuous behavior of the girders. Negative moments are induced adjacent to the columns, and positive moments of usually lesser magnitude occur in the mid-span regions. The continuity also causes the maximum girder moments to be sensitive to the pattern of live loading. This must be considered when estimating the worst moment conditions. For example, the gravity load maximum hogging momentadjacent to an edge column occurs when live load acts only on the edge span and alternate other spans, as for A in Fig. 7.3a. The maximum hogging moments adjacent to an interior column are caused, however, when live load acts only on the spans adjacent to the column, as for B in Fig. 7.3b. The maximum mid-span sagging moment occurs when live load acts on the span under consideration, and alternate other spans, as for spans AB and CD in Fig. 7.3a.The dependence of a rigid frame on the moment capacity of the columns for resisting horizontal loading usually causes the columns of a rigid frame to be larger than those of the corresponding fully braced simply connected frame. On the other hand, while girders in braced frames are designed for their mid-span sagging moment, girders in rigid frames are designed for the end-of-span resultant hogging moments, which may be of lesser value. Consequently, girders in a rigid frame may be smaller than in the corresponding braced frame. Such reductions in size allow economy through the lower cost of the girders and possible reductions in story heights. These benefits may be offset, however, by the higher cost of the more complex rigid connections.7.2 APPROXIMATE DETERMINATION OF MEMBER FORCES CAUSED BY GRAVITY LOADSIMGA rigid frame is a highly redundant structure; consequently, an accurate analysis can be made only after the member sizes are assigned. Initially, therefore, member sizes are decided on the basis of approximate forces estimated either by conservative formulas or by simplified methods of analysis that are independent of member properties. Two approaches for estimating girder forces due to gravity loading are given here.7.2.1 Girder Forces—Code Recommended ValuesIn rigid frames with two or more spans in which the longer of any two adjacent spans does not exceed the shorter by more than 20 %, and where the uniformly distributed design live load does not exceed three times the dead load, the girder moment and shears may be estimated from Table 7.1. This summarizes the recommendations given in the Uniform Building Code [7.1]. In other cases a conventional moment distribution or two-cycle moment distribution analysis should be made for a line of girders at a floor level.7.2.2 Two-Cycle Moment Distribution [7.2].This is a concise form of moment distribution for estimating girder moments in a continuous multibay span. It is more accurate than the formulas in Table 7.1, especially for cases of unequal spans and unequal loading in different spans.The following is assumed for the analysis:1. A counterclockwise restraining moment on the end of a girder is positive anda clockwise moment is negative.2. The ends of the columns at the floors above and below the considered girder are fixed.3. In the absence of known member sizes, distribution factors at each joint aretaken equal to 1 /n, where n is the number of members framing into the joint in the plane of the frame.Two-Cycle Moment Distribution—Worked Example. The method is demonstrated by a worked example. In Fig, 7.4, a four-span girder AE from a rigid-frame bent is shown with its loading. The fixed-end moments in each span are calculated for dead loading and total loading using the formulas given in Fig, 7.5. The moments are summarized in Table 7.2.The purpose of the moment distribution is to estimate for each support the maximum girder moments that can occur as a result of dead loading and pattern live loading.A different load combination must be considered for the maximum moment at each support, and a distribution made for each combination.The five distributions are presented separately in Table 7.3, and in a combined form in Table 7.4. Distributions a in Table 7.3 are for the exterior supports A and E. For the maximum hogging moment at A, total loading is applied to span AB with dead loading only on BC. The fixed-end moments are written in rows 1 and 2. In this distribution only .the resulting moment at A is of interest. For the first cycle, joint B is balanced with a correcting moment of - (-867 + 315)/4 = - U/4 assigned to M BA where U is the unbalanced moment. This is not recorded, but half of it, ( - U/4)/2, is carried over to M AB. This is recorded in row 3 and then added to the fixed-end moment and the result recorded in row 4.The second cycle involves the release and balance of joint A. The unbalanced moment of 936 is balanced by adding -U/3 = -936/3 = -312 to M BA (row 5), implicitly adding the same moment to the two column ends at A. This completes the second cycle