预应力混凝土连续梁毕业设计含外文翻译
土木工程结构设计专业毕业设计英语翻译
XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间目录1、第一篇 (3)2、第二篇 (6)3、第三篇 (9)Concrete, Reinforced Concrete, and PrestressedConcreteConcrete is a stone like material obtained by permitting a carefully proportioned mixture of cement, sand and gravel or other aggregate, and water to harden in forms of the shape and dimensions of the desired structure. The bulk of the material consists of fine and coarse aggregate. Cement and water interact chemically to bind the aggregate particles into a solid mass. Additional water, over and above that needed for this chemical reaction, is necessary to give the mixture workability that enables it to fill the forms and surround the embedded reinforcing steel prior to hardening. Concretes with a wide range of properties can be obtained by appropriates adjustment of the proportions of the constituent materials. Special cements, special aggregates, and special curing methods permit an even wider variety of properties to be obtained.These properties depend to a very substantial degree on the proportions of the mix, on the thoroughness with which the various constituents are intermixed, and on the conditions of humidity and temperature in which the mix is maintained from the moment it is placed in the forms of humidity and hardened. The process of controlling conditions after placement is known as curing. To protect against the unintentional production of substandard concrete, a high degree of skillful control and supervision is necessary throughout the process, from the proportioning by weight of the individual components, trough mixing and placing, until the completion of curing.The factors that make concrete a universal building material are so pronounced that it has been used, in more primitive kinds and ways than at present, for thousands of years, starting with lime mortars from 12,000 to 600 B.C. in Crete, Cyprus, Greece, and the Middle East. The facility with which , while plastic, it can be deposited and made to fill forms or molds of almost any practical shape is one of these factors. Its high fire and weather resistance are evident advantages. Most of the constituent materials, with the exception of cement and additives, are usually available at low cost locally or at small distances from the construction site. Its compressive strength, like that of natural stones, is high, which makes it suitable for members primarily subject to compression, such as columns and arches. On the other hand, again as in natural stones, it is a relatively brittle material whose tensile strength is small compared with its compressive strength. This prevents its economical use in structural members that ate subject to tension either entirely or over part of their cross sections.To offset this limitation, it was found possible, in the second half of thenineteenth century, to use steel with its high tensile strength to reinforce concrete, chiefly in those places where its low tensile strength would limit the carrying capacity of the member. The reinforcement, usually round steel rods with appropriate surface deformations to provide interlocking, is places in the forms in advance of the concrete. When completely surrounded by the hardened concrete mass, it forms an integral part of the member. The resulting combination of two materials, known as reinforced concrete, combines many of the advantages of each: the relatively low cost , good weather and fire resistance, good compressive strength, and excellent formability of concrete and the high tensile strength and much greater ductility and toughness of steel. It is this combination that allows the almost unlimited range of uses and possibilities of reinforced concrete in the construction of buildings, bridges, dams, tanks, reservoirs, and a host of other structures.In more recent times, it has been found possible to produce steels, at relatively low cost, whose yield strength is 3 to 4 times and more that of ordinary reinforcing steels. Likewise, it is possible to produce concrete 4 to 5 times as strong in compression as the more ordinary concrete. These high-strength materials offer many advantages, including smaller member cross sections, reduced dead load, and longer spans. However, there are limits to the strengths of the constituent materials beyond which certain problems arise. To be sure, the strength of such a member would increase roughly in proportion to those of the materials. However, the high strains that result from the high stresses that would otherwise be permissible would lead to large deformations and consequently large deflections of such member under ordinary loading conditions. Equally important, the large strains in such high-strength reinforcing steel would induce large cracks in the surrounding low tensile strength concrete, cracks that would not only be unsightly but that could significantly reduce the durability of the structure. This limits the useful yield strength of high-strength reinforcing steel to 80 ksi according to many codes and specifications; 60 ksi steel is most commonly used.A special way has been found, however, to use steels and concrete of very high strength in combination. This type of construction is known as prestressed concrete. The steel, in the form of wires, strands, or bars, is embedded in the concrete under high tension that is held in equilibrium by compressive stresses in the concrete after hardening, Because of this precompression, the concrete in a flexural member will crack on the tension side at a much larger load than when not so precompressed. Prestressing greatly reduces both the deflections and the tensile cracks at ordinaryloads in such structures, and thereby enables these high-strength materials to be used effectively. Prestressed concrete has extended, to a very significant extent, the range of spans of structural concrete and the types of structures for which it is suited.混凝土，钢筋混凝土和预应力混凝土混凝土是一种经过水泥，沙子和砂砾或其他材料聚合得到经过细致配比的混合物，在液体变硬使材料石化后可以得到理想的形状和结构尺寸。
