土木工程毕业论文中英文翻译
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。
本科毕业土木工程专业英语翻译翻译
Discuss the construction temperature and crack of theconcrete lightlyBy G. K. Kululanga, W. Kuotcha，R. McCaffer，Member，ASCE, and F。
Edum-Fotwe ，The American Society of Civil EngineersThe summary , In order to prevent the owners of the concrete work of claims，we must do a good job in the construction process in the temperature and crackcontrol,through observation live for many years, through consulting the monograph about stress within the concrete，explain to concrete temperature reason , on—the-spot concrete control and measure , prevention of crack of temperature that crack produce。
Keyword Concrete Temperature stress Crack Control1.The concrete occupies the important position in modern engineering construction。
But today，the crack of the concrete is comparatively general，the cracks are nearly omnipresent in the science of bridge building. Though we take various kinds of measures in constructing，careful, but the crack still occurs now and then。
土木工程外文翻译70683
本科毕业设计（论文）外文翻译译文学生姓名：院 （系）：专业班级：指导教师：完成日期：钢筋混凝土填充框架结构对拆除两个相邻的柱的响应作者： 美国波士顿东北大学，斯奈尔 设计中心收稿日期： 年 月 日，修整后收稿日期 年 月 日，录用日期 年 月 日，网上上传日期 年 月 日。
摘要：本文是评价圣地亚哥旅馆对同时拆除两根相邻的外柱的响应问题，圣地亚哥旅馆是个 层钢筋混凝土填充框架结构。
结构的分析模型应用了有限元法和以此为基础的分析模型来计算结构的整体和局部变形。
分析结果跟实验结果非常吻合。
当测量的竖向位移增加到为四分之一英寸（即 ）的时候，结构就发生连续倒塌。
通过实验分析方法评价和讨论随着柱的移除而产生的变形沿着结构高度上的发展和荷载动态重分配。
讨论了轴向和弯曲的变形传播的不同。
结构横向和纵向的三维桁架在填充墙的参与下被认为是荷载重分配的主要构件。
讨论了两种潜在的脆性破坏模型（没有拉力加强的梁的脆断和有加筋肋的梁的挤出）。
分析评价了结构对额外的重力和无填充墙时的响应。
有限责任公司对此文保留所有权利。
关键词：连续倒塌；荷载重分配；对荷载抵抗能力；动态响应；非线性分析；脆性破坏。
介绍：作为减小由于结构的局部损坏而造成大量伤亡的可能性措施的一部分，美国总务管理局【 】和国防部【 】出台了一系列制度来评价结构对连续倒塌的抵抗力。
【 】定义连续倒塌为，由原始单元的局部破坏在单元间的扩展最终造成结构的整体或不成比例的大部破坏。
通过 和 【 】建议的方法， 定义了两种一般模型来减小结构设计时连续倒塌效应产生的损害，它们分为直接和间接的设计方法。
一般建筑规范和标准用增加结构的整体性的间接设计方法。
间接设计法也应用于美国国防部的降低连续倒塌设计和未归档设备标准中。
尽管间接设计法可以降低连续破坏的风险【 ， 】，对基于此法设计的结构破坏后的表现的判断是不容易实现的。
有一种基于直接设计的方法通过研究瞬间消除受载构件，比如柱子，对结构的影响来评价结构的连续倒塌。
【设计】土木工程毕业设计英语论文及翻译
【关键字】设计土木工程毕业设计英语论文及翻译篇一：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 place during 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, theconcrete 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, masoy, 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 verywidely 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 instrength 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 ueinforced 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.篇二：土木工程毕业设计中英文翻译附录：中英文翻译英文部分：LOADSLoads that act on structures are usually classified as dead loads or live loads.Dead loads are fixed in location and constant in magnitude throughout the life of the ually the self-weight of a structure is the most important part of the structure and the unit weight of the material.Concrete density varies from about 90 to 120 pcf (14 to 19 KN/m2)for lightweight concrete,and is about 145 pcf (23 KN/mKN/m2)for normal concrete.In calculating the dead load of structural concrete,usually a 5pcf (1 )increment is included with the weight of the concrete to account for the presence of the 2 reinforcement.Live loads are loads such as occupancy,snow,wind,or traffic loads,or seismic forces.They may be either fully or partially in place,or not present at all.They may also change in location.Althought it is the responsibility of the engineer to calculate dead loads,live loads are usually specified by local,regional,or national codes and specifications.Typical sources are the publications of the American National Standards Institute,the American Association of State Highway and Transportation Officials and,for wind loads,the recommendations of the ASCE Task Committee on Wind Forces.Specified live the loads usually include some allowance for overload,and may include measures such as posting of maximum loads will not be exceeded.It is oftern important to distinguish between the specified load,and what is termed the characteristic load,that is,the load that actually is in effect under normal conditions of service,which may be significantly less.In estimating the long-term deflection of a structure,for example,it is the characteristic load that is important,not the specified load.The sum of the calculated dead load and the specified live load is called the service load,because this is the maximum load which may reasonably be expected to act during the service resisting is a multiple of the service load.StrengthThe strength of a structure depends on the strength of the materials from which it is made.Minimum material strengths are specified in certain standardized ways.The properties of concrete and its components,the methods of mixing,placing,and curing to obtain the required quality,and the methods for testing,are specified by the American Concrete Insititue(ACI).Included by refrence in the same documentare standards of the American Society for Testing Materials(ASTM)pertaining to reinforcing and prestressing steels and concrete.Strength also depends on the care with which the structure is built.Member sizes may differ from specified dimensions,reinforcement may be out of position,or poor placement of concrete may result in voids.An important part of the job of the ergineer is to provide proper supervision of construction.Slighting of this responsibility has had disastrous consequences in more than one instance.Structural SafetySafety requires that the strength of a structure be adequate for all loads that may conceivably act on it.If strength could be predicted accurately and if loads were known with equal certainty,then safely could be assured by providing strength just barely in excess of the requirements of the loads.But there are many sources of uncertainty in the estimation of loads as well as in analysis,design,and construction.These uncertainties require a safety margin.In recent years engineers have come to realize that the matter of structural safety isprobabilistic in nature,and the safety provisions of many current specifications reflect this view.Separate consideration is given to loads and strength.Load factors,larger than unity,are applied to the calculated dead loads and estimated or specified service live loads,to obtain factorde loads that the member must just be capable of sustaining at incipient failure.Load factors pertaining to different types of loads vary,depending on the degree of uncertainty associated with loads of various types,and with the likelihood of simultaneous occurrence of different loads.Early in the development of prestressed concrete,the goal of prestressing was the complete elimination of concrete ternsile stress at service loads.The concept was that of an entirely new,homogeneous material that woukd remain uncracked and respond elastically up to the maximum anticipated loading.This kind of design,where the limiting tensile stressing,while an alternative approach,in which a certain amount of tensile amount of tensile stress is permitted in the concrete at full service load,is called partial prestressing.There are cases in which it is necessary to avoid all risk of cracking and in which full prestressing is required.Such cases include tanks or reservious where leaks must be avoided,submerged structures or those subject to a highly corrosive envionment where maximum protection of reinforcement must be insured,and structures subject to high frequency repetition of load where faatigue of the reinforcement may be a consideration.However,there are many cses where substantially improved performance,reduced cost,or both may be obtained through the use of a lesser amount of prestress.Full predtressed beams may exhibit an undesirable amount of upward camber because of the eccentric prestressing force,a displacement that is only partially counteracted by the gravity loads producing downward deflection.This tendency is aggrabated by creep in the concrete,which magnigies the upward displacement due to the prestress force,but has little influence on the should heavily prestressed members be overloaded and fail,they may do so in a brittle way,rather than gradually as do beams with a smaller amount of prestress.This is important from the point of view of safety,because suddenfailure without warning is dangeroud,and gives no opportunity for corrective measures to be taken.Furthermore,experience indicates that in many cases improved economy results from the use of a combination of unstressed bar steel and high strength prestressed steel tendons.While tensile stress and possible cracking may be allowed at full service load,it is also recognized that such full service load may be infrequently applied.The typical,or characteristic,load acting is likely to be the dead load plus a small fraction of the specified live load.Thus a partially predtressed beam may not be subject to tensile stress under the usual conditions of loading.Cracks may from occasionally,when the maximum load is applied,but these will close completely when that load is removed.They may be no more objectionable in prestressed structures than in ordinary reinforced.They may be no more objectionable in prestressed structures than in ordinary reinforced concrete,in which flexural cracks alwaysform.They may be considered a small price for the improvements in performance and economy that are obtained.It has been observed that reinforced concrete is but a special case of prestressed concrete in which the prestressing force is zero.The behavior of reinforced and prestressed concrete beams,as the failure load is approached,is essentially the same.The Joint European Committee on Concrete establishes threee classes of prestressed beams.Class 1:Fully prestressed,in which no tensile stress is allowed in the concrete at service load.Class 2:Partially prestressed, in which occasional temporary cracking is permitted under infrequent high loads.Class 3:Partially prestressed,in which there may be permanent cracks provided that their width is suitably limited.The choise of a suitable amount of prestress is governed by a variety of factors.These include thenature of the loading (for exmaple,highway or railroad bridged,storage,ect.),the ratio of live to dead load,the frequency of occurrence of loading may be reversed,such as in transmission poles,a high uniform prestress would result ultimate strength and in brittle failure.In such a case,partial prestressing provides the only satifactory solution.The advantages of partial prestressing are important.A smaller prestress force will be required,permitting reduction in the number of tendons and anchorages.The necessary flexural strength may be provided in such cases either by a combination of prestressed tendons and non-prestressed reinforcing bars,or by an adequate number of high-tensile tendons prestredded to level lower than the prestressing force is less,the size of the bottom flange,which is requied mainly to resist the compression when a beam is in the unloaded stage,can be reduced or eliminated altogether.This leads in turn to significant simplification and cost reduction in the construction of forms,as well as resulting in structures that are mor pleasing esthetically.Furthermore,by relaxing the requirement for low service load tension in the concrete,a significant improvement can be made in the deflection characteristics of a beam.Troublesome upward camber of the member in the unloaded stage fan be avoeded,and the prestress force selected primarily to produce the desired deflection for a particular loading condition.The behavior of partially prestressed beamsm,should they be overloaded to failure,is apt to be superior to that of fully prestressed beams,because the improved ductility provides ample warning of distress.英译汉：荷载作用在结构上的荷载通常分为恒载或活载。
土木工程毕业设计中英文翻译.doc
附录：中英文翻译英文部分：LOADSLoads that act on structures are usually classified as dead loads or live loads.Dead loads are fixed in location and constant in magnitude throughout the life of the ually the self-weight of a structure is the most important part of the structure and the unit weight of the material.Concrete density varies from about 90 to 120 pcf (14 to 19 2KN/m)for lightweight concrete,and is about 145 pcf (23 2KN/m)for normal concrete.In calculating the dead load of structural concrete,usually a 5 pcf (1 2KN/m)increment is included with the weight of the concrete to account for the presence of the reinforcement.Live loads are loads such as occupancy,snow,wind,or traffic loads,or seismic forces.They may be either fully or partially in place,or not present at all.They may also change in location.Althought it is the responsibility of the engineer to calculate dead loads,live loads are usually specified by local,regional,or national codes and specifications.Typical sources are the publications of the American National Standards Institute,the American Association of State Highway and Transportation Officials and,for wind loads,the recommendations of the ASCE Task Committee on Wind Forces.Specified live the loads usually include some allowance for overload,and may include measures such as posting of maximum loads will not be exceeded.It is oftern important to distinguish between the specified load,and what is termed the characteristic load,that is,the load that actually is in effect under normal conditions of service,which may be significantly less.In estimating the long-term deflection of a structure,for example,it is the characteristic load that is important,not the specified load.The sum of the calculated dead load and the specified live load is called the service load,because this is the maximum load which may reasonably be expected to act during the service resisting is a multiple of the service load.StrengthThe strength of a structure depends on the strength of the materials from which it is made.Minimum material strengths are specified in certain standardized ways.The properties of concrete and its components,the methods of mixing,placing,and curing to obtain the required quality,and the methods for testing,are specified by the American Concrete Insititue(ACI).Included by refrence in the same documentare standards of the American Society for Testing Materials(ASTM)pertaining to reinforcing and prestressing steels and concrete.Strength also depends on the care with which the structure is built.Member sizes may differ from specified dimensions,reinforcement may be out of position,or poor placement of concrete may result in voids.An important part of the job of the ergineer is to provide proper supervision of construction.Slighting of this responsibility has had disastrous consequences in more than one instance.Structural SafetySafety requires that the strength of a structure