土木工程英文论文翻译
土木工程毕业设计外文翻译原文+翻译
The bridge crack produced the reason to simply analyseIn recent years, the traffic capital construction of our province gets swift and violent development, all parts have built a large number of concrete bridges. In the course of building and using in the bridge, relevant to influence project quality lead of common occurrence report that bridge collapse even because the crack appears The concrete can be said to " often have illness coming on " while fracturing and " frequently-occurring disease ", often perplex bridge engineers and technicians. In fact , if take certain design and construction measure, a lot of cracks can be overcome and controlled. For strengthen understanding of concrete bridge crack further, is it prevent project from endanger larger crack to try one's best, this text make an more overall analysis , summary to concrete kind and reason of production , bridge of crack as much as possible, in order to design , construct and find out the feasible method which control the crack , get the result of taking precautions against Yu WeiRan.Concrete bridge crack kind, origin cause of formation In fact, the origin cause of formation of the concrete structure crack is complicated and various, even many kinds of factors influence each other , but every crack has its one or several kinds of main reasons produced . The kind of the concrete bridge crack, on its reason to produce, can roughly divide several kinds as follows :(1) load the crack caused Concrete in routine quiet .Is it load to move and crack that produce claim to load the crack under the times of stress bridge, summing up has direct stress cracks , two kinds stress crack onces mainly. Direct stress crack refer to outside load direct crack that stress produce that cause. The reason why the crack produces is as follows, 1, Design the stage of calculating , does not calculate or leaks and calculates partly while calculating in structure; Calculate the model is unreasonable; The structure is supposed and accorded with by strength actually by strength ; Load and calculate or leak and calculate few; Internal force and matching the mistake in computation of muscle; Safety coefficient of structure is not enough. Do not consider the possibility that construct at the time of the structural design; It is insufficientto design the section; It is simply little and assigning the mistake for reinforcing bar to set up; Structure rigidity is insufficient; Construct and deal with improperly; The design drawing can not be explained clearly etc.. 2, Construction stage, does not pile up and construct the machines , material limiting ; Is it prefabricate structure structure receive strength characteristic , stand up , is it hang , transport , install to get up at will to understand; Construct not according to the design drawing, alter the construction order of the structure without authorization , change the structure and receive the strength mode; Do not do the tired intensity checking computations under machine vibration and wait to the structure . 3, Using stage, the heavy-duty vehicle which goes beyond the design load passes the bridge; Receive the contact , striking of the vehicle , shipping; Strong wind , heavy snow , earthquake happen , explode etc.. Stress crack once means the stress of secondary caused by loading outside produces the crack. The reason why the crack produces is as follows, 1, In design outside load function , because actual working state and routine , structure of thing calculate have discrepancy or is it consider to calculate, thus cause stress once to cause the structure to fracture in some position. Two is it join bridge arch foot is it is it assign " X " shape reinforcing bar , cut down this place way , section of size design and cut with scissors at the same time to adopt often to design to cut with scissors, theory calculate place this can store curved square in , but reality should is it can resist curved still to cut with scissors, so that present the crack and cause the reinforcing bar corrosion. 2, Bridge structure is it dig trough , turn on hole , set up ox leg ,etc. to need often, difficult to use a accurate one diagrammatic to is it is it calculate to imitate to go on in calculating in routine, set up and receive the strength reinforcing bar in general foundation experience. Studies have shown , after being dug the hole by the strength component , it will produce the diffraction phenomenon that strength flows, intensive near the hole in a utensil, produced the enormous stress to concentrate. In long to step prestressing force of the continuous roof beam , often block the steel bunch according to the needs of section internal force in stepping, set up the anchor head, but can often see the crack in the anchor firm section adjacent place. So if deal with improper, in corner or component form sudden change office , block place to be easy to appear crack strengthreinforcing bar of structure the. In the actual project, stress crack once produced the most common reason which loads the crack. Stress crack once belong to one more piece of nature of drawing , splitting off , shearing. Stress crack once is loaded and caused, only seldom calculate according to the routine too, but with modern to calculate constant perfection of means, times of stress crack to can accomplish reasonable checking computations too. For example to such stresses 2 times of producing as prestressing force , creeping ,etc., department's finite element procedure calculates levels pole correctly now, but more difficult 40 years ago. In the design, should pay attention to avoiding structure sudden change (or section sudden change), when it is unable to avoid , should do part deal with , corner for instance, make round horn , sudden change office make into the gradation zone transition, is it is it mix muscle to construct to strengthen at the same time, corner mix again oblique to reinforcing bar , as to large hole in a utensil can set up protecting in the perimeter at the terms of having angle steel. Load the crack characteristic in accordance with loading differently and presenting different characteristics differently. The crack appear person who draw more, the cutting area or the serious position of vibration. Must point out , is it get up cover or have along keep into short crack of direction to appear person who press, often the structure reaches the sign of bearing the weight of strength limit, it is an omen that the structure is destroyed, its reason is often that sectional size is partial and small. Receive the strength way differently according to the structure, the crack characteristic produced is as follows: 1, The centre is drawn. The crack runs through the component cross section , the interval is equal on the whole , and is perpendicular to receiving the strength direction. While adopting the whorl reinforcing bar , lie in the second-class crack near the reinforcing bar between the cracks. 2, The centre is pressed. It is parallel on the short and dense parallel crack which receive the strength direction to appear along the component. 3, Receive curved. Most near the large section from border is it appear and draw into direction vertical crack to begin person who draw curved square, and develop toward neutralization axle gradually. While adopting the whorl reinforcing bar , can see shorter second-class crack among the cracks. When the structure matches muscles less, there are few but wide cracks, fragility destruction may take place in thestructure 4, Pressed big and partial. Heavy to press and mix person who draw muscle a less one light to pigeonhole into the component while being partial while being partial, similar to receiving the curved component. 5, Pressed small and partial. Small to press and mix person who draw muscle a more one heavy to pigeonhole into the component while being partial while being partial, similar to the centre and pressed the component. 6, Cut. Press obliquly when the hoop muscle is too dense and destroy, the oblique crack which is greater than 45?? direction appears along the belly of roof beam end; Is it is it is it destroy to press to cut to happen when the hoop muscle is proper, underpart is it invite 45?? direction parallel oblique crack each other to appear along roof beam end. 7, Sprained. Component one side belly appear many direction oblique crack, 45?? of treaty, first, and to launch with spiral direction being adjoint. 8, Washed and cut. 4 side is it invite 45?? direction inclined plane draw and split to take place along column cap board, form the tangent plane of washing. 9, Some and is pressed. Some to appear person who press direction roughly parallel large short cracks with pressure.(2) crack caused in temperature changeThe concrete has nature of expanding with heat and contract with cold, look on as the external environment condition or the structure temperature changes, concrete take place out of shape, if out of shape to restrain from, produce the stress in the structure, produce the temperature crack promptly when exceeding concrete tensile strength in stress. In some being heavy to step foot-path among the bridge , temperature stress can is it go beyond living year stress even to reach. The temperature crack distinguishes the main characteristic of other cracks will be varied with temperature and expanded or closed up. The main factor is as follows, to cause temperature and change 1, Annual difference in temperature. Temperature is changing constantly in four seasons in one year, but change relatively slowly, the impact on structure of the bridge is mainly the vertical displacement which causes the bridge, can prop up seat move or set up flexible mound ,etc. not to construct measure coordinate , through bridge floor expansion joint generally, can cause temperature crack only when the displacement of the structure is limited, for example arched bridge , just bridge etc. The annual difference in temperature of our country generally changes therange with the conduct of the average temperature in the moon of January and July. Considering the creep characteristic of the concrete, the elastic mould amount of concrete should be considered rolling over and reducing when the internal force of the annual difference in temperature is calculated. 2, Rizhao. After being tanned by the sun by the sun to the side of bridge panel , the girder or the pier, temperature is obviously higher than other position, the temperature gradient is presented and distributed by the line shape . Because of restrain oneself function, cause part draw stress to be relatively heavy, the crack appears. Rizhao and following to is it cause structure common reason most , temperature of crack to lower the temperature suddenly 3, Lower the temperature suddenly. Fall heavy rain , cold air attack , sunset ,etc. can cause structure surface temperature suddenly dropped suddenly, but because inside temperature change relatively slow producing temperature gradient. Rizhao and lower the temperature internal force can adopt design specification or consult real bridge materials go on when calculating suddenly, concrete elastic mould amount does not consider converting into and reducing 4, Heat of hydration. Appear in the course of constructing, the large volume concrete (thickness exceeds 2. 0), after building because cement water send out heat, cause inside very much high temperature, the internal and external difference in temperature is too large, cause the surface to appear in the crack. Should according to actual conditions in constructing, is it choose heat of hydration low cement variety to try one's best, limit cement unit's consumption, reduce the aggregate and enter the temperature of the mould , reduce the internal and external difference in temperature, and lower the temperature slowly , can adopt the circulation cooling system to carry on the inside to dispel the heat in case of necessity, or adopt the thin layer and build it in succession in order to accelerate dispelling the heat. 5, The construction measure is improper at the time of steam maintenance or the winter construction , the concrete is sudden and cold and sudden and hot, internal and external temperature is uneven , apt to appear in the crack. 