预应力混凝土Prestressed-Concrete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：预应力混凝土文献、资料英文题目：Prestressed 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毕业设计（论文）外文资料翻译外文出处：The Concrete structure附件：1、外文原文；2、外文资料翻译译文。
1、外文资料原文Prestressed ConcreteConcrete is strong in compression, but weak in tension: Its tensile strength varies from 8 to 14 percent of its compressive strength. Due tosuch a Iow tensile capacity, fiexural cracks develop at early stages ofloading. In order to reduce or prevent such cracks from developing, aconcentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at thecritical midspan and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections. The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.Such an imposed longitudinal force is called a prestressing force,i.e., a compressive force that prestresses the sections along the span ofthe structural elementprior to the application of the transverse gravitydead and live loads or transient horizontal live loads. The type ofprestressing force involved, together with its magnitude, are determined mainly on the basis of the type of system to be constructed and the span length and slenderness desired.~ Since the prestressing force is applied longitudinally along or parallel to the axis of the member, the prestressing principle involved is commonly known as linear prestressing.Circular prestressing, used in liquid containment tanks, pipes,and pressure reactor vessels, essentially follows the same basic principles as does linear prestressing. The circumferential hoop, or "hugging" stress on the cylindrical or spherical structure, neutralizes the tensile stresses at the outer fibers of the curvilinear surface caused by the internal contained pressure.Figure 1.2.1 illustrates, in a basic fashion, the prestressing action in both types of structural systems and the resulting stress response. In(a), the individual concrete blocks act together as a beam due to the large compressive prestressing force P. Although it might appear that the blocks will slip and vertically simulate shear slip failure, in fact they will not because of the longitudinal force P. Similarly, the wooden staves in (c) might appear to be capable of separating as a result of the high internal radial pressure exerted on them. But again, because of the compressive prestress imposed by the metal bands as a form of circular prestressing, they will remain in place.From the preceding discussion, it is plain that permanent stresses in the prestressed structural member are created before the full dead and live loads are applied in order to eliminate or considerably reduce the net tensile stresses caused by these loads. With reinforced concrete,it is assumed that the tensile strength of the concrete is negligible and disregarded. This is because the tensile forces resulting from the bending moments are resisted bythe bond created in the reinforcement process. Cracking and deflection are therefore essentially irrecoverable in reinforced concrete once the member has reached its limit state at service load.The reinforcement in the reinforced concrete member does not exert any force of its own on the member, contrary to the action of prestressing steel. The steel required to produce the prestressing force in the prestressed member actively preloads the member, permitting a relatively high controlled recovery of cracking and deflection. Once the flexural tensile strength of the concrete is exceeded, the prestressed member starts to act like a reinforced concrete element.Prestressed members are shallower in depth than their reinforced concrete counterparts for the same span and loading conditions. In general, the depth of a prestressed concrete member is usually about 65 to 80 percent of the depth of the equivalent reinforced concrete member. Hence, the prestressed member requires less concrete, and,about 20 to 35 percent of the amount of reinforcement. Unfortunately, this saving in material weight is balanced by the higher cost of the higher quality materials needed in prestressing. Also, regardless of the system used, prestressing operations themselves result in an added cost: Formwork is more complex, since the geometry of prestressed sections is usually composed of. flanged sections with thin-webs.In spite of these additional costs, if a large enough number of precast units are manufactured, the difference between at least the initial costs of prestressed and reinforced concrete systems is usually not very large.