be adequate for all loads that may conceivably act on it.If strength could be predicted accurately and if loads were known with equal certainty,then safely could be assured by providing strength just barely in excess of the requirements of the loads.But there are many sources of uncertainty in the estimation of loads as well as in analysis,design,and construction.These uncertainties require a safety margin.In recent years engineers have come to realize that the matter of structural safety is probabilistic in nature,and the safety provisions of many current specifications reflect this view.Separate consideration is given to loads and strength.Load factors,larger than unity,are applied to the calculated dead loads and estimated or specified service live loads,to obtain factorde loads that the member must just be capable of sustaining at incipient failure.Load factors pertaining to different types of loads vary,depending on the degree of uncertainty associated with loads of various types,and with the likelihood of simultaneous occurrence of different loads.Early in the development of prestressed concrete,the goal of prestressing was the complete elimination of concrete ternsile stress at service loads.The concept was that of an entirely new,homogeneous material that woukd remain uncracked and respond elastically up to the maximum anticipated loading.This kind of design,where the limiting tensile stressing,while an alternative approach,in which a certain amount of tensile amount of tensile stress is permitted in the concrete at full service load,is called partial prestressing.There are cases in which it is necessary to avoid all risk of cracking and in which full prestressing is required.Such cases include tanks or reservious where leaks must be avoided,submerged structures or those subject to a highly corrosive envionment where maximum protection of reinforcement must be insured,and structures subject to high frequency repetition of load where faatigue of the reinforcement may be a consideration.However,there are many cses where substantially improved performance,reduced cost,or both may be obtained through the use of a lesser amount of prestress.Full predtressed beams may exhibit an undesirable amount of upward camber because of the eccentric prestressing force,a displacement that is only partially counteracted by the gravity loads producing downward deflection.This tendency is aggrabated by creep in the concrete,which magnigies the upward displacement due to the prestress force,but has little influence on the should heavily prestressed members be overloaded and fail,they may do so in a brittle way,rather than gradually as do beams with a smaller amount of prestress.This is important from the point of view of safety,because suddenfailure without warning is dangeroud,and gives no opportunity for corrective measures to be taken.Furthermore,experience indicates that in many cases improved economy results from the use of a combination of unstressed bar steel and high strength prestressed steel tendons.While tensile stress and possible cracking may be allowed at full service load,it is also recognized that such full service load may be infrequently applied.The typical,or characteristic,load acting is likely to be the dead load plus a small fraction of the specified live load.Thus a partially predtressed beam may not be subject to tensile stress under the usual conditions of loading.Cracks may from occasionally,when the maximum load is applied,but these will close completely when that load is removed.They may be no more objectionable in prestressed structures than in ordinary reinforced.They may be no more objectionable in prestressed structures than in ordinary reinforced concrete,in which flexural cracks always form.They may be considered a small price for the improvements in performance and economy that are obtained.It has been observed that reinforced concrete is but a special case of prestressed concrete in which the prestressing force is zero.The behavior of reinforced and prestressed concrete beams,as the failure load is approached,is essentially the same.The Joint European Committee on Concrete establishes threee classes of prestressed beams.Class 1:Fully prestressed,in which no tensile stress is allowed in the concrete at service load.Class 2:Partially prestressed, in which occasional temporary cracking is permitted under infrequent high loads.Class 3:Partially prestressed,in which there may be permanent cracks provided that their width is suitably limited.The choise of a suitable amount of prestress is governed by a variety of factors.These include thenature of the loading (for exmaple,highway or railroad bridged,storage,ect.),the ratio of live to dead load,the frequency of occurrence of loading may be reversed,such as in transmission poles,a high uniform prestress would result ultimate strength and in brittle failure.In such a case,partial prestressing provides the only satifactory solution.The advantages of partial prestressing are important.A smaller prestress force will be required,permitting reduction in the number of tendons and anchorages.The necessary flexural strength may be provided in such cases either by a combination of prestressed tendons and non-prestressed reinforcing bars,or by an adequate number of high-tensile tendons prestredded to level lower than the prestressing force is less,the size of the bottom flange,which is requied mainly to resist the compression when a beam is in the unloaded stage,can be reduced or eliminated altogether.This leads in turn to significant simplification and cost reduction in the construction of forms,as well as resulting in structures that are mor pleasing esthetically.Furthermore,by relaxing the requirement for low service load tension in the concrete,a significant improvement can be made in the deflection characteristics of a beam.Troublesome upward camber of the member in the unloaded stage fan be avoeded,and the prestress force selected primarily to produce the desired deflection for a particular loading condition.The behavior of partially prestressed beamsm,should they be overloaded to failure,is apt to be superior to that of fully prestressed beams,because the improved ductility provides ample warning of distress.英译汉：荷 载作用在结构上的荷载通常分为恒载或活载。
08土木工程质量管理毕业论文中英文资料外文翻译文献
土木工程质量管理中英文资料外文翻译文献On civil engineering construction project quality management1 IntroductionCivil engineering building project success lies in the quality of quality, separate, other everything is out of the question. Therefore, to take civil engineering construction quality management in the construction project implementation plan and implementation process.In practice, no more than the use of engineering quality of care. But to ensure the construction quality, using the party there is a need for the organization experienced professional quality management team, design of the wholeconstruction process, including engineering design, construction units, building material, construction process and supervision and other aspects of the management, but also guide the construction unit of the construction personnel to timely and effectively encourages training. This article from the above several aspects to discuss.2.construction of the effective surveillance on the use of unit, design unit as a design once, is the work of supervisors, why should I organize the quality surveillance team? Because our country construction there are still many unsatisfactory objective or objective aspects, the unit is necessary to hire have the sense of responsibility, have management experience, familiar with the policies and regulations, have good communication ability quality management, set up quality management team, the construction design and construction process for effective management monitoring. The management team, can according to the engineering build pause status stop adjustment, implementation of compulsory system. On ordinary civil construction, quality management is relatively easy, with the possible exception of new information on the use of new technology, the whole quality management more rule-based. On special request of civil building engineering, quality management will be arranged to stop.First of all, on the quality of project design management. This stage, mainly for the design units in strict accordance with the unit can the fundamental request stop design, to check whether reasonable design plan, design intent can and thesurrounding geographical environment as well as local humane environment of harmony, in the technology and the budget is feasible, can be advanced technology, reliable structure can safely, whether the unit in charge of construction appropriate technology request etc..These aspects of the management and inspection, in relation to the whole building after project completion, in the use of function, quality, human physical performance and other aspects whether can reach certain degree of satisfaction of the big issue.At this stage, management personnel more to listen to designers to design the idea", a lot of advisory application unit in macroscopical and microcosmic staff views on initiative, make design to perfection.In addition, to check the design drawings can correctly reflect the design plan, calculated correctly, drawing dimensioning can have mistakenly, selection of materials and construction request whether reasonable, the overall design of various departments such as can harmonious design. Because our country is in the design and supervision work still is lacked very much, in the aspects of management and examination must be careful, in order to prevent subsequent quality disputes.Secondly, to the construction supervision supervision.Construction supervision is the key to guarantee the construction quality. Quality management departments should promptly to supervision departments to key local construction quality monitoring report, implement supervision duty. At the same time, but also in a timely manner, sampling test, certain constructiontechnology can fit design request. On construction supervision departments, to check its supervision can improve the supervision work procedure, to check whether supervision report specification, not in conformity with the requests of construction operation can be corrected in a timely manner.Again, on the construction equipment and construction personnel basic quality supervision and inspection construction can stop, with safe and reliable, can satisfy the design request and to complete construction; construction team consisting of whether reasonable, the construction of the technical staff to whether accord with basic request, especially on special request link, can have the equivalent level technical personnel in charge of participating in the construction process. Pay attention to the quality of construction unit, it progresses to the legal view. On raw materials procurement and construction of test procedures are detailed records.In addition, to stop the construction effect of sampling, discover a problem, timely and inspect manage personnel contact, stop the rectification, to prevent the engineering dispute, avoid engineering quality formation of waste.3construction of the various communication quality management work is not a design and construction method for cubic, but the entire project important constituent, it is designed with all relevant units of the divergent interests of. Present quality problems, the parties involved have the duty, have loss. At this point, the quality management must communicate with relevant parties, won the understanding and support. In addition, in the process of construction, also oftenencounter the construction side of the design request of doubt problem. The generation of these problems, sometimes due to the use of units of detailed request, some are the result of the design concept and design thoughts of the reasons, some due to the construction process the request of different caused. These problems cannot be ignored, should be promptly to communicate, understand the request, the timely adjustment. Not conscious construction, so that the practical results and design request is betrayed, and the use of units of the basic request of betrayal, unnecessary disputes and losses.4construction personnel training and encourage civil engineering building operators is worker of a gleam of. From the present situation, the construction team of individual technical quality is also very important. Some construction unit, construction personnel activity, the construction of personnel practice degree no true assessment, making the construction quality to sell at a discount greatly.Then, is it right? A start to construction personnel examination, request to high level? At least from the now situation, which is not ideal. First, each building project on the detailed construction technology has different request. In the organization of the construction process, request a certain proportion of with some degree of worker technician, another local can have initial operation skills of construction workers. During the construction process, to guide the construction of a reasonable distribution of work, make the workers work in practice to further mature some basic types of operational procedures and technical requirements, andon this basis, the organization staff to stop training, make the understanding of the new technology, become established during the construction of the backbone. Then let them in the work of a scheme to other construction personnel to impart technical.In this respect, the construction unit according to the detailed status of layout. There has been a reasonable training mechanism, the construction personnel to understand the practical operation level, and improve their technical level of power. In the long run, the overall quality of the progress of the construction unit is also very important.On the other hand, effective encouragement and improve construction worker job enthusiasm and learning enthusiasm of the necessary measures. Frontline workers mostly from rural, energy consumption, the low pay, the mood is stable. Therefore, to establish effective encouraging mechanism. To ensure that the wage Qing month, labor safeguard measures, management of human nature, care workers and Ankang. In addition, to organize the workers involved in the construction management and technology research, fully adjustable open invention enthusiasm of workers. Technology progress leads to an increase in income, so as to promote the stable construction team, the construction quality is very important. It is hard to imagine that a majority of people full of grievances of the construction team can achieve the task.5ConclusionIt is often said, should be " a matter of expediency in construction, quality first", however, the quality problem is emerge in an endless stream. If in the construction process of some links, quality difference, these difference basically from accumulated will change the whole engineering quality. Therefore, do not let every link of the quality monitoring, on the problem of construction promptly corrected, is to use units, design units, as for as to construction unit as, namely to society as. With such a sense of duty, our engineering degree will gradually progress, can form the good work habits. Constitute the benign development of building construction environment. On the other hand, quality management can't think of what to do what, to systematic, procedural, design the whole management process, all the data, project compilation record, best to establish a computer database, stored in the computer. Management of examination conclusions, text, image, and correcting the situation chart problem timely records. This is the construction quality management informatization is the inevitable trend of development. This is my civil engineering construction quality management shortcomings, to be further developed.译文：关于土木工程施工工程的质量管理1.引言土木工程建立工程的成败在于质量，分开质量，其他一切都无从谈起。
