土木工程钢筋混凝土结构中英文对照外文翻译文献

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土木工程混凝土结构中英文对照外文翻译文献

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

钢筋混凝土中英文对照外文翻译文献

中英文资料对照外文翻译目录1 中文翻译 (1)1.1钢筋混凝土 (1)1.2土方工程 (2)1.3结构的安全度 (3)2 外文翻译 (6)2.1 Reinforced Concrete (6)2.2 Earthwork (7)2.3 Safety of Structures (9)1 中文翻译1.1钢筋混凝土素混凝土是由水泥、水、细骨料、粗骨料（碎石或；卵石）、空气，通常还有其他外加剂等经过凝固硬化而成。

将可塑的混凝土拌合物注入到模板内，并将其捣实，然后进行养护，以加速水泥与水的水化反应，最后获得硬化的混凝土。

其最终制成品具有较高的抗压强度和较低的抗拉强度。

其抗拉强度约为抗压强度的十分之一。

因此，截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝土构件中较弱的受拉区的强度。

由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异，因此，需要对结构设计的基本原理进行修改。

将钢筋混凝土这种非均质截面的两种组成部分按一定比例适当布置，可以最好的利用这两种材料。

这一要求是可以达到的。

因混凝土由配料搅拌成湿拌合物，经过振捣并凝固硬化，可以做成任何一种需要的形状。

如果拌制混凝土的各种材料配合比恰当，则混凝土制成品的强度较高，经久耐用，配置钢筋后，可以作为任何结构体系的主要构件。

浇筑混凝土所需要的技术取决于即将浇筑的构件类型，诸如：柱、梁、墙、板、基础，大体积混凝土水坝或者继续延长已浇筑完毕并且已经凝固的混凝土等。

对于梁、柱、墙等构件，当模板清理干净后应该在其上涂油，钢筋表面的锈及其他有害物质也应该被清除干净。

浇筑基础前，应将坑底土夯实并用水浸湿6英寸，以免土壤从新浇的混凝土中吸收水分。

一般情况下，除使用混凝土泵浇筑外，混凝土都应在水平方向分层浇筑，并使用插入式或表面式高频电动振捣器捣实。

必须记住，过分的振捣将导致骨料离析和混凝土泌浆等现象，因而是有害的。

水泥的水化作用发生在有水分存在，而且气温在50°F以上的条件下。

钢筋混凝土结构中英文对照外文翻译文献

中英文对照外文翻译(文档含英文原文和中文翻译)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 concreteproduced 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, the concrete must be able to flow around, between, and past the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. The choice of structural system is made by the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shape and 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 forsurfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are very widely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume.The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled,and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course in strength of materials for homogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because unreinforced concrete is brittle, it cannot undergo large deformations under load and failssuddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to cover construction in a given region, often a city or a state. The objective of a building code is also to protect the public by accounting for the influence of the local environmental conditions on construction. For example, local authorities may specify additional provisions to account for such regional conditions as earthquake, heavy snow, or tornados. National structural codes genrally are incorporated into local building codes.The American Concrete Institute ( ACI ) Building Code covering the design of reinforced concrete buildings. It contains provisions covering all aspects of reinforced concrete manufacture, design, and construction. It includes specifications on quality of materials, details on mixing and placing concrete, design assumptions for the analysis of continuous structures, and equations for proportioning members for design forces.All structures must be proportioned so they will not fail or deform excessively under any possible condition of service. Therefore it is important that an engineer use great care in anticipating all the probableloads to which a structure will be subjected during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the forces produced by wind, impact, shrinkage, temperature change, creep and support settlements, earthquake, and so forth.The load associated with the weight of the structure itself and its permanent components is called the dead load. The dead load of concrete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately until members have been sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the members sized, and architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initial estimate of its value ( or slightly less ), the design is complete, but if a significant difference exists between the computed and estimated values of dead weight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly important when spans are long, say over 75 ft ( 22.9 m ), because dead load constitutes a major portion of the design load.Live loads associated with building use are specific items of equipment and occupants in a certain area of a building, building codes specify values of uniform live for which members are to be designed.After the structure has been sized for vertical load, it is checked for wind in combination with dead and live load as specified in the code. Wind loads do not usually control the size of members in building less than 16 to 18 stories, but for tall buildings wind loads become significant and cause large forces to develop in the structures. Under these conditions economy can be achieved only by selecting a structural system that is able to transfer horizontal loads into the ground efficiently.钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。

土木工程专业毕业设计外文文献及翻译

英文原文：Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP compositesAhmed Khalifa a,* , Antonio Nanni ba Department of Structural Engineering, University of Alexandria, Alexandria 21544, Egyptb Department of Civil Engineering, University of Missouri at Rolla, Rolla, MO 65409, USAReceived 28 April 1999; received in revised form 30 October 2001; accepted 10 January 2002AbstractThe present study examines the shear performance and modes of failure of rectangular simply supported reinforced concrete(RC) beams designed with shear deficiencies. These members were strengthened with externally bonded carbon fiber reinforced polymer (CFRP) sheets and evaluated in the laboratory. The experimental program consisted of twelve full-scale RC beams tested to fail in shear. The variables investigated within this program included steel stirrups, and the shear span-to-effective depth ratio, as well as amount and distribution of CFRP. The experimental results indicated that the contribution of externally bonded CFRP to the shear capacity was significant. The shear capacity was also shown to be dependent upon the variables investigated. Test results were used to validate a shear design approach, which showed conservative and acceptable predictions.○C2002 Elsevier Science Ltd. All rights reserved.Keywords: Rehabilitation; Shear; Carbon fiber reinforced polymer1. IntroductionFiber reinforced polymer (FRP) composite systems, composed of fibers embedded in a polymeric matrix, can be used for shear strengthening of reinforced con-crete(RC) members [1–7]. Many existing RC beams are deficient and in need of strengthening. The shear failure of an RC beam is clearly different from its flexural failure. In shear, the beam fails suddenly without sufficient warning and diagonal shear cracks are consid-erably wider than the flexural cracks [8].The objectives of this program were to:1. Investigate performance and mode of failure of simply supported rectangular RC beams with shear deficien-cies after strengthening with externally bonded CFRP sheets.2. Address the factors that influence shear capacity of strengthened beams such as: steel stirrups, shear span-to-effective depth ratio (a/d ratio), and amount and distribution of CFRP.3. Increase the experimental database on shear strength-ening with externally bonded FRP reinforcement.4. Validate the design approach previously proposed by the authors [9].For these objectives, 12 full-scale, RC beams designed to fail in shear were strengthened with different CFRP schemes. These members were tested as simple beams using a four-point loading configuration with two different a/d ratios.2. Experimental program2.1. Test specimens and materialsTwelve full-scale beam specimens with a total span of 3050 mm. and a rectangular cross-section of 150-mm-wide and 305-mm-deep were tested. The specimens were grouped into two main series designated SW and SO depending on the presence of steel stirrups in the shear span of interest.Series SW consisted of four specimens. The details and dimensions of the specimens designated series SW are illustrated in Fig. 1a. In this series, four 32-mm steel bars were used as longitudinal reinforcement with two at top and two at bottom face of the cross-section to induce a shear failure. The specimens were reinforced with 10-mm steel stirrups throughout their entire span. The stirrups spacing in the shear span of interest, right half, was selected to allow failure in that span.Series SO consisted of eight beam specimens, which had the same cross-section dimension and longitudinal steel reinforcement as for series SW. No stirrups were provided in the test half span as illustrated.Each main series (i.e. series SW and SO) was subdivided into two subgroups according to shear span-to-effective depth ratio. This was selected to be a/d = 3 and 4, resulting in the following four subgroups: SW3;SW4; SO3; and SO4.The mechanical properties of the materials used for manufacturing the test specimens are listed in Table 1.Fabrication of the specimens including surface preparation and CFRP installation is described elsewhere [10].2.2. Strengthening schemesOne specimen from each series (SW3-1, SW4-1, SO3-1 and SO4-1) was left without strengthening as a control specimen, whereas eight beam specimens were strengthened with externally bonded CFRP sheets following three different schemes as illustrated in Fig. 2.In series SW3, specimen SW3-2 was strengthened with two CFRP plies having perpendicular fiber directions (90°/0°). The first ply was attached in the form of continuous U-wrap with the fiber direction oriented perpendicular to the longitudinal axis of the specimen (90°). The second ply was bonded on the two sides of the specimen with the fiber direction parallel to the beam axis（0°）.This ply [i.e. 0°ply] was selected to investigate the impact of additional horizontal restraint on shear strength.In series SW4, specimen SW4-2 was strengthened with two CFRP plies having perpendicular fiber direction (90°/0°) as for specimen SW3-2.Four beam specimens were strengthened in series SO3. Specimen SO3-2 was strengthened with one-ply CFRP strips in the form of U-wrap with 90°-fiber orientation. The strip width was 50 mm with center-to-center spacing of 125 mm. Specimen SO3-3 was strengthened in a manner similar to that of specimen SO3-2, but with strip width equal to 75 mm. Specimen SO3-4 was strengthened with one-plycontinuous U-wrap (90°). Specimen SO3-5 was strengthened with twoCFRP plies (90°/0°) similar to specimens SW3-2 and SW4-2.In series SO4, two beam specimens were strengthened. Specimen SO4-2 was strengthened with one-ply CFRP strips in the form of U-wrap similar to specimen SO3-2. Specimen SO4-3 was strengthened with one-ply continuous U-wrap (90°) similar to SO3-4.2.3. Test set-up and instrumentationAll specimens were tested as simple span beams subjected to a four-point load as illustrated in Fig. 3. A universal testing machine with 1800 KN capacity was used in order to apply a concentrated load on a steel distribution beam used to generate the two concentrated loads. The load was applied progressively in cycles, usually one cycle before cracking followed by three cycles with the last one up to ultimate. The applied load vs. deflection curves shown in this paper are the envelopes of these load cycles.Four linear variable differential transformers (LVDTs) were used for each test to monitor vertical displacements at various locations as shown in Fig. 3. Two LVDTs were located at mid-span on each side of the specimen. The other two were located at the specimen supports to record support settlement.For each specimen of series SW, six strain gauges were attached to three stirrups to monitor the stirrup strain during loading as illustrated in Fig. 1a. Three strain gauges were attached directly to the FRP sheet on the sides of each strengthened beam to monitor strain variation in the FRP. The strain gauges were oriented in the vertical direction and located at the section mid-height with distances of 175, 300 and 425 mm, respectively, from the support for series SW3 and SO3. For beam specimens of series SW4 and SO4, the strain gauges were located at distance of 375, 500 and 625 mm, respectively, from the support.3. Results and discussionIn the following discussion, reference is always made to weak shear span or spanof interest.3.1. Series SW3Shear cracks in the control specimen SW3-1 were observed close to the middle of the shear span when the load reached approximately 90 kN. As the load increased, additional shear cracks formed throughout, widening and propagating up to final failure at a load of 253 kNIn specimen SW3-2 strengthened with CFRP (90°/0°), no cracks were visible on the sides or bottom of the test specimen due to the FRP wrapping. However，a longitudinal splitting crack initiated on the top surface of the beam at a high load of approximately 320 kN.The crack initiated at the location of applied load and extended towards the support. The specimen failed by concrete splitting at total load of 354 kN. This was an increase of 40% in ultimate capacity compared to the control specimen SW3-1. The splitting failure was due to the relatively high longitudinal compressive stress developed at top of the specimen, which created a transverse tension, led to the splitting failure. In addition, the relatively large amount of longitudinal steel reinforcement combined with over-strengthening for shear by CFRP wrap probably caused this mode of failure. The load vs. mid-span deflection curves for specimens SW3-1 and SW3-2 are illustrated , to show the additional capacity gained by CFRP. The maximum CFRP vertical strain measured at failure in specimen SW3-2 was approximately 0.0023 mm/mm, which corresponded to 14% of the reported CFRP ultimate strain. This value is not an absolute because it greatly depends on the location of the strain gauges with respect to a crack. However, the recorded strain indicates that if the splitting did not occur, the shear capacity could have reached higher load.Comparison between measured local stirrup strains in specimens SW3-1 and SW3-2 are shown in Fig. 6. The stirrups 1, 2 and 3 were located at distance of 175, 300 and 425 mm from the support, respectively. The results showed that the stirrups2 and3 did not yield at ultimate for both specimens. The strains (and the forces) in the stirrups of specimen SW3-2 were, in general, smaller than those of specimen SW3-1 at the same level of loading due to the effect of CFRP.3.2. Series SW4In specimen SW4-1, the first diagonal crack was formed in the member at a total applied load of 75 kN. As the load increased, additional shear cracks appeared throughout the shear span. Failure of the beam occurred when the total applied load reached 200 kN. This was a decrease of 20% in shear capacity compared to the specimen SW3-1In specimen SW4-2, the failure was controlled by concrete splitting similar to test specimen SW3-2. The total applied load at ultimate was 361 kN with an 80% increase in shear capacity compared to the control specimen SW4-1. In addition, the measured strains in the stirrups for specimen SW4-2 were less than those of specimen SW4-1. The applied load vs. mid-span deflection curves for beams SW4-1 and SW4-2 are illustrated . It may be noted that specimen SW4-2 resulted in greater deflection when compared to specimen SW4-1.When comparing the test results of series SW3 specimens to that of series SW4, the ultimate failure load of specimen SW3-2 and SW4-2 was almost the same. However, the enhanced capacity of specimen SW3-2 (a/d=3) due to the addition of the CFRP reinforcement was 101 kN, while specimen SW4-2 (a/d=4) was 161 kN. This indicates that the contribution of external CFRP reinforcement may be influenced by the ayd ratio and appears to decrease with a decreasing a/d ratio. Further, for both strengthened specimens (SW3-2 and SW4-2), CFRP sheets did not fracture or debond from the concrete surface at ultimate and this indicates that CFRP could provide additional strength if the beams did not failed by splitting.3.3. Series SO3Fig. 8 illustrates the failure modes for series SO3 specimens. That details the applied load vs. mid-span deflection for the specimens.The failure mode of control specimen SO3-1 was shear compression. Failure of the specimen occurred at a total applied load of 154 kN. This load was a decrease of shear capacity by 54.5 kN compared to the specimen SW3-1 due to the absent of the steel stirrups. In addition, the crack pattern in specimen SW3-1 was different from of specimen SO3-1. In specimen SW3-1, the presence of stirrups provided a better distribution of diagonal cracks throughout the shear span.In specimen SO3-2, strengthened with 50-mm CFRP strips spaced at 125 mm, the first diagonal shear crack was observed at an applied load of 100 kN. The crack propagated as the load increased in a similar manner to that of specimen SO3-1. Sudden failure occurred due to debonding of the CFRP strips over the diagonal shear crack, with spalled concrete attached to the CFRP strips. The total ultimate load was 262 kN with a 70% increase in shear capacity over the control specimen SO3-1. The maximum local CFRP vertical strain measured at failure in specimen SO3-2 was 0.0047 mm/mm (i.e. 28% of the ultimate strain), which indicated that the CFRP did not reach its ultimate.Specimen SO3-3, strengthened with 75-mm CFRP strips failed as a result of CFRP debonding at a total applied load of 266 kN. No significant increase in shear capacity was noted compared to specimen SO3-2. The maximum-recorded vertical CFRP strain at failure was 0.0052 mmymm (i.e. 31% of the ultimate strain).Specimen SO3-4, which was strengthened with a continuous CFRP U-wrap (908), failed as a result of CFRP debonding at an applied load of 289 kN. Results show that specimen SO3-4 exhibited increase in shear capacity of 87, 10 and 8.5% over specimens SO3-1,SO3-2 and SO3-3, respectively. Applied load vs. vertical CFRP strain for specimen SO3-4 is illustrated in Fig. 10 in which strain gauges sg1, sg2 and sg3 were located at mid-height with distances of 175, 300 and 425 mm from the support, respectively. Fig. 10 shows that the CFRP strain was zero prior to diagonal crack formation, then increased slowly until the specimen reached a load in the neighborhood of theultimate strength of the control specimen. At this point, the CFRP strain increased significantly until failure. The maximum local CFRP vertical strain measured at failure was approxi- mately 0.0045 mm/mm.When comparing the results of beams SO3-4 and SO3-2, the CFRP amount used to strengthen specimen SO3-4 was 250% of that used for specimen SO3-2. Only a 10% increase in shear capacity was achieved for the additional amount of CFRP used. This means that if an end anchor to control FRP debonding is not used, there is an optimum FRP quantity, beyond which the strengthening effect is questionable. A previous study [11] showed that by using an end anchor system, the failure mode of FRP debonding could be avoided. Reported findings are consistent with those of other research [7], which was based on a review of the experimental results available in the literature, and indicated that the contribution of FRP to the shear capacity increases almost linearly, with FRP axial rigidity expressed byf f E ρ(f ρ is the FRP area fraction and f E is the FRP elastic modulus) up to approximately 0.4 GPa. Beyond this value, the effectiveness of FRP ceases to be positive.In specimen SO3-5, the use of a horizontal ply over the continuous U-wrap (i.e. 90°/0°) resulted in a concrete splitting failure rather than a CFRP debonding failure. The failure occurred at total applied load of 339 kN with a 120% increase in the shear capacity compared to the control specimen SO3-1. The strengthening with two perpendicular plies (i.e. 90°/0°) resulted in a 17% increase in shear capacity compared to the specimen with only one CFRP ply in 90° orientation (i.e. specimen SO3-4). The maximum local CFRP vertical strain measured at failure was 0.0043 mm/mm.By comparing the test results of specimens SW3-2 and SO3-5, having the same a/d ratio and strengthening schemes but with different steel shear reinforcement, the shear strength (i.e. 177 and 169.5 kN for specimens SW3-2 and SO3-5, respectively), and the ductility are almost identical. One may conclude that the contribution of CFRP benefits the beam capacity to a greater degree for beams without steel shear reinforcement than for beams with adequate shear reinforcement.3.4. Series SO4Series SO4 exhibited the largest increase in shear capacity compared to the other series investigated with this research study. The experimental results in terms of applied load vs mid-span deflection for this series is illustrated in Fig. 11.The control specimen SO4-1 failed as a result of shear compression at a total applied load of 130 kN. Specimen SO4-2, strengthened with CFRP strips, the failure was controlled by CFRP debonding at a total load of 255 kN with 96% increase in shear capacity over the control specimen SO4-1. The maximum local CFRP vertical strain measured at failure was 0.0062mmymm.When comparing the test results of specimen SO4-2 to that of specimen SO3-2, the enhanced shear capacity of specimen SO4-2 (a/d=4) due to addition of CFRP strips was 62.5 kN, while specimen SO3-2 (a/d=3) resulted in added shear capacity of 54 kN. As expected, the contribution of CFRP reinforcement to resist the shear appeared to decrease with decreasing a/d ratio. Specimen SO4-3, strengthened with continuous U- wrap, failed as a result of concrete splitting at an applied load of 310 kN with a 138% increase in shear capacity compared to that of specimen SO4-1. The maximum local CFRP vertical strain measured at failure was 0.0037 mm/mm.4. Design approachThe design approach for computing the shear capacity of RC beams strengthened with externally bonded CFRP reinforcement, expressed in ACI design code [12] format, was proposed and published in 1998 [13]. The design model described two possible failure mechanisms of CFRP reinforcement namely: CFRP fracture; and CFRP debonding. Furthermore, two limits on the contribution of CFRP shear were proposed. The first limit was set to control the shear crack width and loss of aggregate interlock, and the second was to preclude web crushing. Also, the concrete strength and CFRP wrap- ping schemes were incorporated as design parameters. In recent study [9,10], modifications were proposed to the 1998 design approach toinclude results of a new study on bond mechanism between CFRP sheets and concrete surface [14]. In addition, the model was extended to provide the shear design equations in Eurocode as well as ACI format. Comparing with all test results available in the literature to date, 76 tests, the design approach showed acceptable and conservative estimates [10,13]. In this section, the summary of the design approach is presented. The comparison between experimental results and the calculated factored shear strength demonstrates the ability of the design approach to predict the shear capacity of the strengthened beams. demonstrates the ability of the design approach to predict the shear capacity of the strengthened beams.4.1. Summary of the shear design approach — ACI formatIn traditional shear design (including the ACI Code), the nominal shear strength of an RC section is the sum of the nominal shear strengths of concrete and steel shear reinforcement. For beams strengthened with externally bonded FRP reinforcement, the shear strength may be computed by the addition of a third term to account of the FRP contribution. This is expressed as follows:The design shear strength,n Vφ, is obtained by multiplying the nominal shear strength by a strength reduction factor for shear,φ. It was suggested that the reduction factor φ=0.85 given in ACI [12] be main-tained for the concrete and steel terms. However, a more stringent strength reduction factor of 0.7 for the CFRP contribution was suggested w10x. This is due to the relative novelty of this repair technique. Thus, the design shear strength is expressed as follows.4.2. Contribution of CFRP reinforcement to the shear capacityThe expression used to compute shear contribution of CFRP reinforcement is given in Eq. (3). This equation is similar to that for shear contribution of steel stirrups and consistent with the ACI format.The area of CFRP shear reinforcement,f A , is the total thickness of the sheet (usually f t 2or sheets on both sides of the beam) times the width of the CFRP stripf ω. The dimensions used to define the area of CFRP in addition to the spacingf s and the effective depth of CFRP,f d ， are shown in Fig. 12. Note that for continuousvertical shear reinforcement, the spacing of the strip,f s , and the width of the strip,f ω, are equal.In Eq. (3), an effective average CFRP stressfe f , smaller than its ultimate strength,fu f , was used to replace the yield stress of steel. At the ultimate limit state for the member in shear, it is not possible to attain the full strength of the FRP [7,13]. Failure is governed by either fracture of the FRP sheet at average stress levels well below FRP ultimate capacity due to stress concentrations, debonding of the FRP sheet from the concrete surface, or a significant decrease in the post- cracking concrete shear strength from a loss of aggregate interlock. Thus, the effective average CFRP stress is computed by applying a reduction coefficient, R, to the CFRP ultimate strength as expressed in Eq. (4).The reduction coefficient depends on the possible failure modes (either CFRPfracture or CFRP debonding). In either case, an upper limit for the reduction coefficient is established in order to control shear crack width and loss of aggregate interlock.4.3. Reduction coefficient based on CFRP sheet fracture failureThe proposed reduction coefficient was calibrated on all available test results to date, 22 tests with failure controlled by CFRP fracture [10，13]. The reduction coefficient was established as a function of f f E ρ (where f ρis the area fraction ofCFRP) and expressed in Eq.(5) for ≤f f E ρ0.7 GPa.4.4. Reduction coefficient based on CFRP debonding failureThe shear capacity governed by CFRP debonding from the concrete surface was presented [9,10]as a function of CFRP axial rigidity, concrete strength, effective depth of CFRP reinforcement, and bonded surface configurations. In determining the reduction coefficient for bond, the effective bond length, e L , has to be determined first. Based on analytical and experimental data from bond tests, Miller [14] showed that the effective bond length slightly increases as CFRP axial rigidity,f f E t , increases. However, he suggested a constant conservative value e L for equal to 75 mm. The value may be modified when more bond tests data becomes available.After a shear crack develops, only that portion of the width of CFRP extending past the crack by the effective bonded length is assumed to be capable of carrying shear.[13] The effective width, fe W , based on the shear crack angle of 45°, and the wrapping scheme is expressed in Eqs. (6a) and (6b);if the sheet in the form of a U-wrap (6a)if the sheet is bonded only to the sides of the beam. (6b)The final expression for the reduction coefficient, R, for the mode of failure controlled by CFRP debonding is expressed in Eq. (8)Eq. (7) is applicable for CFRP axial rigidity, f f E t , ranging from 20 to 90 mm-GPa (kN/mm). Research into quantifying the bond characteristics for axial rigidities above 90 mm·GPa is being conducted at the University of Missouri, Rolla (UMR).4.5. Upper limit of the reduction coefficientIn order to control the shear crack width and loss of aggregate interlock, an upper limit of reduction coefficient, R, was suggested and calibrated with all of the availabletest results [10] to be equal to fu ε/006.0where fu εis the ultimate tensile CFRP strain. This limit is such that the average effective strain in CFRP materials at ultimate can not be greater than 0.006 mm/mm (without the strengthening reduction factor,φ).4.6. Controlling reduction coefficientThe final controlling reduction coefficient for the CFRP system is taken as the lowest value determined from the two possible modes of failure and the upper limit. Note that if the sheet is wrapped entirely around the beam or an effective end anchor is used, the failure mode of CFRP debonding is not to be considered. The reduction coefficient is only controlled by FRP fracture and the upper limit.4.7. CFRP spacing requirementsSimilar to steel shear reinforcement, and consistent with ACI provision for the stirrups spacing[12], the spacing of FRP strips should not be so wide as to allow the formation of a diagonal crack without intercepting a strip. For this reason, if strips are used, they should not be spaced by more than the maximum given in Eq. (8).4.8. Limit on total shear reinforcementACI 318M-95 [12] 11.5.6.7 and 11.5.6.8 set a limit on the total shear strength that may be provided by more than one type of shear reinforcement to preclude the web crushing. FRP shear reinforcement should be included in this limit. A modification to ACI 318M-95 Section 11.5.6.8 was suggested as follows:4.9. Shear capacity of a CFRP strengthened section — Eurocode formatThe proposed design equation wEq. (3)x for computing the contribution of externally bonded CFRP reinforcement may be rewritten in Eurocode (EC2 1992) [15] format as Eq. (10).In this equation, the partial safety factor for CFRP materials,f , was suggestedequal to 1.3 [10].5. Conclusions and further recommendation An experimental investigation was conducted to study the shear behavior and the modes of failure of simply supported rectangular section RC beams with shear deficiencies, strengthened with CFRP sheets. The parameters investigated in this program were existence of steel shear reinforcement, shear span-to-effective depth ratio (ayd ratio), and CFRP amount and distribution.The results confirm that the strengthening technique using CFRP sheets can be used to increase significantly shear capacity, with efficiency that varies depending on the tested variables. For the beams tested in this program, increases in shear strength of 40–138% were achieved.Conclusions that emerged from this study may be summarized as follows:● The contribution of externally CFRP reinforcement to the shear capacity isinfluenced by the a/d ratio.● Increasing the amount of CFRP may not result in a proportional increase in theshear strength. The CFRP amount used to strengthen specimen SO3-4 was 250% of that used in specimen SO3-2, which resulted in a minimal (10%) increase in shear capacity. An end anchor is recommended if FRP debonding is to be avoided. ● The test results indicated that contribution of CFRP benefits the shear capacity ata greater degree for beams without shear reinforcement than for beams with adequate shear reinforcement.● The results of series SO3 indicated that the 0° ply improved the shear capacity byproviding horizontal restraint.● The shear design algorithms provided acceptable and conservative estimates forthe strengthened beams. Recommendations for future research are as follows:● Experimental and analytical investigations are required to link the shearcontribution of FRP with the load condition. These studies have to consider both the longitudinal steel reinforcement ratio and the concrete strength as parameters. Laboratory specimens should maintain practical dimensions.● The strengthening effectiveness of FRP has to be addressed in the cases of shortand very short shear spans in which arch action governs failure.● The interaction between the contribution of external FRP and internal steel shearreinforcement has to be investigated.● To optimize design algorithms, additional specimens need to be tested withdifferent CFRP amount and configurations to create a large database of information.● Shear design algorithms need to be expanded to include strengthening witharamid FRP and glass FRP sheets in addition to CFRP .6. NomenclatureA: Shear spanf A :Area of CFRP shear reinforcements=2t f w fw b : Width of the beam cross-sectionD: Depth from the top of the section to the tension steel reinforcement centroidf d :Effective depth of the CFRP shear reinforcement (usually equal to d for rectangular sections and dyts for T-sections)f E :Elastic modulus of FRP (GPa)'c f :Nominal concrete compressive strength (MPa)fef :Effective tensile stress in the FRP sheet in the direction of the principal fibers (stress level in the FRP at failure)fu f :Ultimate tensile strength of the FRP sheet in the direction of the principal fibers e L :Effective bond length (mm)。