~ And the indirect long-term savings are quite substantial, because less maintenance is needed; a longer working life is possible due to better quality control of the concrete, and lighter foundations are achieved due to the smaller cumulative weight of the superstructure.Once the beam span of reinforced concrete exceeds 70 to 90 feet (21.3 to 27.4m), the dead weight of the beam becomes excessive, resulting in heavier members and, consequently, greater long-term deflection and cracking. Thus, for larger spans, prestressed concrete becomes mandatory since arches are expensive to construct and do not perform as well due to the severe long-term shrinkage and creep they undergo.~ Very large spans such as segmental bridges or cable-stayed bridges can only be constructed through the use of prestressing.Prestressd concrete is not a new concept, dating back to 1872, when P. H. Jackson, an engineer from California, patented a prestressing system that used a tie rod to construct beams or arches from individual blocks [see Figure 1.2.1 (a)]. After a long lapse of time during which little progress was made because of the unavailability of high-strength steel to overcome prestress losses, R. E. Dill of Alexandria, Nebraska, recognized the effect of the shrinkage and creep (transverse material flow) of concrete on the loss of prestress. He subsequently developed the idea that successive post-tensioning of unbonded rods would compensate for the time-dependent loss of stress in the rods due to the decrease in the length of the member because of creep and shrinkage. In the early 1920s,W. H. Hewett of Minneapolis developed the principles of circular prestressing. He hoop-stressed horizontal reinforcement around walls of concrete tanks through the use of turnbuckles to prevent cracking due to internalliquid pressure, thereby achieving watertightness. Thereafter, prestressing of tanks and pipes developed at an accelerated pace in the United States, with thousands of tanks for water, liquid, and gas storage built and much mileage of prestressed pressure pipe laid in the two to three decades that followed.Linear prestressing continued to develop in Europe and in France, in particular through the ingenuity of Eugene Freyssinet, who proposed in 1926--1928 methods to overcome prestress losses through the use of high-strength and high-ductility steels. In 1940, he introduced thenow well-known and well-accepted Freyssinet system.P. W. Abeles of England introduced and developed the concept of partial prestressing between the 1930s and 1960s. F. Leonhardt of Germany, V. Mikhailov of Russia, and T. Y. Lin of the United States also contributed a great deal to the art and science of the design of prestressed concrete. Lin's load-balancing method deserves particular mention in this regard, as it considerably simplified the design process, particularly in continuous structures. These twentieth-century developments have led to the extensive use of prestressing throughoutthe world, and in the United States in particular.Today, prestressed concrete is used in buildings, underground structures, TV towers, floating storage and offshore structures, power stations, nuclear reactor vessels, and numerous types of bridge systems including segn~ental and cable-stayed bridges, they demonstrate the versatility of the prestressing concept and its all-encompassing application. The success in the development and construction of all these structures has been due in no small measures to the advances in the technology of materials, particularly prestressing steel, and the accumulated knowledge in estimating the short-and long-term losses in the prestressing forces.~2、外文资料翻译译文预应力混凝土混凝土的力学特性是抗压不抗拉：它的抗拉强度是抗压强度的8％一14％。
预应力混凝土梁桥设计外文文献翻译
预应力混凝土梁桥设计外文文献翻译(文档含中英文对照即英文原文和中文翻译)原文：Analysis of Con tin uous Prestressed Concrete BeamsChris Burgoyne1、IntroductionThis conference is devoted to the development of structural analysis rather than the strength of materials, but the effective use of prestressed concrete relies on an appropriate combination of structural analysis techniques with knowledge of the material behaviour. Design of prestressed concrete structures is usually left to specialists; the unwary will either make mistakes or spend inordinate time trying to extract a solution from the various equations.There are a number of fundamental differences between the behaviour of prestressed concrete and that of other materials. Structures are not unstressed when unloaded; the design space of feasible solutions is totally bounded；in hyperstatic structures, various states of self-stress can be induced by altering the cable profile, and all of these factors get influenced by creep and thermal effects. How were these problemsrecognised and how have they been tackled?Ever since the development of reinforced concrete by Hennebique at the end of the 19th century (Cusack 1984), it was recognised that steel and concrete could be more effectively combined if the steel was pretensioned, putting the concrete into compression. Cracking could be reduced, if not prevented altogether, which would increase stiffness and improve durability. Early attempts all failed because the initial prestress soon vanished, leaving the structure to be- have as though it was reinforced; good descriptions of these attempts are given by Leonhardt (1964) and Abeles (1964).It was Freyssineti’s observations of the sagging o f the shallow arches on three bridges that he had just completed in 1927 over the River Allier near Vichy which led directly to prestressed concrete (Freyssinet 1956). Only the bridge at Boutiron survived WWII (Fig 1). Hitherto, it had been assumed that concrete