本科毕业土木工程专业英语翻译翻译
Discuss the construction temperature and crack of theconcrete lightlyBy G. K. Kululanga, W. Kuotcha，R。
McCaffer, Member，ASCE，and F. Edum-Fotwe ,The American Society of Civil EngineersThe summary，In order to prevent the owners of the concrete work of claims, we must do a good job in the construction process in the temperature and crackcontrol，through observation live for many years，through consulting the monograph about stress within the concrete，explain to concrete temperature reason ，on-the—spot concrete control and measure , prevention of crack of temperature that crack produce. Keyword Concrete Temperature stress Crack Control1。
The concrete occupies the important position in modern engineering construction。
But today，the crack of the concrete is comparatively general, the cracks are nearly omnipresent in the science of bridge building. Though we take various kinds of measures in constructing, careful，but the crack still occurs now and then. Tracing it to its cause，it is one of them incompletely that our change to concrete temperature stress pays attention to。
土木工程毕业设计外文翻译
你如果认识从前的我，也许会原谅现在的我。
毕业设计（论文）外文翻译设计（论文）题目：宁波新城艺术宾馆2#楼结构设计与预算学院名称：建筑工程专业：土木工程学生姓名：顾丽敏学号： 06404010101指导教师：袁坚敏2010年01月10日外文原文I：A fundamental explanation of the behaviour ofreinforced concrete beams in flexure basedon the properties of concrete under multiaxial stressM. D. KotsovosDepartment of Civil EngineeringImperial College of Science and TechnologyLondon (U. K.)The paper questions the validity of the generally accepted view that for a reinforced concretestructure to exhibit "ductile" behaviour under increasing load it is necessary for the stressstrain relationships of concrete to have a gradually descending post-ultimate branch.Experimental data are presented for reinforced concrete beams in bending which indicate the presence of longitudinal compressive strains on the compressive face in excess of 0.0035. It is shown that these strains which are essential for "ductile" behaviourare caused by acomplex multiaxial compressive state of stress below ultimate strength rather than postultimate material characteristics. The presence of a complex stress system provides a fundamental explanation for beam behaviour which does not affect existing design procedures.1. INTRODUCTIONThe "plane sections" theory notonly is generally considered to describe realistically the deformation response of reinforced and prestressed concrete beams under flexure and axial loadbut is also formulated so that it provides a design tool noted for both its effectiveness and simplicity [1]. The theory describes analytically the relationshipbetween load-carrying capacity and geometric characteristics of a beam by considering the equilibrium conditions at critical cross-sections. Compatibility of deformation is satisfied by the "plane cross-sections remain plane" assumption and the longitudinal concrete and steel stresses are evaluated by the material stress-strain characteristics. Transverse stresses and strains are ignored for the purposes of simplicity.The stress-strain characteristics of concrete in compression are considered to be adequately described by the deformational response of concrete specimens such as prisms or cylinders under uniaxial compression and the stress distribution in the compression zone of a cross-section at the ultimate limit stateas proposed by current codes of practice such as CP 110 [1]exhibits a shape similar to that shown in figure 1. The figure indicates that the longitudinal stress increases with thedistance from the neutral axis up to a maximum value and then remains constant. Such a shape of stress distribution has been arrived at on the basis of both safety considerations and the widely held view that the stress-strain relationship of concrete in compression consists of both an ascending and a gradually descending portion (seefig. 2). The portion beyond ultimate defines the post-ultimate stress capacity of the material whichTypical stress-strain relationship for concrete in compression. as indicated in figure 1is generally considered to make a major contribution to the maximum load-carrying capacity of the beam.Howevera recent analytical investigation of the behaviour of concrete under concentrations of load has indicated that the post-ultimate strength deformational response of concrete under compressive states of stress has no apparent effect on the overall behaviour of the structural forms investigated ( [2][3]). If such behaviour is typical for any structurethen the large compressivestrains (in excess of 0.0035) measured on the top surface of a reinforced concrete beam at its ultimate limit state (see fig. 1)cannot be attributed to post-ultimate uniaxial stress-strain characteristics. Furthermoresince the compressive strain at the ultimate strength level of any concrete under uniaxial compression is of the order of 0.002 (see fig. 2)it would appear that a realistic prediction of the beam response under load cannot be based solely on the ascending portion of the uniaxial stress-strain relationship of concrete.In view of the abovethe work described in the following appraises the widely held view that a uniaxial stress-strain relationship consisting of an ascending and a gradually descending portion is essential for the realistic description of the behaviour of a reinforcedconcrete beam in flexure. Results obtained from beams subjected to flexure under two-point loading indicate that the large strains exhibited by concrete in the compression zone of the beams are due to a triaxial state of stress rather than the uniaxial post-ultimate stress-strain characteristics of concrete. It is shown that the assumption that the material itself suffers a completeand immediate loss of load-carrying capacity when ultimate strength is exceeded is compatible with the observed "ductile" structural behaviour as indicated by load-deflexion or moment-rotation relationships.2. EXPERIMENTAL DETAILS2.1. SpecimensThree rectangular reinforced concrete beams of 915 mm span and 102 mm height x 51 mm width cross-section were subjected to two-point load with shear spans of 305 mm (see fig. 3). The tension reinforcement consisted of two 6 mm diameter bars with a yield load of 11.8 kN. The bars were bent back at the ends of the beams so as to provide compression reinforcement along the whole length of the shear pression and tension reinforcement along each shear span were linked by seven 3.2 mm diameter stirrups. Neither compression reinforcement nor stirrups were provided in the central portion of the beams. Due to the above reinforcement arrangement all beams failed in flexure rather than shearalthough the shear span to effective depthratio was 3.The beamstogether with control specimenswere cured under damp hessian at 20~ for seven days and then stored in the laboratory atmosphere (20~and 40% R.H.) for about 2 monthsuntil tested. Full details of the concrete mix used are given in table I.2.2. TestingLoad was applied through a hydraulic ram and spreader beam in increments of approximately 0.5 kN. At each increment the load was maintained constant for approximately 2 minutes in order to measure the load and the deformation response of the specimens. Load was measured by using a load cell and deformation response by using both 20 mm long electrical resistance strain gauges and displacement transducers. The strain gauges were placed on the top and side surfaces of the beams in the longitud{nal and the transverse directions as shown in figure 4. The figure also indicates the position of the linear voltage displacement transducers (LVDT's) which were used to measure deflexion at mid-span and at the loaded cross-sections.The measurements were recorded by an automatic computer-based data-logger (Solatron) capable of measuring strains and displacements to a sensitivity of 2 microstrain and 0.002 ramrespectively.3. EXPERIMENTAL RESULTSThe main results obtained from the experiments together with information essential for a better understanding of beam behaviour are shown in figures 5 to 14. Figure 5 shows the uniaxial compression stressstrain relationships of the concreteused in the investigationwhereas figures 6 and 7 show the relationships between longitudinal and transverse strainsmeasured on the top surface of the beams (a) at the cross-sections where the flexure cracks which eventually cause failure are situated (critical sections) and (b)at cross-sections within the shear spanrespectively.Figures 6 and 7 also include the longitudinal straintransverse strain relationship corresponding to the stress-strain relationships of figure 5.Figure 8 shows the typical change in shape of the transverse deformation profile of the top surface of the beams with load increasing to failure and figure 9 provides a schematic representation of the radial forces and stresses developing with increasing load due to the deflected shape of the beams. Typical load-deflexion relationships of the beams are shown in figure 10whereas figure 11 depicts the variation on critical sections of the average vertical strains measured on the side surfaces of the beams with the transverse strains measured on the top surface. Figure 12 indicates the strength and deformation response of a typical concrete under various states of triaxial stress and figure 13 presents the typical crack pattern of the beams at the moment of collapse. Finallyfigure 14 shows the shape of the longitudinal stress distribution on the compressive zone of a critical section at failure predicted on the basis of the concepts discussed in the following section.中文翻译I：在多向应力作用下从混凝土的特性看受弯钢筋混凝土梁变化的一个基本试验M. D. Kotsovos 伦敦皇家科学与技术学院土木工程系本文所探讨的问题是通常认为在荷载递增下钢筋混凝土结构呈现弹性状态这必须是因为混凝土的应力-应变关系有一个逐渐递减的临界部分的真实性试验数据显示受弯钢筋混凝土梁会在受压面的纵向压应变超出0.0035这表明这些应变是钢筋混凝土结构的本质它是由于一个比极限强度小的复杂多向的应力状态而不是塑性材料的特性引起的一个复杂应力系统的存在为梁的状态提供了一个基本试验而不是想象的一个现有设计过程1.引言"剖面"理论不仅是通常认为能很真实地描述钢筋混凝土梁和预应力混凝土梁在弯矩和轴向荷载下的变形而且能确切地阐述所以它提供了一个设计工具因为它的有效和简单而闻名[1]假设在临界横截面伤是均衡的这个理论分析地描述了一个梁的承载能力和几何特性之间的关系变形协调必须满足"水平横截面荏苒水平"的假定和纵向混凝土和钢筋的应力是通过材料的应力-应变的特性来估算的为了简化计算忽略横向的应力和应变受压混凝土的应力-应变特性认为能够被混凝土试块的变形充分地描述例如在极限的有限状态下棱柱体或圆柱体在横截面的受压区受单轴压力和应力就像现行规范所建议的CP110[1]显示出一个与图1相似的形状图1表明纵向应力随着与中和轴的距离增加而增加至最大值然后保持不变这个分布图已经达到安全性和受压混凝土的应力-应变关系的广泛观点由上升和逐渐下降的两部分组成(如图2所示)超出极限的部分材料的塑性应力能力如图1所示被认为对梁的最大承载能力有较大的作用图1.临界面破坏建议CP为110的应力和应变分布图2.受压混凝土结构的标准应力-应变关系然而最近关于在集中力作用下的混凝土的变化的一个分析性调查表明在压应力作用下混凝土的极限强度变形没有对所有被调查的结果形式的变化产生明显的影响([2][3])如果这个变化对任何结果都是典型的那么在钢筋混凝土梁的顶面被测的很大的压应变(超出量0.0035)在它的极限有限状态下(如图1)不能对极限单轴应力-应变特性产生作用因此因为压应变在单轴压力下的任何混凝土的极限强度等级下为ε=0.002(如图2所示)在混凝土的单轴应力-应变关系下降部分将出现一个在荷载作用下梁变化的现在可行的预测根据以上的观点本文的描述都在以下的评价中广泛的支持观点的一个单轴应力-应变关系由一个上升的和一个逐渐下降的部分组成对受弯的根据混凝土梁的变化的真实描述是非常必要的这个结果是从梁在两点荷载作用下弯曲得到表明很大的应变的通过梁受压的混凝土呈现的由于三维应力而不是一味的混凝土极限应力-应变特性这表明材料本身受到一个完整和直接的承载能力损失当极限强度被超过的假定与弹性结构的变化并存的通过偏心荷载或瞬间旋转关系表明的2.试验细节2.1试块三根矩形钢筋混凝土梁跨度915mm横截面为102mm51mm受剪区跨度为305mm(如图2所示)受力筋由两个直径为6mm屈服荷载为11.8kN的钢筋组成在梁端部钢筋弯起就能为整个受剪跨度提供抗力整个受剪跨度内压缩张拉的加强筋布置了七个直径为3.2mm的箍筋在梁的中间部分没有压缩加强筋和箍筋根据上面所述的钢筋布置所有的梁都是受弯破坏而不是受剪破坏尽管剪跨比为3所有的梁与受控的试块一起放在20 的湿麻袋下七天然后贮存在实验室条件下(2040%湿度)2个月直到试验结束所有混凝土配料都在表格I中2.2试验过程通过液压锤和分布梁加载每次大约增加0.5kN为了测量荷载和试块的形变每次持荷约2分钟荷载用一个荷载单元来测量形变由20mm长的电阻应变片和位移转换器测得应变片贴在梁纵向和横向的顶面和侧面(如图4所示)图4也表明了直流电压位移转换器（LVDT'S）的位置它是用来测量跨中和加载横截面的形变测量数据记录在计算机自动数据记录仪中能够测量应变和形变的灵敏度分别为±2微应变和±0.002mm3.试验结果主要的试验结果是从试验中得到的能更好地了解梁的变化所示图5 至图14的信息是必不可少的图5表明结果的单轴压应力-应变关系应用于调查中而图6 和图7表明纵向应变与横向应变的关系分别位于(a)弯曲裂缝最终导致破坏横截面出和(b)受剪区跨内的横截面出图6和图7也包含了纵向应变-横向应变与图5的应力-应变关系是一致的图8中标准的改变在梁顶面的横向形变轮廓图中和图9提供一个轴力和应力随着荷载的增加而增大导致梁向下变形的图框表示方法梁的标准偏心荷载关系如图10所示而图11描述了测得平均竖向应变的梁侧面的临界截面变形和横向应变在顶面测得图12中标准结果的强度和形变在各种状态的十三轴应力下河图13所呈现的梁标准裂缝图样在破坏的瞬间最后图14表明在临界截面的受压区伤纵向应力的分布形状可根据概念来预测破坏在以下部分将被讨论图3.