桥梁翻译
桥梁外文翻译 ---荷兰跨线高架桥
附录4 外文文献翻译RAILWAY SUSPENSION BRIDGEIN WOERDEN, THE NETHERLANDSSUMMARYIn Woerden, a small town in the west of the Netherlands, a railway fly-over has been builtwhere two railway tracks meet. The fly-over consists of a single-track viaduct. This has alength of 438.5 m. The crossing angle is 10 degrees. At the fly-over site the viaduct issuspended from a pylon that has been constructed over two tracks passing underneath.1. INTRODUCTIONA railway bridge was constructed in Woerden as part of the track expansion of theNetherlands Railways. More trains will be run, the running speeds will be increased and thepossibility of delays must be reduced. In order to make this possible, many line sections mustbe four-track and trains must be able to cross each other at different levels.This paper examines the fly-over in Woerden.2. SITUATION AND REQUIREMENTSThe fly-over in Woerden must bridge the following elements:- two existing tracks;- two future tracks;- a polder drainage pool;- an underpass for all traffic.The subsoil exhibits a great variation in compressibility. The forecast for settlement after 30years for the adjacent track bed on one side is about 0.5 m and on the other side about 3 m. To limit settlement, and due to the lack of space for access, the construction height of thebridge must be as low as possible.The existing tracks and the underpass must remain in operation during the construction. Theflow capacity of the polder drainage pool may not be restricted.3. GENERAL DESCRIPTIONThe total length of the viaduct is 438.5 m, comprising six sections (fig. 1).Section I crosses the underpass and has a length of 82.3 m. The two intermediate supports aresituated immediately adjacent to the concrete casing of the underpass, setting the spans at22.7 m, 35 m and 22.65 m.Sections II to V have a length of 47.3 m and each consists of two spans of 22.65 m. Thelengths and spans were determined by the remaining space between sections I and VI and costoptimisation. Section II crosses the polder drainage pool.Section VI, with a length of 167 m, crosses the two existing and the two future tracks. Thespans range between 26.3 and 46.7 m, with the supports staggered under the side beams. Allbridges have been made from pre-stressed concrete.To limit the construction height, it was decided to employ a U-shapedcross-section (fig. 2). The track floor lies low between the two load-bearing perimeter beams with a breadth of 1.4m. The height of the beams is 1.5 m for the small spans and 2.8 m for the larger. Theappearance of a gradual transition from low to high beams is caused by walls that increase inheight at the ends of the low beams, connecting to the high beams.The track construction consists of a continuous ballast bed. Only for the transition fromsection VI to the track bed are two compensation welds used in the rails to absorb changes inlength due to temperature shifts. At the other joins between the bridge sections the rails runcontinuously through.The lack of space at the site means that the crossing angle with the tracks that are to be newlylaid is only 10 degrees. In addition, points are projected to be positioned in the tracks passingunderneath, so that no columns can be located between the new tracks. For such situations, ‘pergola constructions’ are often built, consisting of long rows of columns along the trackwhich support a concrete deck with a span direction perpendicular to the tracks passingunderneath. The pergola would in this situation be 160 m long and vary between 14 m and 28m in width.For aesthetic and economic reasons, an innovative solution has been developed: Thesuspension of the crossing U-shaped bridge from a pylon which is constructed over the tracksthat will be running underneath (fig. 3). This creates a transparent construction thatguarantees a view of the countryside and clearly expresses the forces at work. This bridge isthe first of its kind in the Netherlands.Despite the high construction cost of the pylon, the total cost of the solution chosen is lowerthan for a pergola.The suspension from the pylon is such that the forces in the U-shaped bridge work as evenlyas possible and high peak stresses are avoided. The load from theU-shaped beams is divertedto the three suspension cable anchors per beam underneath. The cables run via conduitsthrough the beams to the intersection of the ridge beam and the slanting pylon columns (fig. 4).The horizontal loads from the bridge are fed directly to the columns of the pylon via ridgeslocated on the outside of the U-shaped beams.4. CONSTRUCTION ASPECTS4.1 Static system superstructureThe fly-over is constructed from six bridge sections. The bridge parts are mounted onreinforced rubber bearings. At their extremes, the sections are fixed horizontally in the crossdirection by steel guiding constructions that primarily absorb the horizontal thrust forces andcentrifugal forces; the ends of the bridge are free to move in the longitudinal direction. Thesection crossing the track is also fixed at the pylon both in the cross direction and in thelongitudinal direction by horizontal struts between the U-shaped floor and the pylon.4.2 SubstructureThe foundations of the fly-over are primarily pre-fabricated pre-stressed 450 x 450 mm2concrete piles with a length varying between 13 m and 18 m and with a pile depth varyingfrom 12.50 m to 18.00 m below ground level. Both abutments have a foundation of steel pipe piles Ø 508 mm with a wall thickness of 16mm. The piles are filled with concrete and fitted with reinforcement. The use of steel pipepiles for the abutments was made necessary by the settlement of the connecting raised trackbeds as a result of the compressible subsoil which might subject the piles to bending. Prestressedconcrete driven piles turned out not to be able to absorb these bending moments.The columns under the U-shaped bridge ends are coupled crossways with a beam constructiondue to the horizontal forces that are diverted there via the guiding constructions. In order to be able to quantify the interaction of the track with thesubstructure, a tracklongitudinal forces program has been developed in which the whole system is divided intodiscrete components by means of the following elements:- rail elements;- ballast elements;- bridge elements;- bearing elements;- pile elements;- foundation elements.The bridge system is physically described with these elements, and the accompanyingparameters are entered for each type.Generally, CWR track is used. If, however, the expanding bridge lengths become too great, ‘compensation’ welds or compensation constructions, in which the track has overlapping ‘tongues’ and so is free to undergo deformation, must be used due to the rail forces reachingtoo high a level as a result of braking forces and temperature effects. At the location of one of the intermediate supports, bridge section VI is suspended from apylon construction where the bridge is also fixed horizontally. Due to the high stiffness of thisconstruction, this determines the free expansion length to the abutment. This length is greaterthan 60 m, the maximum free expansion length to an abutment for ballasted track. For thisreason two compensation welds are used at the abutment.4.3 Pre-stressingThe U-shaped bridges are constructed from pre-stressed concrete.The following can be distinguished:- longitudinal pre-stressing in the U-shaped beams, through which thebeam’s ownweight, the permanent load and the working load arediverted;- cross pre-stressing of the U-shaped ends in the base. This absorbs theshear tensionsthat are generated as a result of the longitudinalpre-stressing.For the 167 m long track-crossing section VI, a 27-strand longitudinalpre-stressing systemwas chosen with strands Ø 15,2 mm, FeP 1860. Eight units are used for each beam. For thecross pre-stressing, the BBRV system, which is not liable to wedge-settlement, was chosen. This was due to the relatively short length (approx.7.50 m), which means that the effect ofwedge settlement would have been too great on the extent of the pre-stressing.The average pre-stressing level in the U-shaped bridges is between 4.5 and 5.5N/mm2.An additional complication arose at the pylon where the bridge is suspended with vertical guycables. There are three guy cables for each U-shaped beam which are carried via steelconduits Ø 400 mm through the 1.40 m wide U-shaped beams. This provided much concernwith respect to accommodating the eight pre-stressing cables, the shear forces that arise andthe soft steel reinforcement connected with this as a result of the bending of the tensiontrajectories through this deformation. The criterion for the maximum permissible stress (0,45f'‘ck) was the guideline at this site.The U-shaped bridges were calculated with a finite-element model in which such factors as, with a view to fatigue, the main pull in the concrete would not exceed the value of 0,5 f’'ck.4.4 PylonThe pylon was calculated by means of dividing it into discrete bar elements in a finite-elementmodel. The horizontal struts, that can only bear compressive forces, were divided into springelements with the characteristic that they are inactive for an pulling load, so that it is a nonlinearcalculation.The horizontal struts (figs. 5 and 6) that fix the U-shaped bridge both in the longitudinal andin the cross direction, thus bear the longitudinal forces (primarily braking, starting and trackforces) and the cross forces (mainly thrust, centrifugal and wind forces).The horizontal struts comprise four steel pipes Ø 508 mm with a wall thickness of 30 mm. The length varies from 1025 mm to 2285 mm. The brackets are constructed in such a waythat they are able only to bear compressive forces. The steel pipes provide support for concretebrackets at the base level of the bridge. This connection, that cannot absorb pull forces, isfitted with a conical dowel, a ‘seeker dowel’, that ensures that the support construction iscentred at all times, even when it is disengaged by a few millimetres from the connection tothe U-shaped bridge.The maximum compressive force that occurs in the most heavily loaded strut is 3020 kN. Themaximum cross force has been calculated at 248 kN.4.5 Guy cablesAt the pylon, the bridge is suspended with two groups of vertical guy cables. Three cables arefitted to each beam, which move as a group in relation to the axis of this support (fig. 5). Thecables are fed through the U-shaped beam and pylon viain-built steel conduits, with theanchor-heads are supported to accurately horizontally positioned steel anchor plates. The cables are ‘Hiam cables’, composed of 253 strands Ø 7 mm, FeP 1670.Load on the cables:- the six cables absorb a maximum reactive force of 20970 kN, 22% ofwhichis causedby the working load;- the most heavily loaded cable absorbs a maximum reactive force of3880 kN;- the least heavily loaded cable absorbs a reactive force of 3070 kN.In the design of the cables, the following requirements were set:-the maximum deformation due to the working load must be less than1/800 part of theadjoining span;- collapse safety criteria;- fatigue criteria;- changing a cable under the own weight of the bridge and permanentload;- taking over the load after sudden failure of a cable under maximumload;- preservation requirements.荷兰跨线高架桥摘要在荷兰西部的一个小镇两条铁路相交的地方，一座跨线铁路桥已经修建。
桥梁隧道英汉文翻译
LONG-TERM DETERIORATION OF HIGHDAMPING RUBBER BRIDGE BEARINGIn recent years, high damping rubber (HDR) bridge bearings have become widely used because of the excellent ability to provide high damping as well as flexibility. However, there are few systematic studies on the deterioration problems of HDRs during their service life, and usually the long-term performance was not considered in the design stage. In this research, through accelerated thermal oxidation tests on HDR blocks, the property variations inside the HDR bridge bearing are examined. A deterioration prediction model is developed to estimate the property profiles. Then using a constitutive model and carrying out FEM analysis, the behavior of a HDR bridge bearing during its lifespan is clarified. A design procedure is proposed that takes the long-term performance in the site environment into consideration.Key Words:high damping rubber bearing, thermal oxidation, deterioration, long-term performance1. INTRODUCTIONSince Hyogoken-Nanbu earthquake that occurred on January 17th, 1995, bridge bearings have been widely adopted in Japan as an effective means to weaken the severe damage of steel and concrete piers due to an earthquake1), 2). Rubber is frequently applied in bridge bearings because of its special properties such as high elasticity and large elongation at failure. However, natural rubber cannot afford sufficient damping which is indispensable to a seismic isolation system. Usually rubber bearing is used together with steel bars, lead plugs, or other types of damping devices. In order to add energy dissipation to the flexibility existing in laminated rubber bearings, in the early 1980’s, the development in rubber technology led to new rubber compounds, which were termed high damping rubber (HDR). HDR material possesses both flexibility and high damping properties. The bridge bearings made of HDR can not only extend the natural period of the bridge, but also reduce the displacement response of structures3). Moreover, because of the inherent high damping characteristics of HDR, there is no need of additional devices to achieve the required levels of protection from earthquakes for most applications, so that the seismic isolation system becomes more compact.In the manufacture process of HDR, natural rubber is vulcanized together with carbon black, plasticizer, oil and so on. Consequently HDR possesses specific characteristics such as maximum strain-dependency of stress evolution, energy absorbing properties and hardening properties. Yuan et al.4) experimentally studied the dynamic behaviors of HDR bearing. Yoshida et al.5), 6) developed a mathematical model of HDR materials and proposed a three-dimensional finite element modeling methodology to simulate the behaviors of a HDR bearing numerically. Besides, a series of accelerated exposure tests were performed by Itoh et al.7),8) on various rubber materials including HDR to investigate the degradation effects of differentenvironmental factors. It was found that the thermal oxidation is the most predominant degradation factor affecting theHDR material. Since oxygen is able to permeate into the interior of a thick rubber, in this research the deterioration of HDR bridge bearings is assumed to be mainly caused by the thermal oxidation. For the purpose of clarifying the deterioration characteristics of bridge rubber bearings during their lifespan, some bearings practically in use were recalled and their mechanical properties were tested9)～11). However, because of their scatter nature and the lack of data, the long-term performance of HDR is not very clear. During the design process, usually the behaviors of deteriorated bridge rubber bearings during their lifespan are not considered.In the previous research, Itoh et al. 12), 13) studied the long-term performance of natural rubber (NR) bridge bearings. Through accelerated thermal oxidation tests carried out on NR blocks, the deterioration characteristics of both the outer and the interior regions were examined. Based on the test results, a prediction model was established to estimate the property profiles of the deteriorated NR bridge bearing. Then using the constitutive law proposed by Yoshida5), finite element model was built and the analysis was performed, which enabled the long-term performance of NR bridge bearing to be predicted. The relations among property variation, temperature, aging time and bearing size were also investigated.In this research, through the similar accelerated thermal oxidation tests on HDR blocks, the deterioration characteristics of HDR bridge bearings are studied, and their long-term mechanical performance is investigated by taking the site environment taken into consideration. The HDR specimens are provided by Tokai Rubber Industries, Ltd. It is possible that when suffered by aging, the HDR from other companies may behave differently due to the difference of chemical compound. The deterioration characteristics of the HDR material with other compounding ingredients and additives will be discussed in the future study.2. ACCELERATED THERMAL OXIDATIONTESTSAmong different degradation factors such as oxidation, ultraviolet radiation, ozone, temperature, acid and humidity, it is found that thermal oxidation changes the HDR properties more greatly than other factors5), resulting in an increase of HDR’s stiffness and a decreases of elongation at break as well as tensile strength. Besides, for thick rubbers, it is obvious that the surface is more easily affected by deterioration factors than the interior because of the diffusion-limited oxidation effect14), 15). In order to understand the variation of the material properties inside HDR bearings, accelerated tests were performed using rubber blocks focusing on the most significant degradation factor, thermal oxidation. The test method and results are described as follows.2.1 Accelerated thermal oxidation test methodFifteen HDR blocks were tested. The dimension is 220×150×50mm(length×width×thickness). The specimens were kept in a Thermal Aging Geer Oven. The acceleration test conditions are listed in Table 1. The temperatures were kept at three elevated temperatures, 60℃, 70℃, and 80℃in the oven. For the test at each temperature, the