6, Prefabricate T roof beam horizontal baffle when the installation , prop up seat bury stencil plate with transfer flat stencil plate when welding in advance, if weld measure to be improper, iron pieces of nearby concrete easy to is it fracture to burn. Adopt electric heat piece draw law piece draw prestressing force at the component ,prestressing force steel temperature can rise to 350 degrees Centigrade , the concrete component is apt to fracture. Experimental study indicates , are caused the intensity of concrete that the high temperature burns to obviously reduce with rising of temperature by such reasons as the fire ,etc., glueing forming the decline thereupon of strength of reinforcing bar and concrete, tensile strength drop by 50% after concrete temperature reaches 300 degrees Centigrade, compression strength drops by 60%, glueing the strength of forming to drop by 80% of only round reinforcing bar and concrete; Because heat, concrete body dissociate ink evaporate and can produce and shrink sharply in a large amount(3) shrink the crack causedIn the actual project, it is the most common because concrete shrinks the crack caused. Shrink kind in concrete, plasticity shrink is it it shrinks (is it contract to do ) to be the main reason that the volume of concrete out of shape happens to shrink, shrink spontaneously in addition and the char shrink. Plasticity shrink. About 4 hours after it is built that in the course of constructing , concrete happens, the cement water response is fierce at this moment, the strand takes shape gradually, secrete water and moisture to evaporate sharply, the concrete desiccates and shrinks, it is at the same time conduct oneself with dignity not sinking because aggregate,so when harden concrete yet,it call plasticity shrink. The plasticity shrink producing amount grade is very big, can be up to about 1%. If stopped by the reinforcing bar while the aggregate sinks, form the crack along the reinforcing bar direction. If web , roof beam of T and roof beam of case and carry baseplate hand over office in component vertical to become sectional place, because sink too really to superficial obeying the web direction crack will happen evenly before hardenning. For reducing concrete plasticity shrink,it should control by water dust when being construct than,last long-time mixing, unloading should not too quick, is it is it take closely knit to smash to shake, vertical to become sectional place should divide layer build. Shrink and shrink (do and contract). After the concrete is formed hard , as the top layer moisture is evaporated progressively , the humidity is reduced progressively , the volume of concrete is reduced, is called and shrunk to shrink (do and contract). Because concrete top layermoisture loss soon, it is slow for inside to lose, produce surface shrink heavy , inside shrink a light one even to shrink, it is out of shape to restrain from by the inside concrete for surface to shrink, cause the surface concrete to bear pulling force, when the surface concrete bears pulling force to exceed its tensile strength, produce and shrink the crack. The concrete hardens after-contraction to just shrink and shrink mainly .Such as mix muscle rate heavy component (exceed 3% ), between reinforcing bar and more obvious restraints relatively that concrete shrink, the concrete surface is apt to appear in the full of cracks crackle. Shrink spontaneously. Spontaneous to it shrinks to be concrete in the course of hardenning , cement and water take place ink react, the shrink with have nothing to do by external humidity, and can positive (whether shrink, such as ordinary portland cement concrete), can negative too (whether expand, such as concrete, concrete of slag cement and cement of fly ash). The char shrinks. Between carbon dioxide and hyrate of cement of atmosphere take place out of shape shrink that chemical reaction cause. The char shrinks and could happen only about 50% of humidity, and accelerate with increase of the density of the carbon dioxide. The char shrinks and seldom calculates . The characteristic that the concrete shrinks the crack is that the majority belongs to the surface crack, the crack is relatively detailed in width , and criss-cross, become the full of cracks form , the form does not have any law . Studies have shown , influence concrete shrink main factor of crack as follows, 1, Variety of cement , grade and consumption. Slag cement , quick-hardening cement , low-heat cement concrete contractivity are relatively high, ordinary cement , volcanic ash cement , alumina cement concrete contractivity are relatively low. Cement grade low in addition, unit volume consumption heavy rubing detailed degree heavy, then the concrete shrinks the more greatly, and shrink time is the longer. For example, in order to improve the intensity of the concrete , often adopt and increase the cement consumption method by force while constructing, the result shrinks the stress to obviously strengthen . 2, Variety of aggregate. Such absorbing water rates as the quartz , limestone , cloud rock , granite , feldspar ,etc. are smaller, contractivity is relatively low in the aggregate; And such absorbing water rates as the sandstone , slate , angle amphibolite ,etc. are greater, contractivity is relatively high. Aggregate grains of foot-path heavy to shrink light inaddition, water content big to shrink the larger. 3, Water gray than. The heavier water consumption is, the higher water and dust are, the concrete shrinks the more greatly. 4, Mix the pharmaceutical outside. It is the better to mix pharmaceutical water-retaining property outside, then the concrete shrinks the smaller. 5, Maintain the method . Water that good maintenance can accelerate the concrete reacts, obtain the intensity of higher concrete. Keep humidity high , low maintaining time to be the longer temperature when maintaining, then the concrete shrinks the smaller. Steam maintain way than maintain way concrete is it take light to shrink naturall. 6, External environment. The humidity is little, the air drying , temperature are high, the wind speed is large in the atmosphere, then the concrete moisture is evaporated fast, the concrete shrinks the faster. 7, Shake and smash the way and time. Machinery shake way of smashing than make firm by ramming or tamping way concrete contractivity take little by hand. Shaking should determine according to mechanical performance to smash time , are generally suitable for 55s / time. It is too short, shake and can not smash closely knit , it is insufficient or not even in intensity to form the concrete; It is too long, cause and divide storey, thick aggregate sinks to the ground floor, the upper strata that the detailed aggregate stays, the intensity is not even , the upper strata incident shrink the crack. And shrink the crack caused to temperature, worthy of constructing the reinforcing bar againing can obviously improve the resisting the splitting of concrete , structure of especially thin wall (thick 200cm of wall ). Mix muscle should is it adopt light diameter reinforcing bar (8 |? construct 14 |? ) to have priority , little interval assign (whether @ 10 construct @ 15cm ) on constructing, the whole section is it mix muscle to be rate unsuitable to be lower than 0 to construct. 3%, can generally adopt 0 . 3%~0. 5%.(4), crack that causes out of shape of plinth of the groundBecause foundation vertical to even to subside or horizontal direction displacement, make the structure produce the additional stress, go beyond resisting the ability of drawing of concrete structure, cause the structure to fracture. The even main reason that subside of the foundation is as follows, 1, Reconnoitres the precision and is not enough for , test the materials inaccuratly in geology. Designing, constructing without fully grasping the geological situation, this is the main reason that cause the ground not to subside evenly .Such as hills area or bridge, district of mountain ridge,, hole interval to be too far when reconnoitring, and ground rise and fall big the rock, reconnoitring the report can't fully reflect the real geological situation . 2, The geological difference of the ground is too large. Building it in the bridge of the valley of the ditch of mountain area, geology of the stream place and place on the hillside change larger, even there are weak grounds in the stream, because the soil of the ground does not causes and does not subside evenly with the compressing. 3, The structure loads the difference too big. Under the unanimous terms, when every foundation too heavy to load difference in geological situation, may cause evenly to subside, for example high to fill out soil case shape in the middle part of the culvert than to is it take heavy to load both sides, to subside soon heavy than both sides middle part, case is it might fracture to contain 4, The difference of basic type of structure is great. Unite it in the bridge the samly , mix and use and does not expand the foundation and a foundation with the foundation, or adopt a foundation when a foot-path or a long difference is great at the same time , or adopt the foundation of expanding when basis elevation is widely different at the same time , may cause the ground not to subside evenly too 5, Foundation built by stages. In the newly-built bridge near the foundation of original bridge, if the half a bridge about expressway built by stages, the newly-built bridge loads or the foundation causes the soil of the ground to consolidate again while dealing with, may cause and subside the foundation of original bridge greatly 6, The ground is frozen bloatedly. The ground soil of higher moisture content on terms that lower than zero degree expands because of being icy; Once temperature goes up , the frozen soil is melted, the setting of ground. So the ground is icy or melts causes and does not subside evenly . 7, Bridge foundation put on body, cave with stalactites and stalagmites, activity fault,etc. of coming down at the bad geology, may cause and does not subside evenly . 8, After the bridge is built up , the condition change of original ground . After most natural grounds and artificial grounds are soaked with water, especially usually fill out such soil of special ground as the soil , loess , expanding in the land ,etc., soil body intensity meet water drop, compress out of shape to strengthen. In the soft soil ground , season causes the water table to drop to draw water or arid artificially, the ground soil layer consolidates and sinks again,reduce the buoyancy on the foundation at the same time , shouldering the obstruction of rubing to increase, the foundation is carried on one's shoulder or back and strengthened .Some bridge foundation is it put too shallow to bury, erode , is it dig to wash flood, the foundation might be moved. Ground load change of terms, bridge nearby is it is it abolish square , grit ,etc. in a large amount to put to pile with cave in , landslide ,etc. reason for instance, it is out of shape that the bridge location range soil layer may be compressed again. So, the condition of original ground change while using may cause and does not subside evenly Produce the structure thing of horizontal thrust to arched bridge ,etc., it is the main reason that horizontal displacement crack emerges to destroy the original geological condition when to that it is unreasonable to grasp incompletely , design and construct in the geological situation.桥梁裂缝产生原因浅析近年来，我省交通基础建设得到迅猛发展，各地建立了大量的混凝土桥梁。
土木工程专业英语(带翻译)
State-of-the-art report of bridge health monitoring AbstractThe damage diagnosis and healthmonitoring of bridge structures are active areas of research in recent years. Comparing with the aerospace engineering and mechanical engineering, civil engineering has the specialities of its own in practice. For example, because bridges, as well as most civil engineering structures, are large in size, and have quite lownatural frequencies and vibration levels, at low amplitudes, the dynamic responses of bridge structure are substantially affected by the nonstructural components, unforeseen environmental conditions, and changes in these components can easily to be confused with structural damage.All these give the damage assessment of complex structures such as bridges a still challenging task for bridge engineers. This paper firstly presents the definition of structural healthmonitoring system and its components. Then, the focus of the discussion is placed on the following sections:①the laboratory and field testing research on the damage assessment;②analytical developments of damage detectionmethods, including (a) signature analysis and pattern recognition approaches, (b) model updating and system identification approaches, (c) neural networks approaches; and③sensors and their optimum placements. The predominance and shortcomings of each method are compared and analyzed. Recent examples of implementation of structural health monitoring and damage identification are summarized in this paper. The key problem of bridge healthmonitoring is damage automatic detection and diagnosis, and it is the most difficult problem. Lastly, research and development needs are addressed.1 IntroductionDue to a wide variety of unforeseen conditions and circumstance, it will never be possible or practical to design and build a structure that has a zero percent probability of failure. Structural aging, environmental conditions, and reuse are examples of circumstances that could affect the reliability and thelife of a structure. There are needs of periodic inspections to detect deterioration resulting from normal operation and environmental attack or inspections following extreme events, such as strong-motion earthquakes or hurricanes. To quantify these system performance measures requires some means to monitor and evaluate the integrity of civil structureswhile in service. Since the Aloha Boeing 737 accident that occurred on April 28, 1988, such interest has fostered research in the areas of structural health monitoring and non-destructive damage detection in recent years.According to Housner, et al. (1997), structural healthmonitoring is defined as“the use ofin-situ,non-destructive sensing and analysis of structural characteristics, including the structural response, for detecting changes that may indicate damage or degradation”[1]. This definition also identifies the weakness. While researchers have attempted the integration of NDEwith healthmonitoring, the focus has been on data collection, not evaluation. What is needed is an efficient method to collect data from a structure in-service and process the data to evaluate key performance measures, such as serviceability, reliability, and durability. So, the definition byHousner, et al.