梁的细节外文原文II:Some questions on the corrosion of steel in concrete.Part Ⅱ: Corrosion mechanism and monitoringservicelife prediction and protection methodsJ.A. GonzdlezS. FelifdP. RodffguezW. LfpezE. RamlrezC. AlonsoC.AndradeABSTRACTThis second part addresses some important issues that remain controversial despite the vast amounts of work devoted to investigating corrosion in concrete-embedded steel. Specificallythese refer to: 1) the relative significance of galvanic macrocouples and corrosion microcells in reinforced concrete structures; 2) the mechanism by which reinforcements corrode in an active state; 3) the best protective methods for preventing or stopping reinforcement corrosion; 4) the possibility of a reliable prediction of the service life of a reinforced concrete structure ; and 5) the best corrosion measurement and control methods. The responses provided are supported by experimental resultsmost of which were obtained by the authors themselves.1. INTRODUCTIONConcrete-embedded steel is known to remain in apassive state under normal conditions as a result of the highly alkaline pH of concrete. The passivity of reinforcements ensures unlimited durability of reinforced concrete (1KC) structures. Howeverthere are some exceptional conditions that disrupt steel passivity and cause reinforcements to be corroded in an active state. This has raised controversial interpretationssome of which were discussed in Part I of this series [1]. This Part II analyses though far from exhaustivelyother - to the authors minds at least - equally interesting issues on which no general consensus has been reached.2. MATERIALS AND METHODSThe reader is referred to Part I for a detailed description of the materials and methods used in this work. Most of the experimental results discussed herein were obtained with the same types of specimens and slabs.Galvanic couples were determined on speciallydesigned specimenssuch as those shown in Figs. 1 and 2.Near-real conditions were simulated by using a beam that was 160cm long and 7 x 10 cm in cross-section. The beam was made from 350 kg cement/m 3half of whichcontained no additiveswhile the other half included 3% CaC12 by cement weight [2](Fig. 1). In order to study the effect of the Sanod/Scathoa ratio on galvanic macrocouplesthey were modelled by surrounding a small carbon steel anode with a stainless steel (AISI 304) cathode and vice versa(Fig. 2). In this waythe ratio's consistensy was assured. In additionthe potential and icorr of stainless steal and those of the passive structures were very similar.Fig. 1 - Beam used to measure icoTr and Ecorr in Fig. 2 - Scheme of galvanic macrocouples embeddedconcrete with and without chlorides and to in chloride- containing mortar used to study theillustrate the significance of passive steel/active effect of the Sanod/Scathod ratio and their relativesteel macrocouples. significance to corrosion microcells.3. RESULTS AND DISCUSSION3.1 What is the relative significance of galvanic macrocouples and corrosion microcells in RC structures ?According to several authors [35]the polarization resistance method provides an effective means for estimating the corrosion rate of steel in PC ; the method is quite rapidconvenientnon-destructivequantitative and reasonably precise. Howeverit is uncertain whether it may give rise to serious errors with highly-polarized electrodes by the effect of passive/active area galvanicmacrocouples in the reinforcements [6].Based on the authors' own experience with the behaviour of galvanic macrocouples in PCthe contribution of these macrocouples to overall corrosion is very modest rehtive to that of the corrosion microcells formed in the active areas of reinforcements in the presence of sufficient oxygen and moisture [278]. Thusit has been experimentally checked that:(a) Galvanic macrocouples have a slight polarizing effect on anodic areas in wet concretewhose potential is thereby influenced in only a few millivolts.(b) On the other handmacrocouples have a strong polarizing effect on passive areas despite the low galvanic currents involved relative to the overall corrosion current.(c) As a resultgalvanic currents can result in grossly underestimated icorr values for the active areas since they are often smaller than 10% of the ico= values estimated from polarization resistance measurements.(d) The corrosive effect ofcoplanar macrocouples on RC structures only proves dangerous within a small distance from the boundary of active and passive areas. Fig. 3 compares the estimated icorr and ig valuesin mortar containing 3 o~ A CaC12per anode surface unit for a number of anode/cathode surface ratios for AISI 304 stainless steel/carbon steel macrocouples in support of the above conclusions [9].3.2 By what mechanism do reinforcements corrode in an active state ?When the passive state is lostthe rate of reinforcement corrosion in inversely proportional to the resistivity of concrete over a wide resistivity range [10]. BecauseFig. 3 - Relative significance of corrosion microcells Fig. 4 - Trends in ico. and Ecorr for(icorr) and galvanic macrocouples (i.) in corrosion specimens exposed to an oxygen-freeof steel embedded in mortar containing no chloride. environment.Both currents were calculated relative to Sanod(carbon steel in the macrocouples of Fig. 2).the environment's relative humidity and ionic additives of concrete determine concrete resistivitythese factorstogether with oxygen availability at reinforcement surfacescontrol the corrosion rate [11].The electric resistivity of water-saturated concrete structures is relatively very lowand the corrosion rate is believed to be essentially controlled by the diffusion of dissolved oxygen through the concrete cover up to reinforcements. This is consistent with the widespread belief that the sole possible cathodic reaction in neutral and alkaline solutions is oxygen reduction.The significance ascribed to the role of oxygen justifies the efforts to determine its diffusion coefficient in concrete[1213]. The variety of methods and experimental conditions used for this purpose have led to a wide range of diffusivity values (from 10 -12 to 10 -8 m2/s) for oxygen in cement paste [14].Since the diffusion coefficient of oxygen in aqueous solutions (1)O2 = 10 -5 cm2/s-1)is saturation concentration (CO2 = 2.1 x 10 -7 mol/cm 3) and the approximate thickness of diffusion layers in stagnant solutions (8 = 0.01 cm) are wellknownthe limiting diffusion current can be calculated as :ilo2 = - z FD02C02/r = 8 x 10 -4 A/cm 2 (80 pA/cm 2)where z is the number of equivalents per mole (4) and F the Faraday (96500 A.s/eq).For 1-cm thick mortar covers of average porosity 15%(see Fig. 1 in Part I) [1] and a diffusioja layer thickness of the same order as the cover thickness11o2 = 0.12 laA/cm 2which is quite consistent with the icorr values estimated under pore saturation conditions at the end of the curingprocessboth for mortars containing no chloride ions and for those including 24 or 6% C1- [16].On the other handicorr values of ca. 10 liA/cm 2 (see Fig. 9 in Part I) [4] have been obtained by several authors for mortars with chlorides or carbonated mortars which are incompatible with the rates allowed by the limiting diffusion current of oxygen. Thereforein some circumstancesalternative cathodic processes allowing for faster kinetics must therefore be involved. In recent workthe concurrence of creviceschloride ions and dissolved oxygen at the steel/concrete interface was claimed to provide the thermodynamic conditions required for protons to be reduced and the alternative mechanism to occur [1117].There are a number of facts that refute oxygen reduction as being the sole corrosion rate-determining stepnamely:- Under some circumstancesonce corrosion in an activestate has startedit develops at the same rate even though oxygen is being removed from the medium (Fig. 4) [11].- As saturation of concrete pores decreaseconcrete resistivity controls ico~r over a wide resistivity range ; therefore the corrosion rate seems to decrease in proportion to the ease with which oxygen penetrates into the structure(Fig. 5)[10].On the other handthere are several arguments in favour of proton reduction in Ca(OH)2-saturated solutions or cement mortars [11] :- The pH decreases from 12.6 to ca. 5 within crevices at the steel/electrolyte interface upon exposure of the steel to a Ca(OH)2-saturated solution with C1- additions and wellaerated. If sufficient oxygen is availablethe pH can drop as low as 1-2.- The emergence of acid exudates ofpH 1-5 from cracks and macropores in chloride-containing mortar specimens under wet atmospheres at high corrosion rates (5-10 pA/cm2).- The formation of gas bubbles over iron hydroxide membrane-coated pits when the steal is polarized anodically in a Ca(OH)2-saturatedchloride-contaminated solution at potentials below those required for oxygen release. Everything points to pits with a low enough pH for the anodic current applied to overlap with a corrosion process involving proton reduction as a cathodic half-reaction.When concrete-embedded steel is corroded in an active stateits corrosion kinetics rise exponentially with increasing pore saturation (Fig. 6) similarly to atmospheric corrosion in bare steel as the environment's relative humidity increases [18]. At some points in the reinfor- cementsa catalytic cycle may take placee.g.those put forward by Schikorr for atmospheric corrosion of steel [19]with chloride ion rather than SO2-as the catalyst (Fig. 6).Fig. 5 - Relationship between mortar resistivity Fig. 6 - Influence of the degree of pore saturationand the corrosion rate of reinforcements. on the corrosion rate of reinforcements.中文翻译II:混凝土中钢腐蚀的有关问题Ⅱ：腐蚀机理和监督、使用年限的预测和保护方法J.A. GonzdlezS. FelifdP. RodffguezW. LfpezE. RamlrezC. AlonsoC.Andrade摘要:第二部分阐述几个仍然存在争议的重要问题尽管已经在混凝土中钢腐蚀的调查研究投入了大量的工作特别是这几方面：1)在钢筋混凝土结构中的大电偶和腐蚀微电池对的相对重要性；2)激活状态的钢筋腐蚀机理；3)阻止或停止钢筋腐蚀最好的保护方法；4)一个钢筋混凝土结构使用年限的可靠预测的可能性探索；5)最好的防腐措施和控制方法这些回答需要试验得出大部分都由作者们得出1.前言正常条件下强碱混凝土中的钢仍然处于钝化状态钢筋的钝性能保证钢筋混凝土结构无限的耐久性然而有一些能破坏钢的钝性和引起钢筋腐蚀的实验条件在第Ⅰ部分中讨论到的一些实验结构已经引起了很多争论[1]第Ⅱ部分的分析虽然没有竭尽全力但至少是作者的意思就像有趣的问题有不同的意见一样2.材料和方法读者指出在第Ⅰ部分详细描述了用于这项工作的材料和方法这里所讨论的大部分实验结果都是从一样的试块和平板中得到的电偶是由特殊设计的试块确定的如图1和2所示用一根长16m70mm×100 mm横截面的梁模拟近真实条件梁是由每立方米350kg水泥制成梁的一半含有添加剂另一半含有水泥的重量的3%的CaCl2[2](图1)为了了解S正极/S负极的比值对大电偶的影响用在一个小的碳素钢正极环绕一个不锈钢负极并夹紧来模拟这样比值的连贯性是可靠的此外与钝化结果的电位和不锈钢的icorr是非常相似的图1.梁用来分别测量混凝土中含有和不含有氯化物图2.用电耦合牢牢嵌入含有氯化物的砂浆里来研究的icorr和Ecorr来说明钝化钢/活跃钢耦合的意义S正极/S负极的作用和腐蚀微电池对的相对意义的方案3.结果和讨论3.1什么是在钢筋混凝土结构中大电偶和腐蚀微电池对的相对重要性？根据一些作者[35]极化电阻作用为估计钢筋混凝土中腐蚀速度提供了一个有效的方法；这个方法是非常快、方便、非破坏性、适量和相当精确的然而它不确定是否会对高度极化的电极产生严重的错误通过在钢筋中的大电偶的钝化面积与激活面积的比值的影响在作者自己对钢筋混凝土中大电偶性质的实验基础上这些大电偶对所有的腐蚀是非常适度的与存在充分的氧气和水分条件下腐蚀微电池对形成激活状态的钢筋比较[278]因此它已被实验验证：(a)大电偶对潮湿混凝土中的阳极部分由一个轻微的极化作用只要几毫伏就可以影响它的电位(b)在另一方面大电偶对钝化部分有一个很强的极化作用尽管低电流的运用相对于所有腐蚀流(c)因此电流可能会导致非常低估在激活部分的icorr的值因为它们通常比极化电阻值估算的icorr值的10%还小(d)腐蚀剂会引起钢筋混凝土结构上共面的电偶只能证明从激活面积到钝化面积边缘的一个很短的距离存在危险图3是估算的icorr与ig值的比较在砂浆中含有3%的CaCl2每个正极表面单元体为许多正极/负极表面比值作为美国钢铁学会304不锈钢/碳素钢电偶的一部分支持以上结论图3.腐蚀微电池对(icorr)和电耦合(ig)在包裹在图 4.暴露在自由氧环境下试块的icorr和Ecorr不含有氯化物砂浆里的钢腐蚀中的相对意义的变化趋势电流都是相对于S负极而计算得到的(在图2的电耦合中的碳素钢)3.2钢筋腐蚀的机理是什么？当钝化状态消失钢筋的腐蚀速度与混凝土的电阻率成反比例在一个很宽的电阻率范围内[10]因为环境中的相对湿度和混凝土的离子型外加剂确定混凝土的电阻率这些因素与氧气一起在钢筋的表面控制着腐蚀速度[11]饱和水混凝土结构的电阻率是相对非常低的而且腐蚀速度实际上是溶解氧的扩散控制的通过混凝土包住钢筋实现这与在中性和强碱条件下唯一可能的负极反应是氧气的还原作业这个理念是一致的这个重要性归因于氧气的循环作业它证明这些作用对确定它在混凝土中的扩散率是正确的[1213]各种方法和实验条件用于这个目的已得出了一定范围的水泥浆中的氧气的扩散率(从10-12到10-8m2/s)[14]因为水溶液(CO2=10-5cm2/s-1)中氧气的扩散率是饱和浓度(CO2=2.1×10-7mol/cm3) 不流动环境中(?=0.001cm)扩散层的近似密度都是众所周知的这个有限扩散流可以这样计算：其中z是等价的每摩尔(4)的数值而F就是法拉第(96500A?s/eq)平均孔隙率为15%的1cm厚的砂浆保护层厚度与扩散层厚度一样与在养护期的最后空隙饱和条件下估算得的icorr值是非常一致的这些砂浆不含氯化物离子而都含有24或6%的Cl-[16]另一方面ca.10?A/cm2的icorr(见第Ⅰ部分图9)[4]已经由一些作者从含氯化物的砂浆或碳酸盐砂浆与氧气有限的扩散流所允许的速度是不协调的因此在一些环境下替代负极的过程必须有更快的动力在最近的工作中裂缝、氯化物例子和溶解氧并存在钢与混凝土的交界面可以为质子的还原和替换机理的发生提供热动力条件[1117]有很多论据反驳氧气的还原作用作为底面腐蚀的定速步骤即：- 在一些环境下腐蚀一旦开始它发展到同一个速度尽管氧气正在从媒介中排除(图4)[11]- 当混凝土空隙饱和作用降低混凝土的电阻率控制icorr在一个宽泛的电阻率范围内；因此腐蚀速度的减小好像与氧气进入结构的难易成反比例(图5)[10]在另一方面有一些论点支持在饱和Ca(OH)2中或水泥砂浆中的质子还原反应[11]：- PH值由12.6减小到ca.5在暴露的含有Cl-的饱和Ca(OH)2中的钢与电解质溶液的交界面上如果提供充足的氧气PH值可以降低到1-2- 从在潮湿的空气中含有氯化物的砂浆试块的裂缝和大空隙中暴露的PH值1-5的酸性分泌物腐蚀速度很快(5-10?A/cm2)- 在蚀坑处涂上氢氧化铁膜的钢在含有氯化物的饱和Ca(OH)2中极化成阳极时会产生气泡因为电位的降低需要释放氧气每一个蚀坑点有一个足够低的PH因参与质子还原反应就像阴极半反应它们的腐蚀过程与阳极流互相重叠当包裹在混凝土中的钢处于腐蚀状态它的腐蚀动力指数随着空隙饱和作用的上升而升高(图6)就像裸露在大气中的钢的腐蚀随着环境的相对湿度的上升而增加一样[18]在钢筋上的一些点催化循环可能被取代等这些是由Schikorr提出的钢的大气腐蚀[19]是氯化铁而不是SO42-作为催化剂(图6)图5.砂浆电阻与钢筋腐蚀速度的相互关系图6.孔隙饱和度对钢筋腐蚀速度的影响????????宁波工程学院毕业设计（论文）1。
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。
土木工程外文翻译参考3篇
学校毕业设计（论文）附件外文文献翻译学号：xxxxx 姓名：xxx所在系别：xxxxx 专业班级：xxx指导教师：xxxx原文标题：Building construction concrete crack of prevention and processing2012年月日建筑施工混凝土裂缝的预防与处理1摘要混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。
关键词：混凝土裂缝预防处理前言混凝土是一种由砂石骨料、水泥、水及其他外加材料混合而形成的非均质脆性材料。
由于混凝土施工和本身变形、约束等一系列问题，硬化成型的混凝土中存在着众多的微孔隙、气穴和微裂缝，正是由于这些初始缺陷的存在才使混凝土呈现出一些非均质的特性。
微裂缝通常是一种无害裂缝，对混凝土的承重、防渗及其他一些使用功能不产生危害。
但是在混凝土受到荷载、温差等作用之后，微裂缝就会不断的扩展和连通，最终形成我们肉眼可见的宏观裂缝，也就是混凝土工程中常说的裂缝。
混凝土建筑和构件通常都是带缝工作的，由于裂缝的存在和发展通常会使内部的钢筋等材料产生腐蚀，降低钢筋混凝土材料的承载能力、耐久性及抗渗能力，影响建筑物的外观、使用寿命，严重者将会威胁到人们的生命和财产安全。
很多工程的失事都是由于裂缝的不稳定发展所致。
近代科学研究和大量的混凝土工程实践证明，在混凝土工程中裂缝问题是不可避免的，在一定的范围内也是可以接受的，只是要采取有效的措施将其危害程度控制在一定的范围之内。
钢筋混凝土规范也明确规定：有些结构在所处的不同条件下，允许存在一定宽度的裂缝。
但在施工中应尽量采取有效措施控制裂缝产生，使结构尽可能不出现裂缝或尽量减少裂缝的数量和宽度，尤其要尽量避免有害裂缝的出现，从而确保工程质量。
混凝土裂缝产生的原因很多，有变形引起的裂缝：如温度变化、收缩、膨胀、不均匀沉陷等原因引起的裂缝；有外载作用引起的裂缝；有养护环境不当和化学作用引起的裂缝等等。
本科毕业土木工程专业英语翻译翻译
Discuss the construction temperature and crack of theconcrete lightlyBy G. K. Kululanga, W. Kuotcha, R. McCaffer, Member, ASCE, and F. Edum-Fotwe ,The American Society of Civil EngineersThe summary , In order to prevent the owners of the concrete work of claims, we must do a good job in the construction process in the temperature and crackcontrol,through observation live for many years, through consulting the monograph about stress within the concrete, explain to concrete temperature reason , on-the-spot concrete control and measure , prevention of crack of temperature that crack produce. Keyword Concrete Temperature stress Crack Control1. The concrete occupies the important position in modern engineering construction. But today, the crack of the concrete is comparatively general, the cracks are nearly omnipresent in the science of bridge building. Though we take various kinds of measures in constructing, careful, but the crack still occurs now and then. Tracing it to its cause, it is one of them incompletely that our change to concrete temperature stress pays attention to. In the large volume concrete, temperature stress and temperature control are significant. This is mainly because of the reason of two respects. First of all, concrete often appear the temperature crack in not constructing, influence the globality and durability of the structure. Secondly, in the course of operating, the temperature change has remarkable influence that can't be ignored on the stress state of the structure. We meet to construct temperature crack in mainly, so only to origin cause of formation and treatment measure, concrete of crack make a discussion in constructing this text.Reason of a crackHave many kinds of reasons to produce the crack in the concrete, it is mainly the changes of temperature and humidity, fragility and disparity of the concrete, and the structure is unreasonable, the raw materials is not up to standard (if the alkali aggregate react), the template is out of shape, the foundation does not subside etc. evenly . The cement emits a large amount of heat of hydration when the concrete is hardenned, inside temperature is rising constantly, cause the stress of drawing on the surface. In the course of lowering the temperature , is it congeal foundation pay restrain to mix always later stage, will present the stress of drawing within the concrete . Reducing of temperature can surface cause heavy stress of drawing very in concrete too. When these draw the stress and go beyond resisting the ability of splitting of concrete , namely will present the crack .A lot of inside humidity of concrete change very light or change relatively slow, surface humidity might change heavy the violent change takes placing. Such as maintaining thoroughly, when getting wetter when not doing,contract surface there aren't deformation doing, often cause the crack too. The concrete is a kind of fragility material , tensile strength is about 1/10 of the compression strength, is it carry on one's shoulder or back limit when draw out of shape to have *104 only , is it carry on one's shoulder or backlimit location when stretch out of shape to there is *104 to add for a long time to add a short time. Because raw materials even, water dust than unstable, transport and build phenomenon of emanating of course, its tensile strength is not even in the same concrete, a lot of resist the ability of drawing very low, it is apt to present the weak position of the crack. Among armored concrete , draw stress to undertake by reinforcing bar mainly , concrete bear stress of keeping just. Or reinforcing bar mix if edge position gone to to congeal present the stress of drawing in the structure in plain concrete, must rely on the concrete oneself to bear . Require to avoid the stress of drawing or only very small stress of drawing appears of the the general design. But the concrete is cooled from maximum temperature to the steady temperature of operating period in constructing, often cause sizable to draw the stress within the concrete. The temperature stress can exceed other outsides and load the stresses caused sometimes, know change law , temperature of stress for carry on reasonable structural design and construct extremely important.Analysis of 2 temperature stressesCan be divided into following three stages according to the forming process of the temperature stress:(1)It is early: Build concrete is it is it over basically to send out heat to cement to begin , generally one one day by oneself. Two characteristics at this stage, first, the cement emits a large amount of heat of hydration, second , mix and congeal the changing sharply of elastic model quantity. Because of the change of elastic model quantity , form the remaining stress in the concrete in this period.