had a Young’s modulus which remained fixed, but he recognised that the de- ferred strains due to creep explained why the prestress had been lost in the early trials. Freyssinet (Fig. 2) also correctly reasoned that high tensile steel had to be used, so that some prestress would remain after the creep had occurred, and also that high quality concrete should be used, since this minimised the total amount of creep. The history of Freyssineti’s early prestressed concrete work is written elsewhereFigure1:Boutiron Bridge,Vic h yFigure 2: Eugen FreyssinetAt about the same time work was underway on creep at the BRE laboratory in England ((Glanville 1930) and (1933)). It is debatable which man should be given credit for the discovery of creep but Freyssinet clearly gets the credit for successfully using the knowledge to prestress concrete.There are still problems associated with understanding how prestressed concrete works, partly because there is more than one way of thinking about it. These different philosophies are to some extent contradictory, and certainly confusing to the young engineer. It is also reflected, to a certain extent, in the various codes of practice.Permissible stress design philosophy sees prestressed concrete as a way of avoiding cracking by eliminating tensile stresses; the objective is for sufficient compression to remain after creep losses. Untensioned reinforcement, which attracts prestress due to creep, is anathema. This philosophy derives directly from Freyssinet’s logic and is primarily a working stress concept.Ultimate strength philosophy sees prestressing as a way of utilising high tensile steel as reinforcement. High strength steels have high elastic strain capacity, which could not be utilised when used as reinforcement; if the steel is pretensioned, much of that strain capacity is taken out before bonding the steel to the concrete. Structures designed this way are normally designed to be in compression everywhere under permanent loads, but allowed to crack under high live load. The idea derives directly from the work of Dischinger (1936) and his work on the bridge at Aue in 1939 (Schonberg and Fichter 1939), as well as that of Finsterwalder (1939). It is primarily an ultimate load concept. The idea of partial prestressingderives from these ideas.The Load-Balancing philosophy, introduced by T.Y. Lin, uses prestressing to counter the effect of the permanent loads (Lin 1963). The sag of the cables causes an upward force on the beam, which counteracts the load on the beam. Clearly, only one load can be balanced, but if this is taken as the total dead weight, then under that load the beam will perceive only the net axial prestress and will have no tendency to creep up or down.These three philosophies all have their champions, and heated debates take place between them as to which is the most fundamental.2、Section designFrom the outset it was recognised that prestressed concrete has to be checked at both the working load and the ultimate load. For steel structures, and those made from reinforced concrete, there is a fairly direct relationship between the load capacity under an allowable stress design, and that at the ultimate load under an ultimate strength design. Older codes were based on permissible stresses at the working load; new codes use moment capacities at the ultimate load. Different load factors are used in the two codes, but a structure which passes one code is likely to be acceptable under the other.For prestressed concrete, those ideas do not hold, since the structure is highly stressed, even when unloaded. A small increase of load can cause some stress limits to be breached, while a large increase in load might be needed to cross other limits. The designer has considerable freedom to vary both the working load and ultimate load capacities independently; both need to be checked.A designer normally has to check the tensile and compressive stresses, in both the top and bottom fibre of the section, for every load case. The critical sections are normally, but not always, the mid-span and the sections over piers but other sections may become critical ，when the cable profile has to be determined.The stresses at any position are made up of three components, one of which normally has a different sign from the other two; consistency of sign convention is essential.If P is the prestressing force and e its eccentricity, A and Z are the area of the cross-section and its elastic section modulus, while M is the applied moment, then where ft and fc are the permissible stresses in tension and compression.c e t f ZM Z P A P f ≤-+≤Thus, for any combination of P and M , the designer already has four in- equalities to deal with.The prestressing force differs over time, due to creep losses, and a designer is usually faced with at least three combinations of prestressing force and moment;• the applied moment at the time the prestress is first applied, before creep losses occur,• the maximum applied moment after creep losses, and• the minimum applied moment after creep losses.Figure 4: Gustave MagnelOther combinations may be needed in more complex cases. There are at least twelve inequalities that have to be satisfied at any cross-section, but since an I-section can be defined by six variables, and two are needed to define the prestress, the problem is over-specified and it is not immediately obvious