土木工程外文翻译外文文献英文文献

一、外文原文Talling building and Steel construction Although there have been many advancements in building construction technology in general. Spectacular archievements have been made in the design and construction of ultrahigh-rise buildings.The early development of high-rise buildings began with structural steel framing.Reinforced concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes.The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structual systems.Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit.Excessive lateral sway may cause serious recurring damage to partitions,ceilings.and other architectural details. In addition,excessive sway may cause discomfort to the occupants of the building because their perception of such motion.Structural systems of reinforced concrete,as well as steel,take full advantage of inherent potential stiffness of the total building and therefore require additional stiffening to limit the sway.In a steel structure,for example,the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building.Curve A in Fig .1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B represents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.Structural engineers have developed structural systems with a view to eliminating this premium.Systems in steel. Tall buildings in steel developed as a result ofseveral types of structural innovations. The innovations have been applied to the construction of both office and apartment buildings.Frame with rigid belt trusses. In order to tie the exterior columns of a frame structure to the interior vertical trusses,a system of rigid belt trusses at mid-height and at the top of the building may be used. A good example of this system is the First Wisconsin Bank Building(1974) in Milwaukee.Framed tube. The maximum efficiency of the total structure of a tall building, for both strength and stiffness,to resist wind load can be achieved only if all column element can be connected to each other in such a way that the entire building acts as a hollow tube or rigid box in projecting out of the ground. This particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The most significant use of this system is in the twin structural steel towers of the 110-story World Trade Center building in New York Column-diagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with diagonal members interesting at the centre line of the columns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Centre in Chicago, using as much steel as is normally needed for a traditional 40-story building.Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the column-diagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The 110-story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept. The Sears tower, at a height of 1450 ft(442m), is the world’s tallest building.Stressed-skin tube system. The tube structural system was developed for improving the resistance to lateral forces (wind and earthquake) and thecontrol of drift (lateral building movement ) in high-rise building. The stressed-skin tube takes the tube system a step further. The development of the stressed-skin tube utilizes the façade of the building as a structural element which acts with the framed tube, thus providing an efficient way of resisting lateral loads in high-rise buildings, and resulting in cost-effective column-free interior space with a high ratio of net to gross floor area.Because of the contribution of the stressed-skin façade, the framed members of the tube require less mass, and are thus lighter and less expensive. All the typical columns and spandrel beams are standard rolled shapes,minimizing the use and cost of special built-up members. The depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which would encroach on valuable space, is minimized. The structural system has been used on the 54-story One Mellon Bank Center in Pittburgh.Systems in concrete. While tall buildings constructed of steel had an early start, development of tall buildings of reinforced concrete progressed at a fast enough rate to provide a competitive chanllenge to structural steel systems for both office and apartment buildings.Framed tube. As discussed above, the first framed tube concept for tall buildings was used for the 43-story DeWitt Chestnut Apartment Building. In this building ,exterior columns were spaced at 5.5ft (1.68m) centers, and interior columns were used as needed to support the 8-in . -thick (20-m) flat-plate concrete slabs.Tube in tube. Another system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system known as the tube-in-tube system , made it possible to design the world’s present tallest (714ft or 218m)lightweight concrete bu ilding( the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories.Systems combining both concrete and steel have also been developed, an examle of which is the composite system developed by skidmore, Owings &Merril in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The 52-story One Shell Square Building in New Orleans is based on this system.Steel construction refers to a broad range of building construction in which steel plays the leading role. Most steel construction consists of large-scale buildings or engineering works, with the steel generally in the form of beams, girders, bars, plates, and other members shaped through the hot-rolled process. Despite the increased use of other materials, steel construction remained a major outlet for the steel industries of the U.S, U.K, U.S.S.R, Japan, West German, France, and other steel producers in the 1970s.二、原文翻译高层结构与钢结构近年来，尽管一般的建筑结构设计取得了很大的进步，但是取得显著成绩的还要属超高层建筑结构设计。

土木工程专业钢筋混凝土结构设计毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土结构设计文献、资料英文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文参考资料及译文译文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and thestress of steel bars will increase . When the steel approaches the yielding stress ƒy , thedeflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large cross sections .As concrete has high modulus of elasticity, reinforced concrete structures are usuallystiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(b)Reinfoced concrete beam(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures are cheaper.(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforcedconcrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressed concrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid。