(1997)should be modified and the structural health monitoring may be defined as“the use ofin-situ,nondestructive sensing and analysis of structural characteristics, including the structural response, for the purpose of identifying if damage has occurred, determining the location of damage, estimatingthe severityof damage and evaluatingthe consequences of damage on the structures”(Fig.1). In general, a structural health monitoring system has the potential to provide both damage detection and condition assessment of a structure.Assessing the structural conditionwithout removingthe individual structural components is known as nondestructive evaluation (NDE) or nondestructive inspection. NDE techniques include those involving acoustics, dye penetrating,eddy current, emission spectroscopy, fiber-optic sensors, fiber-scope, hardness testing, isotope, leak testing, optics, magnetic particles, magnetic perturbation, X-ray, noise measurements, pattern recognition, pulse-echo, ra-diography, and visual inspection, etc. Mostof thesetechniques have been used successfullyto detect location of certain elements, cracks orweld defects, corrosion/erosion, and so on. The FederalHighwayAdministration(FHWA, USA)was sponsoring a large program of research and development in new technologies for the nondestructive evaluation of highway bridges. One of the two main objectives of the program is to develop newtools and techniques to solve specific problems. The other is to develop technologies for the quantitative assessment of the condition of bridges in support of bridge management and to investigate howbest to incorporate quantitative condition information into bridge management systems. They hoped to develop technologies to quickly, efficiently, and quantitatively measure global bridge parameters, such as flexibility and load-carrying capacity. Obviously, a combination of several NDE techniques may be used to help assess the condition of the system. They are very important to obtain the data-base for the bridge evaluation.But it is beyond the scope of this review report to get into details of local NDE.Health monitoring techniques may be classified as global and local. Global attempts to simultaneously assess the condition of the whole structure whereas local methods focus NDE tools on specific structural components. Clearly, two approaches are complementaryto eachother. All such available informationmaybe combined and analyzed by experts to assess the damage or safety state of the structure.Structural health monitoring research can be categorized into the following four levels: (I) detecting the existence of damage, (II) findingthe location of damage, (III) estimatingthe extentof damage, and (IV) predictingthe remaining fatigue life. The performance of tasks of Level (III) requires refined structural models and analyses, local physical examination, and/or traditional NDE techniques. To performtasks ofLevel (IV) requires material constitutive information on a local level, materials aging studies, damage mechanics, and high-performance computing. With improved instrumentation and understanding of dynamics of complex structures, health monitoring and damage assessment of civil engineering structures has become more practical in systematic inspection andevaluation of these structures during the past two decades.Most structural health monitoringmethods under current investigation focus on using dynamic responses to detect and locate damage because they are global methods that can provide rapid inspection of large structural systems.These dynamics-based methods can be divided into fourgroups:①spatial-domain methods,②modal-domain methods,③time-domain methods, and④frequency- domain methods. Spatial-domain methods use changes of mass, damping, and stiffness matrices to detect and locate damage. Modal-domain methods use changes of natural frequencies, modal damping ratios, andmode shapesto detect damage. In the frequency domain method, modal quantities such as natural frequencies, damping ratio, and model shapes are identified.The reverse dynamic systemof spectral analysis and the generalized frequency response function estimated fromthe nonlinear auto-regressive moving average (NARMA) model were applied in nonlinear system identification. In time domainmethod, systemparameterswere determined fromthe observational data sampled in time. It is necessaryto identifythe time variation of systemdynamic characteristics fromtime domain approach if the properties of structural system changewith time under the external loading condition. Moreover, one can use model-independent methods or model-referenced methods to perform damage detection using dynamic responses presented in any of the four domains. Literature shows that model independent methods can detect the existence of damage without much computational efforts, butthey are not accurate in locating damage. On the otherhand, model-referencedmethods are generally more accurate in locating damage and require fewer sensors than model-independent techniques, but they require appropriate structural models and significant computational efforts. Although time-domain methods use original time-domain datameasured using conventional vibrationmeasurement equipment, theyrequire certain structural information and massive computation and are case sensitive. Furthermore, frequency- and modal-domain methods use transformed data,which contain errors and noise due totransformation.Moreover, themodeling and updatingofmass and stiffnessmatrices in spatial-domain methods are problematic and difficult to be accurate. There are strong developmenttrends that two or three methods are combined together to detect and assess structural damages.For example, several researchers combined data of static and modal tests to assess damages. The combination could remove the weakness of each method and check each other. It suits the complexity of damage detection.Structural health monitoring is also an active area of research in aerospace engineering, but there are significant differences among the aerospace engineering, mechanical engineering, and civil engineering in practice. For example,because bridges, as well as most civil engineering structures, are large in size, and have quite lownatural frequencies and vibration levels, at lowamplitudes, the dynamic responses of bridge structure are substantially affected by the non-structural components, and changes in these components can easily to be confused with structural damage. Moreover,the level of modeling uncertainties in reinforced concrete bridges can be much greater than the single beam or a space truss. All these give the damage assessment of complex structures such as bridges a still challenging task for bridge engineers. Recent examples of research and implementation of structural health monitoring and damage assessment are summarized in the following sections.2 Laboratory and field testing researchIn general, there are two kinds of bridge testing methods, static testing and dynamic testing. The dynamic testing includes ambient vibration testing and forced vibration testing. In ambient vibration testing, the input excitation is not under the control. The loading could be either micro-tremors, wind, waves, vehicle or pedestrian traffic or any other service loading. The increasing popularity of this method is probably due to the convenience of measuring the vibrationresponse while the bridge is under in-service and also due to the increasing availability of robust data acquisition and storage systems. Since the input is unknown, certain assumptions have to be made. Forced vibration testing involves application of input excitation of known force level at known frequencies. The excitation manners include electro-hydraulic vibrators, forcehammers, vehicle impact, etc. The static testing in the laboratory may be conducted by actuators, and by standard vehicles in the field-testing.we can distinguish that①the models in the laboratory are mainly beams, columns, truss and/or frame structures, and the location and severity of damage in the models are determined in advance;②the testing has demonstrated lots of performances of damage structures;③the field-testing and damage assessmentof real bridges are more complicated than the models in the laboratory;④the correlation between the damage indicator and damage type,location, and extentwill still be improved.3 Analytical developmentThe bridge damage diagnosis and health monitoring are both concerned with two fundamental criteria of the bridges, namely, the physical condition and the structural function. In terms of mechanics or dynamics, these fundamental criteria can be treated as mathematical models, such as response models, modal models and physical models.Instead of taking measurements directly to assess bridge condition, the bridge damage diagnosis and monitoring systemevaluate these conditions indirectly by using mathematical models. The damage diagnosis and health monitoring are active areas of research in recentyears. For example, numerous papers on these topics appear in the proceedings of Inter-national Modal Analysis Conferences (IMAC) each year, in the proceedings of International Workshop on Structural HealthMonitoring (once of two year, at Standford University), in the proceedings of European Conference on Smart materials and Structures and European Conference on Structural Damage AssessmentUsing Advanced Signal Processing Procedures, in the proceedings ofWorld Conferences of Earthquake Engineering, and in the proceedings of International Workshop on Structural Control, etc.. There are several review papers to be referenced, for examples,Housner, et al. (1997)provided an extensive summary of the state of the art in control and health monitoring of civil engineering structures[1].Salawu (1997)discussed and reviewed the use of natural frequency as a diagnostic parameter in structural assessment procedures using vibrationmonitoring.Doebling, Farrar, et al. (1998)presented a through review of the damage detection methods by examining changes in dynamic properties.Zou, TongandSteven (2000)summarized the methods of vibration-based damage and health monitoring for composite structures, especially in delamination modeling techniques and delamination detection.4 Sensors and optimum placementOne of the problems facing structural health monitoring is that very little is known about the actual stress and strains in a structure under external excitations. For example, the standard earthquake recordings are made ofmotions of the floors of the structure and no recordings are made of the actual stresses and strains in structural members. There is a need for special sensors to determine the actual performance of structural members. Structural health monitoring requires integrated sensor functionality to measure changes in external environmental conditions, signal processing functionality to acquire, process, and combine multi-sensor and multi-measured information. Individual sensors and instrumented sensor systems are then required to provide such multiplexed information.FuandMoosa (2000)proposed probabilistic advancing cross-diagnosis method to diagnosis-decision making for structural health monitoring. It was experimented in the laboratory respectively using a coherent laser radar system and a CCD high-resolution camera. Results showed that this method was promising for field application. Another new idea is thatneural networktechniques are used to place sensors. For example,WordenandBurrows (2001)used the neural network and methods of combinatorial optimization to locate and classify faults.The static and dynamic data are collected from all kinds of sensorswhich are installed on the measured structures.And these datawill be processed and usable informationwill be extracted. So the sensitivity, accuracy, and