which conditions are superfluous. In the hands of inexperienced engineers, the design process can be very long-winded. However, it is possible to separate out the design of the cross-section from the design of the prestress. By considering pairs of stress limits on the same fibre, but for different load cases, the effects of the prestress can be eliminated, leaving expressions of the form:rangestress e Permissibl Range Moment ≤Z These inequalities, which can be evaluated exhaustively with little difficulty, allow the minimum size of the cross-section to be determined.Once a suitable cross-section has been found, the prestress can be designed using a construction due to Magnel (Fig.4). The stress limits can all be rearranged into the form:()M fZ P A Z e ++-≤1By plotting these on a diagram of eccentricity versus the reciprocal of the prestressing force, a series of bound lines will be formed. Provided the inequalities (2) are satisfied, these bound lines will always leave a zone showing all feasible combinations of P and e. The most economical design, using the minimum prestress, usually lies on the right hand side of the diagram, where the design is limited by the permissible tensile stresses.Plotting the eccentricity on the vertical axis allows direct comparison with the crosssection, as shown in Fig. 5. Inequalities (3) make no reference to the physical dimensions of the structure, but these practical cover limits can be shown as wellA good designer knows how changes to the design and the loadings alter the Magnel diagram. Changing both the maximum and minimum bending moments, but keeping the range the same, raises and lowers the feasible region. If the moments become more sagging the feasible region gets lower in the beam.In general, as spans increase, the dead load moments increase in proportion to the live load. A stage will be reached where the economic point (A on Fig.5) moves outside the physical limits of the beam; Guyon (1951a) denoted the limiting condition as the critical span. Shorter spans will be governed by tensile stresses in the two extreme fibres, while longer spanswill be governed by the limiting eccentricity and tensile stresses in the bottom fibre. However, it does not take a large increase in moment ，at which point compressive stresses will govern in the bottom fibre under maximum moment.Only when much longer spans are required, and the feasible region moves as far down as possible, does the structure become governed by compressive stresses in both fibres.3、Continuous beamsThe design of statically determinate beams is relatively straightforward; the engineer can work on the basis of the design of individual cross-sections, as outlined above. A number of complications arise when the structure is indeterminate which means that the designer has to consider, not only a critical section,but also the behaviour of the beam as a whole. These are due to the interaction of a number of factors, such as Creep, Temperature effects and Construction Sequence effects. It is the development of these ideas which forms the core of this paper. The problems of continuity were addressed at a conference in London (Andrew and Witt 1951). The basic principles, and nomenclature, were already in use, but to modern eyes concentration on hand analysis techniques was unusual, and one of the principle concerns seems to have been the difficulty of estimating losses of prestressing force.3.1 Secondary MomentsA prestressing cable in a beam causes the structure to deflect. Unlike the statically determinate beam, where this motion is unrestrained, the movement causes a redistribution of the support reactions which in turn induces additional moments. These are often termed Secondary Moments, but they are not always small, or Parasitic Moments, but they are not always bad.Freyssinet’s bridge across the Marne at Luzancy, started in 1941 but not completed until 1946, is often thought of as a simply supported beam, but it was actually built as a two-hinged arch (Harris 1986), with support reactions adjusted by means of flat jacks and wedges which were later grouted-in (Fig.6). The same principles were applied in the later and larger beams built over the same river.Magnel built the first indeterminate beam bridge at Sclayn, in Belgium (Fig.7) in 1946. The cables are virtually straight, but he adjusted the deck profile so that the cables were close to the soffit near mid-span. Even with straight cables the sagging secondary momentsare large; about 50% of the hogging moment at the central support caused by dead and live load.The secondary moments cannot be found until the profile is known but the cable cannot be designed until the secondary moments are known. Guyon (1951b) introduced the concept of the concordant profile, which is a profile that causes no secondary moments; es and ep thus coincide. Any line of thrust is itself a concordant profile.The designer is then faced with a slightly simpler problem; a cable profile has to be chosen which not only satisfies the eccentricity limits (3) but isalso concordant. That in itself is not a trivial operation, but is helped by the fact that the bending moment diagram that results from any load applied to a beam will itself be a concordant profile for a cable of constant force. Such loads are termed notional loads to distinguish them from the real loads on the structure. Superposition can