experiment duration were set as 5 stages, with the maximum of 300 days. The similar tests have already been performed on NR10). When the aging test was finished, HDR blocks were sliced into pieces with a thickness of 2mm. From each slice, four specimens with No.3 dumbbell shape were cut out16), as shown in Fig.1. The number of the specimens was 1,500 in total. Then through the tensile tests on these dumbbell specimens, the stress-strain curves were obtained, which represented the rubber properties at the corresponding position.In this research, strain energy was chosen for examination because it can exhibit the effect of thermal oxidation more remarkably than stresses at certain strains. In the following description, U100 stands for the strain energy corresponding to the strain of 100%, UB stands for the strain energy up to the break, and M100 stands for the stress corresponding to the strain of 100%. Similarly, U100 profile stands for the distribution of U100 inside HDR blocks, and property profile means the distribution of the mechanical properties such as stresses corresponding to certain strains, elongation at break (EB) and tensile strength (TS). As for the rubber breakage, EB is focused on. In addition, U0 and EB0 stand for U100 and EB in the initial state, respectively.2.2 Test results and examinationsThe profiles of U100/U0 and EB/EB0 at every test temperature are illustrated in Fig.2 and Fig.3, respectively. The horizontal axis shows the relative position with regard to the thickness of HDR block. The values 0 and 1 on this axis correspond tothe surface of the block. The vertical axis shows the normalized change of U100 with the original value regarded as 1.0 in Fig.2, and shows the normalized change of EB in Fig.3. In these figures, every point represents the mean value of four specimens from the same slice. Because of the scatter nature of rubber materials, at any position four specimens are tested in order to improve the accuracy. Since the oxidized rubber inhibits the ingress of oxygen, and considering the shape of the rubber block, the four specimens are cut out in the area of at least 25mm, a half of the block thickness, away from the around surface. Thus these specimens only reflect the property variations in the thickness direction. The standard deviation of every four-specimen group is quite small and usually less than 5% of the mean value.From Fig.2 and Fig.3, it can be found that at the earliest stage of the test, the material properties at the outside surface change together with the interior regions. The property variation of the interior region soon reaches the equilibrium state and maintains stable. However, the properties near the surface keep changing over the time, and change most greatly at the surface.From the surface to the interior, the properties vary less and less, until to a certain depth,which is called “critical depth”. The critical depth is about 11.5mm from the block surface at 60℃, 8.5mm at 70℃, and 6mm under 80℃. From the results of the same tests on NR blocks12), it is found that generally HDR and NR have a similar tendency of property variation. Both U100 and EB profiles display the features of a diffusion-limited oxidation. Initially the profiles are relatively homogeneous, but strong heterogeneity develops with aging. The properties in the outer region change more than the interior and keep changing over the time. However, unlike the case of NR, the interior region of HDR block experiences a rapid increase and soon reaches the equilibrium state. In contrast, the interior region of NR block does not change at all. In addition, after the same aging time, the property change at the surface of NR block is larger than that of HDR block, which means NR is more vulnerable to thermal oxidation.Fig.4 shows the time-dependency of U100 and EB at the surface and in theinterior of HDR blocks. The horizontal axis shows the deterioration time, and the vertical axis shows the material property variations compared to its initial state. The data of the block surface are taken from the top and the bottom surfaces, while the data of the block interior are taken from two slices close to the middle slice. Therefore, there are 8 points corresponding to every measuring time. From Figs.4(a) and 4(c) it is found that U100 and EB at the block surface change nonlinearly over the time. In Figs.4(b) and 4(d), the properties in the interior region vary in a very short time, and soon become stable. U100 increases by 20～40% and EB decreases by about 20%.Besides the accelerated thermal oxidation test, a HDR block was exposed to the environment of Nagoya, where the yearly average temperature is 15.4℃. The properties of each layer was measured and the profiles were obtained after one year. The normalized change of EB profile is shown in Fig.5. It can be seen that EB decreased by nearly 20% after only one year. This figure offers a good proof of the rapid variation speed in the interior of HDR during the earliest stage. Using the deterioration prediction model that is to be introduced in the following section, the simulation of the deterioration after one year is found to be close to the test results.From the test results, it is clear the deterioration characteristics of HDR block can be observed in two regions, one is in the interior region beyond the critical depth, where the properties only change at the earliest stage, the other is in the outer region from the surface to the critical depth, where the properties continue changing after a rapid initial change. Oxidation cuts the cross-links between chains and accelerates the reformation of molecule structure, however, the latter restricts the ingression of oxygen. It is thought that the equilibrium is reached at the critical depth. The oxidation is a process related to the time, however, the properties in the interior region only vary in a very short time. There should be a factor except for oxidation affecting the interior region of HDR block. Because the property variation in the interior region increases with temperature, it is assumed the reaction is related to temperature. Therefore, it is thought that there are two factors affecting the deterioration of the HDR material, temperature and oxidation. The interior region is mainly affected by temperature, and this reaction finishes in a relatively short time. However, for the outer region near the surface, temperature and oxidation affect HDR simultaneously at first. After the reaction due to temperature reaching the stable state, only the oxidation deterioration continues.3. DETERIORATION PREDICTION MODEL FORHDRBRIDGEBEARING 3.1 Quantification of deterioration characteristicsTo predict the long-term deterioration of HDR bridge bearing, it is necessary to quantify the deterioration characteristics. From the accelerated thermal oxidation test results, the deterioration pattern of the HDR block can be schematically expressed by Fig.6. The vertical axis U/U0 means the relative property variation, which is the ratio of the current material property U comparing to the original value U0. The horizontal axis shows the relative position inside the HDR block. The interior region beyond the critical depth d* is mainly affected by temperature, and the relative property variationis ΔUi. The outer region from surface to the critical depth d* is influenced by both temperature and oxidation, and the property changes most greatly near the block surface. The relative property variation at the bearing surface is represented by the symbol of ΔUs. When pro ceeding into the block, because of the decrease in the amount of oxygen, the oxidation effect becomes weaker, and the property variation also declines. Once exceeding the critical depth, the gradient of the Fig.5 EB/EB0 profile of HDR block in Nagoya (15.4℃)property profile becomes zero.Moreover, from the test results shown in Figs.2 ～5, it can be said that at the lower temperatures, the critical depth becomes larger, however the property variation rate in both the inner and the outer region becomes slower. Hence the property profiles of aged HDR block at different temperatures are expected to be similar to the one shown in Fig.7.3.1.1 Critical depthMuramatsu and Nishikawa17) discovered that the critical depth can be expressed as the exponential function of the reciprocal of the absolute temperature, and the following formula was proposed to express the relationship between the critical depth and the temperature.⎪⎭⎫ ⎝⎛=*T d βαexp （1） where, d* is the critical depth, T is the absolute temperature, and the symbols α and βare coefficients determined by the aging test.The exponential relationship between the critical depth and the temperature is shown in Fig.8. In this fig ure it is found that for HDR, α=0.00012mm, β =3.82×10-3.3.1.2 Property variation of interior regionThe accelerated thermal oxidation test results show that the interior region changes in a relatively very short time, and then keeps stable. The properties change so rapidly that the time-dependency may be neglected. The EB decreases by about 20% and showing no dependency on the temperature. However, the equilibrium state of strain energy is correlated with temperature, as shown in Fig.9. The exact tendency is not clear because of the lack of tests at lower temperatures. In this study, the change of the relative strain energy in the interior region is assumed to be an exponential function of the reciprocal of the absolute temperature as follows:⎪⎭⎫ ⎝⎛=∆T B A U i exp （2） where, ΔUi is the normalized strain energy variation of the interior region, T is the absolute temperature, and the symbols A and B are coefficients.The symbols A and B in Eq.(2) are found to be related to the nominal strain. The strain-dependency of the both coefficients is shown in Fig.10. In this figure, the coefficients A and B versus the strain between 25% and 500% are illustrated. Hence they can be correlated approximately using the following equations.21ln ln b b A +=ε (3a)21ln c c B +=ε (3b)where, εis the nominal strain, the symbols b1, b2, c1, and c2 are the factors determined by the aging test.3.1.3 Property variation at block surfaceThe property variation at the block surface can be deemed as the combined effect of temperature and oxidation. Temperature not only causes the change in HDR properties, but also accelerates the oxidation reaction.Figs.11 (a) and 11(b) show the relative change of U100 and EB at the bearing surface with the propFig.8 Relations between critical depth and temperatureertyvariations due to the temperature eliminated.At a certain temperature, the property of HDR ex-posed to the air depends on time. It is found that the increase of U100 and the decrease of EB are linear with the aging time. For other material properties, the similar relationship is proved. The time-dependency can be expressed by the following equation:1/0+⋅='t k U U s s s（4a ） where, U’s/ Us0 is the relative variation of strain energy at the surface of the rubber bearing due to the oxidation only, ks is coefficient and t is the deterioration time.The relative property variation at the bearing sur-face also depends on strain. The relationship betweenthe coefficient ks and the nominal strain εis shown inFig.12, and the following equation can be obtained.21a a k s +⋅=ε （4b ）where, a1 and a2 are the factors determined by the test.Since the normalized property variation at the bearing surfaceΔUs is affected by the deterioration effects due to both temperature and oxidation, the following equation is obtained.()()111-∆+⋅⋅+=∆i s s U t k U (4c)3.1.4 Shape model of property profileA simple equation is necessary to express the property variation in the region from the rubberbearing surface to the critical depth. The property variation U(t)/U0 should be the function of the position x. The boundary conditions are:()S U U t U ∆+=1/0 ()l or x 0= （5a ）()i U U t U ∆+=1/0 ()**-≤≤d l x d (5b)()0/=dx t dU ()*=d x (5c)where, U(t) and U0 are the HDR properties at time tand initial state, respectively. ΔUi andΔUs are the relative property changes of the interior region and the bearing surface, respectively. l is the width of the HDR bearing.If the property variation U(t)/U0 is assumed to be a square relation of the position x, the function can be expressed as follows: ()32210/g x g x g U t U ++= (6)Considering the boundary conditions Eq.(6) can be written as:()[]i S s sU w U w U U ∆-+∆+='11/0 (7) ()()()()⎪⎪⎪⎩⎪⎪⎪⎨⎧≤≤-⎪⎪⎭⎫ ⎝⎛---≤≤≤≤⎪⎪⎭⎫ ⎝⎛-=********l x d l d d l x d l x d d x d d x w 200 (8) where, w is the coefficient correlated with the position x, the critical depth d* and the width l of the HDR bearing.Next, if the relationship between U(t)/U0 and x is a 3-order equation, it is expressed by:()432210/g g x g x g U t U +++= (9)Eq.(9) is resolved using the boundary conditions, the following equation is obtained.()()()[]{}i S U w U w d x x g U t U ∆-+∆+-=*1/10 （10）From the test results, it is found that the influence of the first part of Eq.(10) is only about 0.01%～10% of U(t)/U0. For simplicity, in this study the square relation as Eq.(7) is adopted.3.2 Comparison with test resultsUsing Eqs.(1)～(6), the property profiles of the deteriorated HDR blocks can be estimated. Based on the test results, the coefficients in these equations are obtained and listed in Table 2. Through the comparisons between test results and simulations shown in Fig.13, it is found that the simulations of the critical depth, the property variations on the block surface and in the interior region are in good agreement with the test results. Thus the feasibility of the deterioration prediction method is verified. Using this model, the material property can be predicted at any position inside the HDR bearing, at any temperature and at any aging time.3.3 Activation energyIn the thermal oxidation test the temperature applied is much higher than the real environment.This is because high temperature can accelerate the deterioration18). The Arrhenius methodology3) is commonly used to correlate the accelerated aging results with the aging under service conditions. Gerenally the thermal oxidation is assumed to be the 1st order chemical reaction for rubber materials3). Then the aging time in the accelerated exposure tests can be converted into the real time under the service conditions through the following formula:⎪⎪⎭⎫ ⎝⎛-=⎪⎭⎫ ⎝⎛T T R E t t r a r 11ln （11） where, Ea is the activation energy of the rubber, R is the gaseous constant (=8.314[J/mol·K]), Tr indicates the absolute temperature under the service condition, and T is the absolute temperature in the thermal oxidation test. The symbols tr and t are the real time and test time, respectively.Since the rubber surface contacts with the air, the surface is thought completely oxidized. Therefore, the time-dependency of the properties at the surface are used to determine the activation energy, for example, the data in Fig.4(a) and Fig.4(c). The principle of time/temperature superposition by shifting the raw data to a selected reference temperature Tref is employed19). This principle is shown in Fig.14. The reference temperature is chosen as 60℃ so that the curve at 60℃ is the master curve. The shift factors aT are chosen to give the best superposition of the data. If the data adhere to an Arrhenius relation, the set of the shift factors aT will be related to the Arrhenius activation energy Ea by the following expression:⎪⎪⎭⎫ ⎝⎛-=T T R E a ref ar 11exp （12） The activation energy is calculated and listed in Table 3. The average value of Ea is about 9.04×104[J/mol]. Then using the Arrhenius methodology, the property variations of HDR under any service condition may be predicted based on the accelerated thermal oxidation test results.。
大学英语四级翻译试题库：中国桥梁.doc
2019年大学英语四级翻译试题库：中国桥梁请将下面这段话翻译成英文：中国的桥梁建设有着悠久的历史。
中国古代桥梁以木材和石头为主要建筑材料,形式多样，极富特色。
中国现存最古老的桥梁为隋代建造的安济桥，位于河北省赵县。
安济桥又名赵州桥，桥长50.82米，桥宽9米，为国家重点保护的文物(cultural relic)。
清朝末年，兰州黄河铁桥建成，标志着中国桥梁建设进入了以钢铁和混凝土(concrete)为主要材料的时期。
如今，中国的桥梁建设保持着多项世界记录，中国跻身于世界桥梁建设强国行列。
参考译文China boasts a long history in bridge construction. With wood and stone as the major building materials, Chinese ancient bridges vary in forms and are highly distinct. Constructed in the Sui Dynasty, Anji Bridge, which is located in Zhao County, Hebei Province is the oldest existing bridge in China. Anji Bridge, also named Zhaozhou Bridge, is a key national protected cultural relic measuring a length of 50.82 meters and a width of 9meters.In the late years of the Qing Dynasty, Huanghe Iron Bridge in Lanzhou was completed, symbolizing that Chinas bridge construction stepped into an era of adopting steel and concrete as the main materials for bridges. Now bearing many world records, China stands among world giants in bridge construction.。
桥梁外文翻译