locations,etc. of sensors are very important for the damage detections. The more information are obtained, the damage identification will be conducted more easily, but the price should be considered. That’s why the sensors are determinedin an optimal ornearoptimal distribution. In aword, the theory and validation ofoptimumsensor locationswill still being developed.5 Examples of health monitoring implementationIn order for the technology to advance sufficiently to become an operational system for the maintenance and safety of civil structures, it is of paramount importance that new analytical developments are ultimately verified with appropriate data obtained frommonitoring systems, which have been implemented on civil structures, such as bridges.Mufti (2001)summarized the applications of SHM of Canadian bridge engineering, including fibre-reinforced polymers sensors, remote monitoring, intelligent processing, practical applications in bridge engineering, and technology utilization. Further study and applications are still being conducted now.FujinoandAbe(2001)introduced the research and development of SHMsystems at the Bridge and Structural Lab of the University of Tokyo. They also presented the ambient vibration based approaches forLaser DopplerVibrometer (LDV) and the applications in the long-span suspension bridges.The extraction of the measured data is very hard work because it is hard to separate changes in vibration signature duo to damage form changes, normal usage, changes in boundary conditions, or the release of the connection joints.Newbridges offer opportunities for developing complete structural health monitoring systems for bridge inspection and condition evaluation from“cradle to grave”of the bridges. Existing bridges provide challenges for applying state-of-the-art in structural health monitoring technologies to determine the current conditions of the structural element,connections and systems, to formulate model for estimating the rate of degradation, and to predict the existing and the future capacities of the structural components and systems. Advanced health monitoring systems may lead to better understanding of structural behavior and significant improvements of design, as well as the reduction of the structural inspection requirements. Great benefits due to the introduction of SHM are being accepted by owners, managers, bridge engineers,etc..6 Research and development needsMost damage detection theories and practices are formulated based on the following assumption: that failure or deterioration would primarily affect the stiffness and therefore affect the modal characteristics of the dynamic response of the structure. This is seldom true in practice, because①Traditional modal parameters (natural frequency, damping ratio and mode shapes, etc.) are not sensitive enough to identify and locate damage. The estimation methods usually assume that structures are linear and proportional damping systems.②Most currently used damage indices depend on the severity of the damage, which is impractical in the field. Most civil engineering structures, such as highway bridges, have redundancy in design and large in size with low natural frequencies. Any damage index should consider these factors.③Scaledmodelingtechniques are used in currentbridge damage detection. Asingle beam/girder models cannot simulate the true behavior of a real bridge. Similitude laws for dynamic simulation and testing should be considered.④Manymethods usually use the undamaged structural modal parameters as the baseline comparedwith the damaged information. This will result in the need of a large data storage capacity for complex structures. But in practice,there are majority of existing structures for which baseline modal responses are not available. Only one developed method(StubbsandKim (1996)), which tried to quantify damagewithout using a baseline, may be a solution to this difficulty. There is a lot of researchwork to do in this direction.⑤Seldommethods have the ability to distinguish the type of damages on bridge structures. To establish the direct relationship between the various damage patterns and the changes of vibrational signatures is not a simple work.Health monitoring requires clearly defined performance criteria, a set of corresponding condition indicators and global and local damage and deterioration indices, which should help diagnose reasons for changes in condition indicators. It is implausible to expect that damage can be reliably detected or tracked byusing a single damage index. We note that many additional localized damage indiceswhich relate to highly localized properties ofmaterials or the circumstances may indicate a susceptibility of deterioration such as the presence of corrosive environments around reinforcing steel in concrete, should be also integrated into the health monitoring systems.There is now a considerable research and development effort in academia, industry, and management department regarding global healthmonitoring for civil engineering structures. Several commercial structural monitoring systems currently exist, but further development is needed in commercialization of the technology. We must realize that damage detection and health monitoring for bridge structures by means of vibration signature analysis is a very difficult task. Itcontains several necessary steps, including defining indicators on variations of structural physical condition, dynamic testing to extract such indication parameters, defining the type of damages and remaining capacity or life of the structure, relating the parameters to the defined damage/aging. Unfortunately, to date, no one has accomplished the above steps. There is a lot of work to do in future.桥梁健康监测应用与研究现状摘要桥梁损伤诊断与健康监测是近年来国际上的研究热点,在实践方面,土木工程和航空航天工程、机械工程有明显的差别,比如桥梁结构以及其他大多数土木结构,尺寸大、质量重,具有较低的自然频率和振动水平,桥梁结构的动力响应极容易受到不可预见的环境状态、非结构构件等的影响,这些变化往往被误解为结构的损伤,这使得桥梁这类复杂结构的损伤评估具有极大的挑战性.本文首先给出了结构健康监测系统的定义和基本构成,然后集中回顾和分析了如下几个方面的问题:①损伤评估的室内实验和现场测试;②损伤检测方法的发展,包括:(a)动力指纹分析和模式识别方法, (b)模型修正和系统识别方法, (c)神经网络方法;③传感器及其优化布置等,并比较和分析了各自方法的优点和不足.文中还总结了健康监测和损伤识别在桥梁工程中的应用,指出桥梁健康监测的关键问题在于损伤的自动检测和诊断,这也是困难的问题;最后展望了桥梁健康监测系统的研究和发展方向.关键词:健康监测系统;损伤检测;状态评估;模型修正;系统识别;传感器优化布置;神经网络方法;桥梁结构1概述由于不可预见的各种条件和情况下，设计和建造一个结构将永远不可能或无实践操作性，它有一个失败的概率百分之零。
土木工程英文文献及翻译-英语论文.doc
土木工程英文文献及翻译-英语论文土木工程英文文献及翻译in Nanjing, ChinaZhou Jin, Wu Yezheng *, Yan GangDepartment of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi’an Jiao Tong University,Xi’an , PR ChinaReceived 4 April 2005; accepted 2 October 2005Available online 1 December 2005AbstractThe bin method, as one of the well known and simple steady state methods used to predict heating and cooling energyconsumption of buildings, requires reliable and detailed bin data. Since the long term hourly temperature records are notavailable in China, there is a lack of bin weather data for study and use. In order to keep the bin method practical in China,a stochastic model using only the daily maximum and minimum temperatures to generate bin weather data was establishedand tested by applying one year of measured hourly ambient temperature data in Nanjing, China. By comparison with themeasured values, the bin weather data generated by the model shows adequate accuracy. This stochastic model can be usedto estimate the bin weather data in areas, especially in China, where the long term hourly temperature records are missingor not available.Ó 2005 Elsevier Ltd. All rights reserved.Keywords: Energy analysis; Stochastic method; Bin data; China1. IntroductionIn the sense of minimizing the life cycle cost of a building, energy analysis plays an important role in devel-oping an optimum and cost effective design of a heating or an air conditioning system for a building. Severalmodels are available for estimating energy use in buildings. These models range from simple steady state mod-els to comprehensive dynamic simulation procedures.Today, several computer programs, in which the influence of many parameters that are mainly functionsof time are taken into consideration, are available for simulating both buildings and systems and performinghour by hour energy calculations using hourly weather data. DOE-2, BLAST and TRNSYS are such* Corresponding author. Tel.: +86 29 8266 8738; fax: +86 29 8266 8725.E-mail address: yzwu@ (W. Yezheng).0196-8904/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.doi:10.1016/NomenclatureZ. Jin et al. / Energy Conversion and Management 47 (2006) 1843–1850number of daysfrequency of normalized hourly ambient temperatureMAPE mean absolute percentage error (%)number of subintervals into which the interval [0, 1] was equally dividednumber of normalized temperatures that fall in subintervalprobability densityhourly ambient temperature (°C)normalized hourly ambient temperature (dimensionless)weighting factorSubscriptscalculated valuemeasured valuemax daily maximummin daily minimumprograms that have gained widespread acceptance as reliable estimation tools. Unfortunately, along withthe increased sophistication of these models, they have also become very complex and tedious touse [1].The steady state methods, which are also called single measure methods, require less data and provideadequate results for simple systems and applications. These methods are appropriate if the utilization ofthe building can be considered constant. Among these methods are the degree day and bin data methods.The degree-day methods are the best known and the simplest methods among the steady state models.Traditionally, the degree-day method is based on the assumption that on a long term average, the solarand internal gains will offset the heat loss when the mean daily outdoor temperature is 18.3 °C and thatthe energy consumption will be proportional to the difference between 18.3 °C and the mean daily tempera-ture. The degree-day method can estimate energy consumption very accurately if the building use and theefficiency of the HVAC equipment are sufficiently constant. However, for many applications, at least oneof the above parameters varies with time. For instance, the efficiency of a heat pump system and HVAC equip-ment may be affected directly or indirectly by outdoor temperature. In such cases, the bin method can yieldgood results for the annual energy consumption if different temperature intervals and time periods areevaluated separately. In the bin method, the energy consumption is calculated for several values of the outdoortemperature and multiplied by the number of hours in the temperature interval (bin) centered around thattemperature. Bin data is defined as the number of hours that the ambient temperature was in each of a setof equally sized intervals of ambient temperature.In the United States, the necessary bin weather data are available in the literature [2,3]. Some researchers[4–8] have developed bin weather data for other regions of the world. However, there is a lack of informationin the ASHRAE handbooks concerning the bin weather data required to perform energy calculations in build-ings in China. The practice of analysis of weather data for the design of HVAC systems and energy consump-tion predictions in China is quite new. For a long time, only the daily value of meteorological elements, such asdaily maximum, minimum and average temperature, was recorded and available in most meteorologicalobservations in China, but what was needed to obtain the bin weather data, such as temperature bin data,were the long term hourly values of air temperature. The study of bin weather data is very limited in China.Only a few attempts [9,10] in which bin weather data for several cities was given have been found in China.Obviously, this cannot meet the need for actual use and research. So, there is an urgent need for developing binweather data in China. The objective of this paper, therefore, is to study the hourly measured air temperaturedistribution and then to establish a model to generate bin weather data for the long term daily temperaturedata.2. Data usedZ. Jin et al. / Energy Conversion and Management 47 (2006) 1843–1850In this paper, to study the hourly ambient temperature variation and to establish and evaluate the model, aone year long hourly ambient temperature record for Nanjing in 2002 was used in the study. These data aretaken from the Climatological Center of Lukou Airport in Nanjing, which is located in the southeast of China(latitude 32.0°N, longitude 118.8°E, altitude 9 m).In addition, in order to create the bin weather data for Nanjing, typical weather year data was needed.Based on the long term meteorological data from 1961 to 1989 obtained from the China MeteorologicalAdministration, the typical weather year data for most cities in China has been studied in our former research[11] by means of the TMY (Typical Meteorological Year) method. The typical weather year for Nanjing isshown in Table 1. As only daily values of the meteorological elements were recorded and available in China,the data contained in the typical