(2)Middle period: Up till the concrete is cooled until stability temperature from cement send out heat function basically when expiring, in this period, the temperature stress is mainly because the cooling of the concrete and external temperature change cause, these stresses and remnants stresses that is formed in early days are superposed , mix and congeal the elastic mould amount that goes to and does not change much during this period.(3)Later period: Operation period after the complete cooling of concrete. Temperature stress whether external temperature change cause mainly, these stresses and first two kinds of remnants stresseses are changed and added .Can be divided into two kinds according to the reason why the temperature stress causes:(1)Spontaneous stress: There are not any restraint or totally static structure at the border, if inside temperature is non-linear distribution, temperature stress appearing because structure restrains from each other. For example, the body of mound of the bridge, the physical dimension is relatively large, surface temperature is low when the concrete is cooled, inside temperature is high, present the stress of drawing on the surface, present the stress of pressing in the middle.(2)Restrain the stress: All of the structure ones or it restrain external one some border,can't out of shape and stress not cause not free. Such as case roof beam roof concrete and guardrail concrete.This two kinds of temperature stresses draw back stresses caused to act on with the doing of concrete together frequently. It is a more complicated job to want to analyse the distribution , size of the temperature stress accurately according to known temperature. In case of great majority , need to rely on the model test or the number value to calculate. Tois it make temperature stress have sizable limp to creep concrete, at the stress accounting temperature, must consider the influence that creep , calculate concretly that no longer states thinly here.Control and preventing the measure of the crack of 3 temperatureFor prevent crack , lighten temperature stress can from control temperature and is it is it set about to restrain terms from two to improve.The measure of controlling temperature is as follows:(1)Is it improve aggregate grade mix , is it do rigid concrete to spend , mix mixture to adopt, is it guide angry pharmaceutical or plastification pharmaceutical ,etc. measure in order to reduce cement consumption of concrete to add;(2)Add water or the water to cool the broken stone in order to reduce the temperature of building of the concrete while mixing and shutting the concrete;(3)Reduce the thickness of building while building the concrete on hot day, utilize and build the aspect to dispel the heat;(4)Bury the water pipe underground in the concrete, enter the cold water to lower the temperature openly;(5)Stipulate rational form removal time, the temperature keeps warm the surface while lowering suddenly, in case that the rapid temperature gradient takes place in the concrete surface;(6)The concrete with medium and long-term and exposed construction builds a piece of surface or thin wall structure, take the measure of keeping warm in cold season;The measure of improving condition of restraining is:(1)Divide and sew and divide one rationally ;(2)Prevent the foundation from rising and falling too big;(3)Rational arrangement construction process, prevent the too big discrepancy in elevation and side from exposing for a long time;In addition, improve the performance of the concrete and improve and resist the ability of splitting, strengthen maintenance , prevent the surface from being done and contracted , especially guarantee the quality of the concrete is very important to preventing the crack, should pay special attention to avoiding producing and running through the crack , the globality resumed its structure after appearing is very difficult, so should rely mainly on preventing the emergence of the running through crack while constructing.In construction of concrete , for raise turnover rate of template , demand concrete form removal as soon as possible that build newly often. Should consider form removal time properly when concrete temperature is higher than the temperature, so as not to cause the superficial early crack of concrete. Building the early form removal newly, cause very large stress of drawing on the surface, the phenomenon that " temperature is assaulted " appears. Build initial stage in concrete, because heat of hydration is sent out, the surface causes sizable to draw the stress, surface temperature is also higher than temperature at this moment, remove the template at this moment , surface temperature is lowered suddenly, must cause temperature gradient , thus add and draw the stress on the surface , change and add with the heat of hydration stress, in addition, the concrete dries and contracts , the superficial stress of drawing reaches very great number value, have danger of causing the crack, but cover a light-duty heat insulator with on the surface in time afterremoving the template , for instance foam sponge ,etc., for prevent concrete surface from produce the too big stress of drawing, have remarkable results.Add muscle influence to large volume temperature stress of concrete very light , because large volume concrete include muscle to be rate very much low. Just have influence on the general armored concrete. On terms that temperature is not very high and the stress is less than limit of surrendering, every performance of the steel is steady, and have nothing to do with stress state , time and temperature. Line bloated coefficient of steel and concrete line bloated coefficient difference very light, take place little internal stress very only between the two while changing in temperature. Because elastic mould amount of steel concrete elastic mould 7~15 of quantity, reach as interior concrete stress tensile strength and when fracturing, the stress of the reinforcing bar will not exceed 10000kg/cm2. . So is it is it prevent tiny appearance difficulty very much of crack from to make use of reinforcing bar to want among concrete. But the crack in the structure generally becomes numerous, the interval is little, the width and depth are smaller after adding the muscle. And if diameter of reinforcing bar detailed and when interval dense, to improve concrete resist result of person who split better. Concrete and surface , armored concrete of structure can take place detailed and shallow crack often, among them the great majority belong to and do and draw back the crack. Though this kind of crack is generally all relatively light, it stills have certain influence on the intensity and durability of the structure.In order to guarantee concrete project quality , prevent fracturing , improve the durability of the concrete, use the admixture to reduce one of the measures that fractures correctly. Whether is it reduce water is it split pharmaceutical to defend , I summarize his main function in practice to use.(1)There is pore Dao of a large number of mao in the concrete , produce capillary tension in the capillary after water is evaporated, make concrete is it contract out of shape to do. Increasing the thin aperture of hair can reduce the capillary surface tension , but will make the intensity of concrete reduce . This surface tension theory has already been confirmed in the world as far back as the sixties.(2)Water dust than influence important factor that concrete shrink, is it reduce water is it split pharmaceutical can make concrete water consumption reduce by 25% to defend to use.(3)Cement consumption important factor, concrete of person who shrink too, is it add and subtract water is it split concrete reducible 15% of the cement consumption on terms that keep the intensity of concrete of pharmaceutical to defend to mix, its volume is supplemented by increasing aggregate consumption.(4)Reduce water is it split pharmaceutical can improve consistency of grout , reduce concrete secrete ink to defend, reduce and sink and draw back deforming.(5)Improve glueing the strength of forming of the grout and aggregate, the concrete improved resists the performance of splitting.(6)Concrete is it produce stress of drawing to restrain from while shrinking, crack when drawing the stress and is greater than concrete tensile strength can produce. Reduce water is it split pharmaceutical effective concrete tensile strength of improvement very to defend , improve resisting the performance of splitting of concrete by a wide margin.(7)It can make the concrete density good to add the admixture to mix , can improveresisting carbonization of concrete effectively , reduce carbonization to shrink.(8)Is it reduce water is it split slow coagulation time proper concrete under pharmaceutical to defend , on the basis of preventing the fast water of cement from sending out heat effectively to mix, prevent the plasticity shrink that brings because the cement is not congealed for a long time from increasing.(9)Mix admixture concrete and getting easy and kind , surface easy to feel flat , form little membrane, reduce the moisture to evaporate, reduce drily and shrink. A lot of admixture all have the functions of slow coagulation , increasing and apt , improvement plasticity, the experiment that we should carry on in this respect more in the project practice is compared with and studied, than lean against not improving terms more simple,may getting simple and more direct, economy.Early maintenance of 4 concretePractice has proved , the common crack of concrete , most is the surface crack of different depth, main reason its whether temperature gradient cause cold temperature of area lower too easy to form crack suddenly. So say the warm - keeping of the concrete is especially important to preventing the early crack of surface.From the viewpoint of temperature stress, should reach and require to keep warm followingly:1)Prevent concrete internal and external temperature poor and concrete surface gradient from , prevent the surface crack.2)Prevent concrete from to be ultra and cold , should is it is it make the minimum temperature is not lower than the steady temperature of concrete service time construction time in concrete to try to try one's best.3)Prevent the old concrete subcooling , in order to reduce the restraint among the old and new concrete.The early maintenance of the concrete, the main purpose lies in keeping the suitable warm and humid condition , in order to get the result of two respects, on the other hand make the concrete avoid the invasion and attack of the unfavorable and warm , humidity out of shape, the ones that prevent from harmfully are cold to contract and do to contract. On one hand make cement water function go on smoothly , is in the hope of reaching the intensity designed and resisting the ability of splitting.The suitable warm damp condition is interrelated. Mix warm - keeping measure paid to congeal often protect wet results too. Analyse , water concrete include moisture can meet demand , cement of water have enough and to spare newly theoretically. But because the reason of evaporating etc. often causes losses of the moisture, thus postpone or hinder water of the cement from, the surface concrete receives this kind of adverse effect easiestly and directly. Key period when maintained in initial a few days after so the concrete is built, should pay attention to conscientiously in constructing.ConclusionsConstruction temperature and relation of crack in concrete the above carry on preliminary discussion of theory and practice, though the academia has different theories to origin cause of formation and computing technology of the concrete crack, but to concrete prevention and improving the measure suggestion to relatively unify , application in practice result fine too at the same time, concrete to is it observe , compare more more by us to want in constructing, analyse more , summarize more after going wrong ,combine many kinds of prevention and deal with the measure, the crack of the concrete can be avoided.2.Quality control of waterproof concrete constructionCombined with experience, from formwork design, fabrication and installation, assembing reinforoement, pouring and curing of concrete and other aspects construction technology of fair-faced concrete is introduced as well as quality control measures and standards in order to reduce engineering cost to acquire satisfied