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。
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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。