of the distribution. The resulting maximum moment at A is then given by the addition of rows 4 and 5, 936 - 312 = 624. The distribution for the maximum moment at E follows a similar procedure.Distribution b in Table 7.3 is for the maximum moment at B. The most severe loading pattern for this is with total loading on spans AB and BC and dead load only on CD. The operations are similar to those in Distribution a, except that the T first cycle involves balancing the two adjacent joints A and C while recording only their carryover moments to B. In the second cycle, B is balanced by adding - (-1012 + 782)/4 = 58 to each side of B. The addition of rows 4 and 5 then gives the maximum hogging moments at B. Distributions c and d, for the moments at joints C and D, follow patterns similar to Distribution b.The complete set of operations can be combined as in Table 7.4 by initially recording at each joint the fixed-end moments for both dead and total loading. Then the joint, or joints, adjacent to the one under consideration are balanced for the appropriate combination of loading, and carryover moments assigned .to the considered joint and recorded. The joint is then balanced to complete the distribution for that support.Maximum Mid-Span Moments. The most severe loading condition for a maximum mid-span sagging moment is when the considered span and alternate other spans and total loading. A concise method of obtaining these values may be included in the combined two-cycle distribution, as shown in Table 7.5. Adopting the convention that sagging moments at mid-span are positive, a mid-span total; loading moment is calculated for the fixed-end condition of each span and entered in the mid-span column of row 2. These mid-span moments must now be corrected to allow for rotation of the joints. This is achieved by multiplying the carryover moment, row 3, at the left-hand end of the span by (1 + 0.5 D.F. )/2, and the carryover moment at the right-hand end by -(1 + 0.5 D.F.)/2, where D.F. is the appropriate distribution factor, and recording the results in the middle column. For example, the carryover to the mid-span of AB from A = [(1 + 0.5/3)/2] x 69 = 40 and from B = -[(1+ 0.5/4)/2] x (-145) = 82. These correction moments are then added to the fixed-end mid-span moment to give the maximum mid-span sagging moment, that is, 733 + 40 + 82 = 855.7.2.3 Column ForcesThe gravity load axial force in a column is estimated from the accumulated tributary dead and live floor loading above that level, with reductions in live loading as permitted by the local Code of Practice. The gravity load maximum column moment is estimated by taking the maximum difference of the end moments in the connected girders and allocating it equally between the column ends just above and below the joint. To this should be added any unbalanced moment due to eccentricity of the girderconnections from the centroid of the column, also allocated equally between the column ends above and below the joint.第七章框架结构高层框架结构一般由平行或正交布置的梁柱结构组成,梁柱结构是由带有能承担弯矩作用节点的梁、柱组成。
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DESIGN AND EXECUTION OF GROUNDINVESTIGATION FOR EARTHWORKSPAUL QUIGLEY, FGSIrish Geotechnical Services LtdABSTRACTThe design and execution of ground investigation works for earthwork projects has become increasingly important as the availability of suitable disposal areas becomes limited and costs of importing engineering fill increase. An outline of ground investigation methods which can augment …traditional investigation methods‟ particularly for glacial till / boulder clay soils is presented. The issue of …geotechnical certification‟ is raised and recommendations outlined on its merits for incorporation with ground investigations and earthworks.1. INTRODUCTIONThe investigation and re-use evaluation of many Irish boulder clay soils presents difficulties for both the geotechnical engineer and the road design engineer. These glacial till or boulder clay soils are mainly of low plasticity and have particle sizes ranging from clay to boulders. Most of our boulder clay soils contain varying proportions of sand, gravel, cobbles and boulders in a clay or silt matrix. The amount of fines governs their behaviour and the silt content makes it very weather susceptible.Moisture contents can be highly variable ranging from as low as 7% for the hard grey black Dublin boulder clay up to 20-25% for Midland, South-West and North-West light grey boulder clay deposits. The ability of boulder clay soils to take-in free water is well established and poor planning of earthworks often amplifies this.The fine soil constituents are generally sensitive to small increases in moisture content which often lead to loss in strength and render the soils unsuitable for re-use as engineering fill. Many of our boulder clay soils (especially those with intermediate type silts and fine sand matrix) have been rejected at the