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

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

土木工程混凝土论文中英文资料外文翻译文献

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

土木工程专业毕业设计外文文献翻译2篇

土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。

土木工程英语文献原文及中文翻译

Civil engineering introduction papers[英语原文]Abstract: the civil engineering is a huge discipline, but the main one is building, building whether in China or abroad, has a long history, long-term development process. The world is changing every day, but the building also along with the progress of science and development. Mechanics findings, material of update, ever more scientific technology into the building. But before a room with a tile to cover the top of the house, now for comfort, different ideas, different scientific, promoted the development of civil engineering, making it more perfect.[key words] : civil engineering; Architecture; Mechanics, Materials.Civil engineering is build various projects collectively. It was meant to be and "military project" corresponding. In English the history of Civil Engineering, mechanical Engineering, electrical Engineering, chemical Engineering belong to to Engineering, because they all have MinYongXing. Later, as the project development of science and technology, mechanical, electrical, chemical has gradually formed independent scientific, to Engineering became Civil Engineering of specialized nouns. So far, in English, to Engineering include water conservancy project, port Engineering, While in our country, water conservancy projects and port projects also become very close and civil engineering relatively independent branch. Civil engineering construction of object, both refers to that built on the ground, underground water engineering facilities, also refers to applied materials equipment and conduct of the investigation, design and construction, maintenance, repair and other professional technology.Civil engineering is a kind of with people's food, clothing, shelter and transportation has close relation of the project. Among them with "live" relationship is directly. Because, to solve the "live" problem must build various types of buildings. To solve the "line, food and clothes" problem both direct side, but also a indirect side. "Line", must build railways, roads, Bridges, "Feed", must be well drilling water, water conservancy, farm irrigation, drainage water supply for the city, that is direct relation. Indirectly relationship is no matter what you do, manufacturing cars, ships, or spinning and weaving, clothing, or even production steel, launch satellites, conducting scientific research activities are inseparable from build various buildings, structures and build all kinds of project facilities.Civil engineering with the progress of human society and development, yet has evolved into large-scale comprehensive discipline, it has out many branch, such as: architectural engineering, the railway engineering, road engineering, bridge engineering, special engineering structure, waterand wastewater engineering, port engineering, hydraulic engineering, environment engineering disciplines. [1]Civil engineering as an important basic disciplines, and has its important attributes of: integrated, sociality, practicality, unity. Civil engineering for the development of national economy and the improvement of people's life provides an important material and technical basis, for many industrial invigoration played a role in promoting, engineering construction is the formation of a fixed asset basic production process, therefore, construction and real estate become in many countries and regions, economic powerhouses.Construction project is housing planning, survey, design, construction of the floorboard. Purpose is for human life and production provide places.Houses will be like a man, it's like a man's life planning environment is responsible by the planners, Its layout and artistic processing, corresponding to the body shape looks and temperament, is responsible by the architect, Its structure is like a person's bones and life expectancy, the structural engineer is responsible, Its water, heating ventilation and electrical facilities such as the human organ and the nerve, is by the equipment engineer is responsible for. Also like nature intact shaped like people, in the city I district planning based on build houses, and is the construction unit, reconnaissance unit, design unit of various design engineers and construction units comprehensive coordination and cooperation process.After all, but is structural stress body reaction force and the internal stress and how external force balance. Building to tackle, also must solve the problem is mechanical problems. We have to solve the problem of discipline called architectural mechanics. Architectural mechanics have can be divided into: statics, material mechanics and structural mechanics three mechanical system. Architectural mechanics is discussion and research building structure and component in load and other factors affecting the working condition of, also is the building of intensity, stiffness and stability. In load, bear load and load of structure and component can cause the surrounding objects in their function, and the object itself by the load effect and deformation, and there is the possibility of damage, but the structure itself has certain resistance to deformation and destruction of competence, and the bearing capacity of the structure size is and component of materials, cross section, and the structural properties of geometry size, working conditions and structure circumstance relevant. While these relationships can be improved by mechanics formula solved through calculation.Building materials in building and has a pivotal role. Building material is with human society productivity and science and technologyimproves gradually developed. In ancient times, the human lives, the line USES is the rocks andTrees. The 4th century BC, 12 ~ has created a tile and brick, humans are only useful synthetic materials made of housing. The 17th century had cast iron and ShouTie later, until the eighteenth century had Portland cement, just make later reinforced concrete engineering get vigorous development. Now all sorts of high-strength structural materials, new decoration materials and waterproof material development, criterion and 20th century since mid organic polymer materials in civil engineering are closely related to the widely application. In all materials, the most main and most popular is steel, concrete, lumber, masonry. In recent years, by using two kinds of material advantage, will make them together, the combination of structure was developed. Now, architecture, engineering quality fit and unfit quality usually adopted materials quality, performance and using reasonable or not have direct connection, in meet the same technical indicators and quality requirements, under the precondition of choice of different material is different, use method of engineering cost has direct impact.In construction process, building construction is and architectural mechanics, building materials also important links. Construction is to the mind of the designer, intention and idea into realistic process, from the ancient hole JuChao place to now skyscrapers, from rural to urban country road elevated road all need through "construction" means. A construction project, including many jobs such as dredging engineering, deep foundation pit bracing engineering, foundation engineering, reinforced concrete structure engineering, structural lifting project, waterproofing, decorate projects, each type of project has its own rules, all need according to different construction object and construction environment conditions using relevant construction technology, in work-site.whenever while, need and the relevant hydropower and other equipment composition of a whole, each project between reasonable organizing and coordination, better play investment benefit. Civil engineering construction in the benefit, while also issued by the state in strict accordance with the relevant construction technology standard, thus further enhance China's construction level to ensure construction quality, reduce the cost for the project.Any building built on the surface of the earth all strata, building weight eventually to stratum, have to bear. Formation Support building the rocks were referred to as foundation, and the buildings on the ground and under the upper structure of self-respect and liable to load transfer to the foundation of components or component called foundation. Foundation, and the foundation and the superstructure is a building of three inseparable part. According to the function is different, but in load, under the action of them are related to each other, is theinteraction of the whole. Foundation can be divided into natural foundation and artificial foundation, basic according to the buried depth is divided into deep foundation and shallow foundation. , foundation and foundation is the guarantee of the quality of the buildings and normal use close button, where buildings foundation in building under loads of both must maintain overall stability and if the settlement of foundation produce in building scope permitted inside, and foundation itself should have sufficient strength, stiffness and durability, also consider repair methods and the necessary foundation soil retaining retaining water and relevant measures. [3]As people living standard rise ceaselessly, the people to their place of building space has become not only from the number, and put forward higher requirement from quality are put car higher demands that the environment is beautiful, have certain comfort. This needs to decorate a building to be necessary. If architecture major engineering constitutes the skeleton of the building, then after adornment building has become the flesh-and-blood organism, final with rich, perfect appearance in people's in front, the best architecture should fully embody all sorts of adornment material related properties, with existing construction technology, the most effective gimmick, to achieve conception must express effect. Building outfit fix to consider the architectural space use requirement, protect the subject institutions from damage, give a person with beautifulenjoying, satisfy the requirements of fire evacuation, decorative materials and scheme of rationality, construction technology and economic feasibility, etc. Housing construction development and at the same time, like housing construction as affecting people life of roads, Bridges, tunnels has made great progress.In general civil engineering is one of the oldest subjects, it has made great achievements, the future of the civil engineering will occupy in people's life more important position. The environment worsening population increase, people to fight for survival, to strive for a more comfortable living environment, and will pay more attention to civil engineering. In the near future, some major projects extimated to build, insert roller skyscrapers, across the oceanBridges, more convenient traffic would not dream. The development of science and technology, and the earth is deteriorating environment will be prompted civil engineering to aerospace and Marine development, provide mankind broader space of living. In recent years, engineering materials mainly is reinforced concrete, lumber and brick materials, in the future, the traditional materials will be improved, more suitable for some new building materials market, especially the chemistry materials will promote the construction of towards a higher point. Meanwhile, design method of precision, design work of automation, information and intelligent technology of introducing, will be people have a morecomfortable living environment. The word, and the development of the theory and new materials, the emergence of the application of computer, high-tech introduction to wait to will make civil engineering have a new leap.This is a door needs calm and a great deal of patience and attentive professional. Because hundreds of thousands, even hundreds of thousands of lines to building each place structure clearly reflected. Without a gentle state of mind, do what thing just floating on the surface, to any a building structure, to be engaged in business and could not have had a clear, accurate and profound understanding of, the nature is no good. In this business, probably not burn the midnight oil of courage, not to reach the goal of spirit not to give up, will only be companies eliminated.This is a responsible and caring industry. Should have a single responsible heart - I one's life in my hand, thousands of life in my hand. Since the civil, should choose dependably shoulder the responsibility.Finally, this is a constant pursuit of perfect industry. Pyramid, spectacular now: The Great Wall, the majestic... But if no generations of the pursuit of today, we may also use the sort of the oldest way to build this same architecture. Design a building structure is numerous, but this is all experienced centuries of clarification, through continuous accumulation, keep improving, innovation obtained. And such pursuit, not confined in the past. Just think, if the design of a building can be like calculation one plus one equals two as simple and easy to grasp, that was not for what? Therefore, a civil engineer is in constant of in formation. One of the most simple structure, the least cost, the biggest function. Choose civil, choosing a steadfast diligence, innovation, pursuit of perfect path.Reference:[1] LuoFuWu editor. Civil engineering (professional). Introduction to wuhan. Wuhan university of technology press. 2007[2] WangFuChuan, palace rice expensive editor. Construction engineering materials. Beijing. Science and technology literature press. 2002[3] jiang see whales, zhiming editor. Civil engineering introduction of higher education press. Beijing.. 1992土木工程概论 [译文]摘要：土木工程是个庞大的学科，但最主要的是建筑，建筑无论是在中国还是在国外，都有着悠久的历史，长期的发展历程。

土木工程专业毕业设计外文文献及翻译

英文原文：Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP compositesAhmed Khalifa a,＊, Antonio Nanni ba Department of Structural Engineering，University of Alexandria，Alexandria 21544，Egyptb Department of Civil Engineering，University of Missouri at Rolla，Rolla，MO 65409，USAReceived 28 April 1999；received in revised form 30 October 2001；accepted 10 January 2002AbstractThe present study examines the shear performance and modes of failure of rectangular simply supported reinforced concrete(RC) beams designed with shear deficiencies。

These members were strengthened with externally bonded carbon fiber reinforced polymer （CFRP）sheets and evaluated in the laboratory. The experimental program consisted of twelve full—scale RC beams tested to fail in shear. The variables investigated within this program included steel stirrups, and the shear span-to—effective depth ratio, as well as amount and distribution of CFRP。