weather year data was also only daily values. In this study, the daily maxi-mum and minimum ambient temperature in the typical weather year data for Nanjing was used.3. Stochastic model to generate bin dataTraditionally, the generation of bin weather data needs long term hourly ambient temperature records.However, in the generation, the time information, namely the exact time that such a temperature occurredin a day, was omitted, and only the numerical value of the temperature was used. So, the value of each hourlyambient temperature can be treated as the independent random variable, and its distribution within the dailytemperature range can be analyzed by means of probability theory.3.1. Probability distribution of normalized hourly ambient temperatureSince the daily maximum and minimum temperatures and temperature range varied day by day, the con-cept of normalized hourly ambient temperature should be introduced to transform the hourly temperatures ineach day into a uniform scale. The new variable, normalized hourly ambient temperature is defined by^ ¼ttmintmaxtminwhere ^ may be termed the normalized hourly ambient temperature, tmaxand tminare the daily maximum andminimum temperatures, respectively, t is the hourly ambient temperature. Obviously, the normalized hourly ambient temperature ^ is a random variable that lies in the interval [0, 1].To analyze its distribution, the interval [0, 1] can be divided equally into several subintervals, and by means ofthe histogram method [12]iin each subinterval can be calculated by1137土木工程英文文献及翻译Based on the one year long hourly ambient temperature data in Nanjing, China, the probability density piwas calculated for the whole day and the 08:00–20:00 period, where the interval [0, 1] was equally divided into50 subintervals, namely n equals 50. The results are shown in Fig. 1.According to the discrete probability density data in Fig. 1, the probability density function of ^ can beobtained by a fitting method. In this study, the quadratic polynomialswere used to fit the probability density data, where a, b and c are coefficients. According to the property of theprobability density function, the following equation should be satisfiedAs shown in Fig. 1, the probability density curve obtained according to the probability density data pointsis also shown. The probability densit y functions that are fitted are described byp ¼ 2:7893^23:1228^ þ 1:6316 for the whole day periodp ¼ 2:2173^20:1827^ þ 0:3522 for the 08 : 00–20 : 00 period3.2. The generation of hourly ambient temperatureAs stated in the beginning of this paper, the objective of this study is to generate the hourly ambient tem-perature needed for bin weather data generation in the case that only the daily maximum and minimum tem-peratures are known. To do this, we can use the obtained probability density function to generate thenormalized hourly ambient temperature and then transform it to hourly temperature. This belongs to theproblem of how to simulate a random variable with a prescribed probability density function and can be doneon a computer by the method described in the literature [13]. For a given probability density function f ð^Þ, ifits distribution function F ð^Þ can be obtained and if u is a random variable with uniform distribution on [0, 1],thenF, we need only setAs stated above, the probability density function of the normalized ambient temperature was fitted using aone year long hourly temperature data. Based on the probability density function obtained, the random nor-malized hourly temperature can be generated. When the daily maximum and minimum temperature areknown, the normalized hourly temperature can be transformed to an actual temperature by the followingequationWhen the hourly temperature for a particular period of the day has been generated using the above method,the bin data can also be obtained. Because the normalized temperature generated using the model in this studyis a random variable, the bin data obtained from each generation shows somedifference, but it has much sim-ilarity. To obtain a stable result of bin data, the generation of the bin data can be performed enough times,and the bin data can be obtained by averaging the result of each generation. In this paper, 50 generations wereaveraged to generate the bin weather data.Z. Jin et al. / Energy Conversion and Management 47 (2006) 1843–18503.4. Methods of model evaluationThe performance of the model was evaluated in terms of the following statistical error test:土木工程英文文献及翻译一种产生bin气象数据的随机方法——中国南京周晋摘要：bin方法是一种众所周知且简捷的稳态的计算方法，可以用来预计建筑的冷热能耗。
土木工程毕业设计英文翻译论文
Structural FormsStructural forms, such as the beam or the arch ,have developed through the ages in relation to the availability of materials and the technology of the time. The arch, for instance, undoubtedly developed as a result of the availability of brick. In the technology of buildings .every structure must work against gravity ,which tends to pull everything down to the ground .A balance must therefore be attained between the force of gravity ,the shape of the structure ,and the strength of the material used. To provide a cover over a sheltered space and permit openings in the walls that surround it ,builders have developed four techniques are post and lintel, arch and vault, truss, and cantilever construction.Post and lintel. In post and lintel construction ,a horizontal beam is placed across the space between two supporting posts. If the support is continuous, it is called a wall; if a series of beams are joined together into a continuous surface, it is called a slab.Simple rectilinear buildings result from post and lintel construction, which is characteristic of much primitive construction as well as of the classical Greek temples. In this type of construction, the post (or column) carries only a vertical weight, or load, and is therefore under compression, and the lintel (or beam) is bent by the loads acting transversely to its axis. Therefore , the post must have compressive strength, and the beam must have bending strength. Both wood and stone were used in early example of this type of construction , although the limited bending strength of stone dictated the close column spacing which is apparent in Greek temples. For example, in the Parthenon in Athens, the space between the columns is approximately equal to the column diameter.Modern building materials such as steel and reinforced concrete are used to advantage in post and lintel construction. The skeleton frame of a modern steel skyscraper, for instance, consists of beams and columns in a three-dimensional post and lintel network, or grid. The typical wood fame house, with closely spaced wooden post, or studs, and floors with a series of closely spaced wood beams, or joists, also illustrates post and lintel construction.Just as a house of cards can support vertical loads but collapses under a slightbreath of air, the post and lintel system can topple under winds or earthquakes, but of which impose a horizontal force. This collapse is due to the fact that the joint between the column and beam acts as if it were a hinge .In earlier times this lateral instability was not apparent because the weight and the mass of the materials (particularly stone) and the limited height of the structures negated the importance of horizontal forces. In tall modern building that have slender elements made of strong and light materials such as steel, lateral instability becomes a significant factor . To provide the necessary lateral resistance, a rigid connection must be made between the vertical column and horizontal beam. This creates a rigid frame; it is used to achieve lateral stability in skyscraper construction.Arch. The arch which is characteristically a masonry type of construction, undoubtedly had its origin in Mesopotamia，a land of brick buildings. Arches consist of masonry blocks in the form of a curved line. In principle, each wedge-shaped masonry block cannot fall inward without pushing the others out ;thus, the whole arch form remains stable as long as a force is applied at the base to keep it from spreading. This force is called a horizontal thrust. A continuous series of arches is known as a vault.The Etruscans, by their examples of arch constructions in bridges and gates, probably inspired the Roman to experiment with this type of construction about 600 B.C. However, it was not until the last years of the Roman republic that tunnel vaults and intersecting, or groined, vaults were used to cover large rooms. The form of the Roman arch or vault is generally semicircular for reasons of geometric simplicity. As a result, all wedge-shaped stones are identical; their curved edges are equidistant from the center of the circle ,and their straight edges lie on equally spaced lines radiating from the center. This type of semicircular arch was widely used by the Romans in buildings such as the Basilica of Constantine and the Baths of Caracalla and in gates such as the Porta Maggiore in Rome.The Gothic arch, which is characterized by its pointed shape ,evolved in France in the 12th century. This form characterizes some of the most magnificent churches of the early Renaissance period such as the Chartres. Amiens, and Rheims cathedral. theform of the Gothic arch is superior to the Roman arch because of its greater structural clarity, which closely approaches the shapes the shape of an idea arch. The concept of the idea arch can best be explained by a comparison with a suspension cable.A chain or a cable supported at each end assumes a curved shape called a catenary (from catena, chain).If the cable were required to support one weight hung from it ,it would change shape to adjust to this condition ;this is due to the fact that a cable carries loads only by the actin of simple tension along the length of the cable. If, instead of a single load, many parabola. The catenary and the parabola are geomertrically similar since the weight of the cable is approximately a uniformly distributed load .An ideal arch may be thought of as a cable frozen in its shape and turned upside down.(Instead of carrying loads by tension, as in the cable, the ideal arch carries loads by simple compression)This ideal shape of load the arch is called the “funicular curve” A different funicular curve exists for every type of load the arch is required to carry. Since the arch ,unlike the flexible cable ,cannot adjust its shape to the load ,then the arch, under a load other than that which gave it its funicular shape, must also carry the load by bending, as in a beam .The structural efficiency of an arch can thus be measured in terms of the proximity of the geometric shape to the funicular curve ,In the semicircular Romans arch ,there is a large difference between the funicular curve of the loads and the circular shape. The pointed Gothic arches are much closer to the funicular curve of the loads and therefore possess a clear advantage over the earlier semicircular form.To resist the horizontal thrust which exists at the base of an arch ,the Roman used massive piers or buttresses. In some of the Gothic cathedrals, which raised the arch high above the nave, flying buttresses over the side aisles were used to counteract the thrust.In modern times ,arch construction has been used extensively for bridge, utilizing steel, wood, or reinforced concrete. The concrete arch bridges built by Robert Maillart in Switzerland are outstanding examples of elegance and structural clarity in modern arch design.Truss. The simplest form of truss is a triangle consisting of three bars. Thiselementary truss form undoubtedly grew out of the use of the gabled roof for small houses and churches. In this construction, two slanting rafters rest on top of a wall and are pinned at the peak. The load of the roof tends to push out the top of the walls. Tying the bottom of the rafters together with a bar or rod counters this outward push. The resulting triangular shape is a rigid form geometrically, because none of its angles can change without changing the length of its sides. Each element in a truss is subject to either tension or compression; in the simple triangular truss, the rafters are in compression and the tie rod is in tension.The elementary triangular truss is limited to spanning relatively short distance because each slanting member is long compared to the span. In a triangular truss with equal angles, for instance, each member is as long as the span. This drawback was recognized by Andrea Palladio in the 16th century. His design for a trussed bridge utilized the principle that if a single triangles is rigid ,combinations of triangles are also rigid . By arranging short lengths of timbers in a series of triangles to form complex trusses, almost any distance can be spanned.It was not until the 19th century , when mathematical methods of analysis became known and iron and steel were introduced, that trusses with a great degree of perfection and elegance were developed. Modern