selection stage, but good planning shows that they can in fact fulfil specification requirements in terms of compaction and strength.The selection process should aim to maximise the use of locally available soils and with careful evaluation it is possible to use or incorporate …poor or marginal soils‟ within fill areas and embankments. Fill material needs to be placed at a moisture content such that it is neither too wet to be stable and trafficable or too dry to be properly compacted.High moisture content / low strength boulder clay soils can be suitable for use as fill in low height embankments (i.e. 2 to 2.5m) but not suitable for trafficking by earthwork plant without using a geotextile separator and granular fill capping layer. Hence, it is vital that the earthworks contractor fully understands the handling properties of the soils, as for many projects this is effectively governed by the trafficability of earthmoving equipment.2. TRADITIONAL GROUND INVESTIGATION METHODSFor road projects, a principal aim of the ground investigation is to classify the suitability of the soils in accordance with Table 6.1 from Series 600 of the NRA Specification for Road Works (SRW), March 2000. The majority of current ground investigations for road works includes a combination of the following to give the required geotechnical data:▪Trial pits▪Cable percussion boreholes▪Dynamic probing▪Rotary core drilling▪In-situ testing (SPT, variable head permeability tests, geophysical etc.)▪Laboratory testingThe importance of …phasing‟ the fieldwork operations cannot be overstressed, particularly when assessing soil suitability from deep cut areas. Cable percussion boreholes are normally sunk to a desired depth or …refusal‟ with disturbed a nd undisturbed samples recovered at 1.00m intervals or change of strata.In many instances, cable percussion boring is unable to penetrate through very stiff, hard boulder clay soils due to cobble, boulder obstructions. Sample disturbance in boreholes should be prevented and loss of fines is common, invariably this leads to inaccurate classification.Trial pits are considered more appropriate for recovering appropriate size samples and for observing the proportion of clasts to matrix and sizes of cobbles, boulders. Detailed and accurate field descriptions are therefore vital for cut areas and trial pits provide an opportunity to examine the soils on a larger scale than boreholes. Trial pits also provide an insight on trench stability and to observe water ingress and its effects.A suitably experienced geotechnical engineer or engineering geologist should supervise the trial pitting works and recovery of samples. The characteristics of the soils during trial pit excavation should be closely observed as this provides information on soil sensitivity, especially if water from granular zones migrates into the fine matrix material. Very often, the condition of soil on the sides of an excavation provides a more accurate assessment of its in-situ condition.3. SOIL CLASSIFICATIONSoil description and classification should be undertaken in accordance with BS 5930 (1999) and tested in accordance with BS 1377 (1990). The engineering description of a soil is based on its particle size grading, supplemented by plasticity for fine soils. For many of our glacial till, boulder clay soils (i.e. …mixed soils‟) difficulties arise with descriptions and assessing engineering performance tests.As outlined previously, Irish boulder clays usually comprise highly variable proportions of sands, gravels and cobbles in a silt or clay matrix. Low plasticity soils with fines contents of around 10 to 15% often present the most difficulties. BS 5930 (1999) now recognises thesedifficulties in describing …mixed soils‟ – the fine soil constituents which govern the engineering behaviour now takes priority over particle size.A key parameter (which is often underestimated) in classifying and understanding these soils is permeability (K). Inspection of the particle size gradings will indicate magnitude of permeability. Where possible, triaxial cell tests should be carried out on either undisturbed samples (U100‟s) or good quality core samples to evaluate the drainage characteristics of the soils accurately.Low plasticity boulder clay soils of intermediate permeability (i.e. K of the order of 10-5 to 10-7 m/s) can often be …conditioned‟ by drainage measures. This usually entails the installation of perimeter drains and sumps at cut areas or borrow pits so as to reduce the moisture content. Hence, with small reduction in moisture content, difficult glacial till soils can become suitable as engineering fill.4. ENGINEERING PERFORMANCE TESTING OF SOILSLaboratory testing is very much dictated by the proposed end-use for the soils. The engineering parameters set out in Table 6.1 pf the NRA SRW include a combination of the following:▪Moisture content▪Particle size grading▪Plastic Limit▪CBR▪Compaction (relating to optimum MC)▪Remoulded undrained shear strengthA number of key factors should be borne in mind when scheduling laboratory testing:▪Compaction / CBR / MCV tests are carried out on < 20mm size material.