土木工程建筑外文文献及翻译

土木工程建筑外文文献及翻译土木工程建筑外文文献及翻译Cyclic behavior of steel moment frame connections under varying axial load and lateral displacementsAbstractThis paper discusses the cyclic behavior of four steel moment connections tested under variable axial load and lateral displacements. The beam specim- ens consisted of a reducedbeam section, wing plates and longitudinal stiffeners. The test specimens were subjected to varying axial forces and lateral displace- ments to simulate the effects on beams in a Coupled-Girder Moment-Resisting Framing system under lateral loading. The test results showed that the specim- ens responded in a ductile manner since the plastic rotations exceeded 0.03 rad without significant drop in the lateral capacity. The presence of the longitudin- al stiffener assisted in transferring the axial forces and delayed the formation of web local buckling.1. IntroductionAimed at evaluating the structural performance of reduced-beam section(RBS) connections under alternated axial loading and lateral displacement, four full-scale specimens were tested. These tests were intended to assess the performance of the moment connection design for the Moscone Center Exp- ansion under the Design Basis Earthquake (DBE) and the Maximum Considered Earthquake (MCE). Previous research conducted on RBS moment connections [1,2] showed that connections with RBS profiles can achieve rotations in excess of 0.03 rad. However, doubts have been cast on the quality of the seismic performance of theseconnections under combined axial and lateral loading.The Moscone Center Expansion is a three-story, 71,814 m2 (773,000 ft2) structure with steel moment frames as its primary lateral force-resisting system. A three dimensional perspective illustration is shown in Fig. 1. The overall height of the building, at the highest point of the exhibition roof, is approxima- tely 35.36 m (116ft) above ground level. The ceiling height at the exhibition hall is 8.23 m (27 ft) , and the typical floor-to-floor height in the building is 11.43 m (37.5 ft). The building was designed as type I according to the requi- rements of the 1997 Uniform Building Code. The framing system consists of four moment frames in the East–West direct- ion, one on either side of the stair towers, and four frames in the North–South direction, one on either side of the stair and elevator cores in the east end and two at the west end of the structure [4]. Because of the story height, the con- cept of the Coupled-Girder Moment-Resisting Framing System (CGMRFS) was utilized.By coupling the girders, the lateral load-resisting behavior of the moment framing system changes to one where structural overturning moments are resisted partially by an axial compression–tension couple across the girder system, rather than only by the individual flexural action of the girders. As a result, a stiffer lateral load resisting system is achieved. The vertical element that connects the girders is referred to as a coupling link. Coupling links are analogous to and serve the same structural role as link beams in eccentrically braced frames. Coupling links are generally quite short, having a large shear- to-moment ratio.Under earthquake-type loading, the CGMRFS subjects its girders to wariab- ble axial forces in addition to their endmoments. The axial forces in theFig. 1. Moscone Center Expansion Project in San Francisco, CAgirders result from the accumulated shear in the link.2. Analytical model of CGMRFNonlinear static pushover analysis was conducted on a typical one-bay model of the CGMRF. Fig. 2 shows the dimensions and the various sections of the 10 in) and the ?254 mm (1 1/8 in ?model. The link flange plates were 28.5 mm 18 3/4 in). The SAP 2000 computer ?476 mm (3 /8 in ?web plate was 9.5 mm program was utilized in the pushover analysis [5]. The frame was characterized as fully restrained(FR). FR moment frames are those frames for 1170 which no more than 5% of the lateral deflections arise from connection deformation [6]. The 5% value refers only to deflection due to beam–column deformation and not to frame deflections that result from column panel zone deformation [6, 9].The analysis was performed using an expected value of the yield stress and ultimate strength. These values were equal to 372 MPa (54 ksi) and 518 MPa (75 ksi), respective ly. The plastic hinges’ load–deformation behavior was approximated by the generalized curve suggested by NEHRP Guidelines for the Seismic Rehab ilitation of Buildings [6] as shown in Fig. 3. △y was calcu- lated based on Eqs. (5.1) and (5.2) from [6], as follows: P–M hinge load–deformation model points C, D and E are based on Table 5.4 from [6] for△y was taken as 0.01 rad per Note 3 in [6], Table 5.8. Shear hinge load- load–deformation model points C, D and E are based on Table 5.8 [6], Link Beam, Item a. A strain hardening slope between points B and C of 3% of the elastic slope was assumedfor both models.The following relationship was used to account for moment–axial load interaction [6]:where MCE is the expected moment strength, ZRBS is the RBS plastic section modulus (in3), is the expected yield strength of the material (ksi), P is the axial force in the girder (kips) and is the expected axial yield force of the RBS, equal to (kips). The ultimate flexural capacities of the beam and the link of the model are shown in Table 1.Fig. 4 shows qualitatively the distribution of the bending moment, shear force, and axial force in the CGMRF under lateral load. The shear and axial force in the beams are less significant to the response of the beams as compared with the bending moment, although they must be considered in design. The qualita- tive distribution of internal forces illustrated in Fig. 5 is fundamentally the same for both elastic and inelastic ranges of behavior. The specific values of the internal forces will change as elements of the frame yield and internal for- ces are redistributed. The basic patterns illustrated in Fig. 5, however, remain the same.Inelastic static pushover analysis was carried out by applying monotonically increasing lateral displacements, at the top of both columns, as shown in Fig. 6. After the four RBS have yielded simultaneously, a uniform yielding in the web and at the ends of the flanges of the vertical link will form. This is the yield mechanism for the frame , with plastic hinges also forming at the base of the columns if they are fixed. The base shear versus drift angle of the model is shown in Fig. 7 . The sequence of inelastic activity in the frame is shown on the figure. An elastic component, a long transition (consequence of the beam plastic hinges being formed simultaneously) and a narrow yield plateaucharacterize the pushover curve.The plastic rotation capacity, qp, is defined as the total plastic rotation beyond which the connection strength starts to degrade below 80% [7]. This definition is different from that outlined in Section 9 (Appendix S) of the AISC Seismic Provisions [8, 10]. Using Eq. (2) derived by Uang and Fan [7], an estimate of the RBS plastic rotation capacity was found to be 0.037 rad:Fyf was substituted for Ry?Fy [8], where Ry is used to account for the differ- ence between the nominal and the expected yield strengths (Grade 50 steel, Fy=345 MPa and Ry =1.1 are used).3. Experimental programThe experimental set-up for studying the behavior of a connection was based on Fig. 6(a). Using the plastic displacement dp, plastic rotation gp, and plastic story drift angle qp shown in the figure, from geometry, it follows that:And:in which d and g include the elastic components. Approximations as above are used for large inelastic beam deformations. The diagram in Fig. 6(a) suggest that a sub assemblage with displacements controlled in the manner shown in Fig. 6(b) can represent the inelastic behavior of a typical beam in a CGMRF.The test set-up shown in Fig. 8 was constructed to develop the mechanism shown in Fig. 6(a) and (b). The axial actuators were attached to three 2438 mm × 1219 mm ×1219 mm (8 ft × 4 ft × 4 ft) RC blocks. These blocks were tensioned to the laboratory floor by means of twenty-four 32 mm diameter dywidag rods. This arrangement permitted replacement of the specimen after each test.Therefore, the force applied by the axial actuator, P, can beresolved into two or thogonal components, Paxial and Plateral. Since the inclination angle of the axial actuator does not exceed , therefore Paxial is approximately equal to P [4]. However, the lateral 3.0 component, Plateral, causes an additional moment at the beam-to column joint. If the axial actuators compress the specimen, then the lateral components will be adding to the lateral actuator forces, while if the axial actuators pull the specimen, the Plateral will be an opposing force to the lateral actuators. When the axial actuators undergoaxial actuators undergo a lateral displacement _, they cause an additional moment at the beam-to-column joint (P-△effect). Therefore, the moment at the beam-to column joint is equal to: where H is the lateral forces, L is the arm, P is the axial force and _ is the lateral displacement.Four full-scale experiments of beam column connections were conducted.The member sizes and the results of tensile coupon tests are listed in Table 2All of the columns and beams were of A572 Grade 50 steel (Fy 344.5 MPa). The actual measured beam flange yield stress value was equal to 372 MPa (54 ksi), while the ultimate strength ranged from 502 MPa (72.8 ksi) to 543 MPa (78.7 ksi).Table 3 shows the values of the plastic moment for each specimen (based on measured tensile coupon data) at the full cross-section and at the reduced section at mid-length of the RBS cutout.The specimens were designated as specimen 1 through specimen 4. Test specimens details are shown in Fig. 9 through Fig. 12. The following features were utilized in the design of the beam–column connection:The use of RBS in beam flanges. A circular cutout was provided, as illustr- ated in Figs. 11 and 12. For all specimens, 30% of the beam flange width was removed. The cuts were made carefully, and then ground smooth in a direct- tion parallel to the beam flange to minimize notches.Use of a fully welded web connection. The connection between the beam web and the column flange was made with a complete joint penetration groove weld (CJP). All CJP welds were performed according to AWS D1.1 Structural Welding Code Use of two side plates welded with CJP to exterior sides of top and bottom beam flan- ges, from the face of the column flange to the beginning of the RBS, as shown in Figs. 11 and 12. The end of the side plate was smoothed to meet the beginning of the RBS. The side plates were welded with CJP with the column flanges. The side plate was added to increase the flexural capacity at the joint location, while the smooth transition was to reduce the stress raisers, which may initiate fractureTwo longitudinal stiffeners, 95 mm × 35 mm (3 3/4 in × 1 3/8 in), were welded with 12.7 mm (1/2 in) fillet weld at the middle height of the web as shown in Figs. 9 and 10. The stiffeners were welded with CJP to column flanges.Removal of weld tabs at both the top and bottom beam flange groove welds. The weld tabs were removed to eliminate any potential notches introduced by the tabs or by weld discontinuities in the groove weld run out regionsUse of continuity plates with a thickness approximately equal to the beam flange thickness. One-inch thick continuity plates were used for all specimens.While the RBS is the most distinguishing feature of these test specimens, the longitudinal stiffener played an important role indelaying the formation of web local buckling and developing reliable connection4. Loading historySpecimens were tested by applying cycles of alternated load with tip displacement increments of _y as shown in Table 4. The tip displacement of the beam was imposed by servo-controlled actuators 3 and 4. When the axial force was to be applied, actuators 1 and 2 were activated such that its force simulates the shear force in the link to be transferred to the beam. 0.5_y. After The variable axial force was increased up to 2800 kN (630 kip) at that, this lo- ad was maintained constant through the maximum lateral displacement.maximum lateral displacement. As the specimen was pushed back the axialforce remained constant until 0.5 y and then started to decrease to zero as the specimen passed through the neutral position [4]. According to the upper bound for beam axial force as discussed in Section 2 of this paper, it was concluded that P =2800 kN (630 kip) is appropriate to investigate this case in RBS loading. The tests were continued until failure of the specimen, or until limitations of the test set-up were reached.5. Test resultsThe hysteretic response of each specimen is shown in Fig. 13 and Fig. 16. These plots show beam moment versus plastic rotation. The beam moment is measured at the middle of the RBS, and was computed by taking an equiva- lent beam-tip force multiplied by the distance between the centerline of the lateral actuator to the middle of the RBS (1792 mm for specimens 1 and 2, 3972 mm for specimens 3 and 4). The equivalent lateral force accounts for the additional moment due to P–△effect. Therotation angle was defined as the lateral displacement of the actuator divided by the length between the centerline of the lateral actuator to the mid length of the RBS. The plastic rotation was computed as follows [4]:where V is the shear force, Ke is the ratio of V/q in the elastic range. Measurements and observations made during the tests indicated that all of the plastic rotation in specimen 1 to specimen 4 was developed within the beam. The connection panel zone and the column remained elastic as intended by design.5.1. Specimens 1 and 2The responses of specimens 1 and 2 are shown in Fig. 13. Initial yielding occurred during cycles 7 and 8 at 1_y with yielding observed in the bottom flange. For all test specimens, initial yielding was observed at this location and attributed to the moment at the base of the specimen [4]. Progressing through the loading history, yielding started to propagate along the RBS bottom flange. During cycle 3.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 5_y with the increased axial compression load to 3115 KN (700 kips) a severe web buckle developed along with flange local buckling. The flange and the web local buckling became more pronounced with each successive loading cycle. It should be noted here that the bottom flange and web local buckling was not accompanied by a significant deterioration in the hysteresis loops.A crack developed in specimen 1 bottom flange at the end of the RBS where it meets the side plate during the cycle 5.75_y. Upon progressing through the loading history, 7_y, the crackspread rapidly across the entire width of the bottom flange. Once the bottom flange was completely fractured, the web began to fracture. This fracture appeared to initiate at the end of the RBS，then propagated through the web net section of the shear tab, through the middle stiffener and the through the web net section on the other side of the stiffener. The maximum bending moment achieved on specimen 1 during theDuring the cycle 6.5 y, specimen 2 also showed a crack in the bottom flange at the end of the RBS where it meets the wing plate. Upon progressing thou- gh the loading history, 15 y, the crack spread slowly across the bottom flan- ge. Specimen 2 test was stopped at this point because the limitation of the test set-up was reached.The maximum force applied to specimens 1 and 2 was 890 kN (200 kip). The kink that is seen in the positive quadrant is due to the application of the varying axial tension force. The load-carrying capacity in this zone did not deteriorate as evidenced with the positive slope of the force–displacement curve. However, the load-carrying capacity deteriorated slightly in the neg- ative zone due to the web and the flange local buckling.Photographs of specimen 1 during the test are shown in Figs.14 and 15. Severe local buckling occurred in the bottom flange and portion of the web next to the bottom flange as shown in Fig. 14. The length of this buckle extended over the entire length of the RBS. Plastic hinges developed in the RBS with extensive yielding occurring in the beam flanges as well as the web. Fig. 15 shows the crack that initiated along the transition of the RBS to the side wing plate. Ultimate fracture of specimen 1 was caused by a fracture in the bottom flange. This fracture resulted in almost total loss of the beam- carrying capacity. Specimen 1 developed0.05 rad of plastic rotation and showed no sign of distress at the face of the column as shown in Fig. 15.5.2. Specimens 3 and 4The response of specimens 3 and 4 is shown in Fig. 16. Initial yielding occured during cycles 7 and 8 at 1_y with significant yielding observed in the bottom flange. Progressing through the loading history, yielding started to propagate along the bottom flange on the RBS. During cycle 1.5_y initiation of web buckling was noted adjacent to the yielded bottom flange. Yielding started to propagate along the top flange of the RBS and some minor yielding along the middle stiffener. During the cycle of 3.5_y a severe web buckle developed along with flange local buckling. The flange and the web local buckling bec- ame more pronounced with each successive loading cycle.During the cycle 4.5 y, the axial load was increased to 3115 KN (700 kips) causing yielding to propagate to middle transverse stiffener. Progressing through the loading history, the flange and the web local buckling became more severe. For both specimens, testing was stopped at this point due to limitations in the test set-up. No failures occurred in specimens 3 and 4. However, upon removing specimen 3 to outside the laboratory a hairline crack was observed at the CJP weld of the bottom flange to the column.The maximum forces applied to specimens 3 and 4 were 890 kN (200 kip) and 912 kN (205 kip). The load-carrying capacity deteriorated by 20% at the end of the tests for negative cycles due to the web and the flange local buckling. This gradual reduction started after about 0.015 to 0.02 rad of plastic rotation. The load-carrying capacity during positive cycles (axial tension applied in the girder) did not deteriorate as evidenced with the slope of the force–displacement envelope for specimen 3 shownin Fig. 17.A photograph of specimen 3 before testing is shown in Fig.18. Fig. 19 is aFig. 16. Hysteretic behavior of specimens 3 and 4 in terms of moment at middle RBS versus beam plastic rotation.photograph of specimen 4 taken after the application of 0.014 rad displacem- ent cycles, showing yielding and local buckling at the hinge region. The beam web yielded over its full depth. The most intense yielding was observed in the web bottom portion, between the bottom flange and the middle stiffener. The web top portion also showed yielding, although less severe than within the bottom portion. Yielding was observed in the longitudinal stiffener. No yiel- ding was observed in the web of the column in the joint panel zone. The un- reduced portion of the beam flanges near the face of the column did not show yielding either. The maximum displacement applied was 174 mm, and the maximum moment at the middle of the RBS was 1.51 times the plastic mom ent capacity of the beam. The plastic hinge rotation reached was about 0.032 rad (the hinge is located at a distance 0.54d from the column surface,where d is the depth of the beam).5.2.1. Strain distribution around connectionThe strain distribution across the flanges–outer surface of specimen 3 is shown in Figs. 20 and 21. The readings and the distributions of the strains in specimens 1, 2 and 4 (not presented) showed a similar trend. Also the seque- nce of yielding in these specimens is similar to specimen 3.The strain at 51 mm from the column in the top flange–outer surface remained below 0.2% during negative cycles. The top flange, at the same location, yielded in compression only Thelongitudinal strains along the centerline of the bottom–flange outer face are shown in Figs. 22 and 23 for positive and negative cycles, respectively. From Fig.23, it is found that the strain on the RBS becomes several times larg- er than that near the column after cycles at –1.5_y; this is responsible for theflange local buckling. Bottom flange local buckling occurred when the average strain in the plate reached the strain-hardening value (esh _ 0.018) and the reduced-beam portion of the plate was fully yielded under longitudinal stresses and permitted the development of a full buckled wave.5.2.2. Cumulative energy dissipatedThe cumulative energy dissipated by the specimens is shown in Fig. 24. The cumulative energy dissipated was calculated as the sum of the areas enclosed the lateral load–lateral displacement hysteresis loops. Energy dissipation sta- rted to increase after cycle 12 at 2.5 y (Fig. 19). At large drift levels, energy dissipation augments significantly with small changes in drift. Specimen 2 dissipated more energy than specimen 1, which fractured at RBS transition. However, for both specimens the trend is similar up to cycles at q =0.04 radIn general, the dissipated energy during negative cycles was1.55 times bigger than that for positive cycles in specimens 1 and2. For specimens 3 and 4 the dissipated energy during negative cycles was 120%, on the average, that of the positive cycles. The combined phenomena of yielding, strain hardening, in-plane and out- of-plane deformations, and local distortion all occurred soon after the bottom flange RBS yielded.6. ConclusionsBased on the observations made during the tests, and on the analysis of the instrumentation, the following conclusions weredeveloped:1. The plastic rotation exceeded the 3% radians in all test specimens.2. Plastification of RBS developed in a stable manner.3. The overstrength ratios for the flexural strength of the test specimens were equal to 1.56 for specimen 1 and 1.51 for specimen4. The flexural strength capacity was based on the nominal yield strength and on the FEMA-273 beam–column equation.4. The plastic local buckling of the bottom flange and the web was not accompanied by a significant deterioration in the load-carrying capacity.5. Although flange local buckling did not cause an immediate degradation of strength, it did induce web local buckling.6. The longitudinal stiffener added in the middle of the beam web assisted in transferring the axial forces and in delaying the formation of web local buckling. How ever, this has caused a much higher overstrength ratio, which had a significant impact on the capacity design of the welded joints, panel zone and the column.7. A gradual strength reduction occurred after 0.015 to 0.02 rad of plastic rotation during negative cycles. No strength degradation was observed during positive cycles.8. Compression axial load under 0.0325Py does not affect substantially the connection deformation capacity.9. CGMRFS with properly designed and detailed RBS connections is a reliable system to resist earthquakes.AcknowledgementsStructural Design Engineers, Inc. of San Francisco financially supported the experimental program. The tests were performedin the Large Scale Structures Laboratory of the University of Nevada, Reno. The participation of Elizabeth Ware, Adrianne Dietrich and of the technical staff is gratefully acknowledged.References受弯钢框架结点在变化轴向荷载和侧向位移的作用下的周期性行为摘要这篇论文讨论的是在变化的轴向荷载和侧向位移的作用下，接受测试的四种受弯钢结点的周期性行为。

土木工程专业外文翻译--钢筋混凝土结构设计

外文原文：Design of Reinforced Concrete StructuresSecond Edition(USA) Williams·Alan2Structure in Design of Architecture And StructuralMaterial，China Water Power Press，Beijing,2002. P37～57钢筋混凝土结构设计第二版(美)艾伦·威廉斯著第二章，在建筑学的设计构成和结构的材料，中国水利水电出版社，北京,2002.P37页～57页.Structure in Design of Architecture And Structural Material We have and the architects must deal with the spatial aspect of activity, physical, and symbolic needs in such a way that overall performance integrity is assured. Hence, he or she well wants to think of evolving a building environment as a total system of interacting and space forming subsystems. Is represents a complex challenge, and to meet it the architect will need a hierarchic design process that provides at least three levels of feedback thinking: schematic, preliminary, and final.Such a hierarchy is necessary if he or she is to avoid being confused , atconceptual stages of design thinking ,by the myriad detail issues that candistract attention from more basic considerations .In fact , we can say thatan architect’s ability to distinguish the more basic form the more detailedissues is essential to his success as a designer .The object of the schematic feed back level is to generate and evaluate overallsite-plan, activity-interaction, and building-configuration options .To do sothe architect must be able to focus on the interaction of the basic attributes of the site context, the spatial organization, and the symbolism as determinants of physical form. This means that ,in schematic terms ,the architect may first conceive and model a building design as an organizational abstraction of essential performance-space in teractions.Then he or she may explore the overall space-form implications of the abstraction. As an actual building configuration option begins to emerge, it will be modified to include consideration for basic site conditions.At the schematic stage, it would also be helpful if the designer could visualize his or her options for achieving overall structural integrity and consider the constructive feasibility and economic of his or her scheme .But this will require that the architect and/or a consultant be able to conceptualize total-system structural options in terms of elemental detail .Such overall thinking can be easily fed back to improve the space-form scheme.At the preliminary level, the architect’s emphasis will shift to the elaboration of his or her more promising schematic design options .Here the architect’s structural needs will shift to approximate design of specific subsystem options. At this stage the total structural scheme is developed to a middle level of specificity by focusing on identification and design of major subsystems to the extent that their key geometric, component, and interactive properties are established .Basic subsystem interaction and design conflicts can thus be identified and resolved in the context of total-system objectives. Consultants can play a significant part in this effort; these preliminary-level decisions may also result in feedback that calls for refinement or even major change in schematic concepts.When the designer and the client are satisfied with the feasibility of a design proposal at the preliminary level, it means that the basic problems of overall design are solved and details are not likely to produce major change .The focus shifts again ,and the design process moves into the final level .At this stagethe emphasis will be on the detailed development of all subsystem specifics . Here the role of specialists from various fields, including structural engineering, is much larger, since all detail of the preliminary design must be worked out. Decisions made at this level may produce feedback into Level II that will result in changes. However, if Levels I and II are handled with insight, the relationship between the overall decisions, made at the schematic and preliminary levels, and the specifics of the final level should be such that gross redesign is not in question, Rather, the entire process should be one of moving in an evolutionary fashion from creation and refinement (or modification) of the more general properties of a total-system design concept, to the fleshing out of requisite elements and details.To summarize: At Level I, the architect must first establish, in conceptual terms, the overall space-form feasibility of basic schematic options. At this stage, collaboration with specialists can be helpful, but only if in the form of overall thinking. At Level II, the architect must be able to identify the major subsystem requirements implied by the scheme and substantial their interactive feasibility by approximating key component properties .That is, the properties of major subsystems need be worked out only in sufficient depth to very the inherent compatibility of their basic form-related and behavioral interaction . This will mean a somewhat more specific form of collaboration with specialists then that in level I .At level III ,the architect and the specific form of collaboration with specialists then that providing for all of the elemental design specifics required to produce biddable construction documents . Of course this success comes from the development of the Structural Material. The principal construction materials of earlier times were wood and masonry brick, stone, or tile, and similar materials. The courses or layers were bound together with mortar or bitumen, a tar like substance, or some other binding agent. The Greeks and Romans sometimes used iron rods or claps to strengthen their building. The columns of the Parthenon in Athens, for example, have holes drilled in themfor iron bars that have now rusted away. The Romans also used a natural cement called puzzling, made from volcanic ash, that became as hard as stone under water. Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. Steel, basically an alloy of iron and a small amount of carbon had been made up to that time by a laborious process that restricted it to such special uses as sword blades. After the invention of the Bessemer process in 1856, steel was available in large quantities at low prices. The enormous advantage of steel is its tensile force which, as we have seen, tends to pull apart many materials. New alloys have further, which is a tendency for it to weaken as a result of continual changes in stress.Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone and clay, which is heated and then ground into a power. It is mixed at or near the construction site with sand, aggregate small stones, crushed rock, or gravel, and water to make concrete. Different proportions of the ingredients produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, the two substances complement each other.They also complement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tensions will develop. Concrete and steel also form such a strong bond─ the force that unites them─ that the steel cannot slip within the concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid. The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices. It was no longer necessary to use thickwalls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors. Both these changes served to reduce the cost of construction. It also became possible to erect buildings with greater heights and longer spans.Since the weight of modern structures is carried by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.Another advance in steel construction is the method of fastening together the beams. For many years the standard method was riveting. A rivet is a bolt with a head that looks like a blunt screw without threads. It is heated, placed in holes through the pieces of steel, and a second head is formed at the other end by hammering it to hold it in place. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting a steel material between them under high heat.Priestess’s concrete is an improved form of reinforcement. Steel rods are bent into the shapes to give them the necessary degree of tensile strengths. They are then used to priestess concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to the shapes of the steel rods. When the rods are run through the channels, they are then bonded to the concrete by filling the channels with grout, a thin mortar or binding agent. In the other (and more common) method, the priestesses steel rods are placed in the lower part of a form that corresponds to the shape of the finished structure, and the concrete is poured around them. Priestess’s concrete uses less steel and less concrete. Because it is a highly desirable material. Progressed concrete has made it possible to develop buildings with unusualshapes, like some of the modern, sports arenas, with large spaces unbroken by any obstructing supports. The uses for this relatively new structural method are constantly being developed.中文译文：在建筑学的设计构成和结构的材料我们有，并且建筑师一定在一个如此的方法中处理活动，身体检查和代号需要的空间方面全部的表现正直被保证。