economic and social benefits.The factors of influening waterproof- concrete quality are very manyAny links does not pay attention to the water-proof concrete of field loss hinders the water function without exception jointly with degree.Engineering construction in the basement adopts secondary form board fabrication and installation, reinforced bar fabrication and bind, concrete stirring and mixing system and transport, concrete concrete covibration beat with a stick, construction joint practice, concrete curing and dismantle model and beingready for backfill and so on aspects.These are very critical to quality method to ensure that water-proof concrete self water-proof, and the way of practice has wan out.Method being under construction2.1 Fabrication and InstallationAccording to the concrett of closely knit , demand of reason why to form board since the water-proof also concrete have made and have assembled corresponding rise is special , be to require that not leaving out thick fluid , firm closely knit block of wood deformation , water absorption Character should be small and ought to give priority to select and using bamboo slab rubber form board or the steel form.. Strict control form board room gap size, necessary exceeding 2 mms uses foam rubber or plastic to squeeze a crack in , porous form board nonutility without exception to board face Be ready for wall post at the same time rotting the prevention and cure job Adopt the cement mortar pouring same ,indicia in before the root segment sticking the foam rubber or plastic strip , the bottom puts on a cement mortar , concrete a concrete, first 5 cm ~ 10 cm. Since water-proof, concrete structure wall thickness is mostly more infertile .Be to ensure that component geometry dimension , Chang adopt the inside and outside bolt to pull the measure meeting attention to, responds to on play receive bolt centre interpose stop water iron plate, to prevent water from forming pilotage passage along bolt leakage.2.2 Assembing reinforoementWater-proof concrete structure has demanding as follows to the reinforced bar 1) reinforced bar should adopt twisted steel as far as possible , increases by hold wrap a force composing in reply a water ability2) reinforced bars connect should try one's best to adopt to solder connection , stop using and being needless to bind connection to the full3) when binding a reinforced bar, the iron wire head responds to inner bending.4) strict control reinforced bars protective layer thickness.Minimal thickness of water-proof concrete reinforced bar protective layer isnot smaller than 25 mms , the protective layer welcoming water surface especially inadmissibility to disappoint error,. The iron wire and reinforced bar that application buries in advance within mortar piece whileusing mortar heel block as protective layer, are boundsolid .When the cavalry puts up the fixed reinforced bar if adopt a reinforced bar, Ying Jia also solders water iron plate or fixation just goes ahead, to strengthen water-proof effect in theheel block.This project uses new materials nylon to have fixed there is an effect's had guarded against reinforced bar protective layer deviation piece big mass common failings.The concrete stirring and mixing makes and transportsSince the water-proof concrete requires that higher closely knit , reason why stir and mix system also need to have the fairly good homogeneity , should be ready for burning as follows almost for this purpose1) ensures that mixing time , mixing at every time are secondary jump into a expect the general ejection of compact block of wood less than 2 mins.2) should use the apposition agent , the solution queen who should manufacture certain thickness from apposition agent adds the mixer inner, the dried powder or high concentration solution will add an agent extra not to adds the mixer inner directly ,prevent from mixing is uneven but partconcentrates, both lose the apposition agent effect, and affect concrete mass.3) responds to the assured source of life degree having a spot test on the admeasurement concrete at the regular intervals collapsing in the process being under construction , construction is middleif Yu rains or other cause, respond to the ratio determining whose water ratio, and adjusting the composition being under construction in time when change happened in sandstone moisture content.4) project uses the commodity concrete , has boundary have raised a concrete stirring mass and of all kinds effect apposition agent adulterating falls when amounts , the water ash having controlled a concrete strictly collapsing.5) concretes concrete adopt a pump to have given handicraft , effective avoidinga concrete producing the phenomenon isolating Mi Shui and leaving out thick fluid in theprocess of transportation.2.4 Matters needing attention in being under construction1) construction school assignment soft and floury is divided .Water-proof concreting should stratify strictly being in progress, and a continuous construction iscompletedThe front and back and high and low connect between the tier should subjugate within the cement initial settingtime，For this purpose ,with handling a worker dividing into several, at the same time each other, school assignment group faces or it is all right for each other, carry on the back .2)Achieve strictly fixed point determines the amounts of the components of a substance material down According to the vehicle capacities stratifying concretealtitude and the means of transport, the quantify carrying out fixed point strictly is able to go down one important ring expecting that this is to improve water-proof concreting mass.3) insist that you go down material opening the door or use string to expect that under barrel (chute)Be to prevent a cement paste from parting from aggregate for , to expect that liberty should not exceed 1.5 ms now and then highly under water-proof concrete。
土木工程毕业翻译及译文
素混凝土的尺寸效应及动态响应摘要：本文研究了素混凝土试样动力响应的尺寸效应。
该报告是根据作者和其他人的实验数据并考虑了梁的蠕变、弯曲影响下的梁和受轴向冲击载荷作用的圆柱体的试验结果。
尺寸效应是通过使用Ba z ant的规模效应法和多重标法则来监测的，而且缩放模式能够捕捉尺寸效应的强度。
对于断裂能，换言之，规模效应仅仅体现在影响率上。
在准静态荷载作用下，受压素混凝土对试件尺寸更加不敏感。
但是在冲击作用下，压缩反应相对于弯曲作用似乎更依赖尺寸。
然而，考虑到应力变化率的影响，弯曲响应描绘了更加重要的尺寸效应，它类似于准静态荷载作用下的响应。
DOI（数字对象唯一标识）: 10.1061/_ASCE_0899-1561_2006_18:4_485_数据库主题词土木工程数据库主题词：断裂;混凝土;尺寸效应;动态响应。
前言尺度问题在任何物理理论都具有重要地位。
在最近的一篇Bazant所写的文章中介绍了运用固体力学解决这一问题的历史。
在现代，自从Weibull提出其办法以来该问题已经归于统计学领域，其方法是基于“薄弱环节”理念和“薄弱环节”的发生概率随试样尺寸大增大而增加。
早些时候，Griffith的基于能量的用于解决裂纹扩展的方法假象过规模效应，不过这种方法具有物质依赖性。
在过去的几十年中，在过去的几十年中，有许多关于准脆性材料试件尺寸效应的报告。
针对这些材料，Bazant认为源于裂纹能量吸收率和释放率的不匹配。
能量吸收率的增加的很大一部分随着尺寸平方的增加而增加，然而释放率的增加确实线性的。
因此，通过减少标本的能源释放率，减少名义应力被看作是补偿差额的一种手段。
不同于准静态荷载，在动力学领域样本尺寸效应的研究还没有获得很大的重视。
这种尝试是主要限于纤维增强聚合物。
关于水泥基材料的数据极为稀缺并且近期已开始关注冲击速率。
设计规范及试验标准方法的缺乏阻止我们赋予建筑材料抵抗冲击和爆炸的能力。
此外，冲击试验介绍一些不相干的影响，诸如惯性和试验机的影响。
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 loadsCommonly 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 thestructural 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 in conjunction 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 narrowoverturning, 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 wall in 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 overturning 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 (i.e, the webs of the framed tube) while the flexural component is associated with the axial shortening and lengthening of columns (i.e, 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 (i.e, 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 even higher, 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 (i.e, shear-stiff) tube while the outer tube is conceived as a framed (i.e, 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% sti ffer 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 shear stiffness 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 (28.6m) wide, 196ft(59.7m) long, and 601ft (183.3m) high.2.Two inner tubes are provided, each 31ft(9.4m) by 40 ft (12.2m), centered 90 ft (27.4m) apart in the long direction of thebuilding.3.The inner tubes are braced in the short direction, but with zero shear stiffness in the long direction.4. A single outer tube is supplied, which encircles the building perimeter.5.The outer tube is a moment-resisting frame, but with zero shear stiffness for the center50ft (15.2m) of each of the longsides.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 twin steel-plate tubes, because the shear stiffness of the outertube 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 Tower contains 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 (3.66m) floor-to-floor distances and an average compressive stress of 15 ksi (138MPa), the shortening of a column under load is 15 (12)(12)/29,000 or 0.074in (1.9mm) per story. At 50 stories, the column will have shortened to 3.7 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 simulating the 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。
土木工程毕业设计外文翻译最终中英文
7 Rigid-Frame StructuresA rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders.The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rigid frames are considered economical for buildings of up to' about25 stories, above which their drift resistance is costly to control. If, however,a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components.As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically include the following stages:1. Estimation of gravity load forces in girders and columns by approximate method.2. Preliminary estimate of member sizes based on gravity load forces witharbitrary increase in sizes to allow for horizontal loading.3. Approximate allocation of horizontal loading to bents and preliminary analysisof member forces in bents.4. Check on drift and adjustment of member sizes if necessary.5. Check on strength of members for worst combination of gravity and horizontalloading, and adjustment of member sizes if necessary.6. Computer analysis of total structure for more accurate check on memberstrengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift..7. Detailed design of members and connections.This chapter considers methods of analysis for the deflections and forces for both gravity and horizontal loading. The methods are included in roughly the order of the design procedure, with approximate methods initially and computer techniques later. Stability analyses of rigid frames are discussed in Chapter 16.7.1 RIGID FRAME BEHAVIORThe horizontal stiffness of a rigid frame is governed mainly by the bending resistance of the girders, the columns, and their connections, and, in a tall frame, by the axial rigidity of the columns. The accumulated horizontal shear above any story of a rigid frame is resisted by shear in the columns of that story (Fig. 7.1). The shear causes the story-height columns to bend in double curvature with points of contraflexure at approximately mid-story-height levels. The moments applied to a joint from the columns above and below are resisted by the attached girders, which also bend in double curvature, with points of contraflexure at approximately mid-span. These deformations of the columns and girders allow racking of the frame and horizontal deflection in each story. The overall deflected shape of a rigid frame structure due to racking has a shear configuration with concavity upwind, a maximum inclination near the base, and a minimum inclination at the top, as shown in Fig.7.1.The overall moment of the external horizontal load is resisted in each story level by the couple resulting from the axial tensile and compressive forces in the columns on opposite sides of the structure (Fig. 7.2). The extension and shortening of the columns cause overall bending and associated horizontal displacements of the structure. Because of the cumulative rotation up the height, the story drift dueto overall bending increases with height, while that due to racking tends to decrease. Consequently the contribution to story drift from overall bending may, in. the uppermost stories, exceed that from racking. The contribution of overall bending to the total drift, however, will usually not exceed 10% of that of racking, except in very tall, slender,, rigid frames. Therefore the overall deflected shape of a high-rise rigid frame usually has a shear configuration.The response of a rigid frame to gravity loading differs from a simply connected frame in the continuous behavior of the girders. Negative moments are induced adjacent to the columns, and positive moments of usually lesser magnitude occur in the mid-span regions. The continuity also causes the maximum girder moments to be sensitive to the pattern of live loading. This must be considered when estimating the worst moment conditions. For example, the gravity load maximum hogging moment adjacent to an edge column occurs when live load acts only on the edge span and alternate other spans, as for A in Fig. 7.3a. The maximum hogging moments adjacent to an interior column are caused, however, when live load acts only on the spans adjacent to the column, as for B in Fig. 7.3b. The maximum mid-span sagging moment occurs when live load acts on the span under consideration, and alternate other spans, as for spans AB and CD in Fig. 7.3a.The dependence of a rigid frame on the moment capacity of the columns for resisting horizontal loading usually causes the columns of a rigid frame to be larger than those of the corresponding fully braced simply connected frame. On the other hand, while girders in braced frames are designed for their mid-span sagging moment, girders in rigid frames are designed for the end-of-span resultant hogging moments, which may be of lesser value. Consequently, girders in a rigid frame may be smaller than in the corresponding braced frame. Such reductions in size allow economy through the lower cost of the girders and possible reductions in story heights. These benefits may be offset, however, by the higher cost of the more complex rigid connections.7.2 APPROXIMATE DETERMINATION OF MEMBER FORCES CAUSED BY GRAVITY LOADSIMGA rigid frame is a highly redundant structure; consequently, an accurate analysis can be made only after the member sizes are assigned. Initially, therefore, member sizes are decided on the basis of approximate forces estimated either by conservative formulas or by simplified methods of analysis that are independent of member properties. Two approaches for estimating girder forces due to gravity loading are given here.7.2.1 Girder Forces—Code Recommended ValuesIn rigid frames with two or more spans in which the longer of any two adjacent