▪Moisture content values should relate to < 20mm size material to provide a valid comparison.▪Pore pressures are not taken into account during compaction and may vary considerably between laboratory and field.▪Preparation methods for soil testing must be clearly stipulated and agreed with the designated laboratory.Great care must be taken when determining moisture content of boulder clay soils. Ideally, the moisture content should be related to the particle size and have a corresponding grading analysis for direct comparison, although this is not always practical.In the majority of cases, the MCV when used with compaction data is considered to offer the best method of establishing (and checking) the suitability characteristics of a boulder clay soil. MCV testing during trial pitting is strongly recommended as it provides a rapid assessment of the soil suitability directly after excavation. MCV calibration can then be carried out in the laboratory at various moisture content increments. Sample disturbance can occur during transportation to the laboratory and this can have a significant impact on the resultant MCV‟s.IGSL has found large discrepancies when p erforming MCV‟s in the field on low plasticity boulder clays with those carried out later in the laboratory (2 to 7 days). Many of the aforementioned low plasticity boulder clay soils exhibit time dependant behaviour with significantly different MCV‟s reco rded at a later date –increased values can be due to the drainage of the material following sampling, transportation and storage while dilatancy and migration of water from granular lenses can lead to deterioration and lower values.This type of information is important to both the designer and earthworks contractor as it provides an opportunity to understand the properties of the soils when tested as outlined above. It can also illustrate the advantages of pre-draining in some instances. With mixed soils, face excavation may be necessary to accelerate drainage works.CBR testing of boulder clay soils also needs careful consideration, mainly with the preparation method employed. Design engineers need to be aware of this, as it can have an order of magnitude difference in results. Static compaction of boulder clay soils is advised as compaction with the 2.5 or 4.5kg rammer often leads to high excess pore pressures being generated – hence very low CBR values can result. Also, curing of compacted boulder clay samples is important as this allows excess pore water pressures to dissipate.5. ENGINEERING CLASSIFICATION OF SOILSIn accordance with the NRA SRW, general cohesive fill is categorised in Table 6.1 as follows: ▪2A Wet cohesive▪2B Dry cohesive▪2C Stony cohesive▪2D Silty cohesiveThe material properties required for acceptability are given and the design engineer then determines the upper and lower bound limits on the basis of the laboratory classification and engineering performance tests. Irish boulder clay soils are predominantly Class 2C.Clause 612 of the SRW sets out compaction methods. Two procedures are available: ▪Method Compaction▪End-Product CompactionEnd product compaction is considered more practical, especially when good compaction control data becomes available during the early stages of an earthworks contract. A minimum Target Dry Density (TDD) is considered very useful for the contractor to work with as a means of checking compaction quality. Once the material has been approved and meets the acceptability limits, then in-situ density can be measured, preferably by nuclear gauge or sand replacement tests where the stone content is low.As placing and compaction of the fill progresses, the in-situ TDD can be checked and non-conforming areas quickly recognised and corrective action taken. This process requires the design engineer to review the field densities with the laboratory compaction plots and evaluate actual with …theoretical densities‟.6. SUPPLEMENTARY GROUND INVESTIGATION METHODS FOR EARTHWORKSThe more traditional methods and procedures have been outlined in Section 2. The following are examples of methods which are believed to enhance ground investigation works for road projects:▪Phasing the ground investigation works, particularly the laboratory testing▪Excavation & sampling in deep trial pits▪Large diameter high quality rotary core drilling using air-mist or polymer gel techniques▪Small-scale compaction trials on potentially suitable cut material6.1 PHASINGPhasing ground investigation works for many large projects has been advocated for many years –this is particularly true for road projects where significant amounts of geotechnical data becomes available over a short period. On the majority