1 INTRODUCTION1.1 BackgroundBridges are a major part of the infrastructure system in developed countries. It has been estimated that in the USA about 600,000 bridges (Dunker 1993), in the UK about 150,000 bridges (Woodward et al. 1999), in Germany about 120,000 bridges (Der Prüfingenieur 2004) and in China more then 500,000 road bridges (Yan and Shao 2008) exist. Historical stone arch bridges still represent a major part of this multitude. It has been estimated that 60 % of all railway bridges and culverts in Europe are arch bridges (UIC 2005). Recent estimations regarding the number of historical railway natural stone arch bridges and culverts in Europe lie between 200,000 (UIC 2005) and 500,000 (Harvey et al. 2007). Also in some regions in Germany about one third of all road bridges are historical arch bridges (Bothe et al. 2004, Bartuschka 1995). Dawen & Jinxiang estimate that 70 % of all bridges in China are arch bridges.The success of historical natural stone arch bridges - which are often more than 100 years old- is based on the excellent vertical load bearing behaviour (Proske et al. 2006) and the low cost of maintenance (Jackson 2004) - not only in mountainous regions. However, changes in loads or new types of loads (Hannawald et al. (2003) have measured 70 tonne trucks on German highways under regular traffic conditions and Pircher et al. have measured 100 tonne trucks) might endanger the safety of such historical structures. Obviously, bridges with an age of more than 100 years were not designed for motorcars since this mode of transportation has only been in existence for approximately 110 years. The increase of loads does not only include vertical loads but also horizontal loads in the longitudinal direction and perpendicular to the longitudinal direction of these bridges. For example, the weight of inland waterway ships in Germany has increased dramatically in the last decades, which also corresponds with increasing horizontal ship impact forces (Proske 2003).Furthermore some loads from natural processes such as gravitational processes may not have been considered during the design process of the bridges. Especially in mountain regions this Historical stone arch bridges under horizontal debris flow impact Klaudia Ratzinger and Dirk ProskeUniversity of Natural Resources and Applied Life Sciences, Vienna, AustriaABSTRACT: Many historical arch bridges are situated in Mountain regions. Such historical bridges may be exposed to several natural hazards such as flash floods with dead wood and debris flows. For example, in the year 2000 a heavy debris flow destroyed an arch bridge in Log Pod Mangartom, Slovenia and only recently, in September 2008 an arch bridge was overflowed by a debris flow. A new launched research project at the University of Natural Resources and Applied Life Sciences, Vienna tries to combine advanced numerical models of debris flows with advanced models of historical masonry arch bridges under horizontal loads. The research project starts with separate finite element modelling of different structural elements of arch bridges such as spandrel walls, the arch itself, roadway slabs, pavements and foundations under single and distributed horizontal loads. Furthermore miniaturized tests are planned to investigate the behaviour of the overall bridge under debris flow impacts. The results will be used to combine the modelling of the different structural elements considering the interaction during a horizontal loading. Furthermore this bridge model will then be combined with debris flow simulation. Also earlier works considering horizontal ship impacts against historical arch bridges will be used control. The paper will present latest research results.400 ARCH’10 – 6th International Conference on Arch Bridgesgravitational processes (debris flow impacts (Zhang 1993), rock falls (Erismann and Abele 2001) and flash floods (Eglit et al. 2007) including water born missiles or avalanches) can cause high horizontal impact loads.1.2 Historical EventsIn the year 2000, a debris flow destroyed two bridges in Log Pod Mangartom, Slovenia, one of them was a historical arch bridge. In October 2007 the historical arch bridge in Beniarbeig, Spain was destroyed by a flash flood. Similarly the Pöppelmann arch bridge in Grimma, Germany was destroyed in 2002, in 2007 a farm track and public footpath arch bridge over the River Devon collapsed.Figure 1: Debris flow impact at the Lattenbach (Proske & Hübl, 2007)Fig.1 shows an example of the historical arch bridge at the Lattenbach, before and after a debris flow event, where the bridge is nearly completely filled with debris.Due to far too expensive solutions or not applicable methods for historical arch bridges it would be very useful if models were available to estimate the load bearing capacity of historical masonry arch bridges for horizontal loads perpendicular to the longitudinal direction.Since intensive research was carried out for the development of models dealing with vertical loads for historical arch bridges, there is an unsurprising lack of models capable for horizontal impact forces against the superstructure. This might be mainly based on the assumption that horizontal loads are not of major concern for this bridge type due to the great death load of such bridges.The goal of this investigation is the development of engineering models describing the behaviour of historical natural stone arch bridges under horizontal forces, mainly debris flow impacts, focused strongly on the behaviour of the superstructure and based on numerical simulations using discrete element models and finite element models.2 INNOVATIVE ASPECT AND GOALS2.1 Innovative AspectsThe conservation of historical arch bridges is not only an issue of the preservation of cultural heritage but is also an economic issue since the number of historical bridges in developed countries is huge (Proske 2009). Compared to vertical load cases no models currently exist for horizontal loads perpendicular to the longitudinal direction. It is therefore required to develop new models dealing with these capacious horizontal loads which include all types of gravitational hazards like avalanches, debris flow, rock falls or flood borne missiles or impacts from modes of transportation. First works related to the development of debris flow design impact forces and the behaviour of arch bridges under such an impact have started already 2007 at the Institute of Alpine Mountain Risk Engineering at the University of Natural Resources and Applied Life Sciences, Vienna (see Fig.2)Klaudia Ratzinger and Dirk Proske 401Figure 2 : Examples of the structural behaviour under impacts (left against the pier, right against the arch itself) (Proske and Hübl 2007)This investigation and its results regarding debris flow impact will flow into the development of the new Austrian code of practice Ö-Norm 24801 for the design of structures exposed to debris flow impacts as well.2.2 GoalTo develop load bearing behavior models of historical natural stone arch bridges under horizontal loads perpendicular to the longitudinal direction, a realistic model of debris flow against solid structures has to be implemented indifferent programs. Separate finite element modelling of different structural elements of arch bridges such as spandrel walls, the arch itself, roadway slabs, pavements and foundations under single and distributed horizontal loads are part of this investigation. Furthermore miniaturized tests are part of the project to investigate the behaviour of the overall bridge under debris flow impacts. The results will be used to combine the modelling of the different structural elements considering the interaction during a horizontal loading. Furthermore this bridge model will then be combined with debris flow simulation. Also earlier works considering horizontal ship impacts against historical arch bridges will be used. Therefore three models of historical arch bridges are developed:(1) Discrete element program model (PFC),(2) Explicit finite difference program model (FLAC),(3) Finite element program model (ANSYS, ATENA).The first and second models are developed to simulate an overall debris flow impact scenario, whereas the third model is used to investigate details, such as single force against a spandrel wall, single force against parapets, friction at the arch, single impact force against the arch. Results from the impact simulation against the superstructure should give an answer, whether the complete process can be separated into forces acting on the bridge. This reference force (force-time-function) will then be applied on the finite element models.The numerical modelling will be accompanied by testing to permit validation of the models. The tests will be carried out as miniaturized tests (scale about 1:20…50). Already miniaturized tests of the impact of debris flows against debris flow barriers were already carried out at the Institute of Mountain Risk Engineering (Proske et al. 2008, Hübl & Holzinger 2003,Fig.3). Based on this experience, miniaturized arch bridges (span about 40 to 50 cm) will be constructed and investigated. Also single parts of the arch structure will be investigated in testing machines, such as behaviour of a pure arch under a horizontal load. Since the machine cannot be turned, force redirection mechanisms will be used to allow the application of a standard compression test machine from the University of Natural Resources and Applied Life Sciences, Vienna.402 ARCH’10 – 6th International Conference on Arch BridgesFigure 3 : Side view and view from above of the used debris flow impact measurement test set-up (Hübl & Holzinger 2003)3 CALCULATIONS3.1 Discrete element methodsDiscrete element modeling can be done by usingPFC3D (Particle Flow Code 3D) which is used in analysis, testing and research in any field where the interaction of many discrete objects exhibiting large-strain and/or fracturing is required. By using the program PFC3D, materials can be modeled as either bonded (cemented) or granular assemblies of particle s.3.2 Finite element methodsThe finite element method (FEM) is one of the most powerful computer methods for solving partial differential equations applied on complex shapes and with complex boundary conditions.A mesh made of a complex system of points is programmed containing material and structural properties defining the reaction of the structure to certain loading conditions. Nodes are assigned at a certain density throughout the material depending on the anticipated stress levels of a certain area.Two types of analysis are commonly used: 2-D modelling and 3-D modelling. 2-D modelling allows the analysis to be run on a normal computer but tends to yield less accurate results whereas 3-D modelling shows more accurate results.For this investigation two FEM programs are used:(1) ANSYS(2) ATENAANSYS is the leading finite element analysis package for numerically solving a wide varietyof mechanical problems in 2D and 3D. By using ANSYS, the analysis can be done linear and non-linear, is applicable to static and dynamic structural analysis, heat transfer and fluid problems as well as acoustic and electromagnetic problems.The ATENA program is determined for nonlinear finite element analysis of structures, offers tools specially designed for computer simulation of concrete and reinforced concrete structural behaviour. Moreover, structures from other materials, such as soils, metals etc. can be treated as well.In the first step finite element methods are used to simulate the behaviour of historical natural stone arch bridges under an impact. Required data for the debris flow models are taken from the database of the Institute of Mountain Risk Engineering as well from the Austrian RailwayService (ÖBB).Klaudia Ratzinger and Dirk Proske 403The basic requirements for an appropriate assessment of stone arch bridges are:(1) Choice of a realistic calculation model(2) Consideration of geometrical and material nonlinearities(3) Using applicable material models for masonry(4) Adapted evidence based on the chosen material models.Therefore, a simplified arch bridge model with various lengths (L), rising of the vault (r) and thickness of the stone arch (t) was chosen (Fig.4) – first by using a two-dimensional model –with the purpose to investigate the importance of geometrical properties to their structural performance and to demonstrate different results. Further models are in process and will be implemented in the FEM programs as well.Figure 4 : FE model of a simplified arch bridge (Becke, 2005)4 CONCLUSIONSThis research project launched by the University of Natural Resources and Applied Life Sciences, Vienna combines advanced numerical models of debris flows with advanced models of historical masonry arch bridges under horizontal loads. It started with the implementation of separate finite element modelling of different structural elements of arch bridges. Furthermore miniaturized tests will be done in 2010 to investigate the behaviour of the overall bridge under debris flow impacts. The results will be used to combine the modelling of the different structural elements considering the interaction during a horizontal loading and the bridge model will be combined with debris flow simulation.Last but not least recommendation values for such bridge types should be given by this investigation that may include further formulas considering for example the adaptation of masonry stiffness or strength values.1介绍1．1背景桥梁是发达国家的基础设施系统的一个主要部分。
道路与桥梁工程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)Bridge research in EuropeA brief outline is given of the development of the European Union, together with the research platform in Europe. The special case of post-tensioned bridges in the UK is discussed. In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio: relating to the identification of voids in post-tensioned concrete bridges using digital impulse radar.IntroductionThe challenge in any research arena is to harness the findings of different research groups to identify a coherent mass of data, which enables research and practice to be better focused. A particular challenge exists with respect to Europe where language barriers are inevitably very significant. The European Community was formed in the 1960s based upon a political will within continental Europe to avoid the European civil wars, which developed into World War 2 from 1939 to 1945. The strong political motivation formed the original community of which Britain was not a member. Many of the continental countries saw Britain’s interest as being purelyeconomic. The 1970s saw Britain joining what was then the European Economic Community (EEC) and the 1990s has seen the widening of the community to a European Union, EU, with certain political goals together with the objective of a common European currency.Notwithstanding these financial and political developments, civil engineering and bridge engineering in particular have found great difficulty in forming any kind of common thread. Indeed the educational systems for University training are quite different between Britain and the European continental countries. The formation of the EU funding schemes —e.g. Socrates, Brite Euram and other programs have helped significantly. The Socrates scheme is based upon the exchange of students between Universities in different member states. The Brite Euram scheme has involved technical research grants given to consortia of academics and industrial partners within a number of the states— a Brite Euram bid would normally be led by an industrialist.In terms of dissemination of knowledge, two quite different strands appear to have emerged. The UK and the USA have concentrated primarily upon disseminating basic research in refereed journal publications: ASCE, ICE and other journals. Whereas the continental Europeans have frequently disseminated basic research at conferences where the circulation of the proceedings is restricted.Additionally, language barriers have proved to be very difficult to break down. In countries where English is a strong second language there has been enthusiastic participation in international conferences based within continental Europe —e.g. Germany, Italy, Belgium, The Netherlands and Switzerland. However, countries where English is not a strong second language have been hesitant participants }—e.g. France.European researchExamples of research relating to bridges in Europe can be divided into three types of structure:Masonry arch bridgesBritain has the largest stock of masonry arch bridges. In certain regions of the UK up to 60% of the road bridges are historic stone masonry arch bridges originally constructed for horse drawn traffic. This is less common in other parts of Europe as many of these bridges were destroyed during World War 2.Concrete bridgesA large stock of concrete bridges was constructed during the 1950s, 1960s and 1970s. At the time, these structures were seen as maintenance free. Europe also has a large number of post-tensioned concrete bridges with steel tendon ducts preventing radar inspection. This is a particular problem in France and the UK.Steel bridgesSteel bridges went out of fashion in the UK due to their need for maintenance as perceived in the 1960s and 1970s. However, they have been used for long span and rail bridges, and they are now returning to fashion for motorway widening schemes in the UK.Research activity in EuropeIt gives an indication certain areas of expertise and work being undertaken in Europe, but is by no means exhaustive.In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio. The example relates to the identification of voids in post-tensioned concrete bridges, using digital impulse radar.Post-tensioned concrete rail bridge analysisOve Arup and Partners carried out an inspection and assessment of the superstructure of a 160 m long post-tensioned, segmental railway bridge in Manchester to determine its load-carrying capacity prior to a transfer of ownership, for use in the Metrolink light rail system..Particular attention was paid to the integrity of its post-tensioned steel elements. Physical inspection, non-destructive radar testing and other exploratory methods were used to investigate for possible weaknesses in the bridge.Since the sudden collapse of Ynys-y-Gwas Bridge in Wales, UK in 1985, there has been concern about