土木工程混凝土强度中英文对照外文翻译文献

<文献翻译一：原文>Strength of Concrete in Slabs, Investigates along Direction of Concreting ABSTRACTIn theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor slab’s or a beam’s streng th is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strength along the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations [1-3].Keywords: Concrete; Compressive Strength of Concrete; Non-Destructive1. IntroductionIn a building structure there are components which are expected to have special properties but not necessarily in the whole cross section. Components under bending, such as beams and floor slabs are generally compressed in their upper zone and the concrete’s compressive strength is vital mainly in this zone. The components are usually moulded in the same position in which they later remain in service, i.e. with their upper zone under compression. Concrete in the upper zone is expected to be slightly weaker than in the lower zone, but it is unclear how much weaker [4,5]. Also flooring slabs in production halls are most exposed to abrasion and impact loads in their upper zone which is not their strongest part. It is known from practice that industrial floors belong to the most often damaged building components.When reinforced concrete beams or floor slabs are to be tested they can be accessed only from their undersides and so only the bottom parts are tested and on this basis conclusions are drawn about the strength of the concrete in the whole cross section, including in the compressed upper zone. Thus a question arises: how large are the errors committed in this kind of investigations?In order to answer the above and other questions, tests of the strength of concrete in various structural components, especially in horizontally concreted slabs, were carried out. The variation of strength along the thickness of the components was analyzed.2. Research SignificanceThe research results presented in the paper show that the compressive strength of concrete in horizontally formed structural elements varies along their thickness. In the top zone the strength is by 25% - 30% lower than the strength in the middle zone, and it can be by as much as 100% lower than the strength in the bottom zone. The observations are based on the results of nondestructive tests carried out on drill cores taken from the structure, and verified by a destructive method. It is interesting to note that despite the great advances in concrete technology, the variation in compressive strength along the thickness of structural elements is characteristic of both old (over 60 years old) concretes and contemporary ordinary concretes.3. Test MethodologyBefore Concrete strength was tested by the ultrasonic method using exponential heads with a point contact with concrete. The detailed specifications of the heads can be found in [2,3]. The heads’ frequency was 40 and 100 kHz and the diameter of their concentrators amounted to 1 mm.In order to determine the real strength distributions in the existing structures, cylindrical cores 80 mm or 114 mm diameter (Figure 2) were drilled from them in the direction of concreting. Then specimens with their height equal to their diameter were cut out of the cores.Ultrasonic measurements were performed on the cores according to the scheme shown in Figure3. Ultrasonic pulses (pings) were passed through in two perpendicular directions I and II in planes spaced every 10 mm. In this way one could determine how ping velocity varied along the core’s height, i.e. along the thickness of the tested component.In both test directions ping pass times were determined and velocities CL were calculated. The velocities from the two directions in a tested measurement plane were averaged.Subsequently, specimens with their height equal to their diameter of 80 mm were cut out of the cores. Aver-age ultrasonic pulse velocity CL for the specimen’s central zone was correlated with fatigue strength fc determined by destructive tests carried out in a strength tester.For the different concretes different correlation curves with a linear, exponential or power equation were obtained. Exemplary correlation curve equations are given below:Lc c L c C f L f C f 38.1exp 0951.01.003.56705.232621.4=⋅=-⨯=where:fc —the compressive strength of concrete MPa,CL —ping velocity km/s.The determined correlation curve was used to calculate the strength of concrete in each tested core cross section and the results are presented in the form of graphs illustrating concrete strength distribution along the thickness of the tested component. 4. Investigation of Concrete in Industrial FloorsAfter Floor in sugar factory’s raw materials storage hall Concrete in an industrial floor must have particularly good characteristics in the top layer. Since it was to be loaded with warehouse trucks and stored sugar beets and frequently washed the investigated concrete floor (built in 1944) was designed as consisting of a 150 mm thick underlay and a 50 mm thick surface layer and made of concrete with a strength of 20 MPa (concrete A).As part of the investigations eight cores, each 80 mm in diameter, were drilled from the floor. The investigations showed significant departures from the design. The concrete subfloor’s thickness varied from 40 to 150 mm. The surface layer was not made of concrete, but of cement mortar with sand used as the aggregate. Also the thickness of this layer was uneven, varying from 40 to 122mm. After the ultrasonic tests specimens with their height equal to their diameter of 80 mm were cut out of the cores. Two scaling curves: one for the surface layer and the other for the bottom concrete layer were determined.A characteristic concrete compressive strength distribution along the floor’s thickness is shown in Figure 4.Strength in the upper zone is much lower than in thelower zone: ranging from 4.7 to 9.8 MPa for the mortar and from 13.9 to 29.0 MPa for the concrete layer. The very low strength of the upper layer of mortar is the result of strong porosity caused by air bubbles escaping upwards during the vibration of concrete. Figure 5 shows t he specimen’s porous top surface.Floor in warehouse hall with forklift truck transport The floor was built in 1998. Cellular concrete was used as for the underlay and the 150 mm thick surface layer was made of ordinary concrete with fibre (steel wires) reinforcement (concrete B). Cores 80 mm high and 80 mm in diameter were drilled from the surface layer. Ultrasonic measurements and destructive tests were performed as described above. Also the test results were handled in a similar way. An exemplary strength distribution along the floor’s thickness is shown in Figure 6.5. ConclusionsTests of ordinary concretes show unexpectedly greatly reduced strength in the upper zone of horizontally moulded structural components. This is to a large degree due to the vibration of concrete as a result of which coarse aggregate displaces downwards making the lower layers more compact while air moves upwards aerating the upper layers and thereby increasing their porosity. The increase in the concrete’s porosity results in a large drop in its compressive strength. Thanks to the use of the ultrasonic method and probes with exponential concentrators it could be demonstrated how the compressive strength of ordinary concrete is distributed along the thickness of structural components in building structures. It became apparent that the reduction in compressive strength in the compressed zone of structural components under bending and in industrial concrete floors can be very large (amounting to as much as 50% of the strength of t he slab’s lower zone). Therefore this phenomenon should be taken into account at the stage of calculating slabs, reinforced concrete beams and industrial floors [6].The results of the presented investigations apply to ordinary concretes (OC) which are increasingly supplanted by self-compacting concretes (SCC) and high-performance concretes (HPC). Since no intensive vibration is required to mould structures from such concretes one can expect that they are much more homogenous along their thickness [7]. This will be known once the ongoing experimental research is completed.Bohdan StawiskiStrength of Concrete in Slabs, Investigates along Direction of Concreting[D]Institute of Building Engineering, Wroclaw University of Technology Wybrzeze Wyspianskiego, Wroclaw, Poland Received October 15, 2011; revised November 21, 2011; accepted November 30, 2011<文献翻译一：译文>混凝土强度与混凝土浇筑方向关系的研究摘要从理论上看，假设混凝土复合材料是各项同性的从宏观尺度上讲。

土木工程毕业设计外文翻译最终中英文

7 Rigid-Frame StructuresA rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders.The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rigid frames are considered economical for buildings of up to' about25 stories, above which their drift resistance is costly to control. If, however,a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components.As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically include the following stages:1. Estimation of gravity load forces in girders and columns by approximate method.2. Preliminary estimate of member sizes based on gravity load forces witharbitrary increase in sizes to allow for horizontal loading.3. Approximate allocation of horizontal loading to bents and preliminary analysisof member forces in bents.4. Check on drift and adjustment of member sizes if necessary.5. Check on strength of members for worst combination of gravity and horizontalloading, and adjustment of member sizes if necessary.6. Computer analysis of total structure for more accurate check on memberstrengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift..7. Detailed design of members and connections.This chapter considers methods of analysis for the deflections and forces for both gravity and horizontal loading. The methods are included in roughly the order of the design procedure, with approximate methods initially and computer techniques later. Stability analyses of rigid frames are discussed in Chapter 16.7.1 RIGID FRAME BEHAVIORThe horizontal stiffness of a rigid frame is governed mainly by the bending resistance of the girders, the columns, and their connections, and, in a tall frame, by the axial rigidity of the columns. The accumulated horizontal shear above any story of a rigid frame is resisted by shear in the columns of that story (Fig. 7.1). The shear causes the story-height columns to bend in double curvature with points of contraflexure at approximately mid-story-height levels. The moments applied to a joint from the columns above and below are resisted by the attached girders, which also bend in double curvature, with points of contraflexure at approximately mid-span. These deformations of the columns and girders allow racking of the frame and horizontal deflection in each story. The overall deflected shape of a rigid frame structure due to racking has a shear configuration with concavity upwind, a maximum inclination near the base, and a minimum inclination at the top, as shown in Fig.7.1.The overall moment of the external horizontal load is resisted in each story level by the couple resulting from the axial tensile and compressive forces in the columns on opposite sides of the structure (Fig. 7.2). The extension and shortening of the columns cause overall bending and associated horizontal displacements of the structure. Because of the cumulative rotation up the height, the story drift dueto overall bending increases with height, while that due to racking tends to decrease. Consequently the contribution to story drift from overall bending may, in. the uppermost stories, exceed that from racking. The contribution of overall bending to the total drift, however, will usually not exceed 10% of that of racking, except in very tall, slender,, rigid frames. Therefore the overall deflected shape of a high-rise rigid frame usually has a shear configuration.The response of a rigid frame to gravity loading differs from a simply connected frame in the continuous behavior of the girders. Negative moments are induced adjacent to the columns, and positive moments of usually lesser magnitude occur in the mid-span regions. The continuity also causes the maximum girder moments to be sensitive to the pattern of live loading. This must be considered when estimating the worst moment conditions. For example, the gravity load maximum hogging moment adjacent to an edge column occurs when live load acts only on the edge span and alternate other spans, as for A in Fig. 7.3a. The maximum hogging moments adjacent to an interior column are caused, however, when live load acts only on the spans adjacent to the column, as for B in Fig. 7.3b. The maximum mid-span sagging moment occurs when live load acts on the span under consideration, and alternate other spans, as for spans AB and CD in Fig. 7.3a.The dependence of a rigid frame on the moment capacity of the columns for resisting horizontal loading usually causes the columns of a rigid frame to be larger than those of the corresponding fully braced simply connected frame. On the other hand, while girders in braced frames are designed for their mid-span sagging moment, girders in rigid frames are designed for the end-of-span resultant hogging moments, which may be of lesser value. Consequently, girders in a rigid frame may be smaller than in the corresponding braced frame. Such reductions in size allow economy through the lower cost of the girders and possible reductions in story heights. These benefits may be offset, however, by the higher cost of the more complex rigid connections.7.2 APPROXIMATE DETERMINATION OF MEMBER FORCES CAUSED BY GRAVITY LOADSIMGA rigid frame is a highly redundant structure; consequently, an accurate analysis can be made only after the member sizes are assigned. Initially, therefore, member sizes are decided on the basis of approximate forces estimated either by conservative formulas or by simplified methods of analysis that are independent of member properties. Two approaches for estimating girder forces due to gravity loading are given here.7.2.1 Girder Forces—Code Recommended ValuesIn rigid frames with two or more spans in which the longer of any two adjacent spans does not exceed the shorter by more than 20 %, and where the uniformly distributed design live load does not exceed three times the dead load, the girder moment and shears may be estimated from Table 7.1. This summarizes the recommendations given in the Uniform Building Code [7.1]. In other cases a conventional moment distribution or two-cycle moment distribution analysis should be made for a line of girders at a floor level.7.2.2 Two-Cycle Moment Distribution [7.2].This is a concise form of moment distribution for estimating girder moments in a continuous multibay span. It is more accurate than the formulas in Table 7.1, especially for cases of unequal spans and unequal loading in different spans.The following is assumed for the analysis:1. A counterclockwise restraining moment on the end of a girder is positive anda clockwise moment is negative.2. The ends of the columns at the floors above and below the considered girder are fixed.3. In the absence of known member sizes, distribution factors at each joint aretaken equal to 1 /n, where n is the number of members framing into the joint in the plane of the frame.Two-Cycle Moment Distribution—Worked Example. The method is demonstrated by a worked example. In Fig, 7.4, a four-span girder AE from a rigid-frame bent is shown with its loading. The fixed-end moments in each span are calculated for dead loading and total loading using the formulas given in Fig, 7.5. The moments are summarized in Table 7.2.The purpose of the moment distribution is to estimate for each support the maximum girder moments that can occur as a result of dead loading and pattern live loading.A different load combination must be considered for the maximum moment at each support, and a distribution made for each combination.The five distributions are presented separately in Table 7.3, and in a combined form in Table 7.4. Distributions a in Table 7.3 are for the exterior supports A andE. For the maximum hogging moment at A, total loading is applied to span AB with dead loading only on BC. The fixed-end moments are written in rows 1 and 2. In this distribution only .the resulting moment at A is of interest. For the first cycle, joint B is balanced with a correcting moment of- (-867 + 315)/4 = - U/4 assigned to M BA where U is the unbalanced moment. This is not recorded, but half of it, ( - U/4)/2, is carried over to M AB. This is recorded in row 3 and then added to the fixed-end moment and the result recorded in row 4.The second cycle involves the release and balance of joint A. The unbalanced moment of 936 is balanced by adding-U/3 = -936/3 = -312 to M BA (row 5), implicitly adding the same moment to the two column ends at A. This completes the second cycle of the distribution. The resulting maximum moment at A is then given by the addition of rows 4 and 5, 936 - 312 = 624. The distribution for the maximum moment at E follows a similar procedure.Distribution b in Table 7.3 is for the maximum moment at B. The most severe loading pattern for this is with total loading on spans AB and BC and dead load only on CD. The operations are similar to those in Distribution a, except that the T first cycle involves balancing the two adjacent joints A and C while recording only their carryover moments to B. In the second cycle, B is balanced by adding - (-1012 + 782)/4 = 58 to each side of B. The addition of rows 4 and 5 then gives the maximum hogging moments at B. Distributions c and d, for the moments at joints C and D, follow patterns similar to Distribution b.The complete set of operations can be combined as in Table 7.4 by initially recording at each joint the fixed-end moments for both dead and total loading. Then the joint, or joints, adjacent to the one under consideration are balanced for the appropriate combination of loading, and carryover moments assigned .to the considered joint and recorded. The joint is then balanced to complete the distribution for that support.Maximum Mid-Span Moments. The most severe loading condition for a maximum mid-span sagging moment is when the considered span and alternate other spans and total loading. A concise method of obtaining these values may be included in the combined two-cycle distribution, as shown in Table 7.5. Adopting the convention that sagging moments at mid-span are positive, a mid-span total; loading moment is calculated for the fixed-end condition of each span and entered in the mid-span column of row 2. These mid-span moments must now be corrected to allow for rotation of the joints. This is achieved by multiplying the carryover moment, row 3, at the left-hand end of the span by (1 + 0.5 D.F. )/2, and the carryover moment at the right-hand end by -(1 + 0.5 D.F.)/2, where D.F. is the appropriate distribution factor, and recording the results in the middle column. For example, the carryover to the mid-span of AB from A = [(1 + 0.5/3)/2] x 69 = 40 and from B = -[(1+ 0.5/4)/2] x (-145) = 82. These correction moments are then added to the fixed-end mid-span moment to give the maximum mid-span sagging moment, that is, 733 + 40 + 82 = 855.7.2.3 Column ForcesThe gravity load axial force in a column is estimated from the accumulated tributary dead and live floor loading above that level, with reductions in live loading as permitted by the local Code of Practice. The gravity load maximum column moment is estimated by taking the maximum difference of the end moments in the connected girders and allocating it equally between the column ends just above and below the joint. To this should be added any unbalanced moment due to eccentricity of the girderconnections from the centroid of the column, also allocated equally between the column ends above and below the joint.第七章框架结构高层框架结构一般由平行或正交布置的梁柱结构组成，梁柱结构是由带有能承担弯矩作用节点的梁、柱组成。