trusses with a variety of configurations are used to span auditoriums, armories, and convention halls , creating large column-free spaces. The type of trusses most commonly used in buildings are the Pratt, Howe, and Warren trusses, all named after their inventors. The Pratt and Howe trusses have top and bottom chords (horizontal elements), and both verticals and diagonals between the chords. The Warren truss has only diagonals joining the top and bottom chord .Cantilever. In cantilever construction, building elements are projected outward from a fixed support. An early kind of cantilever construction was the corbel; it had its origin in the late Stone Age and can be found in the form of corbelled domes built in Sarrdinia about 2,500 B.C. In corbel construction, each successive layer of stone stands out farther from a wall in the form of upside-down steps. Only the weight of the stones above and behind the face of the wall prevent a corbel from collapsing. Anexcessive amount of material is required for corbel construction because of the necessity for heavy masonry walls.Cantilevering building elements from a wall or other fixed support permits projecting part of a building beyond the ground-level construction to gain more living area above, as in many of the Renaissance town houses.The cantilever is much used in modern buildings as a result of the availability of steel and reinforced concrete. It is a simple matter in a concrete apartment building to create a cantilevered balcony when the balcony slab is merely a continuation of the interior slab. The Kaumfman house, built by Frank Lloyd Wright in 1939, is an example of a dramatic use of cantilevers and demonstrates the potential of this type of construction. In a steel-framed building, beams can project beyond column to permit the face of the building to be a curtain wall with large glass areas. This cantilever construction was exemplified by the Bauhaus (1926) ,which was used as a model for many skyscrapers built after World WarⅡ结构形式结构形式，如梁或拱，通过发展有关的材料供应和当时的技术的年龄。
土木工程英文文献及翻译
Civil engineeringCivil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like bridges, roads, canals, dams, and buildings.[1][2][3] Civil engineering is the oldest engineering discipline after military engineering,[4] and it was defined to distinguish non-military engineering from military engineering.[5] It is traditionally broken into several sub-disciplines including environmental engineering, geotechnical engineering, structural engineering, transportation engineering, municipal or urban engineering, water resources engineering, materials engineering, coastal engineering,[4] surveying, and construction engineering.[6] Civil engineering takes place on all levels: in the public sector from municipal through to national governments, and in the private sector from individual homeowners through to international companies.History of the civil engineering professionSee also: History of structural engineeringEngineering has been an aspect of life since the beginnings of human existence. The earliest practices of Civil engineering may have commenced between 4000 and 2000 BC in Ancient Egypt and Mesopotamia (Ancient Iraq) when humans started to abandon a nomadic existence, thus causing a need for the construction of shelter. During this time, transportation became increasingly important leading to the development of the wheel and sailing.Until modern times there was no clear distinction between civil engineering and architecture, and the term engineer and architect were mainly geographical variations referring to the same person, often used interchangeably.[7]The construction of Pyramids in Egypt (circa 2700-2500 BC) might be considered the first instances of large structure constructions. Other ancient historic civil engineering constructions include the Parthenon by Iktinos in Ancient Greece (447-438 BC), theAppian Way by Roman engineers (c. 312 BC), the Great Wall of China by General Meng T'ien under orders from Ch'in Emperor Shih Huang Ti (c. 220 BC)[6] and the stupas constructed in ancient Sri Lanka like the Jetavanaramaya and the extensive irrigation works in Anuradhapura. The Romans developed civil structures throughout their empire, including especially aqueducts, insulae, harbours, bridges, dams and roads.In the 18th century, the term civil engineering was coined to incorporate all things civilian as opposed to military engineering.[5]The first self-proclaimed civil engineer was John Smeaton who constructed the Eddystone Lighthouse.[4][6]In 1771 Smeaton and some of his colleagues formed the Smeatonian Society of Civil Engineers, a group of leaders of the profession who met informally over dinner. Though there was evidence of some technical meetings, it was little more than a social society.In 1818 the Institution of Civil Engineers was founded in London, and in 1820 the eminent engineer Thomas Telford became its first president. The institution received a Royal Charter in 1828, formally recognising civil engineering as a profession. Its charter defined civil engineering as:the art of directing the great sources of power in nature for the use and convenience of man, as the means of production and of traffic in states, both for external and internal trade, as applied in the construction of roads, bridges, aqueducts, canals, river navigation and docks for internal intercourse and exchange, and in the construction of ports, harbours, moles, breakwaters and lighthouses, and in the art of navigation by artificial power for the purposes of commerce, and in the construction and application of machinery, and in the drainage of cities and towns.[8] The first private college to teach Civil Engineering in the United States was Norwich University founded in 1819 by Captain Alden Partridge.[9] The first degree in Civil Engineering in the United States was awarded by Rensselaer Polytechnic Institute in 1835.[10] The first such degree to be awarded to a woman was granted by Cornell University to Nora Stanton Blatchin 1905.History of civil engineeringCivil engineering is the application of physical and scientific principles, and its history is intricately linked to advances in understanding of physics and mathematics throughout history. Because civil engineering is a wide ranging profession, including several separate specialized sub-disciplines, its history is linked to knowledge of structures, materials science, geography, geology, soils, hydrology, environment, mechanics and other fields.Throughout ancient and medieval history most architectural design and construction was carried out by artisans, such as stone masons and carpenters, rising to the role of master builder. Knowledge was retained in guilds and seldom supplanted by advances. Structures, roads and infrastructure that existed were repetitive, and increases in scale were incremental.[12]One of the earliest examples of a scientific approach to physical and mathematical problems applicable to civil engineering is the work of Archimedes in the 3rd century BC, including Archimedes Principle, which underpins our understanding of buoyancy, and practical solutions such as Archimedes' screw. Brahmagupta, an Indian mathematician, used arithmetic in the 7th century AD, based on Hindu-Arabic numerals, for excavation (volume) computations.[13]Civil engineers typically possess an academic degree with a major in civil engineering. The length of study for such a degree is usually three to five years and the completed degree is usually designated as a Bachelor of Engineering, though some universities designate the degree as a Bachelor of Science. The degree generally includes units covering physics, mathematics, project management, design and specific topics in civil engineering. Initially such topics cover most, if not all, of thesub-disciplines of civil engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.[14]While anUndergraduate (BEng/BSc) Degree will normally provide successful students with industry accredited qualification, some universities offer postgraduate engineering awards (MEng/MSc) which allow students to further specialize in their particular area of interest within engineering.[15]In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements (including work experience and exam requirements) before being certified. Once certified, the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa), Chartered Engineer (in most Commonwealth countries), Chartered Professional Engineer (in Australia and New Zealand), or European Engineer (in much of the European Union). There are international engineering agreements between relevant professional bodies which are designed to allow engineers to practice across international borders.The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may prepare, sign and seal, and submit engineering plans and drawings to a public authority for approval, or seal engineering work for public and private clients.".[16]This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.[17]In other countries, no such legislation exists. In Australia, state licensing of engineers is limited to the state of Queensland. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.[18] In this way, these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, thecharge of criminal negligence.[citation needed] An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.CareersThere is no one typical career path for civil engineers. Most people who graduate with civil engineering degrees start with jobs that require a low level of responsibility, and as the new engineers prove their competence, they are trusted with tasks that have larger consequences and require a higher level of responsibility. However, within each branch of civil engineering career path options vary. In some fields and firms, entry-level engineers are put to work primarily monitoring construction in the field, serving as the "eyes and ears" of senior design engineers; while in other areas, entry-level engineers perform the more routine tasks of analysis or design and interpretation. Experienced engineers generally do more complex analysis or design work, or management of more complex design projects, or management of other engineers, or into specialized consulting, including forensic engineering.In general, civil engineering is concerned with the overall interface of human created fixed projects with the greater world. General civil engineers work closely with surveyors and specialized civil engineers to fit and serve fixed projects within their given site, community and terrain by designing grading, drainage, pavement, water supply, sewer service, electric and communications supply, and land divisions. General engineers spend much of their time visiting project sites, developing community consensus, and preparing construction plans. General civil engineering is also referred to as site engineering, a branch of civil engineering that primarily focuses on converting a tract of land from one usage to another. Civil engineers typically apply the principles of geotechnical engineering, structural engineering, environmental engineering, transportation engineering and construction engineering toresidential, commercial, industrial and public works projects of all sizes and levels of construction翻译：土木工程土木工程是一个专业的工程学科，包括设计，施工和维护与环境的改造，涉及了像桥梁，道路，河渠，堤坝和建筑物工程交易土木工程是最古老的军事工程后，工程学科，它被定义为区分军事工程非军事工程的学科它传统分解成若干子学科包括环境工程，岩土工程，结构工程，交通工程，市或城市工程，水资源工程，材料工程，海岸工程，勘测和施工工程等土木工程的范围涉及所有层次：从市政府到国家，从私人部门到国际公司。
【设计】土木工程毕业设计英语论文及翻译