the long-term integrity of segmental, post-tensioned concrete bridges which may b e prone to ‘brittle’ failure without warning. The corrosion protection of the post-tensioned steel cables, where they pass through joints between the segments, has been identified as a major factor affecting the long-term durability and consequent strength of this type of bridge. The identification of voids in grouted tendon ducts at vulnerable positions is recognized as an important step in the detection of such corrosion.Description of bridgeGeneral arrangementBesses o’ th’ Barn Bridge is a 160 m long, three span, segmental, post-tensionedconcrete railway bridge built in 1969. The main span of 90 m crosses over both the M62 motorway and A665 Bury to Prestwick Road. Minimum headroom is 5.18 m from the A665 and the M62 is cleared by approx 12.5 m.The superstructure consists of a central hollow trapezoidal concrete box section 6.7 m high and 4 m wide. The majority of the south and central spans are constructed using 1.27 m long pre-cast concrete trapezoidal box units, post-tensioned together. This box section supports the in site concrete transverse cantilever slabs at bottom flange level, which carry the rail tracks and ballast.The center and south span sections are of post-tensioned construction. These post-tensioned sections have five types of pre-stressing:1. Longitudinal tendons in grouted ducts within the top and bottom flanges.2. Longitudinal internal draped tendons located alongside the webs. These are deflected at internal diaphragm positions and are encased in in site concrete.3. Longitudinal macalloy bars in the transverse cantilever slabs in the central span .4. Vertical macalloy bars in the 229 mm wide webs to enhance shear capacity.5. Transverse macalloy bars through the bottom flange to support the transverse cantilever slabs.Segmental constructionThe pre-cast segmental system of construction used for the south and center span sections was an alternative method proposed by the contractor. Current thinking suggests that such a form of construction can lead to ‘brittle’ failure of the ent ire structure without warning due to corrosion of tendons across a construction joint，The original design concept had been for in site concrete construction.Inspection and assessmentInspectionInspection work was undertaken in a number of phases and was linked with the testing required for the structure. The initial inspections recorded a number of visible problems including:Defective waterproofing on the exposed surface of the top flange.Water trapped in the internal space of the hollow box with depths up to 300 mm.Various drainage problems at joints and abutments.Longitudinal cracking of the exposed soffit of the central span.Longitudinal cracking on sides of the top flange of the pre-stressed sections.Widespread sapling on some in site concrete surfaces with exposed rusting reinforcement.AssessmentThe subject of an earlier paper, the objectives of the assessment were:Estimate the present load-carrying capacity.Identify any structural deficiencies in the original design.Determine reasons for existing problems identified by the inspection.Conclusion to the inspection and assessmentFollowing the inspection and the analytical assessment one major element of doubt still existed. This concerned the condition of the embedded pre-stressing wires, strands, cables or bars. For the purpose of structural analysis these elements、had been assumed to be sound. However, due to the very high forces involved,、a risk to the structure, caused by corrosion to these primary elements, was identified.The initial recommendations which completed the first phase of the assessment were:1. Carry out detailed material testing to determine the condition of hidden structural elements, in particularthe grouted post-tensioned steel cables.2. Conduct concrete durability tests.3. Undertake repairs to defective waterproofing and surface defects in concrete.Testing proceduresNon-destructi v e radar testingDuring the first phase investigation at a joint between pre-cast deck segments the observation of a void in a post-tensioned cable duct gave rise to serious concern about corrosion and the integrity of the pre-stress. However, the extent of this problem was extremely difficult to determine. The bridge contains 93 joints with an average of 24 cables passing through each joint, i.e. there were approx. 2200 positions where investigations could be carried out. A typical section through such a joint is that the 24 draped tendons within the spine did not give rise to concern because these were protected by in site concrete poured without joints after the cables had been stressed.As it was clearly impractical to consider physically exposing all tendon/joint intersections, radar was used to investigate a large numbers of tendons and hence locate duct voids within a modest timescale. It was fortunate that the corrugated steel ducts around the tendons were discontinuous through the joints which allowed theradar to detect the tendons and voids. The problem, however, was still highly complex due to the high density of other steel elements which could interfere with the radar signals and the fact that the area of interest was at most 102 mm wide and embedded between 150 mm and 800 mm deep in thick concrete slabs.Trial radar investigations.Three companies were invited to visit the bridge and conduct a trial investigation. One company decided not to proceed. The remaining two were given 2 weeks to mobilize, test and report. Their results were then compared with physical explorations.To make the comparisons, observation holes were drilled vertically downwards into the ducts at a selection of 10 locations which included several where voids were predicted and several where the ducts were predicted to be fully grouted. A 25-mm diameter hole was required in order to facilitate use of the chosen horoscope. The results from the University of Edinburgh yielded an accuracy of around 60%.Main radar sur v ey, horoscope verification of v oids.Having completed a radar survey of the total structure, a baroscopic was then used to investigate all predicted voids and in more than 60% of cases this gave a clear confirmation of the radar findings. In several other cases some evidence of honeycombing in the in site stitch concrete above the duct was found.When viewing voids through the baroscopic, however, it proved impossible to determine their actual size or how far they extended along the tendon ducts although they only appeared to occupy less than the top 25% of the duct diameter. Most of these voids, in fact, were smaller than the diameter of the flexible baroscopic being used (approximately 9 mm) and were seen between the horizontal top surface of the grout and the curved upper limit of the duct. In a very few cases the tops of the pre-stressing strands were visible above the grout but no sign of any trapped water was seen. It was not possible, using the baroscopic, to see whether those cables were corroded.Digital radar testingThe test method involved exciting the joints using radio frequency radar antenna: 1 GHz, 900 MHz and 500 MHz. The highest frequency gives the highest resolution but has shallow depth penetration in the concrete. The lowest frequency gives the greatest depth penetration but yields lower resolution.The data collected on the radar sweeps were recorded on a GSSI SIR System 10.This system involves radar pulsing and recording. The data from the antenna is transformed from an analogue signal to a digital signal using a 16-bit analogue digital converter giving a very high resolution for subsequent data processing. The data is displayed on site on a high-resolution color monitor. Following visual inspection it is then stored digitally on a 2.3-gigabyte tape for subsequent analysis and signal processing. The tape first of all records a ‘header’ noting the digital radar settings together with the trace number prior to recording the actual data. When the data is played back, one is able to clearly identify all the relevant settings —making for accurate and reliable data reproduction.At particular locations along the traces, the trace was marked using a marker switch on the recording unit or the antenna.All the digital records were subsequently downloaded at the University’s NDT laboratory on to a micro-computer.（The raw data prior to processing consumed 35 megabytes of digital data.）Post-processing was undertaken using sophisticated signal processing software. Techniques available for the analysis include changing the color transform and changing the scales from linear to a skewed distribution in order to highlight、突出certain features. Also, the color transforms could be changed to highlight phase changes. In addition to these color transform facilities, sophisticated horizontal and vertical filtering procedures are available. Using a large screen monitor it is possible to display in split screens the raw data and the transformed processed data. Thus one is able to get an accurate indication of the processing which has taken place. The computer screen displays the time domain calibrations of the reflected signals on the vertical axis.A further facility of the software was the ability to display the individual radar pulses as time domain wiggle plots. This was a particularly valuable feature when looking at individual records in the vicinity of the tendons.Interpretation of findingsA full analysis of findings is given elsewhere, Essentially the digitized radar plots were transformed to color line scans and where double phase shifts were identified in the joints, then voiding was diagnosed.Conclusions1. An outline of the bridge research platform in Europe is given.2. The use of impulse radar has contributed considerably to the level of confidence in the assessment of the Besses o’ th’ Barn Rail Bridge.3. The radar investigations revealed extensive voiding within the post-tensioned cable ducts. However, no sign of corrosion on the stressing wires had been found except for the very first investigation.欧洲桥梁研究欧洲联盟共同的研究平台诞生于欧洲联盟。
外文翻译----桥梁走向未来
中文4867字附录ABridge to the FutureThe Chao Phraya River Bridgeis designed to accommodate marinetraffic. The 500 m main span willprovid50.5 m of vertical clearance, and thetwo towers will be situated away from the main navigation channel.The final component of Thailand's new Outer Bangkok Ring Road, the eight-lane cable-stayed Chao Phraya River Bridge, will not only alleviate Bangkok's notoriously heavy traffic but also contribute a new architectural symbol to the capital city. By Ruchu Hsu, RE.The bridge will carry four lanes of traffic ineach direction. The upper portion of each tower willhave an enclosed chamber for cable anchors, a 1.5 msquare opening at the bottom providing easy accessfor maintenance and inspection.For the past 20 years, Thailand's capital, Bangkok, has been constructing expressways to lleviate traffic congestion. Among the major expressway projects in the capital is the Outer Bangkok Ring Road, a 170 km long highway encircling the city. The road is nearly complete; only the eastern half of the southern leg--theSouthern Outer Bangkok Ring Road, or S-OBRR--remains to be constructed. Scheduled for completion in 2007, the 21 km elevated viaduct will incorporate four major interchanges and a cable-stayed bridge over the Chao Phraya River. With a main span of 500 m and two side spans of 220.5 m, the Chao Phraya River Bridge will be the longest in Thailand.In 1996 the Department of Highways retained a joint venture team of consultants to design the S-OBRR. The design team included Asian Engineering Consultants (AEC), Thai Engineering Consultants (TEC), and Siam General Engineering Consultants, all of Bangkok; Oriental Consultants, of Tokyo; and Parsons Brinckerhoff (PB), of New York City. Once the joint venture was formed, designers began a feasibility study of the Chao Phraya River crossing and set about determining the most suitable type of crossing. Tunnels and cable-stayed bridges were developed and evaluated. Eventually, however, it became clear that a bridge would be more economical, would not interrupt marine traffic, and would best lend itself to the highway interchange.In 1999 engineers began to design the S-OBRR. The Chao Phraya River Bridge design was led by PB and supported by AEC and TEC. Conceptual and preliminary designs were pre-pared by PB'S New York staff, and Thai engineers working in Bangkok with the author completed the subsequent final design. The engineers established four design goals. They wanted a bridge that would (1) be long lasting and easily maintained, (2) enhance the city architecturally, (3) be economical and incorporate the maximum amount of localmaterial, and (4) not disrupt marine traffic theChao Phraya River during construction. Superstructure true that will carry four traffic lanes in each direction and provide 50.5 m of vertical clearance for marine traffic. The bridge's two A-shaped towers will straddle the 500 m main span and will stand as stylized representations of the traditional Thai greeting, the hands steep led together. The superstructure is a steel frame composite with a concrete deck. Stay cables spaced at 12 m intervals along the edge girders are designed to carry the superstructure load. Three anchor piers on each side will provide stability. The bridge features a symmetrical profile and slopes no more than 3 percent. The bridge was designed for 208 KN loads from trucks--loads 30 percent higher than those set forth by the American Association of State Highway and Transportation Officials in the 16th edition of its Standard Specifications for Highway Bridges (1996).The hollow legs of the two 187 m high towers are made of reinforced concrete.A horizontal strut just below deck level provides lateral support for the slender legs and reduces deflection. The legs, each supported by two 24 by 24 by 4 m footings, join at the top to form a chamber for cable anchors. Decorative spheres 3 m in diameter and spires 8 m tall at the top of the towers will be gilded in traditional Thai style. The two towers--one located in shallow water on the east bank, the other behind a wharf on the west bank--will be situated away from the main navigation channel to eliminate the possibility of collisions with the bridge and ensure that marine traffic and wharf operations can proceed unimpeded.The three anchor piers will be situated behind each tower on the bridge's back spans. The piers will maximize the vertical and lateral stiffness of the bridge superstructure and the tensional stiffness of the main-span superstructure and will stabilize the bridge during strong winds. The A-shaped towers will also contribute to the tensionalstiffness of the superstructure. Moment connections between the superstructure and the anchor piers eliminate the need for wind locks, which attach the deck to the anchor piers and require special inspection and maintenance. The direct connection with the anchor pier will substantially reduce the stress range in the stay cables located adjacent to the pier and lessen the possibility of cable fatigue. Cables, not the more commonly used bearings, will support the superstructure at the towers and reduce the negative bending moment in the edge girders at the towers under certain live-load conditions.The composite superstructure includes a rein-forced-concrete deck, steel floor beams, and two teel edge girders. A deck slab that varies in thickness from 260 to directly supports vehicle loads310 mm. The thicker slab segments will extend98.5 m from each tower in both directions. Recast deck panels will span between the floor beams but will not fully cover the top flanges of the beams. Cast-in-place (CIP) concrete will be placed on top of the floor beams and the exposed portions of the, flanges to make the concrete deck composite with the steel-supporting frame. A 40 mm thick high-performance concrete overlay will protect the deck from corrosion. To reduce stress in the overlay from Bangkok's heavy traffic, the bridge has bee designed to have a 3 percent maximum slope.To ensure bridge longevity and facilitate deck, replacement operations, engineers will use reinforcing bars instead of post tensioning tendons in the deck slab. Reinforcing bars will also be used as ties in the footings to resist lateral thrust between the inclined tower legs. Built-up I-shaped steel beams spaced 4 m apart will form the floor beams and will match the 1.625 m height of the connecting edge girders. The top flanges of the floor beams will follow the cross, slope of the deck. Three longitudinal beams will provide temporary lateral support for the floor beam top flanges before the CIP concrete strips reach sufficient strength. The top flanges of the longitudinal beams will be wide enough to serve as forms for the CIP concrete strips between precast deck panels.The bridge is designed so that the superstructure of the main span can be erected by delivering the major structural components to the deck from the towers. The box-shaped steel edge girders have high tensional strength and are designed tocantilever during floor beam erection. With an inclined outside web and a vertical inside web, this 1.625 m high, box-shaped steel edge girders will deepen to 2.2 m as they approach the ends to match the depth of the concrete box girders in the approaches. The top flange will be 1.5 m wide and the bottom flange will be 1.9 m wide. To make the concrete deck and steel edge girder composite, shear studs will be welded to the flange. Four rubber