土木工程类外文文献翻译---钢筋混凝土可编辑

土木工程类外文文献翻译---钢筋混凝土外文文献翻译院系_________________________班级_________________________姓名_________________________指导教师_________________________2012年2月20 日2 外文翻译21 Reinforced ConcretePlain concrete is formed from a hardened mixture of cement water fine aggregate coarse aggregate crushed stone or gravel air and often other admixtures The plastic mix is placed and consolidated in the formwork then cured to facilitate the acceleration of the chemical hydration reaction lf the cementwater mix resulting in hardened concrete The finished product has high compressive strength and low resistance to tension such that its tensile strength is approximately one tenth lf its compressive strength Consequently tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete elementIt is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved This is possible because concrete can easily be givenany desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned the finished product becomes strong durable and in combination with the reinforcing bars adaptable for use as main members of any structural system The techniques necessary for placing concrete depend on the type of member to be cast that is whether it is a column a bean a wall a slab a foundation a mass columns or an extension of previously placed and hardened concrete For beams columns and walls the forms should be well oiled after cleaning them and the reinforcement should be cleared of rust and other harmful materials In foundations the earth should be compacted and thoroughly moistened to about 6 in in depth to avoid absorption of the moisture present in the wet concrete Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type as the case requires unless it is placed by pumping It must be kept in mind however that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concreteHydration of the cement takes place in the presence of moisture at temperatures above 50°F It is necessary to maintain such a condition in order that the chemical hydration reaction can take place If drying is too rapid surface cracking takes place This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydrationIt is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element such as geometrical widthdepth area of reinforcement steel strain concrete strain steel stress and so on Consequently trial and adjustment is necessary in the choice of concrete sections with assumptions based on conditions at site availability of the constituent materials particular demands of the owners architectural and headroom requirements the applicable codes and environmental reinforced concrete is often a site-constructed composite in contrast to the standard mill-fabricated beam and column sections in steel structuresA trial section has to be chosen for each critical location in a structural system The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load Since more than one trial is often necessary to arrive at the required section the first design input step generates into a series of trial-and-adjustment analysesThe trial-and –adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design Hence every design is an analysis once a trial section is chosen The availability of handbooks charts and personal computers and programs supports this approach as a more efficient compact and speedy instructional method compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design22 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering this is a field where there are real opportunities for the enthusiast In 1935 most of the methods now inuse for carrying and excavating earth with rubber-tyred equipment did not exist Most earth was moved by narrow rail track now relatively rare and the main methods of excavation with face shovel backacter or dragline or grab though they are still widely used are only a few of the many current methods To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines Generally the only reliable up-to-date information on excavators loaders and transport is obtainable from the makersEarthworks or earthmoving means cutting into ground where its surface is too high cuts and dumping the earth in other places where the surface is too low fills Toreduce earthwork costs the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness From the available maps ahd levels the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork On the site when further information becomes available he can make changes in jis sections and layoutbut the drawing lffice work will not have been lost It will have helped him to reach the best solution in the shortest timeThe cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine This is not always possible but when it canbe done it is ideal being both quick and cheap Draglinesbulldozers and face shovels an do this The largest radius is obtained with the draglineand the largest tonnage of earth is moved by the bulldozer though only over short distancesThe disadvantages of the dragline are that it must dig below itself it cannot dig with force into compacted material it cannot dig on steep slopws and its dumping and digging are not accurate Face shovels are between bulldozers and draglines having a larger radius of action than bulldozers but less than draglines They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful but its dumping radius is considerably less than that of the same escavator fitted with a face shovelRubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel They can dig the material deeply but only below themselves to a fairly flat surface carry it hundreds of meters if need be then drop it and level it roughly during the dumping For hard digging it is often found economical to keep a pusher tractor wheeled or tracked on the digging site to push each scraper as it returns to dig As soon as the scraper is fullthe pusher tractor returns to the beginning of the dig to heop to help the nest scraperBowl scrapers are often extremely powerful machinesmany makers build scrapers of 8 cubic meters struck capacity which carry 10 m 3 heaped The largest self-propelled scrapers are of 19 m 3 struck capacity 25 m 3 heaped and they are driven by a tractor engine of 430 horse-powersDumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials Dumpers have the earth container over the front axle on large rubber-tyred wheels and the container tips forwards on most types though in articulated dumpers the direction of tip can be widely varied The smallest dumpers have a capacity of about 05 m 3 and the largest standard types are of about 45 m 3 Special types include the self-loading dumper of up to 4 m 3 and the articulated type of about 05 m 3 The distinction between dumpers and dump trucks must be remembered dumpers tip forwards and the driver sits behind the load Dump trucks are heavy strengthened tipping lorries the driver travels in front lf the load and the load is dumped behind him so they are sometimes called rear-dump trucks23 Safety of StructuresThe principal scope of specifications is to provide general principles and computational methods in order to verify safety of structures The safety factor which according to modern trends is independent of the nature and combination of the materials used can usually be defined as the ratio between the conditions This ratio is also proportional to the inverse of the probability risk of failure of the structureFailure has to be considered not only as overall collapse of the structure but also as unserviceability or according to a more precise Common definition As the reaching of a limit state which causes the construction not to accomplish the task it was designed for There are two categories of limit state1 Ultimate limit sate which corresponds to the highest value of the load-bearing capacity Examples include local buckling or global instability of the structure failure of some sections and subsequent transformation of the structure into a mechanism failure by fatigue elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure and sensitivity of the structure to alternating loads to fire and to explosions2 Service limit states which are functions of the use and durability of the structure Examples include excessive deformations and displacements without instability early or excessive cracks large vibrations and corrosionComputational methods used to verify structures with respect to the different safety conditions can be separated into1 Deterministic methods in which the main parameters are considered as nonrandom parameters2 Probabilistic methods in which the main parameters are considered as random parametersAlternatively with respect to the different use of factors of safety computational methods can be separated into1 Allowable stress method in which the stresses computed under imum loads are compared with the strength of the material reduced by given safety factors2 Limit states method in which the structure may be proportioned on the basis of its imum strength This strength as determined by rational analysis shall not be less than that required to support a factored loadequal to the sum of the factored live load and dead load ultimate state The stresses corresponding to working service conditions with unfactored live and dead loads are compared with prescribed values service limit state From the four possible combinations of the first two and second two methods we can obtain some useful computational methods Generally two combinations prevail1 deterministic methods which make use of allowable stresses2 Probabilistic methods which make use of limit statesThe main advantage of probabilistic approaches is that at least in theory it is possible to scientifically take into account all random factors of safety which are then combined to define the safety factor probabilistic approaches depend upon1 Random distribution of strength of materials with respect to the conditions of fabrication and erection scatter of the values of mechanical properties through out the structure2 Uncertainty of the geometry of the cross-section sand of the structure faults and imperfections due to fabrication and erection of the structure3 Uncertainty of the predicted live loads and dead loads acting on the structure4 Uncertainty related to the approximation of the computational method used deviation of the actual stresses from computed stresses Furthermore probabilistic theories mean that the allowable risk can be based on several factors such as1 Importance of the construction and gravity of the damage byits failure2 Number of human lives which can be threatened by this failure3 Possibility andor likelihood of repairing the structure4 Predicted life of the structureAll these factors are related to economic and social considerations such as1 Initial cost of the construction2 Aortization funds for the duration of the construction3 Cost of physical and material damage due to the failure of the construction4 Adverse impact on society5 Moral and psychological viewsThe definition of all these parameters for a given safety factor allows construction at the optimum cost However the difficulty of carrying out a complete probabilistic analysis has to be taken into account For such an analysis the laws of the distribution of the live load and its induced stresses of the scatter of mechanical properties of materials and of the geometry of the cross-sections and the structure have to be known Furthermore it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material on the cross-sections and upon the load acting on the structure These practical difficulties can be overcome in two ways The first is to apply different safety factors to the material and to the loads without necessarily adopting the probabilistic criterion The second is an approximate probabilistic method which introduces some simplifyingassumptions semi-probabilistic methods1 中文翻译11钢筋混凝土素混凝土是由水泥水细骨料粗骨料碎石或卵石空气通常还有其他外加剂等经过凝固硬化而成将可塑的混凝土拌合物注入到模板内并将其捣实然后进行养护以加速水泥与水的水化反应最后获得硬化的混凝土其最终制成品具有较高的抗压强度和较低的抗拉强度其抗拉强度约为抗压强度的十分之一因此截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝土构件中较弱的受拉区的强度由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异因此需要对结构设计的基本原理进行修改将钢筋混凝土这种非均质截面的两种组成部分按一定比例适当布置可以最好的利用这两种材料这一要求是可以达到的因混凝土由配料搅拌成湿拌合物经过振捣并凝固硬化可以做成任何一种需要的形状如果拌制混凝土的各种材料配合比恰当则混凝土制成品的强度较高经久耐用配置钢筋后可以作为任何结构体系的主要构件浇筑混凝土所需要的技术取决于即将浇筑的构件类型诸如柱梁墙板基础大体积混凝土水坝或者继续延长已浇筑完毕并且已经凝固的混凝土等对于梁柱墙等构件当模板清理干净后应该在其上涂油钢筋表面的锈及其他有害物质也应该被清除干净浇筑基础前应将坑底土夯实并用水浸湿6英寸以免土壤从新浇的混凝土中吸收水分一般情况下除使用混凝土泵浇筑外混凝土都应在水平方向分层浇筑并使用插入式或表面式高频电动振捣器捣实必须记住过分的振捣将导致骨料离析和混凝土泌浆等现象因而是有害的水泥的水化作用发生在有水分存在而且气温在50°F以上的条件下为了保证水泥的水化作用得以进行必须具备上述条件如果干燥过快则会出现表面裂缝这将有损与混凝土的强度同时也会影响到水泥水化作用的充分进行设计钢筋混凝土构件时显然需要处理大量的参数诸如宽度高度等几何尺寸配筋的面积钢筋的应变和混凝土的应变钢筋的应力等等因此在选择混凝土截面时需要进行试算并作调整根据施工现场条件混凝土原材料的供应情况业主提出的特殊要求对建筑和净空高度的要求所用的设计规范以及建筑物周围环境条件等最后确定截面钢筋混凝土通常是现场浇注的合成材料它与在工厂中制造的标准的钢结构梁柱等不同因此对于上面所提到的一系列因素必须予以考虑对结构体系的各个部位均需选定试算截面并进行验算以确定该截面的名义强度是否足以承受所作用的计算荷载由于经常需要进行多次试算才能求出所需的截面因此设计时第一次采用的数值将导致一系列的试算与调整工作选择混凝土截面时采用试算与调整过程可以使复核与设计结合在一起因此当试算截面选定后每次设计都是对截面进行复核手册图表和微型计算机以及专用程序的使用使这种设计方法更为简捷有效而传统的方法则是把钢筋混凝土的复核与单纯的设计分别进行处理12土方工程由于和土木工程中任何其他工种的施工方法与费用相比较土方挖运的施工方法与费用的变化都要快得多因此对于有事业心的人来说土方工程是一个可以大有作为的领域在1935年目前采用的利用轮胎式机械设备进行土方挖运的方法大多数还没有出现那是大部分土方是采用窄轨铁路运输在这目前来说是很少采用的当时主要的开挖方式是使用正铲反铲拉铲或抓斗等挖土机尽管这些机械目前仍然在广泛应用但是它们只不过是目前所采用的许多方法中的一小部分因此一个工程师为了使自己在土方挖运设备方面的知识跟得上时代的发展他应当花费一些时间去研究现代的机械一般说来有关挖土机装载机和运输机械的唯一可靠而又最新的资料可以从制造厂商处获得土方工程或土方挖运工程指的是把地表面过高处的土壤挖去挖方并把它倾卸到地表面过低的其他地方填方为了降低土方工程费用填方量应该等于挖方量而且挖方地点应该尽可能靠近土方量相等的填方地点以减少运输量和填方的二次搬运土方设计这项工作落到了从事道路设计的工程师的身上因为土方工程的设计比其他任何工作更能决定工程造价是否低廉根据现有的地图和标高道路工程师应在设计绘图室中的工作也并不是徒劳的它将帮助他在最短的时间内获得最好的方案费用最低的运土方法是用同一台机械直接挖方取土并且卸土作为填方这并不是经常可以做到的但是如果能够做到则是很理想的因为这样做既快捷又省钱拉铲挖土机推土机和正铲挖土机都能做到这点拉铲挖土机的工作半径最大推土机所推运的图的数量最多只是运输距离很短拉铲挖土机的缺点是只能挖比它本身低的土不能施加压力挖入压实的土壤内不能在陡坡上挖土而且挖卸都不准确正铲挖土机介于推土机和拉铲挖土机的之间其作用半径大于推土机但小于拉铲挖土机正铲挖土机能挖取竖直陡峭的工作面这种方式对推土机司机来说是危险的而对拉铲挖土机则是不可能的每种机械设备应该进行最适合它的性能的作业正铲挖土机不能挖比其停机平面低很多的土而深挖坚实的土壤时反铲挖土机最适用但其卸料半径比起装有正铲的同一挖土机的卸料半径则要小很多在比较平坦的场地开挖如果用拉铲或正铲挖土机运输距离太远时则装有轮胎式的斗式铲运机就是比不可少的它能在比较平的地面上挖较深的土但只能挖机械本身下面的土需要时可以将土运至几百米远然后卸土并在卸土的过程中把土大致铲平在挖掘硬土时人们发现在开挖场地经常用一辆助推拖拉机轮式或履带式对返回挖土的铲运机进行助推这种施工方法是经济的一旦铲运机装满助推拖拉机就回到开挖的地点去帮助下一台铲运机斗式铲运机通常是功率非常大的机械许多厂家制造的铲运机铲斗容量为8 m3满载时可达10 m3最大的自行式铲运机铲斗容量为19立方米满载时为25 m3由430马力的牵引发动机驱动翻斗机可能是使用最为普遍的轮胎式运输设备因为它们还可以被用来送混凝土或者其他建筑材料翻斗车的车斗位于大橡胶轮胎车轮前轴的上方尽管铰接式翻斗车的卸料方向有很多种但大多数车斗是向前翻转的最小的翻斗车的容量大约为05立方米而最大的标准型翻斗车的容量大约为45m3特殊型式的翻斗车包括容量为4 m3的自装式翻斗车和容量约为05 m3的铰接式翻斗车必须记住翻斗车与自卸卡车之间的区别翻斗车车斗向前倾翻而司机坐在后方卸载因此有时被称为后卸卡车13结构的安全度规范的主要目的是提供一般性的设计原理和计算方法以便验算结构的安全度就目前的趋势而言安全系数与所使用的材料性质及其组织情况无关通常把它定义为发生破坏的条件与结构可预料的最不利的工作条件之比值这个比值还与结构的破坏概率危险率成反比破坏不仅仅指结构的整体破坏而且还指结构不能正常的使用或者用更为确切的话来说把破坏看成是结构已经达到不能继续承担其设计荷载的极限状态通常有两种类型的极限状态即1强度极限状态它相当于结构能够达到的最大承载能力其例子包括结构的局部屈曲和整体不稳定性某此界面失效随后结构转变为机构疲劳破坏引起结构几何形状显著变化的弹性变形或塑性变形或徐变结构对交变荷载火灾和爆炸的敏感性2使用极限状态它对应着结构的使用功能和耐久性器例子包括结构失稳之前的过大变形和位移早期开裂或过大的裂缝较大的振动和腐蚀根据不同的安全度条件可以把结构验算所采用的计算方法分成1确定性的方法在这种方法中把主要参数看作非随机参数2概率方法在这种方法中主要参数被认为是随机参数此外根据安全系数的不同用途可以把结构的计算方法分为1容许应力法在这种方法中把结构承受最大荷载时计算得到的应力与经过按规定的安全系数进行折减后的材料强度作比较2极限状态法在这种方法中结构的工作状态是以其最大强度为依据来衡量的由理论分析确定的这一最大强度应不小于结构承受计算荷载所算得的强度极限状态计算荷载等于分别乘以荷载系数的活载与恒载之和把对应于不乘以荷载系数的活载和恒载的工作使用条件的应力与规定值使用极限状态相比较根据前两种方法和后两种方法的四种可能组合我们可以得到一些实用的计算方法通常采用下面两种计算方法确定性的方法这种方法采用容许应力概率方法这种方法采用极限状态至少在理论上概率法的主要优点是可以科学的考虑所有随机安全系数然后将这些随机安全系数组合成确定的安全系数概率法取决于1制作和安装过程中材料强度的随机分布整个结构的力学性能数值的分散性2截面和结构几何尺寸的不确定性由结构制作和安装造成的误差和缺陷而引起的对作用在结构上的活载和恒载的预测的不确定性所采用的近似计算方法有关的不精确性实际应力与计算应力的偏差此外概率理论意味着可以基于下面几个因素来确定允许的危险率例如建筑物的重要性和建筑物破坏造成的危害性2由于建筑物破坏使生活受到威胁的人数3修复建筑的可能性4建筑物的预期寿命所有这些因素均与经济和社会条件有关例如1建筑物的初始建设费2建筑物使用期限内的折旧费3由于建筑物破坏而造成的物质和材料损失费4在社会上造成的不良影响5精神和心理上的考虑就给定的安全系数而论所有这些参数的确定都是以建筑物的最佳成本为依据的但是应该考虑到进行全概率分析的困难对于这种分析来说应该了解活载及其所引起的盈利的分布规律材料的力学性能的分散性和截面的结构几何尺寸的分散性此外由于强度的分布规律和应力的分布规律之间的相互关系是困难的这些实际困难可以采用两种方法来克服第一种方法对材料和荷载采用不同的安全系数而不需要采用概率准则第二种方法是引入一些而简化假设的近似概率方法半概率方法1建筑工程学院土木工程系土木084班。