of large ground investigation projects no peri od is left to …digest‟ or review the preliminary findings and re-appraise the suitability of the methods.With regard to soil laboratory testing, large testing schedules are often prepared with no real consideration given to their end use. In many cases, the schedule is prepared by a junior engineer while the senior design engineer who will probably design the earthworks will have no real involvement.It is highlighted that the engineering performance tests are expensive and of long duration (e.g. 5 point compaction with CBR & MCV at each point takes in excess of two weeks). When classification tests (moisture contents, particle size analysis and Atterberg Limits) are completed then a more incisive evaluation can be carried out on the data and the engineering performance tests scheduled. If MCV‟s are performed during trial pitting then a good assessment of the soil suitability can be immediately obtained.6.2 DEEP TRIAL PITSThe excavation of deep trial pits is often perceived as cumbersome and difficult and therefore not considered appropriate by design engineers. Excavation of deep trial pits in boulder clay soils to depths of up to 12m is feasible using benching techniques and sump pumping of groundwater.In recent years, IGSL has undertaken such deep trial pits on several large road ground investigation projects. The data obtained from these has certainly enhanced the geotechnical data and provided a better understanding of the bulk properties of the soils.It is recommended that this work be carried out following completion of the cable percussion boreholes and rotary core drill holes. The groundwater regime within the cut area will play an important role in governing the feasibility of excavating deep trial pits. The installation of standpipes and piezometers will greatly assist the understanding of the groundwater conditions, hence the purpose of undertaking this work late on in the ground investigation programme.Large representative samples can be obtained (using trench box) and in-situ shear strength measured on block samples. The stability of the pit sidewalls and groundwater conditions can also be established and compared with levels in nearby borehole standpipes or piezometers. Over a prominent cut area of say 500m, three deep trial pits can prove invaluable and the spoil material also used to carry out small-scale compaction trials.From a value engineering perspective, the cost of excavating and reinstating these excavations can be easily recovered. A provisional sum can be allocated in the ground investigation and used for this work.6.3 HIGH QUALITY LARGE DIAMETER ROTARY CORE DRILLINGThis system entails the use of large diameter rotary core drilling techniques using air mist or polymer gel flush. Triple tube core drilling is carried out through the overburden soils with the recovered material held in a plastic core liner.Core recovery in low plasticity boulder clay has been shown to be extremely good (typically in excess of 90%). The high core recovery permits detailed engineering geological logging and provision of samples for laboratory testing.In drumlin areas, such as those around Cavan and Monaghan, IGSL has found the use of large diameter polymer gel rotary core drilling to be very successful in recovering very stiff / hard boulder clay soils for deep road cut areas (where cable percussion boreholes and trial pits have failed to penetrate). In-situ testing (vanes, SPT‟s etc) can also be carried out within the drillhole to establish strength and bearing capacity of discrete horizons.Large diameter rotary drilling costs using the aforementioned systems are typically 50 to 60% greater than conventional HQ core size, but again from a value engineering aspect can prove much more worthwhile due to the quality of geotechnical information obtained.6.4 SMALL-SCALE COMPACTION TRIALSThe undertaking of small-scale compaction trials during the ground investigation programme is strongly advised,particularly where …marginally suitable‟ soils are present in prominent cut areas. In addition to validating the laboratory test data, they enable more realistic planning of the earthworks and can provide considerable cost savings.The compaction trial can provide the following:▪Achievable field density, remoulded shear strength and CBR▪Establishing optimum layer thickness and number of roller passes▪Response of soil during compaction (static v dynamic)▪Monitor trafficability & degree of rutting.A typical size test pad would be approximately 20 x 10m in plan area and up to 1.5m in thickness. The selected area should be close to the cut area or borrow pit and have adequate room for stockpiling of material. Earthwork plant would normally entail a tracked excavator (CAT 320 or equivalent), 25t dumptruck, D6 dozer and either a towed or self-propelled roller. In-situ density measurement on the compacted fill by