bumpers at the deck level of each tower are designed to transfer horizontal wind loads from the superstructure. Bumpers eliminate the use of bearings, which require costly, labor-intensive inspections and replacements. The bumpers are easily accessible for inspection and can be replaced by a single person. Cable anchors are located inside the edge girder, which protects the cable-to-girder anchors from the elements. A circular access hole ii1 the inside web and a platform will be constructed at every cable connection between the floor beams to provide easy access to the cable anchors for inspection and main- tenancy purposes. For aesthetic reasons, the bottoms of the girders have smooth edges.168 stay cables consisting of 24 to 77 low-relaxation, seven-wire welds less strands will support the bridge’s superstructure. The strands are 15 mm in diameter and conform to ASTM International's specification A412-90a for grade 270 strands. The bridge design incorporates the latest advances for protecting cable strands from corrosion, including galvanizing and coating individual strands with wax or grease and then sheathing them in a layer of polyethylene. The protected strands will be placed in a high-density polyethylene (HDPE) pipe, which, beingwhite, will reduce heat absorption. Welded beads will be placed in a spiral pattern along the exterior surface of the HDPE pipes to control cable vibrations caused by wind and rain.. Since the long cables (up to 260 m) are prone to large-amplitude vibrations, crossties-an effective and economical method of controlling cable vibration-will be installed.The wind ties suppress individual cableresonance by forcing cables withdifferent mode frequencies to vibrate together.The Post Tensioning Institute, based inPhoenix, requires that stay cables bereplaceable. The engineers have designed the Chao Phraya River Bridge so that one stay cable can be replaced while traffic continues on two lanes in each direction. The bridge has also been designed to allow for the accidental loss of any one cable without bridge failure.The bridge design includes a large chamber on each tower to house cable anchors. The chamber is 8.8 by 3.4 m at the top and 23 by 5 m at the bottom and will provide sufficient space for ladders and platforms to directly access all of the cable anchors. A 1.5 by 1.5 m opening in the bottom slab will allow for the lifting of heavy equipment or materials directly from the deck to the chamber. This opening will ease construction, inspection, maintenance, and future cable replacement. Each anchor pier will consist of double columns. The 4 by 4 m hollow reinforced-concrete structures have 0.6 m thick walls to facilitate construction and ensure a long service life. The two columns are tied on top for lateral stability. Cantilever arms will extend from the top of each column longitudinally, carrying the weight of the concrete counterweights before the anchor cables are installed. The cantilever arms will also increase superstructure stiffness and reduce bending moments in the edge girders. The concrete counterweights will eliminate uplift at the anchor piers and, in contrast to such commonly used tie-down devices, as steel rods, cables, and pins, require only minimal inspection and no maintenance.The bridge, like much of Bangkok, is located in a floodplain, and there is a 15 m layer of soft clay near the site's surface. To properly support the towers and anchor piers, engineers will drill shafts 2 m in diameter to a depth of 50 m. The engineers chose 2 m shafts because they possess the lateral bending capacity required for large foundations in soft soils. To facilitate inspection and maintenance, the designers provided easy access to all of the major structural components. No special equipment or falsework will be required to gain access to the superstructure, cable-to-tower connections, or cable-to-girder connections. A catwalk provides access to the area beneath the deck, and the bottoms of the edge girders will be accessible by means of a snooper-a specialized lift truck that extends under the bridge for maintenance and inspection.Because cable-stayed bridges tend to be highly redundant, the engineers foundit necessary to use computers to calculate the multitude of member forces under various loading conditions. EARS& a structural analysis program developed by Larsa, Inc., of Melville, New York, were used in the design. Linear analyses were performed for live loads, wind loads, and temperature loads; nonlinear analyses were performed for dead loads, cable replacements, and cable loss; dynamic analyses were performed for seismic loads and to compute eigenvalues for mode shapes and frequencies for wind tunnel testing; and a finite-element analysis was performed for the floor beam opening stress distribution. PIGLET---developed by the University of Western Australia to handle soil-structure interactions in three dimensions--was used to compute the bending moments and axial forces in the drilled In addition to the computer tools used in the structural analysis, engineers paid careful attention to the engineering assumptions informing the design. They also trained a keen eye on the accuracy of the initial input data, keeping computer models as simple as possible to ease the data verification process.Because the aerodynamic stability of long-span bridges is always a major concern, the engineers designed the A-shaped tower and anchor pier combination to achieve the greatest possible stiffness when connected with a flexible superstructure, thereby increasing aerodynamic stability. Using a 1:60 sectional model, Rowan Williams Davies &Irwin, Inc., an engineering consulting firm inGuelph, Ontario, tested the bridge's aerodynamic stability in a wind tunnel. The test measured static wind force and moment coefficients. The results were as follows: The design wind speed is substantially lower than the tested flutter speed, which means that the bridge is designed to endure higher wind speeds than those found at the project site. (Flutter is a self-excited aerodynamic instability that can increase to very large amplitudes with tensional or vertical motion.) The bridge has been designed to withstand a wind speed of 56 m/s, a value with a 10,000-year return period.The bridge deck can experience vortex-shedding vibrations at 25 m/s. The peak deck acceleration was found to be lower than the allowable specifications set forth in 1980 by ASCE'S Committee on Loads and Forces on Bridges. The bridge can withstand buffeting--a random vibration caused by unsteady wind loading arising from turbulence. In particular, the test showed that the bridge is able to withstand wind load distributions having a 100-year return period.The concrete, reinforcing steel, steel shapes, gratings, and HDPE pipes necessary for the S-OBRR'S Chao Phraya River Bridge will be produced locally. Only such specialty items as cable anchorages will be imported. Construction of the bridgebegan in August and is expected to be completed in early 2007, providing a badly needed solution to traffic problems and a structure that promises to add to the beauty of this bustling Asian metropolis.The piles. 40 in long and 3 m in diameter, arc driven into the sandy river bottom from above the water level. This foundation system was considered to be more effective than concrete piling because of the steel piles’ lateral stiffness and strength. Research was conducted into the possibility of improving the axial stiffness by means of pressure grout injection at the pile bottom. However, because this method had not before been applied in similar situations and because the operational risks were considered severe, the method was dropped in favor of increasing the depth of the piles.Prefabricated-concrete caissons measuring 25 by 10 in were installed on top of the piles at each pier location. Casting concrete underwater made the rigid connection between the piles and the caissons. The design of the piles and the bending connection was governed by the requirement that the structure withstand a 30 MN ship impact at a level 3 m above the waterline and allow a lateral displacement of no more than 80 mm at the track level. Once the pile heads were installed and sealed, the caisson was pumped dry. Since the top of the casing is 0.5 m below the water level, temporary water retaining skirts were employed, and the hollow casings were then cast with concrete.On top of each casing a hollow rectangular vertical shaft of varying crosssection was cast in site. The shafts vary in height by as much as 7 m from the middle of the bridge to the ends. The shaft heads include anchors for the bridge supports, so the shafts had to be positioned within tolerances as small as 10 mm. The top plane of each shaft, measuring just 5 by 6 m, included space for the vertical supports at the edges, jacks for bridge lifting, horizontal supports, and a central lower-level inspection space accessible from the bridge deck.The acceptable vertical tolerance of the deck was set at ±15 mm, or 1/7000 of the span. Considering the length of the spans, the fact that the girder was continuous over multiple spans, and the composite nature of the structure, however, and this standard proved difficult to meet. In consultation with the rail authorities the acceptable tolerance was increased to ±40 mm.The hammer sections, identical except for small details, also were reassembled, but here six subsections were involved. These parts were manufactured to within a tolerance of ±5 mm. Since the bridge site is between two existing bridges, the height of the parts to be transported was limited to the vertical clearance of the existing structures. Thus the 10.5 m high hammer sections were transported not in their upright position but on their sides. On the hammer sections, therefore, the concrete deck could not be applied in advance.The project also included the design and construction of approach structures on both ends of the crossing, because the trains may reach speeds of more than 300 km/h, the approaches must provide a smooth track to enable trains to come from 20 m below mean sea level in the tunnel north of the bridge to 20 m above mean sea level at the summit of the bridge, in the middle of the river. The alignment has a maximum slope of 2.5 percent and has a horizontal radius of curvature of 15 km. At the south end of the bridge the approach spans connect the bridge with track that runs through the polder at a level of3 m below mean sea level.Ruchu Hsu, P.E., M.ASCE, is a supervising structural engineer for Parsons Brinckerhoff, Inc., in New York City. This paper was presented at the 21st Annual International Bridge Conference, which took place in Pittsburgh June 12-I6, 2004.桥梁走向未来过去20 年里，泰国的首都曼谷,已经修筑高速道路以减轻交通拥挤。
公路桥梁专业词汇英语翻译
桥梁bridge公路干道highway工程工程学engineering公路工程highway engineering路基roadbase路面pavement构造物建造构成制造construct施工（名）construction试验室laboratory现场检测field test（名）试验检验（不）进行试验experiment 试验检测测量test质量上流社会的quality合格，取得资格qualify材料material沥青柏油以沥青铺（一般指沥青路）asphalt 沥青（指原材料）bitumen沥青的bituminous沥青混合料bituminous mixture混凝土concrete钢筋混凝土RC (reinforced concrete)信誉信用贷款credit进度快慢tempo计划plan评定evaluation检查（名）检验inspection标准水准规格标准的合格的standard技术性的工业的technical技术技巧技术的工艺的专门的technic水泥cement碎石路碎石路macadam砂砾碎石砂砾层gravel钢筋reinforcing steel bar或reinfored steel石石头石场石的石制的stone检查员inspector测量（名）measuring测量（及）检测（及）勘测测绘（名）survey 设备仪器装置device申请application铺路工人paver经理manager加强reinforce（被加强的reinforced ）sign 签字署名通知list 表名册目录列举tabulation 制表列表表格mapping 绘图制图camera 照相机photo 照片给。
拍照拍照lime 石灰petrol 汽油diesel-oil 柴油planer 计划者planed 有计划的根据计划的pile 柱桩把桩打入用桩支撑weld 焊接焊牢焊接点welder 焊接者焊工laborer 劳动者劳工辅助工manpower 人力劳动力人力资源雇佣使用利用employ职业租用受雇employment项目条款item关税税款税impostresign 放弃辞去辞职document 公文文件证件time limit from project 工期weighbridge 地磅台秤transbit 经纬仪mention 提到说起表扬career 职业经历skill 技术技能trade 行业商业owe 欠债organization 组织机构团体traffic 交通交往通行交易买卖spend 预算花钱浪费interest 股息股份兴趣cost 费用成本花费wage 薪水报酬earning 工资收入利润cash 现金现款把...兑现tax 税负担向...纳税deficit 赤字不足额业主owner（北美用）、employer（英语国用）发展商（房屋等业主）client 或developer承包商contractor总承包商prime contractor或general contractor 分承包商nominated contractor专业承包商specialist contractor咨询公司consulting firm 或consultants咨询工程师consulting engineer建筑师architect建筑工程经理constraction manager项目经理program manager材料供应商supplier建筑经济学contraction economics亚洲开发银行asian development bank世界银行集团world bank group学会institute协会association组织结构organizational styucture基础设施infrastructure环境environment质量管理体系qulity management system 质量方针quality policy质量目标quality objective职能，函数，职务function计量的metrological鉴定qualification评审review效率efficiency验证verification顾客,消费者customer过程process产品product项目,预计的，计划的project程序procedure特性characteristic记录record检验inspection文件document信息information能力capabitily 满意satisfaction投标邀请书invitation for bids公开招标unlimited competitive open biding 投标者须知instruction to bidders银行保函bank guarantee担保公司security company支付保函payment guarantee资质说明statement of qualification单位成本cost per unit成本计划cost plan成本价price cost业主要求client´s requirements投标书tender 或bid 或proposal 合同条件condition of contract合同协议书agreement图纸drawings工程量表bill of quantities投标保证bid security保价offer开标tender 或bid评标bid evaluation施工项目work items总价合同lump sum contract专题报告subjective report审核audit 审核员auditor测量控制measurement control测量设备measureing equipment技术专家technical expert习惯，惯例custom选择selection确定，决定definition合格conformity不合格nonconformity缺陷defect预防措施preventive action纠正措施corrective action返工rework降级regrade返修repair报废serap让步concession放行release。
桥梁设计外文翻译---日本钢桥建筑的近期发展趋向
Considerations on recent trends in, steel bridgeconstruction in JapanAbstract In this paper, consideration is given on recent trends in, steel bridge construction in Japan. As far as recent trends are concerned, it is observed that the construction of long and big steel bridges has practically been completed. Consequently, the focus of recent main works is the maintenance of superannuated (averaged) bridges and the seismic retrofitting of existing bridges. The refreshment and regeneration of some superannuated bridges is also needed recently in order to mitigate the uncomfortable influence of these bridges on their surrounding environment. For this purpose, maintenance and retrofitting works should be economically reasonable jobs. The necessity and importance of these works should be understood by the nation through retrofitting existing bridges against disasters and mitigating the unfavorable influence of bridge structures on the bridge environment on the basis of the code of ethics for civil engineers promulgated by JSCE. Moreover, bridge engineers should seek better social status and the bridge engineering field should become attractive to young students who will bear the future of this field.1.1 Construction trendIn Japan, many bridges were intensively constructed in the 1960s–80s, during the period of high economic growth, with the number of bridges constructed per year decreasing recently to half of the overall peak. More specifically, the steel bridge industry reached the golden age in the latter half of the 1960s. However, the latest data indicates that the recent number of1constructed steel bridges has declined to approximately 40% of its peak, though the number of constructed RC and PC bridges remains almost constant from the beginning of 1960 to date.After the construction of many bridges as one of the important infrastructures, bridges were constructed predominantly in places of direct need. Recently, it is observed that various kinds of damage have occurred to many bridges mainly constructed in the 1960s.Especially following the investigation of damage to steel structures due to the Hyogo-ken Nambu Earthquake which occurred in 1995, importance has been attached to seismic design for the construction of new bridges and to seismic retrofitting for existing steel bridges, aiming to utilize the ductility of steel bridge members and structures. Many repair and seismic retrofitting works of bridge structures damaged as a result of the earthquake have been carried out and these works are due to finish in the near future. Damaged parts in steel bridges were mainly classified into piers, bearings and restraining parts protecting bridges from falling down.Recently, the seismic retrofitting works of long-span steel bridges has started. For example, the seismic retrofitting work of the Minato Bridge in Osaka, a big cantilever truss bridge with a main span of 510 m is now under way, with an estimated budget of 6000 million Japanese Yen and a works duration of 5 years. The Maitani Bridge located in Nara Prefecture, a deck-type steel girder bridge with the span length of 112 m is also undergoing seismic retrofitting.Nowadays, many existing steel bridges exhibit some form of deterioration, such as the corrosion of steel members, fatigue cracks in RC slabs, steel decks and steel members due to the passage of many overweight vehicles,2much heavier than those specified in the Japanese Specifications for Highway Bridges (JSHB), and so on. As a result, many bridges require substantial strengthening and repair works. Instead of the construction of large and long-span bridges, the retrofitting, strengthening, repair and maintenance of existing steel bridges already constructed will take an increasingly important part of the future steel bridge market in Japan.In Japan, many bridges have been constructed to establish an efficient highway network since World War II. Attention has been, however, paid mainly to the construction of safe and standard bridges with, as far as possible, uniform quality with regard to design loads. Until recently, governments could not afford to consider the harmony between the bridges and their surrounding environment.For example, it is very difficult to have a clear and unobstructed view of the beautiful and historically important Osaka Castle due to the high-rise buildings and elevated highway bridges. This is an example of the undesirable influence of elevated bridges on their surrounding environment.1.2. Recent main works（1）Construction of new bridgesIn the new construction sector, there is severe competition between the steel bridge and concrete bridge industries. This is because the construction of long-span and big bridges, which occupied the steel bridge industry, has declined and, consequently, the steel bridge industry tries to win jobs mainly in the construction of mid-span bridges, typically with a span length of 40–80 m. As a result, many economical, rational and mid-span bridges with new types of structures have been developed by both steel and concrete bridge industries.3The following new types of steel bridges were developed in seeking to expand the market for new construction, to include bridges with medium span length: – Plate girder bridges made of thick steel plates, with fewer stiffeners and less welding lines for cost reduction.