【关键字】设计土木工程毕业设计英语论文及翻译篇一：土木工程毕业设计外文文献翻译外文文献翻译Reinforced ConcreteConcrete and reinforced concrete are used as building materials in every country. In many, including the United States and Canada, reinforced concrete is a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete and reinforced concrete are used in bridges, buildings of all sorts underground structures, water tanks, television towers, offshore oil exploration and production structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed in their final location, or they may be precast concrete produced in a factory and erected at the construction site. Concrete structures may be severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engineer such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whenever loads, or restrained shrinkage of temperature changes, give rise to tensile stresses in excess of the tensile strength of the concrete. In a plain concrete beam, the moments about the neutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beam fails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the concrete in such a way that the tension forces needed for moment equilibrium after the concrete cracks can be developed in the bars.The construction of a reinforced concrete member involves building a from of mold in the shape of the member being built. The form must be strong enough to support both the weight and hydrostatic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies, wind, and so on. The reinforcement is placed in this form and held in place during the concreting operation. After the concrete has hardened, the forms are removed. As the forms are removed, props of shores are installed to support the weight of the concrete until it has reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength to resist the loads and adequate stiffness to prevent excessive deflections. In beam must be proportioned so that it can be constructed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the concrete is placed in the form after the reinforcement is in place, theconcrete must be able to flow around, between, and past the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masoy, or timber depends on the availability of materials and on a number of value decisions. The choice of structural system is made by the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shapeand texture by means of the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearing elements while providing the finished floor and / or ceiling surfaces. Similarly, reinforced concrete walls can provide architecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Finally, the choice of size of shape is governed by the designer and not by the availability of standard manufactured members.3. Fire resistance. The structure in a building must withstand the effects of a fire and remain standing while the building is evacuated and the fire is extinguished. A concrete building inherently has a 1- to 3-hour fire rating without special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratings.4. Low maintenance. Concrete members inherently require less maintenance than do structural steel or timber members. This is particularly true if dense, air-entrained concrete has been used for surfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are verywidely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength. The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume. The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled, and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course instrength of materials forhomogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because ueinforced concrete is brittle, it cannot undergo large deformations under load and fails suddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.篇二：土木工程毕业设计中英文翻译附录：中英文翻译英文部分：LOADSLoads that act on structures are usually classified as dead loads or live loads.Dead loads are fixed in location and constant in magnitude throughout the life of the ually the self-weight of a structure is the most important part of the structure and the unit weight of the material.Concrete density varies from about 90 to 120 pcf (14 to 19 KN/m2)for lightweight concrete,and is about 145 pcf (23 KN/mKN/m2)for normal concrete.In calculating the dead load of structural concrete,usually a 5pcf (1 )increment is included with the weight of the concrete to account for the presence of the 2 reinforcement.Live loads are loads such as occupancy,snow,wind,or traffic loads,or seismic forces.They may be either fully or partially in place,or not present at all.They may also change in location.Althought it is the responsibility of the engineer to calculate dead loads,live loads are usually specified by local,regional,or national codes and specifications.Typical sources are the publications of the American National Standards Institute,the American Association of State Highway and Transportation Officials and,for wind loads,the recommendations of the ASCE Task Committee on Wind Forces.Specified live the loads usually include some allowance for overload,and may include measures such as posting of maximum loads will not be exceeded.It is oftern important to distinguish between the specified load,and what is termed the characteristic load,that is,the load that actually is in effect under normal conditions of service,which may be significantly less.In estimating the long-term deflection of a structure,for example,it is the characteristic load that is important,not the specified load.The sum of the calculated dead load and the specified live load is called the service load,because this is the maximum load which may reasonably be expected to act during the service resisting is a multiple of the service load.StrengthThe strength of a structure depends on the strength of the materials from which it is made.Minimum material strengths are specified in certain standardized ways.The properties of concrete and its components,the methods of mixing,placing,and curing to obtain the required quality,and the methods for testing,are specified by the American Concrete Insititue(ACI).Included by refrence in the same documentare standards of the American Society for Testing Materials(ASTM)pertaining to reinforcing and prestressing steels and concrete.Strength also depends on the care with which the structure is built.Member sizes may differ from specified dimensions,reinforcement may be out of position,or poor placement of concrete may result in voids.An important part of the job of the ergineer is to provide proper supervision of construction.Slighting of this responsibility has had disastrous consequences in more than one instance.Structural SafetySafety requires that the strength of a structure be adequate for all loads that may conceivably act on it.If strength could be predicted accurately and if loads were known with equal certainty,then safely could be assured by providing strength just barely in excess of the requirements of the loads.But there are many sources of uncertainty in the estimation of loads as well as in analysis,design,and construction.These uncertainties require a safety margin.In recent years engineers have come to realize that the matter of structural safety isprobabilistic in nature,and the safety provisions of many current specifications reflect this view.Separate consideration is given to loads and strength.Load factors,larger than unity,are applied to the calculated dead loads and estimated or specified service live loads,to obtain factorde loads that the member must just be capable of sustaining at incipient failure.Load factors pertaining to different types of loads vary,depending on the degree of uncertainty associated with loads of various types,and with the likelihood of simultaneous occurrence of different loads.Early in the development of prestressed concrete,the goal of prestressing was the complete elimination of concrete ternsile stress at service loads.The concept was that of an entirely new,homogeneous material that woukd remain uncracked and respond elastically up to the maximum anticipated loading.This kind of design,where the limiting tensile stressing,while an alternative approach,in which a certain amount of tensile amount of tensile stress is permitted in the concrete at full service load,is called partial prestressing.There are cases in which it is necessary to avoid all risk of cracking and in which full prestressing is required.Such cases include tanks or reservious where leaks must be avoided,submerged structures or those subject to a highly corrosive envionment where maximum protection of reinforcement must be insured,and structures subject to high frequency repetition of load where faatigue of the reinforcement may be a consideration.However,there are many cses where substantially improved performance,reduced cost,or both may be obtained through the use of a lesser amount of prestress.Full predtressed beams may exhibit an undesirable amount of upward camber because of the eccentric prestressing force,a displacement that is only partially counteracted by the gravity loads producing downward deflection.This tendency is aggrabated by creep in the concrete,which magnigies the upward displacement due to the prestress force,but has little influence on the should heavily prestressed members be overloaded and fail,they may do so in a brittle way,rather than gradually as do beams with a smaller amount of prestress.This is important from the point of view of safety,because suddenfailure without warning is dangeroud,and gives no opportunity for corrective measures to be taken.Furthermore,experience indicates that in many cases improved economy results from the use of a combination of unstressed bar steel and high strength prestressed steel tendons.While tensile stress and possible cracking may be allowed at full service load,it is also recognized that such full service load may be infrequently applied.The typical,or characteristic,load acting is likely to be the dead load plus a small fraction of the specified live load.Thus a partially predtressed beam may not be subject to tensile stress under the usual conditions of loading.Cracks may from occasionally,when the maximum load is applied,but these will close completely when that load is removed.They may be no more objectionable in prestressed structures than in ordinary reinforced.They may be no more objectionable in prestressed structures than in ordinary reinforced concrete,in which flexural cracks alwaysform.They may be considered a small price for the improvements in performance and economy that are obtained.It has been observed that reinforced concrete is but a special case of prestressed concrete in which the prestressing force is zero.The behavior of reinforced and prestressed concrete beams,as the failure load is approached,is essentially the same.The Joint European Committee on Concrete establishes threee classes of prestressed beams.Class 1:Fully prestressed,in which no tensile stress is allowed in the concrete at service load.Class 2:Partially prestressed, in which occasional temporary cracking is permitted under infrequent high loads.Class 3:Partially prestressed,in which there may be permanent cracks provided that their width is suitably limited.The choise of a suitable amount of prestress is governed by a variety of factors.These include thenature of the loading (for exmaple,highway or railroad bridged,storage,ect.),the ratio of live to dead load,the frequency of occurrence of loading may be reversed,such as in transmission poles,a high uniform prestress would result ultimate strength and in brittle failure.In such a case,partial prestressing provides the only satifactory solution.The advantages of partial prestressing are important.A smaller prestress force will be required,permitting reduction in the number of tendons and anchorages.The necessary flexural strength may be provided in such cases either by a combination of prestressed tendons and non-prestressed reinforcing bars,or by an adequate number of high-tensile tendons prestredded to level lower than the prestressing force is less,the size of the bottom flange,which is requied mainly to resist the compression when a beam is in the unloaded stage,can be reduced or eliminated altogether.This leads in turn to significant simplification and cost reduction in the construction of forms,as well as resulting in structures that are mor pleasing esthetically.Furthermore,by relaxing the requirement for low service load tension in the concrete,a significant improvement can be made in the deflection characteristics of a beam.Troublesome upward camber of the member in the unloaded stage fan be avoeded,and the prestress force selected primarily to produce the desired deflection for a particular loading condition.The behavior of partially prestressed beamsm,should they be overloaded to failure,is apt to be superior to that of fully prestressed beams,because the improved ductility provides ample warning of distress.英译汉：荷载作用在结构上的荷载通常分为恒载或活载。
土木工程专业毕业设计外文文献翻译2篇