be used to progressively build up a set of notional loads whose bending moment diagram gives the desired concordant profile.3.2 Temperature effectsTemperature variations apply to all structures but the effect on prestressed concrete beams can be more pronounced than in other structures. The temperature profile through the depth of a beam (Emerson 1973) can be split into three components for the purposes of calculation (Hambly 1991). The first causes a longitudinal expansion, which is normally released by the articulation of the structure; the second causes curvature which leads to deflection in all beams and reactant moments in continuous beams, while the third causes a set of self-equilibrating set of stresses across the cross-section.The reactant moments can be calculated and allowed-for, but it is the self- equilibrating stresses that cause the main problems for prestressed concrete beams. These beams normally have high thermal mass which means that daily temperature variations do not penetrate to the core of the structure. The result is a very non-uniform temperature distribution across the depth which in turn leads to significant self-equilibrating stresses. If the core of the structure is warm, while the surface is cool, such as at night, then quite large tensile stresses can be developed on the top and bottom surfaces. However, they only penetrate a very short distance into the concrete and the potential crack width is very small. It can be very expensive to overcome the tensile stress by changing the section or the prestress。
外文翻译中英文——预应力混凝土建筑
外文资料：Prestressed Concrete BuildingsPrestressed concrete has been widely and successfully applied to building construction of all types.Both precast pretensioned members and cast-tensioned structures are extensively employed,sometimes in competition with one another, most effectively in combination wit each other.Prestressed concrete offers great advantages for incorporation in a totalaspects of these, that is, structure plus other building. It is perhaps the “integrative”functions,which have made possible the present growth in use of prestressed concrete buildings.These advantages include the following:Structural strength; Structure rigidity;Durability;Mold ability,into desired forms and shapes;Fire resistance;Architectural treatment of surfaces;Sound insulation;Heat insulation; Economy; Availability, through use of local materials and labor to a high degree.Most of the above are also properties of conventionally reinforced concrete. Presrressing,however,makes the structural system more effective by enabling elimination of the technical of difficulty,e.g.,cracks that spoil the architectural treatment.Prestressing greatly enhance the structure efficiency and economy permitting longer spans and thinner elements.Above all,it gives to the architect-engineer a freedom for variation and an ability to control behavior under service conditions.Although prestressed concrete construction involves essentially the same consideration and practices as for all structures, a number of special points require emphasis or elaboration.The construction engineer is involved in design only to a limited extent. First,he muse be able to furnish advice to the architect and engineer on what can he done. Because of his specialized knowledge of techniques relating to prestressed concrete construction, he supplies a very needed service to the architect-engineer.Second, the construction engineer may be made contractually responsible for the working drawings;that is,the layout of tendons,anchorage details,etc.It is particularly important that he gives careful attention to the mild steel and concrete details to ensure these are compatible with his presressing details.Third, the construction engineer is concerned with temporary stresses, stresses at release, stresses in picking, handling and erection, and temporary condition prior to final completion of the structure, such as the need of propping for a composite pour.Fourth,although the responsibility for design rests with the design engineer, nevertheless the construction engineer is also vitally concerned that the structure be successful form the point of view of structural integrity and service behavior. Therefore he will want to look at the bearing and connection details, camber, creep, shrinkage,thermal movements,durability provisions,etc.,and advise the design engineer of any deficiencies he encounters.Information on new techniques and especially application of prestressing to buildings are extensively available in the current technical literature of national and international societies.The International Federation of Prestressing(I.F.P)has attempted to facilitate the dissemination of this information by establishing a Literature Exchange Service,in which the prestressing journals of some thirty countries are regularly exchanged.In addition,an Abstract is published intermittently by I.F.P The Prestressed Concrete Institute(USA)regularly publishes a number of journals and pamphlets on techniques and applications, and proceduresare set up for their dissemination to architects and engineers as well as directly to the construction engineer. It is important that he keep abreast of these national and worldwide developments, so as to be able to recommend the latest and best that is available in the art,and to encourage the engineer to make the fullest