nuclear gauge method is recommended as this facilitates rapid measurement of moisture contents, dry and bulk densities. It alsoenables a large suite of data to be generated from the compacted fill and to assess the relationship between degree of compaction, layer thickness and number of roller passes. Both disturbed and undisturbed (U100) samples of the compacted fill can be taken for laboratory testing and validation checks made with the field data (particularly moisture conte nts). IGSL‟s experience is that with good planning a small-scale compaction trial takes two working days to complete.7. SUPERVISION OF GROUND INVESTIGATION PROJECTSClose interaction and mutual respect between the ground investigation contractor and the consulting engineer is considered vital to the success of large road investigation projects. A senior geotechnical engineer from each of the aforementioned parties should liase closely so that the direction and scope of the investigation can be changed to reflect the stratigraphy and ground conditions encountered.The nature of large ground investigation projects means that there must be good communication and flexibility in approach to obtaining data. Be prepared to compromise as methods and procedures specified may not be appropriate and site conditions can quickly change.From a supervision aspect (both contractor and consulting engineer), the emphasis should be on the quality of site-based geotechnical engineers, engineering geologists as opposed to quantity where work is duplicated.8. GEOTECHNICAL CERTIFICATIONThe Department of Transport (UK) prepared a document (HD 22/92) in 1992 for highway schemes. This sets out the procedures and documentation to be used during the planning and reporting of ground investigations and construction of earthworks.Road projects involving earthmoving activities or complex geotechnical features must be certified by the Design Organisation (DO) - consulting engineer or agent authority. The professional responsibility for the geotechnical work rests with the DO.For such a project, the DO must nominate a chartered engineer with appropriate geotechnical engineering experience. He/she is referred to as the Geotechnical Liaison Engineer (GLE) and is responsible for all geotechnical matters including preparation of procedural statements, reports and certificates.Section 1.18 of HD 22/92 states that “on completion of the ground investigation works, the DO shall submit a report and certificate containing all the factual records and test results produced by the specialist contractor together with an interpretative report produced either by the specialist contractor or DO”. The DO shall then prepare an Earthworks Design Report –this report is the Designer‟s detailed report on his in terpretation of the site investigation data and design of earthworks.The extent and closeness of the liaison between the Project Manager and the GLE will very much depend on the nature of the scheme and geotechnical complexities discovered as the investigation and design proceed.After the earthworks are completed, a geotechnical feedback report is required and is to be prepared by the DO. This addresses the geotechnical issues and problems encountered during the construction earthworks and corrective action or measures taken. Certificates are prepared by the DO to sign off on the geotechnical measures carried out (e.g. unstable slopes, karst features, disused / abandoned mine workings, ground improvement systems employed, etc).9. CONCLUSIONS▪Close co-operation is needed between ground investigation contractors and consulting engineers to ensure that the geotechnical investigation work for the roads NDP can be satisfactorily carried out.▪Many soils are too easily rejected at selection / design stage. It is hoped that the proposed methods outlined in this paper will assist design engineers during scoping and specifying of ground investigation works for road projects.▪With modern instrumentation, monitoring of earthworks during construction is very straightforward. Pore water pressures, lateral and vertical movements can be easily measured and provide important feedback on the performance of the engineered soils.▪Phasing of the ground investigation works, particularly laboratory testing is considered vital so that the data can be properly evaluated.▪Disposal of …marginal‟ soils will become increasingly difficult and more expensive as the waste licensing regulations are tightened. The advent of landfill tax in the UK has seen thorough examination of all soils for use in earthworks. This is likely to provide a similar incentive and challenge to geotechnical and civil engineers in Ireland in the coming years. ▪ A certification approach comparable with that outlined should be considered by the NRA for ground investigation and earthwork activities.土方工程的地基勘察与施工保罗·圭格利爱尔兰岩土工程服务有限公司摘要:当工程场地的处理面积有限且填方工程费用大量增加时,土方工程的地基勘察设计与施工已逐渐地变得重要。