spans does not exceed the shorter by more than 20 %, and where the uniformly distributed design live load does not exceed three times the dead load, the girder moment and shears may be estimated from Table 7.1. This summarizes the recommendations given in the Uniform Building Code [7.1]. In other cases a conventional moment distribution or two-cycle moment distribution analysis should be made for a line of girders at a floor level.7.2.2 Two-Cycle Moment Distribution [7.2].This is a concise form of moment distribution for estimating girder moments in a continuous multibay span. It is more accurate than the formulas in Table 7.1, especially for cases of unequal spans and unequal loading in different spans.The following is assumed for the analysis:1. A counterclockwise restraining moment on the end of a girder is positive anda clockwise moment is negative.2. The ends of the columns at the floors above and below the considered girder are fixed.3. In the absence of known member sizes, distribution factors at each joint aretaken equal to 1 /n, where n is the number of members framing into the joint in the plane of the frame.Two-Cycle Moment Distribution—Worked Example. The method is demonstrated by a worked example. In Fig, 7.4, a four-span girder AE from a rigid-frame bent is shown with its loading. The fixed-end moments in each span are calculated for dead loading and total loading using the formulas given in Fig, 7.5. The moments are summarized in Table 7.2.The purpose of the moment distribution is to estimate for each support the maximum girder moments that can occur as a result of dead loading and pattern live loading.A different load combination must be considered for the maximum moment at each support, and a distribution made for each combination.The five distributions are presented separately in Table 7.3, and in a combined form in Table 7.4. Distributions a in Table 7.3 are for the exterior supports A andE. For the maximum hogging moment at A, total loading is applied to span AB with dead loading only on BC. The fixed-end moments are written in rows 1 and 2. In this distribution only .the resulting moment at A is of interest. For the first cycle, joint B is balanced with a correcting moment of- (-867 + 315)/4 = - U/4 assigned to M BA where U is the unbalanced moment. This is not recorded, but half of it, ( - U/4)/2, is carried over to M AB. This is recorded in row 3 and then added to the fixed-end moment and the result recorded in row 4.The second cycle involves the release and balance of joint A. The unbalanced moment of 936 is balanced by adding-U/3 = -936/3 = -312 to M BA (row 5), implicitly adding the same moment to the two column ends at A. This completes the second cycle of the distribution. The resulting maximum moment at A is then given by the addition of rows 4 and 5, 936 - 312 = 624. The distribution for the maximum moment at E follows a similar procedure.Distribution b in Table 7.3 is for the maximum moment at B. The most severe loading pattern for this is with total loading on spans AB and BC and dead load only on CD. The operations are similar to those in Distribution a, except that the T first cycle involves balancing the two adjacent joints A and C while recording only their carryover moments to B. In the second cycle, B is balanced by adding - (-1012 + 782)/4 = 58 to each side of B. The addition of rows 4 and 5 then gives the maximum hogging moments at B. Distributions c and d, for the moments at joints C and D, follow patterns similar to Distribution b.The complete set of operations can be combined as in Table 7.4 by initially recording at each joint the fixed-end moments for both dead and total loading. Then the joint, or joints, adjacent to the one under consideration are balanced for the appropriate combination of loading, and carryover moments assigned .to the considered joint and recorded. The joint is then balanced to complete the distribution for that support.Maximum Mid-Span Moments. The most severe loading condition for a maximum mid-span sagging moment is when the considered span and alternate other spans and total loading. A concise method of obtaining these values may be included in the combined two-cycle distribution, as shown in Table 7.5. Adopting the convention that sagging moments at mid-span are positive, a mid-span total; loading moment is calculated for the fixed-end condition of each span and entered in the mid-span column of row 2. These mid-span moments must now be corrected to allow for rotation of the joints. This is achieved by multiplying the carryover moment, row 3, at the left-hand end of the span by (1 + 0.5 D.F. )/2, and the carryover moment at the right-hand end by -(1 + 0.5 D.F.)/2, where D.F. is the appropriate distribution factor, and recording the results in the middle column. For example, the carryover to the mid-span of AB from A = [(1 + 0.5/3)/2] x 69 = 40 and from B = -[(1+ 0.5/4)/2] x (-145) = 82. These correction moments are then added to the fixed-end mid-span moment to give the maximum mid-span sagging moment, that is, 733 + 40 + 82 = 855.7.2.3 Column ForcesThe gravity load axial force in a column is estimated from the accumulated tributary dead and live floor loading above that level, with reductions in live loading as permitted by the local Code of Practice. The gravity load maximum column moment is estimated by taking the maximum difference of the end moments in the connected girders and allocating it equally between the column ends just above and below the joint. To this should be added any unbalanced moment due to eccentricity of the girderconnections from the centroid of the column, also allocated equally between the column ends above and below the joint.第七章框架结构高层框架结构一般由平行或正交布置的梁柱结构组成，梁柱结构是由带有能承担弯矩作用节点的梁、柱组成。
土木工程毕业论文外文翻译--盾构(外文原文+中文翻译)
毕业设计（论文）外文文献翻译院系：土木工程与建筑系年级专业：姓名：学号：附件：盾构SHIELDSSHIELDS【Abstract】A tunnel shield is a structural system, used during the face excavation process. The paper mainly discusses the form and the structure of the shield. Propulsion for the shield is provided by a series of hydraulic jacks installed in the tail of the shield and the shield is widespread used in the underground environment where can not be in long time stable. The main enemy of the shield is ground pressure. Non-uniform ground pressure caused by the steering may act on the skin tends to force the shield off line and grade. And working decks inside the shield enable the miners to excavate the face, drill and load holes.【Keywords】shield hydraulic jacks ground pressure steering working decksA tunnel shield is a structural system, normally constructed of steel, used during the face excavation process. The shield has an outside configuration which matches the tunnel. The shield provides protection for the men and equipment and also furnished initial ground support until structural supports can be installed within the tail section of the shield. The shield also provides a reaction base for the breast-board system used to control face movement. The shield may have either an open or closed bottom. In a closed-bottom shield, the shield structure and skin provide 360-degree ground contact and the weight of the shield rests upon the invert section of the shield skin. The open shield has no bottom section and requires some additional provision is a pair of side drifts driven in advance of shield excavation. Rails or skid tracks are installed within these side drifts to provide bearing support for the shield.Shield length generally varies from1/2 to 3/4 of the tunnel diameter. The front of the shield is generally hooded to so that the top of the shield protrudes forward further than the invert portion which provides additional protection for the men working at the face and also ease pressure on the breast-boards. The steel skin of the shield may varyfrom 1.3 to 10 cm in thickness, depending on the expected ground pressures. The type of steel used in the shield is the subject of many arguments within the tunneling fraternity. Some prefer mild steel in the A36 category because of its ductility and case of welding in the underground environment where precision work is difficult. Others prefer a high-strength steel such as T-1 because of its higher strength/weight ratio. Shield weight may range from 5 to 500 tons. Most of the heaviest shields are found in the former Sovier Union because of their preference for cast-iron in both structural and skin elements.Propulsion for the shield is provided by a series of hydraulic jacks installed in the tail of the shield that thrust against the last steel set that has been installed. The total required thrust will vary with skin area and ground pressure. Several shields have been constructed with total thrust capabilities in excess of 10000 tons. Hydraulic systems are usually self-contained, air-motor powered, and mounted on the shield. Working pressures in the hydraulic system may range from 20-70 Mpa. To resist the thrust of the shield jacks, a horizontal structure member (collar brace) must be installed opposite each jack location and between the flanges of the steel set. In addition, some structural provision must be made for transferring this thrust load into the tunnel walls. Without this provision the thrust will extend through the collar braces to the tunnel portal.An Englishman, Marc Brunel, is credited with inventing the shield. Brunel supposedly got his idea by studying the action of the Teredo navalis, a highly destructive woodworm, when he was working at the Chatham dock yard. In 1818 Brunel obtained an English patent for his rectangular shield which was subsequently uses to construct the first tunnel under the River Thames in London. In 1869 the first circular shield was devised by Barlow and Great Head in London and is referred to as the Great Head-type shield. Later that same year, Beach in New York City produced similar shield. The first use of the circular shield came during 1869 when Barlow and Great Head employed their device in the construction of the 2.1 in diameter Tower Subway under the River Thames. Despite the name of the tunnel, it was used only for pedestrian traffic. Beach also put his circular shield to work in 1869 to construct a demonstration project for a proposed NewYork City subway system. The project consisted of a 2.4 m diameter tunnel, 90 m long, used to experiment with a subway car propelled by air pressure.Here are some tunnels which were built by shield principle.Soft-ground tunneling Some tunnels are driven wholly or mostly through soft material. In very soft ground, little or no blasting is necessary because the material is easily excavated.At first, forepoling was the only method for building tunnels through very soft ground. Forepoles are heavy planks about 1.5 m long and sharpened to a point. They were inserted over the top horizontal bar of the bracing at the face of the tunnel. The forepoles were driven into the ground of the face with an outward inclination. After all the roof poles were driven for about half of their length, a timber was laid across their exposed ends to counter any strain on the outer ends. The forepoles thus provided an extension of the tunnel support, and the face was extended under them. When the ends of the forepoles were reached, new timbering support was added, and the forepoles were driven into the ground for the next advance of the tunneling.The use of compressed air simplified working in soft ground. An airlock was built, though which men and equipment passed, and sufficient air pressure was maintained at the tunnel face to hold the ground firm during excavation until timbering or other support was erected.Another development was the use of hydraulically powered shields behind which cast-iron or steel plates were placed on the circumference of the tunnels. These plates provided sufficient support for the tunnel while the work proceeded, as well as full working space for men in the tunnel.Under water tunneling The most difficult tunneling is that undertaken at considerable depths below a river or other body of water. In such cases, water seeps through porous material or crevices, subjecting the work in progress to the pressure of the water above the tunneling path. When the tunnel is driven through stiff clay, the flow of water may be small enough to be removed by pumping. In more porous ground,compressed air must be used to exclude water. The amount of air pressure that is needed increases as the depth of the tunnel increases below the surface.A circular shield has proved to be most efficient in resisting the pressure of soft ground, so most shield-driven tunnels are circular. The shield once consisted of steel plates and angle supports, with a heavily braced diaphragm across its face. The diaphragm had a number of openings with doors so that workers could excavate material in front of the shield. In a further development, the shield was shoved forward into the silty material of a riverbed, thereby squeezing displaced material through the doors and into the tunnel, from which the muck was removed. The cylindrical shell of the shield may extend several feet in front of the diaphragm to provide a cutting edge. A rear section, called the tail, extends for several feet behind the body of the shield to protect workers. In large shields, an erector arm is used in the rear side of the shield to place the metal support segments along the circumference of the tunnel.The pressure against the forward motion of a shield may exceed 48.8 Mpa. Hydraulic jacks are used to overcome this pressure and advance the shield, producing a pressure of about 245 Mpa on the outside surface of the shield.Shields can be steered by varying the thrust of the jacks from left side to right side or from top to bottom, thus varying the tunnel direction left or right or up or down. The jacks shove against the tunnel lining for each forward shove. The cycle of operation is forward shove, line, muck, and then another forward shove. The shield used about 1955 on the third tube of the Lincoln Tunnel in New York City was 5.5 m long and 9.6 m in diameter. It was moved about 81.2 cm per shove, permitting the fabrication of a 81.2 cm support ring behind it.Cast-iron segments commonly are used in working behind such a shield. They are erected and bolted together in a short time to provide strength and water tightness. In the third tube of the Lincoln Tunnel each segment is 2 m long, 81.2 cm wide, and 35.5 cm thick, and weighs about 1.5 tons. These sections form a ring of 14 segments that are linked together