土木工程文献外文翻译(中英互译版)

使用加固纤维聚合物增强混凝土梁的延性作者：Nabil F. Grace, George Abel-Sayed, Wael F. Ragheb摘要：一种为加强结构延性的新型单轴柔软加强质地的聚合物(FRP)已在被研究，开发和生产(在结构测试的中心在劳伦斯技术大学)。

这种织物是两种碳纤维和一种玻璃纤维的混合物，而且经过设计它们在受拉屈服时应变值较低，从而体现出伪延性的性能。

通过对八根混凝土梁在弯曲荷载作用下的加固和检测对研制中的织物的效果和延性进行了研究。

用现在常用的单向碳纤维薄片、织物和板进行加固的相似梁也进行了检测，以便同用研制中的织物加固梁进行性能上的比较。

这种织物经过设计具有和加固梁中的钢筋同时屈服的潜力，从而和未加固梁一样，它也能得到屈服台阶。

相对于那些用现在常用的碳纤维加固体系进行加固的梁，这种研制中的织物加固的梁承受更高的屈服荷载，并且有更高的延性指标。

这种研制中的织物对加固机制体现出更大的贡献。

关键词：混凝土，延性，纤维加固，变形介绍外贴粘合纤维增强聚合物（FRP）片和条带近来已经被确定是一种对钢筋混凝土结构进行修复和加固的有效手段。

关于应用外贴粘合FRP板、薄片和织物对混凝土梁进行变形加固的钢筋混凝土梁的性能，一些试验研究调查已经进行过报告。

Saadatmanesh和Ehsani（1991）检测了应用玻璃纤维增强聚合物(GFRP)板进行变形加固的钢筋混凝土梁的性能。

Ritchie等人（1991）检测了应用GFRP，碳纤维增强聚合物（CFRP）和G/CFRP板进行变形加固的钢筋混凝土梁的性能。

Grace等人（1999）和Triantafillou（1992）研究了应用CFRP薄片进行变形加固的钢筋混凝土梁的性能。

Norris，Saadatmanesh和Ehsani（1997）研究了应用单向CFRP薄片和CFRP织物进行加固的混凝土梁的性能。

在所有的这些研究中，加固的梁比未加固的梁承受更高的极限荷载。

土木工程（钢结构和钢筋混凝土结构）外文文献翻译

⼟⽊⼯程（钢结构和钢筋混凝⼟结构）外⽂⽂献翻译⽂献信息：⽂献标题：Recent research and design developments in steel and composite steel–concrete structures in USA（近期美国在钢结构和钢筋混凝⼟结构研究和设计⽅⾯的发展）国外作者：Theodore V.Galambos⽂献出处：《Journal of Constructional Steel Research》,2000, 55(1-3):289-303字数统计：英⽂4718单词，23395字符；中⽂7671汉字外⽂⽂献：Recent research and design developments in steel and composite steel–concrete structures in USA Abstract A brief review of the status of structural steel research in the US at the end of the Twentieth Century is presented in this paper to show that while many problems are being solved, there are new and challenging problems remaining. The chief impetus for continued research is that provided by natural disasters, such as earthquakes, tropical storms, tornadoes and floods occurring in densely populated urban areas. New materials and new experimental and computational technologies also give rise to new and exciting research problems.Keywords: Bridges; Buildings; Design; Research; Steel structures; United States of America; Seismic behavior; High-performance materials1. IntroductionThe purpose of this paper is to give a brief overview of the current developments in structural steel research in the US, and of the future directions that the structural steel engineering research may take in the coming Century. The drivingforces of research in this field are the following:new construction methods and construction productsnew materialseconomic considerationsnatural disastersThree of these motivations are common to all engineering developments, not just to structural engineering. However, the impetus due to natural disasters is unique to our field. Recent major natural disasters in the US, such as the Northridge earthquake in California and hurricane Andrew in Florida, have spurred much of the current research activity.The presentation here is of necessity incomplete, because the author is not aware of all research going on everywhere in the country and there is not enough space in this presentation. The overview is meant to give a general flavor of the research activities, and to show that a significant effort is going on in the US. The following is a list of 10 major topics in steel research: 1.Limit States Design for bridges2.Monitoring of structural performance in the field3.Design of seismically resistant connections4.Curved girder bridges/doc/c0cdca1fb8f67c1cfbd6b81b.html posite columns with high-performance concrete6.Building frames with semi-rigid joints7.“Advanced Structural Analysis” for buildings8.Repair and retrofit of structures9.Steel structures with high-performance steels10.Cold-formed steel structuresThe next parts of this paper will give brief discussions on some of these topics. Several topics will then be elaborated in more detail. The paper will conclude with a look toward the future of structural steel research.2.Research on steel bridgesThe American Association of State Transportation and Highway Officials (AASHTO) is the authority that promulgates design standards for bridges in the US. In 1994 it has issued a new design specification which is a Limit States Design standard that is based on the principles of reliability theory. A great deal of work went into the development of this code in the past decade, especially on calibration and on the probabilistic evaluation of the previous specification. The code is now being implemented in the design office, together with the introduction of the Systeme Internationale units. Many questions remain open about the new method of design, and there are many new projects that deal with the reliability studies of the bridge as a system. One such current project is a study to develop probabilistic models, load factors, and rational load-combination rules for the combined effects of liveload and wind; live-load and earthquake; live-load, wind and ship collision; and ship collision, wind, and scour. There are also many field measurements of bridge behavior, using modern tools of inspection and monitoring such as acoustic emission techniques and other means of non-destructive evaluation. Such fieldwork necessitates parallel studies in the laboratory, and the evolution of ever more sophisticated high-technology data transmission methods.America has an aging steel bridge population and many problems arise from fatigue and corrosion. Fatigue studies on full-scale components of the Williamsburg Bridge in New York have recently been completed at Lehigh University. A probabilistic AASHTO bridge evaluation regulation has been in effect since 1989, and it is employed to assess the future useful life of structures using rational methods that include field observation and measurement together with probabilistic analysis. Such an activity also fosters additional research because many issues are still unresolved. One such area is the study of the shakedown of shear connectors in composite bridges. This work has been recently completed at the University of Missouri.In addition to fatigue and corrosion, the major danger to bridges is the possibility of earthquake induced damage. This also has spawned many research projects on the repair and retrofit of steel superstructures and the supporting concrete piers. Many bridges in the country are being strengthened for earthquake resistance.One area that is receiving much research attention is the strengthening of concrete piers by “jacketing” them by sheets of high-performance reinforced plastic.The previously described research deals mainly with the behavior of existing structures and the design of new bridges. However, there is also a vigorous activity on novel bridge systems. This research is centered on the application of high-performance steels for the design of innovative plate and box-girder bridges, such as corrugated webs, combinations of open and closed shapes, and longer spans for truss bridges. It should be mentioned here that, in addition to work on steel bridges, there is also very active research going on in the study of the behavior of prestressed concrete girders made from very high strength concrete. The performance and design of smaller bridges using pultruded high-performance plastic composite members is also being studied extensively at present. New continuous bridge systems with steelconcrete composite segments in both the positive moment and the negative moment regions are being considered. Several researchers have developed strong capabilities to model the three-dimensional non-linear behavior of individual plate girders, and many studies are being performed on the buckling and post-buckling characteristics of such structures. Companion experimental studies are also made, especially on members built from high-performance steels. A full-scale bridge of such steel has been designed, and will soon be constructed and then tested under traffic loading. Research efforts are also underway on the study of the fatigue of large expansion joint elements and on the fatigue of highway sign structures.The final subject to be mentioned is the resurgence of studies of composite steelconcrete horizontally curved steel girder bridges. A just completed project at the University of Minnesota monitored the stresses and the deflections in a skewed and curved bridge during all phases of construction, starting from the fabrication yard to the completed bridge. Excellent correlation was found to exist between the measured stresses and deformations and the calculated values. The stresses and deflections during construction were found to be relatively small, that is, the construction process did not cause severe trauma to the system. The bridge has now been tested under service loading, using fully loaded gravel trucks, for two years, and it will continue tobe studied for further years to measure changes in performance under service over time. A major testing project is being conducted at the Federal Highway Administration laboratory in Washington, DC, where a half-scale curved composite girder bridge is currently being tested to determine its limit states. The test-bridge was designed to act as its own test-frame, where various portions can be replaced after testing. Multiple flexure tests, shear tests, and tests under combined bending and shear, are thus performed with realistic end-conditions and restraints. The experiments are also modeled by finite element analysis to check conformance between reality and prediction. Finally design standards will be evolved from the knowledge gained. This last project is the largest bridge research project in the USA at the present time.From the discussion above it can be seen that even though there is no large expansion of the nation’s highway and railr oadsystem, there is extensive work going on in bridge research. The major challenge facing both the researcher and the transportation engineer is the maintenance of a healthy but aging system, seeing to its gradual replacement while keeping it safe and serviceable.3.Research on steel members and framesThere are many research studies on the strength and behavior of steel building structures. The most important of these have to do with the behavior and design of steel structures under severe seismic events. This topic will be discussed later in this paper. The most significant trends of the non-seismic research are the following: ?“Advanced” methods of structural analysis and design are actively studied at many Universities, notably at Cornell, Purdue, Stanford, and Georgia Tech Universities. Such analysis methods are meant to determine the load-deformation behavior of frames up to and beyond failure, including inelastic behavior, force redistribution, plastic hinge formation, second-order effects and frame instability. When these methods are fully operational, the structure will not have to undergo a member check, because the finite element analysis of the frame automatically performs this job. In addition to the research on the best approaches to do this advanced analysis, there are also many studies on simplifications that can be easilyutilized in the design office while still maintaining the advantages of a more complex analysis. The advanced analysis method is well developed for in-plane behavior, but much work is yet to be done on the cases where bi-axial bending or lateraltorsional buckling must be considered. Some successes have been achieved, but the research is far from complete. Another aspect of the frame behavior work is the study of the frames with semirigid joints. The American Institute of Steel construction (AISC) has published design methods for office use. Current research is concentrating on the behavior of such structures under seismic loading. It appears that it is possible to use such frames in some seismic situations, that is, frames under about 8 to 10 stories in height under moderate earthquake loads. The future of structures with semi-rigid frames looks very promising, mainly because of the efforts of researchers such as Leon at Georgia Tech University , and many others. Research on member behavior is concerned with studying the buckling and postbuckling behavior of compact angle and wide-flange beam members by advanced commercial finite element programs. Such research is going back to examine the assumptions made in the 1950s and 1960s when the plastic design compactness and bracing requirements were first formulated on a semi-empirical basis. The non-linear finite element computations permit the “re-testing” of the old experiments a nd the performing of new computer experiments to study new types of members and new types of steels. White of Georgia Tech is one of the pioneers in this work. Some current research at the US military Academy and at the University of Minnesota by Earls is discussed later in this report. The significance of this type of research is that the phenomena of extreme yielding and distortion can be efficiently examined in parameter studies performed on the computer. The computer results can be verified with old experiments, or a small number of new experiments. These studies show a good prospect for new insights into old problems that heretofore were never fully solved.4.Research on cold-formed steel structuresNext to seismic work, the most active part of research in the US is on cold-formed steel structures. The reason for this is that the supporting industry is expanding, especially in the area of individual family dwellings. As the cost of wood goes up, steel framed houses become more and more economical. The intellectual problems of thin-walled structures buckling in multiple modes under very large deformations have attracted some of the best minds in stability research. As a consequence, many new problems have been solved: complex member stiffening systems, stability and bracing of C and Z beams, composite slabs, perforated columns, standing-seam roof systems, bracing and stability of beams with very complicated shapes, cold-formed members with steels of high yield stress-to-tensile strength ratio, and many other interesting applications. The American Iron and Steel Institute (AISI) has issued a new expanded standard in 1996 that brought many of these research results into the hands of the designer.5.Research on steel-concrete composite structuresAlmost all structural steel bridges and buildings in the US are built with composite beams or girders. In contrast, very few columns are built as composite members. The area of composite column research is very active presently to fill up the gap of technical information on the behavior of such members. The subject of steel tubes filled with high-strength concrete is especially active. One of the aims of research performed by Hajjar at the University of Minnesota is to develop a fundamental understanding of the various interacting phenomena that occur in concrete-filled columns and beam-columns under monotonic and cyclic load. The other aim is to obtain a basic understanding of the behavior of connections of wide-flange beams to concrete filled tubes.Other major research work concerns the behavior and design of built-up composite wide-flange bridge girders under both positive and negative bending. This work is performed by Frank at the University of Texas at Austin and by White of Georgia Tech, and it involves extensive studies of the buckling and post-buckling of thin stiffened webs. Already mentioned is the examination of the shakedown of composite bridges. The question to be answered is whether a composite bridgegirder loses composite action under repeated cycles of loads which are greater than the elastic limit load and less than the plastic mechanism load. A new study has been initiated at the University of Minnesota on the interaction between a semi-rigid steel frame system and a concrete shear wall connected by stud shear connectors.6.Research on connectionsConnection research continues to interest researchers because of the great variety of joint types. The majority of the connection work is currently related to the seismic problems that will be discussed in the next section of this paper. The most interest in non-seismic connections is the characterization of the monotonic moment-rotation behavior of various types of semi-rigid joints.7.Research on structures and connections subject to seismic forcesThe most compelling driving force for the present structural steel research effort in the US was the January 17, 1994 earthquake in Northridge, California, North of Los Angeles. The major problem for steel structures was the extensive failure of prequalified welded rigid joints by brittle fracture. In over 150 buildings of one to 26 stories high there were over a thousand fractured joints. The buildings did not collapse, nor did they show any external signs of distress, and there were no human injuries or deaths. A typical joint is shown in Fig. 1.In this connection the flanges of the beams are welded to the flanges of the column by full-penetration butt welds. The webs are bolted to the beams and welded to the columns. The characteristic features of this type of connection are the backing bars at the bottom of the beam flange, and the cope-holes left open to facilitate the field welding of the beam flanges. Fractures occurred in the welds, in the beam flanges, and/or in the column flanges, sometimes penetrating into the webs.Once the problem was discovered several large research projects were initiated at various university laboratories, such as The University of California at San Diego, the University of Washington in Seattle, the University of Texas at Austin, Lehigh University at Bethlehem, Pennsylvania, and at other places. The US Government under the leadership of the Federal Emergency Management Agency (FEMA) instituted a major national research effort. The needed work was deemed so extensive that no single research agency could hope to cope with it. Consequently three California groups formed a consortium which manages the work:1.Structural Engineering Association of California2.Applied Technology Council3.California Universities for Research in Earthquake EngineeringThe first letters in the name of each agency were combined to form the acronym SAC, which is the name of the joint venture that manages the research. We shall read much from this agency as the results of the massive amounts of research performed under its aegis are being published in the next few years.The goals of the program are to develop reliable, practical and cost-effective guidelines for the identification and inspection of at-risk steel moment frame buildings, the repair or upgrading of damaged buildings, the design of new construction, and the rehabilitation of undamaged buildings. As can be seen, the scope far exceeds the narrow look at the connections only.The first phase of the research was completed at the end of 1996, and its main aim was to arrive at interim guidelines so that design work could proceed. It consisted of the following components:A state-of-the-art assessment of knowledge on steel connectionsA survey of building damageThe evaluation of ground motionDetailed building analyses and case studiesA preliminary experimental programProfessional training and quality assurance programsPublishing of the Interim Design GuidelinesA number of reports were issued in this first phase of the work. A partial list of these is appended at the end of this paper.During the first phase of the SAC project a series of full-scale connection tests under static and, occasionally, dynamic cyclic tests were performed. Tests were of pre-Northridge-type connections (that is, connections as they existed at the time of the earthquake), of repaired and upgraded details, and of new recommended connection details. A schematic view of the testing program is illustrated in Fig. 2. Some recommended strategies for new design are schematically shown in Fig. 3.The following possible causes, and their combinations, were found to have contributed to the connection failures: Inadequate workmanship in the field weldsInsufficient notch-toughness of the weld metalStress raisers caused by t he backing barsLack of complete fusion near the backing barWeld bead sizes were too bigSlag inclusion in the weldsWhile many of the failures can be directly attributed to the welding and the material of the joints, there are more serious questions relative to the structural system that had evolved over the years mainly based on economic considerations. The structural system used relatively few rigid-frames of heavy members that were designed to absorb the seismic forces for large parts of the structure. These few lateral-force resistant frames provide insufficient redundancy. More rigid-frames with smaller members could have provided a tougher and more ductile structural system. There is a question of size effect: test results from joints of smaller members were extrapolated to joints with larger members without adequate test verification. The effect of a large initial pulse may have triggered dynamic forces that could have caused brittle fracture in joints with fracture critical details and materials. Furthermore, the yield stress of the beams was about 30 to 40% larger than the minimum specified values assumed in design, and so the connection failed before the beams, which were supposed to form plastic hinges.As can be seen, there are many possible reasons for this massive failure rate, and there is blame to go around for everyone. No doubt, the discussion about why and how the joints failed will go on for many more years. The structural system just did not measure up to demands that were more severe than expected. What should be kept in mind, however, is that no structure collapsed or caused even superficial nonstructural damage, and no person was injured or killed. In the strictest sense the structure sacrificed itself so that no physical harm was done to its users. The economic harm, of course, was enormous. Phase 2 of the SAC project started on Jan. 1, 1996 and is planned to be completed on Dec. 31, 1999. Its aims are to provide advice and guidance to code officials, designers, steel makers, welding engineers, and fabricators, in fact, to anyone connected with earthquake resistant design of steel buildings. The work includes the development of design-criteria for new buildings, and inspection, evaluation, repair and retrofit procedures for existing buildings that are at risk. A broad scope of professional issues is being examined. Ultimately, a performance-based methodology will be recommended to the professions dealing with seismic design problems. All types of moment-frame connections will be studied: bolted and welded connections, semi-rigid connections, connections made with special steels, energy-dissipating connections, etc. The research consists of many new experiments on joints, as well as a systems-reliability-based probabilistic method for optimizing the best structural design and evaluation procedures.The research work of the Phase 2 SAC Project is essentially complete as of the date of this conference (Sep. 1999). The basic analytical and experimental work consists of the following topics:Materials and fracture issuesWelding, joining and inspectionAnalysis and testing of connectionsEarthquake performance of structural systemsSimulation of seismic responseData and concepts from these five teams have been absorbed and utilized by theteam working on the development of the reliability framework for performance prediction and evaluation. A number of extensive State-Of-The-Art (SOA) reports based on the research are now in the final stages of completion. The material from these SOA reports, as well as results from trial designs, cost analyses, loss analyses, and from an evaluation of social, economic and policy issues, will then be the basis of new seismic design criteria for use by building codes.Phase 2 of the SAC Project is by far the largest and most expensive cooperative structural engineering effort in the history of US structural steel research. Much is expected to come of it. The way steel structures will be designed for steel structures is going to be deeply affected. The Northridge earthquake of January 17, 1994 proved a warning and a lesson, as well as a major impetus to learn more and to apply this knowledge more effectively.8.Research on the required properties of high-performance steelsOne other example will be elaborated on a research topic that is not motivated by natural disaster but by technological development, as an illustration among many which could have been presented. Steel makers have recently developed the capability to produce so-called “high-performance” stee ls economically, and there is a desire to use these steels in civil and military construction. Such steels are of high strength, with yield points of around 500 to 700 MPa, they can be produced to a variety of weldability, corrosion and toughness characteristics. Much work has been done on these steels in Japan with theirapplication in seismic structures in mind. Structures from a steel, HSLA80, have been extensively studied at Lehigh University in the US . The research question to be answered is not “Give n a steel of certain properties, what are the member and structural characteristics?” but “Given the desired structural characteristics, what should the properties of the steel be?”. These questions were discussed in a workshop sponsored by the US National Institute of Standards in Technology (NIST) at the University of Minnesota on July 1, 1996. The purpose of this meeting was to define the research needs to adapt the high-performance steels to the requirements of the structural design standards. Many issues were raised, but hereonly the subject of compactness and lateral bracing will be briefly touched. The shape of the stress–strain curve has a profound effect on the inelastic load-deformation behavior of members, as illustrated by the following example. The idealized form of a tensile stress–strain diagram is shown in Fig. 4. Data for four representative steels are given in Table 1. Steel A is a new steel in Japan that has very good ductility and a low yield stress-to-tensile strength ratio (yield ratio), that is, it has about the same capacity to strainharden at structural carbon steel (Steel C; Steel B is a quenched and tempered steel with a very high yield stress but a high yield ratio; Steel D is the steel HSLA80 from the research at Lehigh）.The load-deflection curves in Fig. 5 were obtained from a finite element analysis using the commercial program ABAQUS. The structure was a simply supported beam under a three-point loading. Lateral bracing was provided at the end-supports and under the central load-point. The section was a W200×46 (W8×31 in US units) profile, with a flange slenderness ratio b f/t f=7.8, a web slenderness ratioof h/t w=29.9 and an unbraced length slenderness of L b/r y=71. As seen from Fig. 5, the shape of the stress–strain curve can have a tremendous difference on the inelastic rotation capacity of a structural member. The most important parameter appears to be the yield ratio and the ductility of the steel.In addition to research on the high-performance steels, new work on the definition and improvement of conventional steels is also being conducted, spurred by the realization that the physical properties of steels as they are presently being produced are quite different from the steels for which the plastic design research was done 30 years ago. The yield stress is higher and it seems that due to the rotary straightening process the larger shapes end up with zones in their cross section where the ductility is unacceptably low.Further work on this subject is being pursued by Earls at the US Military Academy and by Ricles and his co-workers at Lehigh University. More finite element analyses and laboratory experiments are being conducted to establish the desired stress–strain characteristics of high-performance steel to achieve optimal dimensions for compactness limits, so that this material can be effectively used in seismic design applications. Additional work is done on the design of the best shapes for bridgegirders, and a full-scale girder bridge will be fabricated and tested at the structural laboratory of the Federal Highway Administration at Washington, DC.9.Future directions of structural steel research and conclusionThe future holds many challenges for structural steel research. The ongoing work necessitated by the two recent earthquakes that most affected conventional design methods, namely, the Northridge earthquake in the US and the Kobe earthquake in Japan, will continue well into the first decade of the next Century. It is very likely that future disasters of this type will bring yet other problems to the steel research community. There is a profound change in the philosophy of design for disasters: we can no longer be content with saving lives only, but we must also design structures which will not be so damaged as to require extensive repairs.Another major challenge will be the emergence of many new materials such as high-performance concrete and plastic composite structures. Steel structures will continually have to face the problem of having to demonstrate viability in the marketplace. This can only be accomplished by more innovative research. Furthermore, the new comprehensive limit-states design codes which are being implemented worldwide, need research to back up the assumptions used in the theories.Specifically, the following list highlights some of the needed research in steel structures:Systems reliability tools have been developed to a high degree of sophistication. These tools should be applied to the studies of bridge and building structures to define the optimal locations of monitoring instruments, to assess the。