and most effective use of prestressed concrete in their buildings.With regard to working drawings, the construction engineer must endeavor to translate the design requirements into the most practicable and economical details of accomplishment,in such a way that the completed element or structure fully complies with the design requirement;for example, the design may indicate only the center of gravity of prestressing and the effective prestress force. The working drawing will have to translate this into tendons having finite physical properties and dimensions.If the center of gravity of pre-stressing is a parabolic path then,for pre-tensioning,and approximation by chords is required,with hold-down points suitably located.The computation of pre-stress losses,form transfer stress to effective stress, must reflect the actual manufacturing and construction process used,as well as thorough knowledge of the properties of the particular aggregates and concrete mix to be employed.With post-tensioning, anchorages and their bearing plates must be laid out in their physical dimension. It is useful in the preparation of complex anchorage detail layouts to use full-scale drawings, so as to better appreciate the congestion of mild steel and anchorages at the end of the member. Tendons and reinforcing bars should be shown in full size rather than as dotted lines. This will permit consideration to be given as to how the concrete can be placed and consolidated.The end zone of both pre-tensioned and post-tensioned concrete memberssubject to high transverse or bursting stresses. These stresses are also influenced by minor concrete details,such as chamfers.Provision of a grid of small bars (sometimes heavy wire mesh is used), as close to the end of a girder as possible, will help to confine and distribute the concentrated forces. Closely spaced stirrups and/or tightly spaced spiral are usually needed at the end of heavily stressed members.Recent tests have confirmed that closeness of spacing is much more effective than increase in the size of bars. Numerous small bars, closely spaced, are thus the best solution.Additional mild-steel stirrups may also be required at hold-down points to resist the shear. This is also true wherever post-tensioned tendons make sharp bends. Practical consideration of concretion dictates the spacing of tendons and ducts. The general rules are that the clear spacing small be one-and-one-half times the maximum size of coarse aggregate. In the overall section, provision must be made for the vibrator stinger.Thus pre-stressing tendons must either be spaced apart in the horizontal plane, or, in special cases, bundled.In the vertical plane close contact between tendons is quite common.With post-tensioned ducts,however,in intimate vertical contact,careful consideration has to be given to prevent one tendon form squeezing into the adjacent duct during stressing.This depends on the size of duct and the material used for the duct.A full-scale layout of this critical cross section should be ually,the best solution is to increase the thickness ( and transverse strength ) of the duct, so that it will span between the supporting shoulders of concrete.As a last rest\ort it may be necessary to stress and grout one duct before stressing the adjacent one.This is time-consuming and runs the risks of grout blockage due to leaks from one duct to the other. Therefore the author recommendsthe use of heavier duct material,or else the respacing of the ducts.The latter,of course, may increase the prestressing force required.中文翻译：预应力混凝土建筑预应力混凝土已经广泛并成功地用于各种类型的建筑。
桥梁专业毕业设计-连续梁(含外文翻译)
二○一○届毕业设计雀鼠谷大桥设计书学院：公路学院专业：桥梁工程姓名：王萌学号：2102060133指导教师：陈峰完成时间：2010-6-12二〇一〇年六月毕业设计（论文）任务书课题名称雀鼠谷大桥设计学院(部) 公路学院桥梁系专业桥梁工程班级21020601学生姓名王萌学号21020601334月 26日至 6 月 18 日共 10 周指导教师(签字)教学院长(签字)年月日一、设计内容（论文阐述的问题）①根据已给设计资料，选择三至四种以上可行的桥型方案，拟定桥梁结构主要尺寸，根据技术经济比较，推荐最优方案进行全桥的纵、横、平面布置，并合理拟定上、下部结构的细部尺寸。
②根据推荐方案桥型确定桥梁施工方案。
③对推荐桥梁方案进行运营及施工阶段的内力计算，上部结构（束）设计；配筋（束）设计，并进行内力组合，强度、刚度、稳定性等验算。
④施工方案制定，施工验算。
⑤绘制上部结构的方案比选图，总体布置图，一般构造图、钢筋构造图及施工示意图。
⑥编写设计计算书。
二、设计原始资料（实验、研究方案）1、设计桥梁的桥位地型及地质图一份。
2、设计荷载：公路—Ⅰ级3、桥面宽度：：2×（0.5+净—11.5＋0.5）4、抗震烈度： 7级烈度设防5．风荷载：500Pa6、通航要求：无7、温度：最高月平均温度405º最低月平均温度0º施工温度22º 8．平曲线半径：7000米竖曲线半径： 4500米9．纵坡： <=3% 横坡：<=1.5%10．桥头引道填土高度：<=4米主要技术指标①设计依据：JTG D60-2004《公路桥涵设计通用规范》JTJ 022-85《公路砖石及混凝土桥涵设计规范》JTG D62-2004《公路钢筋混凝土及预应力混凝土桥涵设计规范》JTG D62-2004《公路钢筋混凝土及预应力混凝土桥涵设计规范》②材料：混凝土：50号；预应力钢筋：φj15钢绞线非预应力钢筋：直径≥12mm的用Ⅱ级螺纹钢筋，直径<12mm 的用Ⅰ级光圆钢筋；锚具：XM锚或OVM锚三、设计完成后提交的文件和图表（论文完成后提交的文件）1、计算说明书部分：(除附录的计算结果文本外，其余必须手写)设计计算书一套。
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。
本科生毕业设计预应力混凝土连续梁桥设计开题报告
本科生毕业设计预应力混凝土连续梁桥设计开题报告一、课题来源、目的、意义，国内外基本研究概况（1）课题来源预应力混凝土连续梁桥是预应力桥梁中的一种，它具有整体性能好、结构刚度大、变形小、抗震性能好，特别是主梁变形挠曲线平缓，桥面伸缩缝少，行车舒适等优点。
故其在当今桥梁的应用中极其普遍[1]。
（2）目的及意义毕业设计是高等教学过程中一个重要的综合性教学实践环节，也是实现本科培养目标要求的重要阶段。
毕业设计是学生学完理论基础课、技术基础课、专业课以后，按照教学大纲的要求，在指导老师下独立完成一项设计或撰写一篇论文。
做好毕业设计可以使学生所学的基础理论知识与专业知识更加系统、巩固、延伸和拓展。
对工科院校而言，可使学生收到工程技术和科学技术的基本训练，以及工程技术人员所必需的综合训练，提高学生调查研究、理论分析、计算、绘图和外语翻译等各方面的能力特别是综合运用所学基本理论只是分析、解决工程实际问题的能力。
毕业设计是完成教学计划达到本科培养目标的重要环节。
此外，通过设计，还能够提高我们的综合能力：1）培养分析和解决问题的独立工作能力；2）提高计算、绘图、查阅文献、使用规范手册和编写技术及计算机辅助设计计算等基本技能，使学生了解生产设计的主要内容和要求；3）掌握大、中桥型的设计原则、设计方法和步骤；4）树立正确设计思想以及严谨负责、实事求是、刻苦钻研、勇于创新的作风，为桥梁建设事业服务。
（3）国内外基本研究情况由于悬臂施工方法的应用，连续梁在预应力混凝土结构中有了飞速的发展。
60年代初期在中等跨径预应力混凝土连续梁中，应用了逐跨架设法与顶推法；60年代中期在德国莱茵河建成的本多夫（Bendorf）桥，采用了悬臂浇筑法[2]。
随着悬臂浇筑施工法和悬臂拼装施工法的不断改进、完善和推广应用，在跨度为40—200米范围内的桥梁中，连续梁桥逐步占据了主要地位。