– Two-main-plate girder bridges with PC decks.– Continuous, composite and two-main-plate girder bridges.–Continuous composite box-girder bridges strengthened by cables to increase their economical span length.– Cable stayed bridges with main girders of H-shaped steels.– Steel bridges consisting of box girders in the vicinity of the interior supports and plate girders in the other parts.On the other hand, the following new types of PC bridges have also been developed in order to face the competition from the steel bridge industry:– PC box girder bridges with corrugated steel webs.– Compound truss bridges with steel diagonal members and PC flanges.– Cable stayed PC box girder bridges with corrugated steel webs.（2）Other developments in steel bridge industry（i）Repair and strengthening works against fatigue damage and cracks in the following types of bridge members:– Fatigue cracks of secondary steel bridge members.– Fatigue cracks of RC slabs.–Fatigue cracks of steel decks (some cracks along welding parts between deck plates and trough ribs).– Many cracks at ends of welding parts between the flange plates of column members and the lower flange plates of horizontal members in steel bridge piers.4Repair and strengthening works of these cracks are carried out now.（ii）Retrofitting works against increased design live load.– Maximum design live load was changed from 200 kN to 250 kN.（iii）Retrofitting works due to revised design specifications.– For example, there was no design method for stiffened plates in JSHB about 40 years ago.(iv) Seismic retrofitting works.(v) Development of bridge management systems based on Life Cycle Cost (LCC) and asset management.（vi）Repair and strengthening works of damage to bridge bearings and expansion joints.（vii）Maintenance works on permeable pavements.1.3. MaintenanceRegarding the maintenance of bridges, there are many issues that can be solved by the bridge engineering community, though there are also many political and economical problems which cannot be solved by the bridge engineering community alone.Issues and problems of bridge maintenance are listed below:（1）Definition of terminology and life cycle.– Definition of bridge maintenance.– Unification of the terminology on bridge maintenance.– Decision of the life cycle of bridges, members and their parts.（2）Inspection and monitoring.–Labor saving of inspection for maintenance through monitoring bridges, members and their parts.– Rationalization and cost reduction of inspection methods.5– Education for maintenance engineers.– Collection and storage of maintenance data by utilizing IT technology.（3）Evaluation/assessment methods.– Establishment of methods for evaluating the safety and durability of existing bridges and the public announcement and communication of evaluated results.–Development of method for deciding the priority ranking of repair and retrofitting of existing bridges.（4）Maintenance system, and repair and retrofitting technique.– Development of bridge maintenance system including repair and retrofitting technique.– Development of effective feedback system from maintenance to design.– Development of techniques for replacing deteriorated bridge structures.– Development of new materials and techniques for maintenance.（5）Harmony between bridges and their surrounding environment.–Maintenance considering the co-existence and harmony of aesthetics, –Improvement and refreshment of environment surrounding bridges for users, inhabitants, and nature.（6）Budget for maintenance.– Maintenance in case of insufficient budget.– Asset assessment and effective budget.1.4. Seismic design and retrofittingVarious design methods, retrofitting methods, technologies and materials for seismic design and retrofitting have been developed after the Hyogo-ken Nambu Earthquake. The seismic design procedures after the Hyogo-ken Nambu Earthquake are highlighted below:6（1）Design seismic loads.There are two levels and two types of design earthquake specified in JSHB. – Level 1: Maximum elastic response acceleration 300 gal.–Level 2 Type I (ocean plate slip type): Maximum elastic response acceleration 1000 gal.–Level 2 Type II (inland fault slip type): Maximum elastic response acceleration 2000 gal.（2）Elastic design is carried out against the Level 1 earthquake with the safety factor of 1.13.（3）Elasto-plastic deformation is allowed against Level 2 earthquakes. The safety of a bridge dimensioned on the basis of a Level 1 earthquake is verified by using a Level 2 earthquake.（4）Two types of seismic design methods against Level 2 earthquakes;– Design method A in which the seismic load is reduced by taking into account the elasto-plastic deformation of main structural members.– Design method B in which the seismic load is reduced by introducing seismic dampers, fuse members, key plastic members, bracing members, and so on.1.5. Design tools（1）Analytical methodsThe computer programs developed in Japan are principally used for almost all the elastic linear analyses associated with bridge design. In investigating issues to which JSHB can not be applied, the elasto-plastic and finite displacement analyses for framed structures are sometimes carried out, for example, by the computer program EPASS developed by our laboratory and JIP Techno Science Corporation. However, corresponding analyses for plated structures are carried out using computer programs developed mainly7in other countries, such as ABAQUS, MARC, NASTRAN etc. and sometimes our own USSP.Dynamic, elasto-plastic and finite displacement analyses for steel bridge piers subjected to the Level 2 earthquakes are carried out by using computer programs using the yield criterion developed in Japan in terms of cross sectional forces (rather than stresses).Our laboratory and JIP Techno Science Corporation have developed a computer program EPASS/USSP , a multi-purpose static/dynamic, elasto-plastic and finite displacement solver for spatial bridge structures consisting of thin-walled steel and composite members considering the local buckling of constituent stiffened plate panels of the members and the elasto-plastic behaviour of the encased concrete of the composite members. （2）Experimental methodsAfter the Hyogo-ken Nambu Earthquake, pseudo-dynamic tests have become very popular in Japan. Kyoto University and our Osaka City University have developed a multi-phase pseudo-dynamic testing system, which can simulate the dynamic behavior of a structure with multi-mass involving collaboration of many different laboratories connected through the internet. 1.6. New materials and technologiesNew high-performance materials are continually developed for bridges. Examples include high-performance steel, high-performance bearings, high-ductility and high-strength bolts, carbon fiber reinforced plastic sheets, carbon fiber reinforced plastic cables and so on. Among them, carbon fiber reinforced plastic sheets are used for the repair of superannuated steel girder bridges and RC slabs, and the seismic retrofitting of steel bridge piers with circular cross section. However, it seems to be very difficult to identify8structural members to which these high-performance materials can be properly applied.On the other hand, various high-performance technologies are being developed for seismic design, seismic retrofitting, cost reduction, control of vibration, and so on .9日本钢桥建筑的近期发展趋向摘要：在本文中，探讨了日本钢桥建筑的最近发展趋向。
土木工程桥梁专业英语翻译
英语翻译Lesson 13 Bridge Forms1、一座好的桥梁必须结构简单，功能完善，美观大方，荷载分布均匀，比例协调，线条流畅，格调沉静并且和周围的环境相协调。
2、桥梁工程后来的发展是结构形式的改进的结果，这有赖于对结构分析和设计逐步深入地理解以及工程材料的改善和施工技术的提高。
3、在桥面建设中相对更新型的材料之一是预应力混凝土（混凝土先经过预压以抵抗最终拉力，于是钢筋混凝土固有的不抗拉的缺陷得到了解决）。
4、混凝土小跨桥的形式包括现浇钢筋混凝土T形梁（及板）；单跨预应力桥（包括预制预应力I形梁或者箱形梁，顶部为现浇的桥面）；以及现浇箱形梁。
5、拱桥用在跨度更大，中间不能修建桥墩的地方，以及有坚硬岩石来支撑桥台处轴向力的地方。
6、有了桥面上方的并连接到桥墩的缆索，就可以去掉中间的桥墩，从而是航行有更大的宽度。
7、由于斜拉索的阻尼效应，斜拉桥面较之悬索桥强不易产生风动摇晃。
8、板桥在美国用于中跨桥。
它们通常是连续结构，梁在桥墩处最厚，跨中最薄。
9、上承桥是桥面在支撑结构的上面，即上部结构的支撑物在桥面以下。
10、混凝土小跨桥的形式包括现浇钢筋混凝土T形梁（及板）；单跨预应力桥（包括预制预应力I形梁或者箱形梁，顶部为现浇的桥面）；以及现浇箱形梁。
Lesson 14 Substructure SystemsA1、在近来的一些设计中，在柱和盖梁之间采用了混凝土铰接支座以避免力矩从桥面转移到柱上。
2、实心桥墩由圬工材料和大体积混凝土浇筑而成，裸露部分可以采用石圬工衬砌，内部用贫混凝土浇注，这样可以减少模板的费用，并且增强美感。
3、倒梯形桥墩具有细长的下部结构，一般适合高架公路，这种桥墩应用在跨河桥时，对河道的限制极小。
4、沿垂直上部结构的轴线方向测量，桥墩顶部应至少比承台长1.2m。
承台尺寸的确定应满足由静载和活载共同产生的支撑应力不超过4.2MPa。
5、桥墩顶部一般比顶部要宽，以便把最终应力限制到允许值范围内。
2019年12月大学英语六级翻译练习题：中国桥梁
2019年12月大学英语六级翻译练习题：中国桥梁2018年12月大学英语六级翻译练习题库英语六级翻译练习题：中国桥梁中国的桥梁建设有着悠久的历史。
中国古代桥梁以木材和石头为主要建筑材料,形式多样，极富特色。
中国现存最古老的桥梁为隋代建造的安济桥，位于河北省赵县。
安济桥又名赵州桥，桥长50.82米，桥宽9米，为国家重点保护的文物(cultural relic)。
清朝末年，兰州黄河铁桥建成，标志着中国桥梁建设进入了以钢铁和混凝土(concrete)为主要材料的时期。
如今，中国的桥梁建设保持着多项世界记录，中国跻身于世界桥梁建设强国行列。
参考翻译：China boasts a long history in bridge construction.With wood and stone as the major buildingmaterials, Chinese ancient bridges vary in forms andare highlydistinct.Constructed in the Sui Dynasty,Anji Bridge, which is located in Zhao County, HebeiProvince, is the oldest existing bridge in China.Anji Bridge, also named Zhaozhou Bridge, is akey national protected cultural relic measuring a length of 50.82 meters and a width of 9meters.In the late years of the Qing Dynasty, Huanghe Iron Bridge in Lanzhou wascompleted,symbolizing that Chinas bridge construction stepped into an era of adopting steel andconcrete as the main materials for bridges.Now, bearing many world records, China standsamong world giants in bridge construction.1.第二句中的“以...为主要建筑材料”可处理为状语，用介词短语with...as the major building materials表达，而“中国古代桥梁”宜译为“形式多样，极富特色”的主语，谓语部分“形式多样，极富特色”可处理为并列内容，用and连接，表达为vary in forms and are highly distinct。
桥梁专业外文翻译--- 一种新的方式,通过和半透过拱桥设计吊带
中英文对译英文原文A new way to design suspenders for through and half-through arch bridgesR.J. Jillian, Y.Y. Chen, Q.M. Wu, W.M. Gaia and D.M. Penpusher Municipal Design & Research Institute, Sazhen, China1ABSTRACTIt is well-known that, in through and half-through arch bridges, the suspenders are important components since they connect the bridge deck to the arch ribs. The collapse of bridge deck or arch ribs may be induced once one or more suspenders are broken. In this paper,the traditional design way of the suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design suspenders for arch bridges is then put forward. The reasonability of this new way is proved by numerical analysis examples. The impact effect of the remaining components of the arch bridge due to the breakage of one or more suspenders is obtained by appropriate simulation using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders for the through and half-through arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.2 INTRODUCTIONWith the rapid development of new materials and construction technologies, the modern arch bridges are now entering a new era. The span length of the modern arch bridges is increasing,and the first two longest modern arch bridges are the Enchainment Yangtze River Bridge and the Lu Pu bridge, respectively. The Enchainment Yangtze River Bridge built in 2008 is a tied steel truss arch bridge with a span length of 552m; and the Lu Pu Bridge built in 2003 is a steel box arch bridge with a central span length of 550m. They are both half-through arch bridges and respectively located in Chongqing and Shanghai, China.Arch bridges can be classified into three categories according to the relative positions between the deck and the arch: deck-arch bridge, half-through arch bridge and through arch bridge (Ch-eng J. et al. 2003). For both half-through arch bridge and through arch bridge, the suspenders are the important components since they connect the bridge deck with arch ribs andtransfer kinds of loads from bridge deck to arches, and finally to foundation. However, at the same time they are the vulnerable members to be damaged or ruined, because they usually work both in formidable natural environment and under fatigue-induced cycling loads (Li D.S.et al. 2007). It is a fact that the service life of the suspender is much shorter than that of the arch bridge, and the suspenders must be replaced timely (Tang H.C. 2005).The damage to the bridge deck or arches may be induced when one or more suspenders break, sometimes, even the collapse of the arch bridge may happen. In recent years, the accidents of arch bridges’collapse caused severe casualties and huge economic loss (Li D.S.and Ou J.P. 2005 ). In order to know well about the health condition of suspenders, kinds of realtime monitoring and diagnoses were conducted (Li D.S. et al. 2007). However, both the technologies and the materials for structural health monitoring and diagnose are not fully developed up to now (Li H.N. et al. 2008).In this paper, the traditional design way of suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design the suspenders in through and half-through modern arch bridges is then put forward. With the application of this new way, the arch bridge will remain safe even though one or more suspenders happen to break.This new design way is a different method from the health monitoring to control the safety of the modern arch bridges under the condition that the break of the suspender is uncontrollable.The reasonability and reliability of this new way is studied and proved by a numerical analysis example based on a real through arch bridge. The impact effect of the remaining components of the arch bridge due to the breakage of one or more suspenders is obtained by appropriate simulation using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders in modern arch bridges can assure the safety of the bridge effectively even though one or more suspend ers happen to break.3 DISCCUSION ON TRADITONAL DESIGN OF ARCH BRIDGE SUSPENDERSFor through-type and half-through-type arch bridges, the suspenders are anchored to arch ribs atone end and transverse beams at the other. Generally speaking, in the traditional arch bridge design the double-suspender anchorage (Fig.1) instead of the single-suspender anchorage is widely adopted in order to keep the arch bridge still safe and make the replacement of the suspenders more convenient when one suspender happens to break.Figure 1 : Double-suspender anchorage traditionally designed: (a) Parallel double-suspender anchorage,(b) Inclined double-suspender anchorageHowever, the two suspenders at the same anchorage are usually designed as the same both in material and cross sections; i.e.,, E1=E2, A1=A2and θ1=θ2, where E, A and θare the elastic modulus, cross section area and inclined angles of the suspender, respectively. That means they have the same or similar stress and variation of stress in service. They are also under the same or similar corrosion environment since they are located at the same anchorage. Hereby, it can be concluded that the two suspenders at the same anchorage will fail at the same or similar time because of the almost equal level of both fatigue load and corrosion environment.Based on the discussion above, it can be seen that the double-suspender system designed in the traditional way will not improve both the safety of the arch bridge and the convenience of suspenders replacement compared to the single-suspender system.4 A NEW WAY TO DESIGN ARCH BRIDGE SUSPENDERSIn order to keep the remaining structure of arch bridge still safe when one suspender happens to break, the double-suspenders must be designed with different service life. The only way to achieve this aim is to design the two suspenders at the same anchorage with different either material or cross section areas since they carry the same fatigue loads and are under the same corrosion environment.If the two suspenders at the same anchorage are designed with different materials, the extra in convenience both in design and construction of the arch bridge will be induced. The better way is to make the two suspenders with different cross section areas A Fand AS(Fig.2)respectively. With different cross section areas, the two suspenders at the same anchorage will have different stress levels and variation of stresses, that is to say,there are σF,max≠σS,max, σF,a≠σF,a. Σmax and σa are the maximum stress and amplitude of the stress of the suspenders,respectively. Based on the basic theories of the material fatigue, the material or member has different service lives with different maximum stress and stress amplitude.Figure 2 : Double-suspender anchorage designed in new way : (a) Parallel double-suspender anchorage,(b) Inclined double-suspender anchorage Thereupon, the two suspenders at the same anchorage may have different service lives if they are appropriately designed