by bolts. The bolts were tightened by hand and then by machine.Immediately after they were in place, the sections were sealed at the joints to ensure permanent water tightness.Shields are most commonly used in ground condition where adequate stand-up time does not exist. The advantage of the shield in this type of ground, in addition to the protection afforded men and equipment , is the time available to install steel ribs, liner plates, or precast concrete segments under the tail segment of the shield before ground pressure and movement become adverse factors.One of the principle problems associated with shield use is steering. Non-uniform ground pressure acting on the skin tends to force the shield off line and grade. This problem is particularly acute with closed bottom shield that do not ride on rails or skid tracks. Steering is accomplished by varying the hydraulic pressure in individual thrust jacks. If the shied is trying to dive, additional pressure on the invert jacks will resist this tendency. It is not unusual to find shield wandering several feet from the required. Although lasers are frequently used to provide continuous line and grade data to operator, once the shield wanders off its course, its sheer bulk resists efforts to bring it back. Heterogeneous ground conditions, such as clay with random boulders, also presents steering problems.One theoretical disadvantage of the shield is the annular space left between the support system and the ground surface. When the support system is installed within the tail section of the shield, the individual support members are separated from the ground surface by the thickness of the tail skin. When steel ribs are used, the annular space is filled with timber blocking as the forward motion of the shield exposes the individual ribs. A continuous support system presents a different problem. In this case, a filler material, such as pea gravel or grout, is pumped behind the support system to fill the void between it and the ground surface.The main enemy of the shield is ground pressure. As ground pressure begins to build, two things happen, more thrust is required for shield propulsion and stress increases in the structural members of the shield. Shields are designed and function undera preselected ground pressure. Designers will select this pressure as a percentage of the maximum ground pressure contemplated by the permanent tunnel design. In some cases, unfortunately, the shield just gets built without specific consideration of the ground pressures it might encounter. When ground pressure exceeds the design limit, the shield gets “stuck”. The friction component of the ground pressure on the skin becomes greater than the thrust capability of the jacks. Several methods, including pumping bentonite slurry into the skin, ground interface, pushing heavy equipment, and bumping with dynamite, have been applied to stuck shields with occasional success.Because ground pressure tends to increase with time, the cardinal rule of operation is “keeping moving”. This accounts for the fracture activity when a shield has suffered a temporary mechanical failure. As ground pressure continues to build on the nonmoving shield , the load finally exceeds its structural limit and bucking begins. An example of shield destruction occurred in California in 1968 when two shields being used to drive the CarlyV.Porter Tunnel were caught by excessive ground pressure and deformed beyond repair. One of the Porter Tunnel shields was brought to a halt in reasonably good ground by water bearing ground fault that required full breast-boards. While the contractor was trying to bring the face under control, skin pressure began to increase. While the face condition finally stabilized, the contractor prepared to resume operations and discovered the shield was stuck. No combination of methods was able to move it, and the increasing ground pressure destroyed the shield.To offset the ground pressure effect, a standard provision in design is a cutting edge radius several inches greater than the main body radius. This allows a certain degree of ground movement before pressure can come to bear on the shield skin. Another approach, considered in theory but not yet put into practice, is the “watermelon seed” design. The theory calls for a continuous taper in the shield configuration; maximum radius at the cutting edge and the minimum radius at the trailing edge of the tail. With this configuration, any amount of forward movement would create a drop in skin pressure.Working decks, spaced 2.4 to 3.0 m vertically, are provided inside the shield. These working decks enable the miners to excavate the face, drill and load holes, if necessary, and adjust the breast-board system. The hydraulic jacks for the breast-board are mounted on the underside of the work decks. Blast doors are sometimes installed as an integral part of the work decks if a substantial amount of blasting is expected.Some form of mechanical equipment is provided on the rear end of the working decks to assist the miners in handing and placing the element of the support system. In large tunnels, these individual support elements can weigh several tons and mechanical assistance becomes essential. Sufficient vertical clearance must be provided between the invert and the first working deck to permit access to the face by the loading equipment.盾构【摘要】隧道盾构是一结构系统，通常用于洞室开挖。
土木工程毕业论文英文翻译
BridgeBridges that span rivers, valleys such a barrier construction, which provides convenient transportation, so far, most of the bridges are highway bridges or railway bridge. A large number of viaducts built in the 19th century in Europe, aims to maintain its navigation of the ship canal. The smallest bridge in New York City's Kennedy Airport, it is primarily the aircraft taxiing onto the runway to the service.Humans is similar to the first bridge built in the primitive built in isolated areas. Early human tools and construction techniques as the original, like humans are the most junior. After they are at least as long as the processing and installation can be completed.In the forest, widely available solid wood and logs, then most likely Hou bridge or by a few logs built side by side, may, in its number of wooden sticks or straw mats on the cover for easy walking.In the tropical regions of India, Africa, and South America are used to build fiber rattan suspension bridge, the vines are tied to trees on both sides of the river or valley or rock.One or more above the walking cane to be stepped on, others are arranged in Gao Yu a few feet, for hand use. Although rattan rope bridge is usually unstable. But there are many rattan rope bridge with incas built strong and stable enough, to be used for the Spanish soldiers and their horses to pass.In rocky areas, the stone is used to bridge across the river to a small stone pestle as piers spaced, and then use a flat stone across the pier adjacent to the channel linking the two sides completed, most of the stone bridge is this types, called the clap bridge. Now in Dartmoor, England are still visible, but they are built in the Middle Ages or even later.The first step changes the original bridge was considered in ancient China, and then into India. Generally wider than the tree bed, Chinese and Indians in the center of the river into two stumps. In this structure, both ends of the frame with one end of logs on the stump, and tilted slightly upward so that each layer of high than a few feet below it. In order to increase stability, both sides each with a bunch of stakes in large and heavy stone anchor; close to the river, in the middle of the river at both ends of the two stakes are connected with beams.In this structure, the natural bridge support bar in the middle of two free pile after a wide span can be achieved.As early as 4000 BC in Mesopotamia, and thousands in the year 3000 in Egypt, with stone or sun dried bricks were used to install the overlapping beams. This structure looks like the arch, the lower more stable, is called sudden arch. To suddenly arch into a more straight arch, it needs to fit the internal structure of the stone smooth. The arch straight arch stronger than sudden, and as early as 500 BC to be used.The stone arch with direct economic and durable, it can rest on the dock by a number of the arch and across the small river. And, it generally will always appear, and its quality in any structure to be better than the previous. In ancient China and Rome, which is widely used in the overall stone arch bridge structure. It has been widely used until the 19th century. There are four categories of basic structure can be used as water or obstructions on the bridge: rigid frame bridge, cantilever bridge, arch, and suspension system.The simplest bridge may be just the first use - or just the river bridge. So that it is relatively fixed at both ends ofthe banks. This rigid frame bridge can form a shaped wooden beams, reinforced concrete beams or more complicated constraints. Just this type of bridge span of the bridge pier was built in the middle can be used or built in the valley support joists, beams connected by a few and then increase the span. Rigid Frame material must be able to bear the stress and tension. Despite its name beam, but in fact the requirements of this dual rod can be used to frame the bridge. Result, the higher part of the beam bending pressure lower than the straight part of the more than half, if he's bearing strength is too weak, it will be into the ring, if the tensile capacity is too weak, he will be destroyed.Cantilever bridge piers in the use of long-span bridges the middle it is usually not feasible in the bridge structure. For example, in the deep and rapid river flow, or ooze, it may make it difficult to build sufficient depth of bridge pier foundation rock. In this case, just on the bridge structure can be extended with two beams --- out of a beam from each shore, and in the two ends of the beam anchorage basis. This simple structure is more rigid frame bridge with static characterization, and each root anchorage of the beam cantilever bridge called such an infrastructure, and perhapsthis most simple and familiar example is the cantilever bridge diving board. Cantilever bridge in general, the gap between the cantilever tip is closed, the road to provide a continuous deck. But if the point of this bridge in its closed off, then do not need each other to set the root cantilever support which can maintain stability. Cantilever is usually only the middle of the gap is closed rigid frame bridge. So while filling grain extended cantilever span.Suspension bridge in the absence than in the case of the middle pier cantilever bridge across the greater distance. Suspension of the support system is a continuous flexible cables by the ends of the anchor, the suspension bridge is the simplest example of high-altitude high-wire acrobat with the circus wire. The original suspension bridge is often a very small few that is tied to steel rails and provide a foothold. At the level of the modern suspension bridge on the road is suspended by the cable on both sides of the roadway below.Arch is the opposite effect on the suspension bridge, suspension bridge cables in the freedom of those who provide support force where it is from the bridge pillars at both ends of its fixed upward. As different in shape, suspension bridgecables tend to stretch all the points of the pillars of the bridge tends to squeeze everywhere. For these reasons, suspension of the cable must be as much as possible to prevent the extension of the bridge material is as hungry to resist compression. Because the arch does not necessarily require materials with a tensile strength, so the bridge can be built with brick or stone, brick or stone arch to pass through the characteristics of the pressure together. This material in other basic bridge structure is useless.In the arch, the load on the vertical transmission from the road down until the arch was destroyed. When the arch was pure pressure to achieve the critical load, they will change the power transmission path. A compression force of the thrust through the node or piers to the ground. This simple and beautiful arch structure of a bridge in one of the basic structure.桥梁桥梁是跨越如河流、山谷这样障碍的一种建筑，从而提供交通便利，到目前为止，大部分桥梁都是公路桥或铁路桥。
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外文翻译班级：xxx 学号：xxx 姓名：xxx一、外文原文：Structural Systems to resist lateral loadsCommonly 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 developedwithout 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 in conjunction 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 resistlateral 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 wall in 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 (i.e, the webs of the framed tube) while the flexural component is associated with the axial shortening and lengthening of columns (i.e, the flanges of the framed tube). In abraced 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 (i.e, 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 even higher, 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 (i.e, shear-stiff) tube while the outer tube is conceived as a framed (i.e, 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 shear stiffness 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 (28.6m) wide, 196ft(59.7m) long, and 601ft (183.3m) high.2.Two inner tubes are provided, each 31ft(9.4m) by 40 ft (12.2m), centered 90 ft (27.4m)apart in the long direction of the building.3.The inner tubes are braced in the short direction, but with zero shear stiffness in the longdirection.4. A single outer tube is supplied, which encircles the building perimeter.5.The outer tube is a moment-resisting frame, but with zero shear stiffness for the center50ft(15.2m) 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 twin steel-plate tubes, because theshear 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 Tower contains 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 (3.66m) floor-to-floor distances and an average compressive stress of 15 ksi (138MPa), the shortening of a column under load is 15 (12)(12)/29,000 or 0.074in (1.9mm) per story. At 50 stories, the column will have shortened to 3.7 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-stressthe lower height columns so as to reconcile the differential deflections of columns in close proximity with the post-tensioning of the shorter column simulating the 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。