目前，无论是城市桥梁、高架道路、山谷高架栈桥，还是跨河大桥，预应力混凝土连续梁都发挥了其独特的优势，成为优胜方案[3]。
预应力混凝土连续梁桥的毕业设计
预应力混凝土连续梁桥的毕业设计北方工业大学本科毕业设计（论文）报告书题目：指导教师：专业班级：学号：姓名：日期：绪论预应力混凝土连续梁桥以结构受力性能好、变形小、伸缩缝少、行车平顺舒适、造型简洁美观、养护工程量小、抗震能力强等而成为最富有竞争力的主要桥型之一。
本章简介其发展：由于普通钢筋混凝土结构存在不少缺点：如过早地出现裂缝，使其不能有效地采用高强度材料，结构自重必然大，从而使其跨越能力差，并且使得材料利用率低。
为了解决这些问题，预应力混凝土结构应运而生，所谓预应力混凝土结构，就是在结构承担荷载之前，预先对混凝土施加压力。
这样就可以抵消外荷载作用下混凝土产生的拉应力。
自从预应力结构产生之后，很多普通钢筋混凝土结构被预应力结构所代替。
我国的预应力混凝土结构起步晚，但近年来得到了飞速发展。
现在，我国已经有了简支梁、带铰或带挂梁的T构、连续梁、桁架拱、桁架梁和斜拉桥等预应力混凝土结构体系。
虽然预应力混凝土桥梁的发展还不到80年。
但是，在桥梁结构中，随着预应力理论的不断成熟和实践的不断发展，预应力混凝土桥梁结构的运用必将越来越广泛。
然而，当跨度很大时，连续梁所需的巨型支座无论是在设计制造方面，还是在养护方面都成为一个难题；而T型刚构在这方面具有无支座的优点。
因此有人将两种结构结合起来，形成一种连续—刚构体系。
这种综合了上述两种体系各自优点的体系是连续梁体系的一个重要发展，也是未来连续梁发展的主要方向。
另外，由于连续梁体系的发展，预应力混凝土连续梁在中等跨径范围内形成了很多不同类型，无论在桥跨布置、梁、墩截面形式，或是在体系上都不断改进。
在城市预应力混凝土连续梁中，为充分利用空间，改善交通的分道行驶，甚至已建成不少双层桥面形式。
在设计预应力连续梁桥时，技术经济指针也是一个很关键的因素，它是设计方案合理性与经济性的标志。
目前，各国都以每平方米桥面的三材（混凝土、预应力钢筋、普通钢筋）用量与每平方米桥面造价来表示预应力混凝土桥梁的技术经济指针。
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石家庄铁道大学毕业设计（20+40+20）m预应力混凝土连续梁结构设计The Construction Design of the (20+40+20)m Prestressed concrete continuous beam2012 届高等技术学院专业道路桥梁工程技术学号20095116学生姓名 1 2 3指导教师 2 2完成日期2012年5月28日毕业设计任务书毕业设计开题报告摘要本设计主要是关于公路预应力混凝土连续梁桥上部结构的设计。
设计跨度(20+40+20)m。
本设计采用国内著名的有限元分析软件——迈达斯计算,全桥共分40个单元，41个截面，两个施工阶段。
因为连续梁的内力与其施工方法密切相关，本设计采用满堂支架法施工。
这种施工方法操作比较简单，相比其他方法从经济效益上讲也比其他方法更有优势，而且施工质量易得到保证。
计算过程中由于涉及到大量的数字运算，采用手算比较繁琐，并且准确性得不到保证，因此采用计算机辅助设计。
设计中使用了迈达斯来计算内力,并且初步估算配筋量和进行初步验算。
但为了提高设计可靠性，最终还会通过以Excel电子表格计算、AutoCAD辅助软件进行手算，使自己的设计能力有较大的提升。
关键词：预应力混凝土连续梁桥; 迈达斯; 满堂支架法ABSTRACTThis graduate design is mainly about the design of the superstructure of the road prestressed concrete continuous bridge. The span of the bridge is 20m+40m+20m.This design adopts the domestic famous analytical software—MIDAS.The bridge is divided totally into 40units、41 sections and 2 construction stages. Because of the internal force of the continuous girder bridge relating to the method of construction closely, the method of construction of this design adopts the full scaffold construction method. Compared with other methods, this method is quite easy to construct and has economic superiority and the quantity of this construction also could get the assurance easily.Because this design involving a great deal of numerical calculation, it's too tedious to work by hand and the accuracy assuranced hardly. So it restores to CAD. Many bridge specialized software are applied, such as MIDAS applied in calculation of internal forces. and the initial estimate amount of reinforcing steel and initial checking. However, in order to improve design reliability, this will eventually be calculated by the Excel, AutoCAD and other auxiliary software by hand, developing design capabilities with a great improvement at the same time.Key word: Prestressed Concrete Continuous Bridge, MIDAS , Full Scaffold Construction目录第1章绪论 (1)1.1引言 (1)1.2预应力混凝土连续梁桥的发展 (1)1.2.1 国内外预应力混凝土连续梁桥的发展状况 (1)1.2.2预应力混凝土结构的特点 (3)第2章桥梁的总体设计概况 (4)2.1设计基本资料 (4)2.1.1总体设计 (4)2.1.2 主要技术标准 (4)2.1.3 主要材料 (4)2.1.4 设计依据 (4)2.2桥型及纵横断面布置 (5)2.2.1桥型布置及孔径划分 (5)2.2.2截面形式与截面尺寸 (5)第3章模型建立及结果分析 (6)3.1MIDAS的建模说明 (6)3.1.1 MIDAS的介绍 (6)3.1.2 MIDAS的建模步骤 (6)3.2恒载内力计算 (10)3.2.1恒载内力计算 (10)3.2.2活载内力计算 (11)3.2.3钢束的布置与计算 (12)第4章预应力损失及有效应力的计算 (20)4.1预应力损失的计算 (20)4.1.1摩阻损失 (20)4.1.2锚具变形损失 (21)4.1.3混凝土的弹性压缩 (21)4.1.4钢束松弛损失 (21)4.1.5收缩徐变损失 (22)4.2有效预应力的计算 (22)第5章预加力产生的次内力及内力组合 (24)5.1原理 (24)5.2计算方法 (25)5.2.1等效荷载法 (25)第6章内力组合 (26)6.1承载能力极限状态下的效应组合 (26)6.2正常使用极限状态下的效应组合 (31)第7章主梁截面验算 (39)7.1正截面抗弯承载力验算 (39)7.2持久状况正常使用极限状态应力验算 (40)7.2.1 正截面抗裂验算（法向拉应力） (40)7.2.2 斜截面抗裂验算（主拉应力） (42)7.2.3 使用阶段预应力混凝土受压区混凝土最大压应力验算 (43)7.2.4 预应力钢筋中的拉应力验算 (44)7.2.5 混凝土的主压应力验算 (44)7.3短暂状况预应力混凝土受弯构件应力验算 (44)第8章结束语 (46)参考文献 (47)致谢 (48)附录 (49)外文翻译 (49)第1章绪论1.1引言随着经济建设的迅速发展，我国城市交通的桥梁建设也进入迅速发展时期。
预应力混凝土连续梁优于普通钢筋混凝土连续梁的另一重要特点，就是它可以有效地避免混凝土开裂，特别是处于负弯矩区的桥面板的开裂。
与预应力混凝土T形刚构桥相比，连续梁桥的下部结构受力和构造简单，节省材料，加之它具有变形和缓、伸缩率小、刚度大、行车平稳、超载能力大、养护简便等优点，尤其是悬臂施工法、顶推法、逐跨施工法在连续梁桥中的应用，这种充分应用预应力技术的优点使施工设备机械化，生产工厂化，从而提高了施工质量，降低了施工费用。
所以在近代桥梁建筑中已得到越来越多的应用。
连续梁是超静定结构，基础不均匀沉降将在结构中产生附加内力，因此，对桥梁基础要求较高，通常宜用于地基较好的场合。
此外，箱梁截面局部温差，混凝土收缩、徐变及预加应力均会在结构中产生附加内力，增加了设计计算的复杂程度。
本桥段采用满堂支架法施工，满堂脚手架又称作满堂红脚手架，是一种搭建脚手架的施工工艺。
本桥段是一级公路上一座预应力混凝土等截面连续梁桥（跨径同设计题目），横桥向宽度为12.5m，单箱单室，下部结构采用实体墩，灌注桩基础。
桥梁设计基准期100年，结构设计安全等级一级，A类构件，可变荷载：汽车荷载：公路—Ⅰ。
1.2预应力混凝土连续梁桥的发展1.2.1国内外预应力混凝土连续梁桥的发展状况连续梁是一种古老的结构体系，它具有变形小，结构刚度好、行车平顺舒适，伸缩缝少，养护简易，抗震能力强等优点。
而在50年代前，预应力混凝土连续梁虽是常被采用的一种体系，但跨径均在百米以下。
当时主要采用满堂支架施工，费工费时，限材了它的发展。
50年代后，预应力混凝土桥梁应用悬臂施工方法后，加速了它的发展步伐。
预应力锚具结构的悬臂体系和悬臂施工方法相结合产生了T型刚构，在60年代，跨径100-200m范围内，几乎是大跨预应力混凝土梁桥中的优胜方案。
早期有典型意义的桥梁便是联邦德国1953年建造的胡尔姆斯桥和1954年建成的科布伦茨(Koblenz)桥。
然而，这种结构，由于中间带铰，并对混疑土徐变，收缩变形估计不足，又因温度影响等因素使结构在铰处形成明显折线变形状态，对行车不利。
因此，对行车条件有利的连续梁获得了新的发展。
对中跨预应力混凝土连续梁，在60年代初期，逐跨架设法与顶推法(F.Leonhardt所创建)的应用，对大跨预应力混凝土连续梁，各种更完善的悬针施工方法的应用，使连续梁废弃了昂贵的满堂的施工方法而代之以经济有效的高度机械化施工方法，从而使连续梁方案获得新的竞争力，逐步在40-200m范围内占主要地位。
如1962年在委内瑞拉的卡尼罗河上，用顶推法修建的6跨连续箱梁桥是顶推法的代表作，主跨为96m。
图1-1预应力混凝土连续梁桥无论是城市桥梁、高架道路、山谷高架栈桥，还是跨越宽阔河流的大桥，预应力混凝土连续梁都发挥了它的优势，往往取代其它体系而成为中选的优胜方案。
预应力混凝土连续梁在中等跨径范围，它更是千姿百态。
无论在桥跨布置、梁、墩赴面形式，或是在体系上(吸取其它结构的优点)不断改进桥型布置，例如V形墩的连续梁体系、双薄壁墩连续梁体系。
值得一提的是法国的SetubedLogoon桥，主跨130m 的五跨连续染，中间墩采用双薄壁结构，双壁相距10m，壁厚仅0.5m。
预应力混凝土连续梁在40-60m的范围，已可以说占绝对优势。
顶推法、移动模架法、逐孔架设法等施工方法经济快速，广泛应用也是关键因素。
如瑞士的Beckenried 高架桥，总长3048m，标准跨径55m。
连续梁的横截面形式在小跨径的城市高架桥中，为求最小建筑高度，常选用板式或肋板式截面，而在中、大跨径主要采用箱式截面。
但总的发展趋势是尽可能加长悬臂桥面板而选用单箱截面，以达到快速施工的目的。
在这种单箱截面的锚具结构中，往往采用三向预应力工艺。
预应力混凝土连续梁用干城市桥梁，为充分利用空间，并改善交通的分道行驶，已建成不少双层桥面的型式。
在这方面的一个突出例子是1980年在维也纳市多瑙河上新建的帝国(New Rei-chs)桥。