with different cross section areas even though they are made of the same material and under the same fatigue loads and corrosion environment. During the service life of the arch bridge, the suspender with the larger cross section will still keep the arch bridge safe when the suspender with the smaller cross section at the same anchorage happens to break.The reasonability and reliability of this new way to consider the suspender design will be proved by numerical comparison study on a trough-type modern arch bridge, Sazhen North Railway Station Bridge, using comprehensive commercial software ANSYS in the following section in this paper.5 NUMERICAL ANALYSIS EXAMPLE5.1 Description of Sazhen North Railway Station BridgeSazhen North Railway Station Bridge with a span length of 150m is a through-type modern concrete-filled steel tubular arch bridge. It was built in 2000 and located at the Sazhen North Railway Station, spanning all railways at that station. Rise-to-span ratio of this bridge is 1/4.5.The elevation view of the bridge is shown in Fig.3. The width of the general bridge deck is23.5m except at the end of the arch ribs with abridge deck width of 28m. Horizontal cables in the steel box girders of the bridge deck are adopted to balance the horizontal force of the arch ribs. This bridge has two vertical arch ribs and each arch rib is composed of four concrete-filled steel tubes and thus has a truss cross section of 2.0m in width and 3.0m in height. The material properties of the bridge are listed in Table 1. The more details about this bridge is found in Li eta. (2002).5.2 Finite element model of the example bridgeA detailed finite element model (Fig.4) of the example bridge was developed using the comprehensive commercial software ANSYS. In this 3 dimensional (3D) finite element model,every component is appropriately modeled.As mentioned above, each arch rib is composed of four concrete-filled steel tubes.These concrete-filled steel tubes are modeled by BEAM4 element. Since the concrete-filled steel tube is a composite member, the equivalent cross sectional properties and material properties are obtained first by editing an APDL file based on some equivalence rules, and then assign these equivalent cross sectional properties and material properties to the corresponding beam elements. The equivalent cross sectional properties and material properties of the concrete-filled steel tubes are listed in Table 2.The BEAM4 element is also adopted to model the arch rib bracings, the longitudinal steel box girders, the steel tubes connecting the four concrete-filled steel tubes of the arch rib. The transverse steel girders of the bridge deck are model-led using BEAM188 element. The concrete plates on the top of the bridge deck are modeled as beam-grid using BEAM4 element. The suspenders are modeled by the LINK8 element. The cross section properties of these components except those of the transverse girders are listed in Table 3, BEAM188 element needs the cross section shape and dimensions as input information, the corresponding cross section properties will be calculated automatically by the program ANSYS. The connections between the longitudinal box girders and transverse girders, the concrete plates and the steel girders are all regarded as rigid and modeled by MPC184 elements. There are 4672 elements and 2448 nodes in total in this 3D finite element model.The boundary conditions of the 3D finite element model are also considered appropriately based on the real situation of the bridge structure. In Sazhen North Railway Station Bridge,the arches are fixed rigidly to the piers. The horizontal cables in the steel box girders of the bridge deck are adopted to balance the horizontal force at the fixed point connecting arch rib sand piers. Since the piers are not considered in this 3D finite element model, the ends of the arch ribs should be treated as fixed in all degrees of freedom, and the horizontal cables are ignored hereby. The two longitudinal steel box girders are supported on the transverse beams located at the inner side of the pier, the boundary conditions at these four ends of the two box girders are summarized in Table 4.There are two arch ribs in Sazhen North Railway Station Bridge and 17 double-suspenders are anchored in each arch rib. For the convenience of the following analysis, the anchorages of each arch rib are numbered from 1 to 17 from west to east; the two suspenders at each anchorage are numbered as a and b for north arch rib, a’and b’for south arch rib, respectively.That is to say, the 34 suspenders in the north arch rib are marked as 1a, 1b, 2a, 2b, …, 17a, and17b respectively; accordingly, those 34 suspenders in the south arch rib are 1a’, 1b’, 2a’,2b’, …, 17a’, and 17b’(Fig.5) .5.3 Impact effect study due to the suspender breakWhen one or more suspenders break, there will be impact effect on the remaining structure and its other components. It is very important to know well the impact effect. In this section, the break of a suspender is appropriately simulated by assuming that two forces with equal value but opposite directions applied respectively to the brokensuspender’s anchorages on arch riband bridge deck decrease to 0 within a time slot δt from the axial force value of that suspender.The impact effect due to a suspender’s break on the other components of the bridge is studied by carrying out time-history analysis based on the 3D finite element model in ANSYS.Of course, the impact effect due to a suspender’s break on the other components of the bridge is closely related to the time slot δt and the structural properties of the bridge. For a bridge in service, the impact effect is mainly dependent on the value of the time slot δt. Here the impact coefficient ηis defined as the ratio of the structural response under both the impact and deal loads to that only under the deal loads. The structural response of the bridge under kinds of loads refer to the stress, bending moment, axial force, displacement, and so on.In order to determine the appropriate value of the suspender break time slot δt for the following analysis, the relationship between the impact coefficient ηand the suspender breaktime slot δtis studied based on different suspender break cases. Theoretically, when a suspender(a or a’) breaks, the other suspender (b or b’) at the same anchorage should be impacted mor strongly than other members of the bridge, such as bridge deck, arch rib, and so on.Because of the symmetric arrangement of the suspenders (Fig.5) in Sazhen North Railway Station Bridge, the suspenders anchored to anchorage 1 to 9 are chosen to carry out the break simulation and impact effect analysis.At each anchorage, assuming the a (or b) suspender breaks, the curve to represent the relationship between the impact coefficient ηof the corresponding b (or a) suspender’stress and the time slot δtare obtained after the time-history analysis in ANSYS. The η-δt curves of four suspender break cases are plotted in Fig.6, shortest suspender 1a, second shortest suspender 1b, medium length suspender 5a and longest suspender9a.From Fig.6, it can be seen that relatively larger variation of ηhappens when the value of the time slot δtin the range of (0.01s, 1.0s) . When the suspender break time δtis longer than 1.0s,the impact effect is small and varies little with the increment of the break time. When the suspender break time δtis shorter than 0.01s, the impact effect is obvious but varies little with the variation of the break time. So the impact effect due to the suspender break can be appropriately simulated and obtained by the time-history analysis if the break time slot δt assumed to be shorted than 0.01s. In the following analysis, the time slot δtis taken as the value of 0.001s.It can also be shown in Fig.6 that the impact effect induced by the shorter suspender’s break is larger than that by the longer one.5.4 Analysis on the present designIn the present design of the example bridge, every suspender is composed of 61×Φ7mm parallel pre-stressed steel wires. The characteristic tension strength of the steel wires is 1670MPa. In this section, the safety of the remaining structure of the example bridge is studied in various cases assuming that different numbers of suspenders at different anchorages happen to break.Theoretically speaking, the two suspenders at the same anchorage should break at the same time since they are designed with the same material and cross section. When two suspenders at the same anchorage happen to break at the same time, the other suspenders, bridge deck,transverse girder and longitudinal girder close to that anchorage will break in succession. For example, when the suspenders 2a and 2b break at the same time, the suspenders 1a, 1b, 3a and3b will break successively, theconcrete plate and the longitudinal steel box girder near to the anchorage 2 will break, too (Fig.7). When the suspenders 7a and 7b break at the same time, the suspenders 6a, 6b, the concrete plate and the longitudinal steel box girder near to the anchorage 6 will fail successively (Fig.8).5.5 Analysis on new designBased on the new way put forward in this paper, the two suspenders at a same anchorage are hereby designed differently, one as 13-7Φ5 pre-stressed steel wire strand, the other 20-7Φ5pre-stressed steel wire strand. The suspenders 1a to 17a and 1b’to 17b’are assigned with13-7Φ5 pre-stressed steel wire strand, 1b to 17b and 1a’to 17a’with 20-7Φ5 pre-stressed steel wire strand. The characteristic tension strength of the pre-stressed steel wire strand is 1860MPa.The allowable stresses of the steel wire stand are 744MPa and 930MPa, respectively for temporary and permanent situation.Two representative cases are studied, (1) the suspender 1a composed of 13-7Φ5 pre-stressed steel wire strand at the anchorage 1 breaks; (2) every suspender composed of 13-7Φ5pre-stressed steel wire strand at every anchorage, i.e. 1a to 17a and 1b’to 17b’, breaks at the same time. In each case, the stresses of the other suspenders at three phases are obtained and summarized, before the assuming break, during the break and after the assuming break. The results of the two cases are shown in Fig.9a, b and 10a, b respectively.From Fig.9 it can be seen that suspender 1a break produces little impact effect on all other suspenders except suspender 1b, and suspender 1b can fully stand the obvious impact effect. It is shown in Fig.10 that when all the suspenders designed with 13-7Φ5 pre-stressed steel wire strand break at the same, the other suspenders are still safe even though they are obviously impacted. In both cases, the other components of the bridge, such as concrete plates, steel girders, arch ribs, remain safeunder the impact effect, i.e. the bridge structure is still fully functional when one or more suspenders happen to break. By now the reasonability and reliability of the new design way for modern arch bridge is proved.6 CONCLUSIONSFor both half-through arch and through arch bridges, the suspenders are the important components. However, at the same time they are the vulnerable members to be damaged or ruined, because they usually work both in formidable natural environment and under fatigue-induced cycling loads. It is a fact that the service life of the suspender is much shorter than that of the arch bridge and the suspenders must be replaced timely. In recent years, the accidents of arch bridges’collapse caused severe casualties and huge economic loss.In this paper, the traditional design way of suspenders in through and half-through arch bridges is discussed first. A new way to design the suspenders in modern arch bridges is put forward successively based on the discussion. With the application of this new way, the arch bridge will remain safe even though one or more its suspenders happen to break. This new design way is a different method from the health monitoring to control the safety of the modern arch bridges under the condition that the break of the suspender is uncontrollable.The reasonability and reliability of this new design way for suspenders in through and half-through arch bridges is studied and proved by a numerical analysis example based on a real through-arch bridge. The impact effect of the remaining components of the arch bridge due to the break of one or more suspenders is obtained by appropriate simulation and time-history analysis by using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders in modern through and half-through arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.REFERENCESCh eng J., Jillian, J.J. Xian R.C. and Xian H.F., 2003. Ultimate load carrying capacity of the Lu Pu steel arch bridge under static wind loads, Computers & Structures 81, p.61-73.Li D.S. and Ou J.P., 2005. Arch bridge suspenders corrosion fatigue life assessment method and its application. Journal of Highway and Transportation Research and Develop men, 8(22): p.106-109.Li D.S., Chou Z., Deng N.C. and Ou J.P., 2007. Fiber Bragg Grating Sensors for Arch Bridge Suspender Health Monitoring, In Yuri N. Kuching, J.P. Ou, Cleg B. Vitric, Z. Chou (eds), Fundamental Problems of Optoelectronics and Microelectronics III; Proc. SPIE, 6595, p.65952U-1-6.Li H.N., Gao D.W. and Yid T.H., 2008. Advances in Structural Health Monitoring Systems in Civil Engineering, Advances in Mechanics 38(2): p.151-166.Li Y., Chen, Y.Y. Nile, J.G. and Chen B.C., 2002. The design and application of the composite bridges.Science Press, Beijing, China.Tang H.C., 2005. The Analysis of Cables’Hidden Trouble. Bridge 3, p.80-82.中文翻译一种新的方式，通过和半透过拱桥设计吊带R.J.江Y.Y.陈，Q.M.吴W.M.盖和D.M. Peng 深圳市政设计研究院，深圳，中国1摘要这是众所周知的是，在通过和半拱桥吊杆的重要组成部分，因为它们连接拱肋，桥面。
桥梁外文翻译
Reinforced cncrete beamsIn the subject of applied inechanics,the behaviour of homogeneous beams has been dealt with.the basic formulae for pure flexure have been established as follows:Using the above formulae.the stresses across the section,curvature,slopes and deflections at anu point in the beam can be found,providec the material is elastic,obeys hooke’s law and Bernoulli’s plane section hypothesis,and the beam is homogeneous and isotropic.in the case of shallow beams made of steel,the above approximations are known to be valid.in the case of concrete,which is strong in compression and relarively weak in intension,a plain concrete beam cracks in the tension zone and fails suddenly.to augment the strength of sucb plain concrete beams,it has become customary toembed steelreinforcement in the tension zone.and hence the emergence and urilization of reinforced cement concrete.since steel has 15 to 30 tines more strength than concrete,steel reinforcement has also been used in compression zones to reduce the size of flexural membets.depending on the quantity of reinforcement a,rsed in the beam,its behaviour can be controlled.in a beam of rectangular cross-section,if there is reinforcement in the tension zone only, it is called a singly reinforced beam .in the case of beams,which have restrictions ondepth(often imposed by the archetect),there is need for reinforcing the tension and also the compression zone.such beams are designated as doubly reinforced beams.beams of simple rectangular cross-section are no!rsed as frequently as beams and slabs which are cast together.in thes case,a part of the slab acts along with the rectangular rib or web.if the slab projection is on one side od the web, the cross-section resembles an inerted ‘L’and if the slab projects on both sides of the web, the cross-section resembles a ‘T’ shape .these are generally known as ell and tee beams .laboratoty tests indicate that when such a reinforced concrete beam is subjected to pure flexure .and the applied moment is gradually increased ,the beam will deflect ,develop cracks ,shift its neutral axis ,develop yielding of reinforcement and eventually fail due to excessire compressire strain in the extreme fibers .the aim of the designer of reinforced comerete beams is to predict tis entire spectrum of benaviour in matbematical terms .identify the parameters which infiuence thes behavroum and obtain the cracking .defiection and collapse limit loads.Analysis and design are really complementary in nature .provided the nature of loading , the beam dimensions,the materials used and the quantity of reiniorcement are known ,the theory of reinforced concrete permits the analyses of reinforoement are knwn ,the theory of reinforced concrete permits the analyses of stresses ,strains ,deflections ,crack spacing and width and also the collapse load .however ,the usual problem is to design a section to satisfy limiting crack widths ,deflections and load carrying capacity and there are usually innumerable answers to a design problem .it is usual to estimate a cross-section based on one of the limiting states and analyse the beam for the satisfaction of the other limet states .thus design is followed by analysis and a final section is obtained by a process of iteration .t e design process becomes clear only when the process of analyses is learnt thoroughly.in the following ,the methods os analysis for flexure will be emphasized.In a reinforced concrete beam ,the following behavioural sequence can be traced:（a）under small loads ,the strains across a cross-section are small ,the neutral axis is at the centroid sf the uncracked section ,the stresses are linearlu related to strains and the deflection is proportional to load as in the case of isotropic ,homogeneous ,linearly elastic beam elements .thisstage(phase 1) persists up to cracking of concrete in tahe rension zone:（b）as the load is increased ,extensive cracking develops at distinct intervals of a purely flexurally loaded beam ,the reinforcement bars come into play,steel strain increases,the neutral axis shifts at the zones of cracking and deflections and rotations increase at a faster rate,but it is found from experiments that plane-sections remain plane and normal .this second stage (phase2) is the normally observed behaviour of a beam in its service state :but the cracks are so fine that they can be noticed only at very close quarters;and(c) the third stage of loading (phase3) starts with the yielding of steel reinforcement ,considerable shift in the neutral axis position ,non-linear deflection increase, extensive cracking and finally ,the crushing of concrete (=0.0035),which leads to the ultimate collapse of the beam,without further increase in load .if the beam is reinforced rather heavily (over-reinforced), the steel may not yield ;in which case the concrete in compression may crush and spall, such failures are usually sudden and catastropnic.most codes of practice do not permit over-reinforced beams to be designed deliberately ,the next step is to develop mathematical models for these three different phases,All mathematical formulations are based on a proper set of assumptions .the assumptions made for analysing theflexural behaviour of reinforced concrete beams are as follows:(a)plane sections remain plane ;(b)stress-strain behaviour is as prescribed by appropriate curves;(c)concrete in rension may be megtected;(d)there is no bond-sllp between steel and concrete ,??strains in the reinforcement and concrete at the same location are the same .stress in steel is the moduiar ratic times that of concrete (m=EE);and(e)there are no initial stresses in steel when it is embedded in concrete.Failure modes of reinforced concrete beamswhen a reinforced concrete beam is loaded to failure .three modes of bending failure are possible .the particular mode of failure is determined by the percentage of steel located in the tension zone .two of these modes are brittle and one is ductile failure mode is possible .Case1 the beam is over-reinforced and the failure mode is a sudden . brittle failure, which the engineer must carefully guard against in design . when the over-reinforced beam is loaded to failure ,the failure is initiated by thecrushing of the concrete followed by the sudden disintegration of the compression zone while the stress in the relatively large area of steel has not reached its yield point . toprevent a brittle failure ,the reinforcement must yield while the strain in the concrete is less than the failure strain of 0.0035Case2 the beam has a moderate percentage of steel, and the failure mode is initiated by a yield while the strains in the concrete are relatively low .such beams can continue to carry load and are able to undergo large deflections before final collapse occurs; this ductile mode of failure is the only acceptable mode.Case3 the beam is lightly reinforced with a very small percentage of steel. And the failure mode is also brittle . when the tensile stress in the concrete exceeds the modulus of rupture ( thetensile strength ), the concrete cracks and immediately releases the tensile force it carries ;the lightly stressed steel must then absorb this increment of load .if the area of steel provided is too small to carry this added force,the steel will snap and total rupture of the section will occur suddenly.To ensure ductile failures, upper and lower limits on the permitted area reinforcing steel are established by the ACI Code. The lower limit ensures that enough steel will be used to prevent the steel from snapping suddenly and causing the beam to split .the upper limit on steel area prevents the design of over-reinforced beams.Since the presence of shear force has little influence on the moment capacity of a-cross section ,shear is not considered in the design of member for bending.Reinforced conerete columnsColumn are members used primaril to support axial compressive loads and have a ratio of height to the leat lateral dimension of 3 or greater .in reinforced concrete buildings , concrete beams ,floors, and columns are cast monolithically ,causing some moments in the columns due to end restraint. Moreover , perfect vertical alignment of columns in a multi-story building is not possible .causing loads to be eccentric relative to the center of columns .the eccentric loads will cause moments in columns . therefore , a column subjected to pure axial loads dose not exest in concrete buildings .however, it can be assumed that axially loaded columns are those weth relatively small eccentricity ,e, of about 0.1 h or less. Where h is the total depth of the column and e is the eccentric distance from the center of the column . because concrete has a high compressseve strength and is an inespenseve material , it can be used in the design of compression members economically.Types of columnsColumns may be classified based on the following different categories (fig.10.1);1.based on loading ,columns may be classified as follows ;a.axially loaded columns ,where loads are assumed acting at the center of the column section .b.eccentrically loaded columns , where loads are acting at a distance e form the center of the colmn section ,the distance e could be along the x or y axis ,causing moments either about the x or y axis.c.biaxially loaded columns , where the load is applied at any point on the column section , causing moments about both the x and y-axes simultaneously .2.based on length, columns may be classified as follows ;a.short columns , where the column’s failure is due to the crushing of concrete or the yielding of the steel bars under the full load capacitu of the column .b.long columns,where buckling effect and slenderness ratio must be taken into consederation in the design ,thus reducing the load capacitu of the column relative to that of a short column .3.based on the shape of the cross section , column sections may be square ,rectangular ,round ,l-shaped,octagonal, or any desired shape with an adequate side width or dimensions .4.based on column ties ,columns may be classified as follows :a.tied columns containing steel ties to confine the main longitudinal bars in the columns .ties are normally apaced uniformly along the height of the column .b.spiral columns containing spirals (spring type reinforcement ) to hold the main longitudinal reinforcement and to help increase the column ductility before failure . in general , ties and spirals prevent the slender , highly stressed longitudinal bars form buckling and bursting the concrete cover .5.based on frame bracing , columns may part of a frame that is braced against sidesway or unbraced against sedesway.bracing may be achieved by using shear walls or bracings in the building frame .in braced frames , coumns resist mainlu gravity loads ,and shear walls resist lateral loads and wind loads ,in unbraced frames ,coumns resist both gravity and lateral loads , which reduce the load capacity of the columns .6.based on materials ,columns may be reinforced ,prestressed ,composite （containing rolled steel sections such as i-sections）,or a combination of rolled steel sections and renforcing bars . concrete columns reinforced with longitudinal reinforcing bars are the most common type used in concrete buildings .\Behaveor of axeally loaded columnsWhen an axial load is applied to a reinforced concrete short colmns , the concrete can be considered to behave elastically up to a low stress of about (1/3)f,if the load on the column is increased to reach its ultimate strength, the concrete will reach the maximum strength and steel will reach its yield strength ,f. the ultimate nominal load capacity of the columns can be written as follows :Where A and A =the net concrete and total steel compressive areas , respectively .Two different types of failure occur in columns , depending onn whether ties or spirals are used . for a tied column . the concrete fails by crushing and shearing outward ,the longitudinal steel bars fail by buckling outward between ties , and the column failure occurs suddenly , much like the failure of a concrete cylinder .A spiral column undergoes a marked yielding , followed by considerable deformation before complete faiure . the concrete in the outer shell fails and spalls off . the comcrete inside the spiral is confined and provides little strength betore the initiation of column failure . a hoop tension develops in the piral ,and for a closely spaced spiral , the steel may yield . a sudden failure is not espected.fig.10.2 shows typical load deformation curves for tied and spiral columns . up to plint a , both columns behave similarly . at plint a , the longitudinal stee bars of the columns yield, and the spiral column shell spalls off , after the ultimate load is reached ,a tied column fails suddenly (curve b ). Whereas a spiral column deforms appreciably before failure (curve c).。
bridge的例句
bridge的例句Bridge是一个常用的英文单词，有多种意思。
它可以是名词，表示桥梁或者桥牌。
也可以是动词，表示架起桥梁或者翻译。
在句子中，bridge经常被用来表示连接或者弥合两个事物之间的空隙。
下面让我们来看看几个关于bridge的例句。
1. The bridge over the river is very long and impressive.这句话中的bridge表示桥梁的意思。
它是一个名词，通常用来描述两地之间的连接。
在这个例子中，桥梁架在河上，这条桥非常长，让人印象深刻。
2. We need to bridge the gap between the rich and the poor.这句话中的bridge表示弥合的意思。
它是一个动词，通常用来表示缩小两者之间的差距。
在这个例子中，我们需要缩小富人和穷人之间的差距，使得社会更加平等。
3. The translator did a great job bridging the language barrier.这句话中的bridge表示翻译的意思。
它是一个动词，通常用来表示翻译或者介绍两种语言之间的沟通。
在这个例子中，翻译做得很好，让两种语言之间的障碍消失了。
4. She's very good at playing bridge.这句话中的bridge表示桥牌的意思。
它是一个名词，指一种有四个玩家的牌类游戏。
在这个例子中，她非常擅长这个游戏，通常与朋友一起玩。
5. The bridge collapsed during the storm.这句话中的bridge表示桥梁的意思。
它是一个名词，通常用来描述连接两地之间的结构物。
在这个例子中，桥梁在暴风雨中倒塌了。
总之，bridge是一个非常常用的英文单词，有多种意思。
了解这些意思和使用方法，可以帮助我们更好地理解和使用英语。
桥梁建筑概论
南京长江大桥
这是我国长江上的第二座桥。 南京长江大桥建成于1968年，是长江上 第一座由我国自行设计建造的双层式铁 路、公路两用桥。上层的公路桥长4589 米，车行道宽15米，可容4辆大型汽车 并行，两侧还各有2米多宽的人行道； 下层的铁路桥长6772米，宽14米，铺 有双轨，两列火车可同时对开。江面上 的正桥长1577米，其余为引桥，是我国 桥梁之最。
四川泸定桥
位于四川省泸定县，跨越大渡河。公元 1705年动工，翌年建成。为大渡河上建 造最早最长的人行吊桥。跨径100米， 全长123.42米，宽３米，高10余米，桥 身由13根铁链组成，每隔５米由一根小 铁链横联主链，９根底链上铺木桥板作 桥面，左右各两根作栏杆扶手，桥台用 条石砌筑，桥亭为木质。1935年5月29 日,红军长征在此飞夺此桥，强渡大渡 河。
江苏苏通长江大桥
法国诺曼底大桥
上海南浦大桥
南京长江二桥
温州大桥
江苏苏通长江大桥
悬索桥
悬索桥是以承受拉力的缆索或链索作为 主要承重构件的桥梁，由悬索、索塔、 锚碇、吊杆、桥面系等部分组成。悬索 通常由抗拉强度高的钢材（钢丝、钢绞 线、钢缆等）制成，用以承受拉力。
日本明石海峡大桥
江阴长江大桥
四川万县长江大桥
故宫金水桥
天台合溪桥
钱塘江四桥
三门健跳大桥
英国福斯桥
刚构桥
从外观上定义，即桥墩和主梁连成整体 的桥梁。 从受力上定义，即桥墩不仅承受竖向作 用，还承受横向作用以及弯矩作用。桥 墩和梁共同承担上部的载荷。
重庆长江大桥
甘肃新田黄河大桥
斜拉桥
斜拉桥由拉索、索塔、主梁和桥面组成， 将梁用若干根斜拉索拉在索塔上，便形 成斜拉桥，桥面荷载经主梁传给拉索、 再由拉索传到索塔。斜拉桥的缆索张拉 成直线形，整个结构为几何不变体，其 刚度比悬索桥大，跨径一般在梁桥和悬 索桥之间。
桥梁外文翻译---一座桥梁更新的施工组织
Fast repair of Bridges桥梁的快速修复——An old wooden bridge-Petersburg in the replacement of the complete work early this year——圣彼得堡一座旧木桥的更换工作在今年年初完成St. Petersburg, Russia in the rise of the traffic development level and the requirements of the old prompted a tram track bridge was transformed into acable-stayed bridge. New Lazarevsky bridge across malaya and Genevieve cardwithin earlier this year completed and open to traffic, replaced a originally for trams passage but now only for pedestrians walking old wooden bridge.在俄罗斯的圣彼得堡，崛起的交通水平和发展要求促使一个旧的电车轨道桥被改造为一个斜拉桥。
新的Lazarevsky大桥横跨马来亚内芙卡，并与今年早些时候建成通车，取代了一座本来供有轨电车通行但是现在只供行人行走的旧木质桥。
The bridge is located in petrograd area, and along with Pionerskaya and Sportivnaya streets will Krestovsky and connected the Petrogradsky islands, both were local transportation hub. It was founded in 1949, when called Koltovsky bridge, Genevieve card within adjacent malaya river. But in 1952, to commemorate the legendary Russian navy admiral mikhail LaZaLieFu embankment and Bridges were renamed, for LaZaLieFu admiral embankment and Lazarevsky bridge.这座桥坐落于彼得格勒区，并且沿着Pionerskaya和Sportivnaya街道将Krestovsky 和Petrogradsky群岛连接了起来，这两者都是当地的交通枢纽。
newbridge翻译
newbridge翻译"Newbridge"的中文翻译可以是“新桥”。
这个词用法灵活，可以指具体的桥梁名称，也可以泛指任何新建的桥梁。
以下是11句关于“新桥”（Newbridge）的双语例句：1. We need to build a new bridge to improvetransportation in this area.我们需要建造一座新桥来改善这个地区的交通状况。
2. The new bridge will connect the two sides of the river, making it easier to cross.这座新桥将连接河流的两岸，使过河变得更容易。
3. The construction of the new bridge will begin next month.新桥的建设将于下个月开始。
4. Many people gathered to witness the opening ceremonyof the new bridge.许多人聚集在一起见证新桥的开幕典礼。
5. The new bridge is designed to withstand earthquakesand other natural disasters.这座新桥的设计能够抵御地震等自然灾害。
6. The government invested a large sum of money in the construction of the new bridge.政府在新桥建设中投入了大笔资金。
7. The new bridge has significantly reduced travel time between the two cities.新桥大大缩短了两城之间的旅行时间。
8. The old bridge was demolished to make way for the new bridge.为了为新桥让路，旧桥被拆除了。
巴西萨尔瓦多大桥 翻译
巴西萨尔瓦多大桥翻译
巴西萨尔瓦多大桥是指巴西里约热内卢市的一座著名桥梁，它
连接了巴西里约热内卢市中心和南区的萨尔瓦多区。
在英文中，巴
西萨尔瓦多大桥的翻译为 "Rio-Niterói Bridge"。
这座大桥是巴
西最重要的交通枢纽之一，也是南美洲最长的悬索桥之一。
巴西萨尔瓦多大桥于1968年开始建设，于1974年完工。
它跨
越了格万纳湾，全长约13.2公里，是一座具有重要历史和建筑意义
的工程。
这座大桥的设计灵感来自美国旧金山金门大桥，采用了悬
索桥的结构形式。
巴西萨尔瓦多大桥的建设对于巴西的交通和经济发展起到了重
要的推动作用。
它连接了里约热内卢市中心和南区的重要交通要道，缩短了两地之间的行车时间，方便了居民和商业活动的往来。
此外，大桥也成为了里约热内卢市的地标之一，吸引了众多游客前来观光
和拍照。
总的来说，巴西萨尔瓦多大桥是巴西里约热内卢市的一座重要
桥梁，连接了市中心和南区，对于交通和经济发展起到了积极的推
动作用。
它是巴西的地标之一，也是南美洲最长的悬索桥之一。
桥梁第十八课翻译
桥光谱提高声音说：“你们没有赶上班车，全是我的过失，大家骂得好，骂得痛快。
不要紧，咱们厂不是有两辆参观和开会用的大轿车吗？等一会人来的差不多了，我叫车队值班的司机送大家回去。
趁等人这功夫，我有个想法说给你们大伙听听，咱们一块儿决定一下。
”他的话似雷，又中又急：“第一，班车站不能由汽车公司管，要我们厂自己管起来。
我明天叫保卫科派个精明强悍的人，专管班车，每辆车上多少人，什么时候发车，听他指挥。
第二，根据带小孩的女工的数目，分出三两或两辆班车，转拉母子，和其他职工两处排队两处上车，省得挤得带孩子的妈妈上不了车。
母子车人不到齐不能走，管班车的人每天掌握带孩子妈妈的出勤数。
第三，明天我叫车队挑选出两辆卡车，安装上座位和帆布篷，作为收容车，这两辆车不受汽车公司的限制，我们厂自己掌握。
每天送那些没有赶上班车的人回家。
刚才我站在这儿就想到了这三条，你们有什么意见再提。
”工人们万没想到，他们骂了厂长，结果却是骂出了这三条！大家一时都不知说什么好，人群里很静。
连西北风的势头似乎也小多了，挂到脸上也不那么疼了。
沉静了一会儿，不知谁带头大喊一声：“厂长要是按这三条办，那就太好了！”工人们嚷起来：“对，太好了！”乔厂长笑了：“先别说好，咱们先实行起来看看，有了问题，你们在骂娘，为了保证你们骂我的时候我能听得到，每周我至少要和大家一起坐一次班车。
当厂长的不见得非得坐小车不可。
不过要是我脱了大衣你们就不敢当着我的面骂街，那就不是好样的！好了，车来了，上车。
”桥光谱喊着大家快上车，可是没有一个争抢，自动让带孩子的妈妈先上。
工人都上去以后，桥光谱又到大门口朝厂里喊了两声：“还有人没有？”他最后一个上了车，站在售票员常站的位子上，对司机喊了一声：“开车！”副课文词语拖拉机车辆摇摆朦胧念头闸咕咚诊断听力课文晚归郊区农门丁力在城里买完大白菜，心情很好，独自一个人去小酒馆喝了点酒，然后驾驶他家那台拖拉机，：“轰隆轰隆”地向城外开去。
城离家三十里地。
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桥梁结构
桥梁起源
第一座人工桥梁是由横架在河流上的树干或者平石而形成的。
毫无疑问，它比基督的诞生还要早几千年建成。
甚至在此之前，古人一定惊讶于，在Ardeche 会有跨度为194英尺、高度为111英尺的Pont d’Arc这样的天然拱桥横跨河流。
但是随着时间的流逝，一些先驱者将两块石头横跨狭窄的小溪并堵在一起形成倒置的“V”形，从而建成了第一座拱桥。
据degrand所言，有所记载的最早的桥是在大约公元前2650年，由埃及的第一任国王Menes在尼罗河上修建的，但是没有更多的细节描述。
Diodorus Siculus提供了另外一座5个世纪后建成的桥梁的详细资料，它是由巴比伦皇后Semiramis在幼发拉底河上建成的。
Herodotus将这座桥视为女王统治Nitocris5个世纪的原因。
首先，河流在经过城市时转向流入一个人工湖，使桥墩可以修建在干燥的河床上。
桥墩的石头采用铁条焊接在一起。
甲板是由不低于30英尺宽的木材、雪松、松柏、棕榈修建的，部分甲板是可移动的，每晚拿掉用来防止土匪。
当桥建成后，河水再被引回到原来的河道。
因此今天还存在一些记录，多少是真实的，多少是随着时间的流逝使我们永远不知道的，但毫无疑问，在4000年前的巴比伦有一座不同寻常的桥。
桥梁类型
我们只能推测这些起源。
我们知道古代的吊桥是用扭曲的藤蔓绑在峡谷两侧的树干上形成的，就像一张充满危险的悬挂着的蜘蛛网。
但是桥梁型式什么时候得到发展，或者第一座桥是什么型式的，我们都不能肯定。
我们只知道三种桥梁类型：板梁桥（在河流上架设一根树干）、拱桥、吊桥，它们在有所记载的早期就开始被建造了。
最常见的板梁桥被称为跨桥，如果两个或者更多的梁相连修建在桥墩上就会连在一起形成跨桥，或者是修建成悬臂桥。
然而，他们仅是不同类型的板梁桥而已，并不是其他类型的桥梁。
改变梁、拱、悬架这三种型式并使其相互结合来共同适应建筑物结构的受力要求，数年来，建筑材料已经越来越普及，涉及到木材、石头，人工材料如砖、水泥、铁和钢材。
板梁桥
一个简单的单跨桥可能是钢结构（可能是板梁），钢筋混凝土或预应力钢筋混凝土。
一个钢结构简支桥梁的最大跨度通常约为100英尺（虽然更成长跨度的桥梁已经建成）。
然而，当跨度很大时，通常采用连续梁。
在德国有一个中央跨度为354英尺、边跨为295英尺的板梁桥。
对于约150英尺的支墩之间的梁，通常采用桁架，并且钢材是必不可少的。
1917年，在伊利诺斯州的俄亥俄河上修建了一座跨度为720英尺的简支桥。
无论有没有悬跨，悬臂桥的布置原则就是在桥墩建成后，在桥墩上架设桥梁。
两个桥墩之间的部分称为悬跨，通常是先放在一个预制单元，再架在适当位置。
因此，这种型式的桥梁是从悬臂的两端用两条锚固的悬臂来支撑桥梁的。
桥墩中间的弯矩和剪力最大，在这些位置通常要求桥墩埋设的更深。
当桥的跨度很大时，就要求桥要有更好的强度，悬臂桥通常采用钢桁架结构（桁梁）。
这种型式可以使桥墩间的跨度达到约1800英尺。
尽管这座桥看起来像是拱桥，事实上它是双悬臂桁架梁。
我们会注意到悬臂桥上的最高强度设计在主墩处，因为这些地方可能有最大应力产生。
拱桥
对于拱桥，拱是最主要的结构，其作用是将施加在桥上的荷载传递到桥基上。
在拱圈上有一部分用来修建道路或铁路，这部分结构的要求比拱顶高，称之为拱肩。
由于钢材和钢筋混凝土可以承受拉应力，因此拱圈的厚度可以比砖石结构的拱圈厚度要薄很多。
桥梁的拱肩往往也采用钢结构，因为它也是桥的一部分，这里的道路由结构拱上的悬吊管所支撑。
另外一种拱桥是stiffened tie darch，通常我们称为弓弦梁。
对于一个弓箭，弦可以防止弓被压扁。
类似地，支撑道路的水平梁做得足够结实用来吸收拱推力，从而使作用在桥墩和桥基上的力是垂直的。
吊桥
当跨度很大，大约2000英尺或者更多时，吊桥是最经济的，但是它们当然也可以用于较小的跨度。
通常有一个中间跨度和两边跨度，跨过支撑桥墩的锚索被锚固在隧道上，或者通过其他方式。
由于每个桥墩上都有锚索，所以桥墩上的荷载几乎是完全垂直的。
道路通过垂直的悬吊管从倾斜的锚索上悬吊下来。
所有的桥梁的设计任务可以归为四个方面：规划，桥型选择，材料选择和受力分析。
桥梁设计
在设计和建造大跨度桥梁时，结构的巨大重量，动荷载如机车或汽车的动态效应，风压力的影响，这些都会引起很多问题，解决这些问题需要大量的知识和智慧。
这些问题中并非最不重要的才涉及到基础的建设，特别是当这些大桥都必须被建在河床上时。
规划
大跨度桥梁建设是一项了不起的成就，在桥梁建设史上发生了许多人文的，浪漫的，甚至悲惨的故事。
建造一座现代大桥前的第一步就是进行综合研究以确定该桥是否是必需的。
例如美国，如果要建一座公路桥，则由国家的桥梁管理局发起规划研究，也可能与当地政府或联邦政府合作。
通过研究来估计桥梁的交通量，缓解附近公路网的交通堵塞，评估对区域经济的影响，以及桥梁的成本。
考虑项目融资的手段，如公共税收或由养路费偿还收益公债券。
如果研究决定项目继续进行，在选定的桥址处需要获得所需的土地和建桥方法。
此时，现场工程的工作已启动。
并已经做了精确的土地测量。
详细研究了潮汐，洪水情况，潮流和其他的航道特性。
在陆地上和水下可能的基础位置钻孔取一些土样和岩石样本。
桥型选择
决定一座桥的种类是板梁桥，悬臂桥，桁架桥，拱桥，吊桥或者其它种类的主要因素有以下几点：（1）桥的位置，比如，跨越河流（2）桥的用途，比如用于通行车辆（3）桥的跨长（4）可用材料的强度（5）成本（6）地理位置的美观和谐。
每一种类型的桥只能在一定范围的跨长内才会保证桥的效用和经济实惠的最大化。
在各种类型的桥中，其适用性的范围也有许多相同之处，在某些地区的桥梁设计中，为了设计的终选方案有一个更好的基础，往往会准备好几种不同的初始设计方案以供选择。
材料选择
桥梁设计师们可以选择许多现代的高强度材料，包括混凝土，钢，以及各种
各样的防腐蚀的合金钢。
以Verrazano-Narrows大桥为例，该桥的设计师至少使用了7种不同的合金钢，其中任意一种钢的屈服强度都达到了50,000磅/平方英寸(351.5MPa)，而且不需要在它的表面进行喷漆保护，因为它的表面有氧化物涂层来防止腐蚀。
设计师们同样可以为吊索选择抗拉强度为250,000磅/平方英寸(1,757.7MPa)的钢丝。
现在，抗压强度为8,000磅/平方英寸(56.25MPa)的混凝土可运用在桥梁上，通过添加特殊的化学制剂和控制硬化过程，可以获得很高的抵抗剥落和风化的耐久性。
预应力混凝土和加钢筋的混凝土有250,000磅/平方英寸(1,757.7MPa)的抗拉强度。
其他有用的桥梁材料包括铝合金和木材。
现在的结构铝合金有超过40,000磅/平方英寸(281.2MPa)的屈服强度。
粘在一起的复合夹板做成的梁是天然木材强度的两倍；例如，胶合的南方松木板可以承受接近3,000磅/平方英寸(21.09MPa)的工作应力。
受力分析
桥梁必须抵抗拉伸、压缩、弯曲、剪切、扭转的复杂合力。
此外，结构必须提供安全系数作为防止结构失效的保险。
受力分析，即结构中单个应力和应变确切性质的计算，也许是桥梁建设中技术上最复杂的方面。
分析的目的是确定可施加在每部分结构的所有外力。
作用在桥梁结构上的力是由静荷载和动荷载这两种荷载产生的。
桥梁结构本身的静荷载—自重，通常是最大的荷载。
动荷载或活荷载，包括由桥承受的车辆荷载、风荷载、冰雪的累积荷载。
尽管在任何时候过桥车辆总重量一般只是静荷载和动荷载的一小部分，但是，移动的车辆对大桥产生振动和冲击应力，这对于设计师来说是一个要解决的很特殊的问题。
例如，由路上车辆运动和颠簸的不规律性而产生的影响，会立即使活荷载对桥梁的影响加倍。
风作用在桥上的力，包括直接冲击在桥梁结构上的力，和过桥的车辆的间接冲击。
如果风引发气动弹性振动，正如在Tacoma Narrows大桥发生的那样，它的影响可能会大大增加。
基于这一危险，桥梁设计师对可能发生在桥址处的最强风采取了预防措施。
对于其他可能作用在桥梁上的力，如地震震动，也必须做好预防措施。
对于桥墩的设计必须加强重视，因为它们可能受到水流、波浪和浮冰和碎屑所施加的重荷。
桥墩甚至可能受到过往船只的撞击。
电子计算机在协助桥梁设计师进行受力分析方面扮演着越来越重要的角色。
运用精确的模型试验，特别是对桥梁动态特性进行研究，也可以辅助设计师。
建造桥梁的缩放模型，并在模型上安装各种测量应变、加速度、和变形的仪表。
然后给模型桥施加各种缩放的载荷或动态条件来研究会产生的结果。
风洞试验也可确保不再有Tacoma Narrows 大桥那样的事故发生。
有了现代科技的帮助，桥梁垮塌的几率已经比过去少很多。