土木工程建筑外文翻译外文文献英文文献钢筋混凝土

2 外文翻译Introduction to reinforced concrete and earthworksAbstract： As a designer must first clear the building structure itself was designed and intensity levels, as well as related issues in-depth discussion and research, this paper describes on the reinforced concrete, earthwork engineering knowledge, let more in-depth understanding of this Discusses the key, and the rational application of knowledge to help us design more excellent buildingKeywords: concrete, earthwork, structural safety2.1 Reinforced ConcretePlain concrete is formed from a hardened mixture of cement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible because concrete can easily be given any desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned, the finished product becomes strong, durable, and, in combination with the reinforcing bars,1adaptable for use as main members of any structural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean, a wall, a slab, a foundation. a mass columns, or an extension of previously placed and hardened concrete. For beams, columns, and walls, the forms should be well oiled after cleaning them, and the reinforcement should be cleared of rust and other harmful materials. In foundations, the earth should be compacted and thoroughly moistened to about 6 in. in depth to avoid absorption of the moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type, as the case requires, unless it is placed by pumping. It must be kept in mind, however, that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures above 50°temperatures above 50°F. It is necessary to maintain such a condition in order that F. It is necessary to maintain such a condition in order that the chemical hydration reaction can take place. If drying is too rapid, surface cracking takes place. This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydration.It is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element, such as geometrical width, depth, area of reinforcement, steel strain, concrete strain, steel stress, and so on. Consequently, trial and adjustment is necessary in the choice of concrete sections, with assumptions based on conditions at site, availability of the constituent materials, particular demands of the owners, architectural and headroom requirements, the applicable codes, and environmental reinforced concrete is often a site-constructed composite, in contrast to the standard mill-fabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive at the required section, the first design input step generates into a series of trial-and-adjustment analyses.The trial-and The trial-and ––adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design. Hence every design is an analysis once atrial section is chosen. The availability of handbooks, charts, and personal computers and programs supports this approach as a more efficient, compact, and speedy instructional method compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design.2.2 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering, this is a field where there are real opportunities for the enthusiast. In 1935 most of the methods now in use for carrying and excavating earth with rubber-tyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab, though they are still widely used are only a few of the many current methods. To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines. Generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmoving means cutting into ground where its surface is too high ( cuts ), and dumping the earth in other places where the surface is too low ( fills). Toreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness. From the available maps ahd levels, the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork. On the site when further information becomes available he can make changes in jis sections and layout,but the drawing lffice work will not have been lost. It will have helped him to reach the best solution in the shortest time.The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine. This is not always possible, but when it canbe done it is ideal, being both quick and cheap. Draglines, bulldozers and face shovels an do this. The largest radius is obtained with the dragline,and the largest tonnage of earth is moved by the bulldozer, though only over short distances.The disadvantages of the dragline are that it must dig below itself, it cannot dig withforce into compacted material, it cannot dig on steep slopws, and its dumping and digging are not accurate.Face shovels are between bulldozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline. Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful, but its dumping radius is considerably less than that of the same escavator fitted with a face shovel.Rubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel. They can dig the material deeply ( but only below themselves ) to a fairly flat surface, carry it hundreds of meters if need be, then drop it and level it roughly during the dumping. For hard digging it is often found economical to keep a pusher tractor ( wheeled or tracked ) on the digging site, to push each scraper as it returns to dig. As soon as the scraper is full,the pusher tractor returns to the beginning of the dig to heop to help the nest scraper.Bowl scrapers are often extremely powerful machines;many makers build scrapers of 8 cubic meters struck capacity, which carry 10 m ³scrapers of 8 cubic meters struck capacity, which carry 10 m ³ heaped. The largest heaped. The largest self-propelled scrapers are of 19 m ³self-propelled scrapers are of 19 m ³ struck capacity ( 25 m ³ struck capacity ( 25 m ³ struck capacity ( 25 m ³ heaped )and they are heaped )and they are driven by a tractor engine of 430 horse-powers.Dumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials. Dumpers have the earth container over the front axle on large rubber-tyred wheels, and the container tips forwards on most types, though in articulated dumpers the direction of tip can be widely varied. The smallest dumpers have a capacity of about 0.5 m ³0.5 m ³, and the largest standard types are of about 4.5 m ³, and the largest standard types are of about 4.5 m ³, and the largest standard types are of about 4.5 m ³. Special types include . Special types include the self-loading dumper of up to 4 m ³the self-loading dumper of up to 4 m ³ and the articulated type of about 0.5 m ³ and the articulated type of about 0.5 m ³ and the articulated type of about 0.5 m ³. . The distinction between dumpers and dump trucks must be remembered .dumpers tip forwards and the driver sits behind the load. Dump trucks are heavy, strengthened tipping lorries, the driver travels in front lf the load and the load is dumped behind him, so they are sometimes called rear-dump trucks.2.3 Safety of StructuresThe principal scope of specifications is to provide general principles andcomputational methods i computational methods in order to verify safety of structures. The “ safety factor ”, n order to verify safety of structures. The “ safety factor ”, which according to modern trends is independent of the nature and combination of the materials used, can usually be defined as the ratio between the conditions. This ratio is also proportional to the inverse of the probability ( risk ) of failure of the structure.Failure has to be considered not only as overall collapse of the structure but also as unserviceability or, according to a more precise. Common definition. As the reaching of a “ limit state ” which causes the construction not to accomplish the task it was designed for. There are two categories of limit state : (1)Ultimate limit sate, which corresponds to the highest value of the load-bearing capacity. Examples include local buckling or global instability of the structure; failure of some sections and subsequent transformation of the structure into a mechanism; failure by fatigue; elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure; and sensitivity of the structure to alternating loads, to fire and to explosions.(2)Service limit states, which are functions of the use and durability of the structure. Examples include excessive deformations and displacements without instability; early or excessive cracks; large vibrations; and corrosion.Computational methods used to verify structures with respect to the different safety conditions can be separated into:(1)Deterministic methods, in which the main parameters are considered as nonrandom parameters.(2)Probabilistic methods, in which the main parameters are considered as random parameters.Alternatively, with respect to the different use of factors of safety, computational methods can be separated into: (1)Allowable stress method, in which the stresses computed under maximum loads are compared with the strength of the material reduced by given safety factors.(2)Limit states method, in which the structure may be proportioned on the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ).The stresses corresponding to working ( service ) conditions with unfactoredlive and dead loads are compared with prescribed values ( service limit state ) . From the four possible combinations of the first two and second two methods, we can obtain some useful computational methods. Generally, two combinations prevail:(1)deterministic methods, which make use of allowable stresses.(2)Probabilistic methods, which make use of limit states.The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which arethen combined to define the safety factor. probabilistic approaches depend upon :(1) Random distribution of strength of materials with respect to the conditions of fabrication and erection ( scatter of the values of mechanical properties through out the structure );(2) Uncertainty of the geometry of the cross-section sand of the structure ( faults and imperfections due to fabrication and erection of the structure );(3) Uncertainty of the predicted live loads and dead loads acting on the structure;(4)Uncertainty related to the approximation of the computational method used ( deviation of the actual stresses from computed stresses ).Furthermore, probabilistic theories mean that the allowable risk can be based on several factors, such as :(1) Importance of the construction and gravity of the damage by its failure;(2)Number of human lives which can be threatened by this failure;(3)Possibility and/or likelihood of repairing the structure;(4) Predicted life of the structure.All these factors are related to economic and social considerations such as：(1) Initial cost of the construction;(2) Amortization funds for the duration of the construction;(3) Cost of physical and material damage due to the failure of the construction;(4) Adverse impact on society;(5) Moral and psychological views.The definition of all these parameters, for a given safety factor, allows construction at the optimum cost. However, the difficulty of carrying out a complete probabilistic analysis has to be taken into account. For such an analysis the laws of the distribution of the live load and its induced stresses, of the scatter ofmechanical properties of materials, and of the geometry of the cross-sections and the structure have to be known. Furthermore, it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material, on the cross-sections and upon theload acting on the structure. These practical difficulties can be overcome in two ways. The first is to apply different safety factors to the material and to the loads, without necessarily adopting the probabilistic criterion. The second is an approximate probabilistic method which introduces some simplifying assumptions( semi-probabilistic methods ) .References：1. Hanjing Yun. Building decoration materials and their application. China Building Industry Press .2000.2. Xia Yan eds. Civil engineering materials. Wuhan University Press .2009.3. From before the king, Huoman Lin. Building materials (first edition). Lanzhou University Press .19974. Zhang Xiong editor. Building functional materials. China Building Industry Press .2000.5. Yanhan Dong, Qian Xiao Qian ed. New Building Materials tutorial. China Building Materials Industry Press .2005.6. Zhang Fen Qin, Zhao Man ed. Building decoration materials. Chongqing University Press, .2007.7. Xuyou Hui ed. Building materials and learning. Southwest Jiaotong University Press .2007.1 中文翻译钢筋混凝土及土方工程简介摘要：作为设计人员首先必须明确自身设计的建筑构筑物得等级和强度，作为设计人员首先必须明确自身设计的建筑构筑物得等级和强度，以及对相关问题进以及对相关问题进行深入的讨论和研究，本文主要叙述了关于钢筋混凝土，土方工程方面的相关知识，让我们更加深入的了解这方面的主要关键论述，以及合理应用知识来帮助我们设计更加优良的建筑。

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

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