土木工程专业毕业设计外文文献翻译2篇XXXXXXXXX学院学士学位毕业设计（论文）英语翻译课题名称英语翻译学号学生专业、年级所在院系指导教师选题时间Fundamental Assumptions for Reinforced ConcreteBehaviorThe chief task of the structural engineer is the design of structures. Design is the determination of the general shape and all specific dimensions of a particular structure so that it will perform the function for which it is created and will safely withstand the influences that will act on it throughout useful life. These influences are primarily the loads and other forces to which it will be subjected, as well as other detrimental agents, such as temperature fluctuations, foundation settlements, and corrosive influences, Structural mechanics is one of the main tools in this process of design. As here understood, it is the body of scientific knowledge that permits one to predict with a good degree of certainly how a structure of give shape and dimensions will behave when acted upon by known forces or other mechanical influences. The chief items of behavior that are of practical interest are (1) the strength of the structure, i. e. , that magnitude of loads of a give distribution which will cause the structure to fail, and (2) the deformations, such as deflections and extent of cracking, that the structure will undergo when loaded underservice condition.The fundamental propositions on which the mechanics of reinforced concrete is based are as follows:1.The internal forces, such as bending moments, shear forces, and normal andshear stresses, at any section of a member are in equilibrium with the effect of the external loads at that section. This proposition is not an assumption but a fact, because any body or any portion thereof can be at rest only if all forces acting on it are in equilibrium.2.The strain in an embedded reinforcing bar is the same as that of thesurrounding concrete. Expressed differently, it is assumed that perfect bonding exists between concrete and steel at the interface, so that no slip can occur between the two materials. Hence, as the one deforms, so must the other. With modern deformed bars, a high degree of mechanical interlocking is provided in addition to the natural surface adhesion, so this assumption is very close to correct.3.Cross sections that were plane prior to loading continue to be plan in themember under load. Accurate measurements have shown that when a reinforced concrete member is loaded close to failure, this assumption is not absolutely accurate. However, the deviations are usually minor.4.In view of the fact the tensile strength of concrete is only a small fraction ofits compressive strength; the concrete in that part of a member which is in tension is usually cracked. While these cracks, in well-designed members, are generally so sorrow as to behardly visible, they evidently render the cracked concrete incapable of resisting tension stress whatever. This assumption is evidently a simplification of the actual situation because, in fact, concrete prior to cracking, as well as the concrete located between cracks, does resist tension stresses of small magnitude. Later in discussions of the resistance of reinforced concrete beams to shear, it will become apparent that under certain conditions this particular assumption is dispensed with and advantage is taken of the modest tensile strength that concrete can develop.5.The theory is based on the actual stress-strain relation ships and strengthproperties of the two constituent materials or some reasonable equivalent simplifications thereof. The fact that novelistic behavior is reflected in modern theory, that concrete is assumed to be ineffective in tension, and that the joint action of the two materials is taken into consideration results in analytical methods which are considerably more complex and also more challenging, than those that are adequate for members made of a single, substantially elastic material.These five assumptions permit one to predict by calculation the performance of reinforced concrete members only for some simple situations. Actually, the joint action of two materials as dissimilar and complicated as concrete and steel is so complex that it has not yet lent itself to purely analytical treatment. For this reason, methods of design and analysis, while using these assumptions, are very largely based on the results of extensive and continuing experimental research. They are modified and improved as additional test evidence becomes available.钢筋混凝土的基本假设作为结构工程师的主要任务是结构设计。
土木工程专业英语课文原文及对照翻译
Civil EngineeringCivil engineering, the oldest of the engineering specialties, is the planning, design, construction, and management of the built environment. This environment includes all structures built according to scientific principles, from irrigation and drainage systems to rocket-launching facilities.土木工程学作为最老的工程技术学科,是指规划,设计,施工及对建筑环境的管理;此处的环境包括建筑符合科学规范的所有结构,从灌溉和排水系统到火箭发射设施;Civil engineers build roads, bridges, tunnels, dams, harbors, power plants, water and sewage systems, hospitals, schools, mass transit, and other public facilities essential to modern society and large population concentrations. They also build privately owned facilities such as airports, railroads, pipelines, skyscrapers, and other large structures designed for industrial, commercial, or residential use. In addition, civil engineers plan, design, and build complete cities and towns, and more recently have been planning and designing space platforms to house self-contained communities.土木工程师建造道路,桥梁,管道,大坝,海港,发电厂,给排水系统,医院,学校,公共交通和其他现代社会和大量人口集中地区的基础公共设施;他们也建造私有设施,比如飞机场,铁路,管线,摩天大楼,以及其他设计用作工业,商业和住宅途径的大型结构;此外,土木工程师还规划设计及建造完整的城市和乡镇,并且最近一直在规划设计容纳设施齐全的社区的空间平台;The word civil derives from the Latin for citizen. In 1782, Englishman John Smeaton used the term to differentiate his nonmilitary engineering work from that of the military engineers who predominated at the time. Since then, the term civil engineering has often been used to refer to engineers who build public facilities, although the field is much broader土木一词来源于拉丁文词“公民”;在1782年,英国人John Smeaton为了把他的非军事工程工作区别于当时占优势地位的军事工程师的工作而采用的名词;自从那时起,土木工程学被用于提及从事公共设施建设的工程师,尽管其包含的领域更为广阔;Scope. Because it is so broad, civil engineering is subdivided into a number of technical specialties. Depending on the type of project, the skills of many kinds of civil engineer specialists may be needed. When a project begins, the site is surveyed and mapped by civil engineers who locate utility placement—water, sewer, and power lines. Geotechnical specialists perform soil experiments to determine if the earth can bear the weight of the project. Environmental specialists study the project’s impact on the local area: the potential for air and groundwater pollution, the project’s impact on local animal and plant life, and how the project can be designed to me et government requirements aimed at protecting the environment. Transportation specialists determine what kind of facilities are needed to ease the burden on local roads and other transportation networks that will result from the completed project. Meanwhile, structural specialists use preliminary data to make detailed designs, plans, and specifications for the project. Supervising and coordinating the work of these civil engineer specialists, from beginning to end of the project, are the construction management specialists. Based on information supplies by the other specialists, construction management civil engineers estimate quantities and costs of materials and labor, schedule all work, order materials and equipment for the job, hire contractors and subcontractors, and perform other supervisory work to ensure the project is completed on time and as specified.领域;因为包含范围太广,土木工程学又被细分为大量的技术专业;不同类型的工程需要多种不同土木工程专业技术;一个项目开始的时候,土木工程师要对场地进行测绘,定位有用的布置,如地下水水位,下水道,和电力线;岩土工程专家则进行土力学试验以确定土壤能否承受工程荷载;环境工程专家研究工程对当地的影响,包括对空气和地下水的可能污染,对当地动植物生活的影响,以及如何让工程设计满足政府针对环境保护的需要;交通工程专家确定必需的不同种类设施以减轻由整个工程造成的对当地公路和其他交通网络的负担;同时,结构工程专家利用初步数据对工程作详细规划,设计和说明;从项目开始到结束,对这些土木工程专家的工作进行监督和调配的则是施工管理专家;根据其他专家所提供的信息,施工管理专家计算材料和人工的数量和花费,所有工作的进度表,订购工作所需要的材料和设备,雇佣承包商和分包商,还要做些额外的监督工作以确保工程能按时按质完成;Throughout any given project, civil engineers make extensive use of computers. Computers are used to design the project’s various elements computer-aided design, or CAD and to manage it. Computers are necessity for the modern civil engineer because they permit the engineer to efficiently handle the large quantities of data needed in determining the best way to construct a project.贯穿任何给定项目,土木工程师都需要大量使用计算机;计算机用于设计工程中使用的多数元件即计算机辅助设计,或者CAD并对其进行管理;计算机成为了现代土木工程师的必备品,因为它使得工程师能有效地掌控所需的大量数据从而确定建造一项工程的最佳方法; Structural engineering. In this specialty, civil engineers plan and design structures of all types, including bridge, dams, power plants, supports for equipment, special structures for offshore projects, the United States space program, transmission towers, giant astronomical and radio telescopes, and many other kinds of projects. Using computers, structural engineers determine the forces a structure must resist: its own weight, wind and hurricane forces, temperature changes that expand or contract construction materials, and earthquakes. They also determine the combination of appropriate materials: steel, concrete, plastic, asphalt, brick, aluminum, or other construction materials.结构工程学;在这一专业领域,土木工程师规划设计各种类型的结构,包括桥梁,大坝,发电厂,设备支撑,海面上的特殊结构,美国太空计划,发射塔,庞大的天文和无线电望远镜,以及许多其他种类的项目;结构工程师应用计算机确定一个结构必须承受的力：自重,风荷载和飓风荷载,建筑材料温度变化引起的胀缩,以及地震荷载;他们也需确定不同种材料如钢筋,混凝土,塑料,石头,沥青,砖,铝或其他建筑材料等的复合作用;Water resources engineering. Civil engineers in this specialty deal with all aspects of the physical control of water. Their projects help prevent floods, supply water for cities and for irrigation, manage and control rivers and water runoff, and maintain beaches and other waterfront facilities. In addition, they design and maintain harbors, canals, and locks, build huge hydroelectric dams and smaller dams and water impoundments of all kinds, help design offshore structures, and determine the location of structures affecting navigation.水利工程学;土木工程师在这一领域主要处理水的物理控制方面的种种问题;他们的项目用于帮助预防洪水灾害,提供城市用水和灌溉用水,管理控制河流和水流物,维护河滩及其他滨水设施;此外,他们设计和维护海港,运河与水闸,建造大型水利大坝与小型坝,以及各种类型的围堰,帮助设计海上结构并且确定结构的位置对航行影响;Geotechnical engineering. Civil engineers who specialize in this field analyze the properties of soils and rocks that support structures and affect structural behavior. They evaluate and work to minimize the potential settlement of buildings and other structures that stems from the pressure of their weight on the earth. These engineers also evaluate and determine how to strengthen the stability of slopes and fills and how to protect structures against earthquakes and the effects ofgroundwater.岩土工程学;专业于这个领域的土木工程师对支撑结构并影响结构行为的土壤和岩石的特性进行分析;他们计算建筑和其他结构由于自重压力可能引起的沉降,并采取措施使之减少到最小;他们也需计算并确定如何加强斜坡和填充物的稳定性以及如何保护结构免受地震和地下水的影响;Environmental engineering. In this branch of engineering, civil engineers design, build and supervise systems to provide safe drinking water and to prevent and control pollution of water supplies, both on the surface and underground. They also design, build, and supervise projects to control or eliminate pollution of the land and air. These engineers build water and wastewater treatment plants, and design air scrubbers and other devices to minimize or eliminate air pollution caused by industrial processes, incineration, or other smoke-producing activities. They also work to control toxic and hazardous wastes through the construction of special dump sites or the neutralizing of toxic and hazardous substances. In addition, the engineers design and manage sanitary landfills to prevent pollution of surrounding land.环境工程学;在这一工程学分支中,土木工程师设计,建造并监视系统以提供安全的饮用水,同时预防和控制地表和地下水资源供给的污染;他们也设计,建造并监视工程以控制甚至消除对土地和空气的污染;他们建造供水和废水处理厂,设计空气净化器和其他设备以最小化甚至消除由工业加工、焚化及其他产烟生产活动引起的空气污染;他们也采用建造特殊倾倒地点或使用有毒有害物中和剂的措施来控制有毒有害废弃物;此外,工程师还对垃圾掩埋进行设计和管理以预防其对周围环境造成污染;Transportation engineering. Civil engineers working in this specialty build facilities to ensure safe and efficient movement of both people and goods. They specialize in designing and maintaining all types of transportation facilities, highways and streets, mass transit systems, railroads and airfields, ports and harbors. Transportation engineers apply technological knowledge as well as consideration of the economic, political, and social factors in designing each project. They work closely with urban planners, since the quality of the community is directly related to the quality of the transportation system.交通工程学;从事这一专业领域的土木工程师建造可以确保人和货物安全高效运行的设施;他们专门研究各种类型运输设施的设计和维护,如公路和街道,公共交通系统,铁路和飞机场,港口和海港;交通工程师应用技术知识及考虑经济,政治和社会因素来设计每一个项目;他们的工作和城市规划者十分相似,因为交通运输系统的质量直接关系到社区的质量;Pipeline engineering. In this branch of civil engineering, engineers build pipelines and related facilities which transport liquids, gases, or solids ranging from coal slurries mixed coal and water and semiliquid wastes, to water, oil, and various types of highly combustible and noncombustible gases. The engineers determine pipeline design, the economic and environmental impact of a project on regions it must traverse, the type of materials to be used-steel, concrete, plastic, or combinations of various materials-installation techniques, methods for testing pipeline strength, and controls for maintaining proper pressure and rate of flow of materials being transported. When hazardous materials are being carried, safety is a major consideration as well.渠道工程学;在土木工程学的这一支链中,土木工程师建造渠道和运送从煤泥浆混合的煤和水和半流体废污,到水、石油和多种类型的高度可燃和不可燃的气体中分离出来的液体,气体和固体的相关设备;工程师决定渠道的设计,项目所处地区必须考虑到的经济性和环境因素,以及所使用材料的类型——钢、混凝土、塑料、或多种材料的复合——的安装技术,测试渠道强度的方法,和控制所运送流体材料保持适当的压力和流速;当流体中携带危险材料时,安全性因素也需要被考虑;Construction engineering. Civil engineers in this field oversee the construction of a project from beginning to end. Sometimes called project engineers, they apply both technical and managerial skills, including knowledge of construction methods, planning, organizing, financing, and operating construction projects. They coordinate the activities of virtually everyone engaged in the work: the surveyors; workers who lay out and construct the temporary roads and ramps, excavate for the foundation, build the forms and pour the concrete; and workers who build the steel framework. These engineers also make regular progress reports to the owners of the structure.建筑工程学;土木工程师在这个领域中从开始到结束监督项目的建筑;他们,有时被称为项目工程师,应用技术和管理技能,包括建筑工艺,规划,组织,财务,和操作项目建设的知识;事实上,他们协调工程中每个人的活动：测量员,布置和建造临时道路和斜坡,开挖基础,支模板和浇注混凝土的工人,以及钢筋工人;这些工程师也向结构的业主提供进度计划报告;Community and urban planning. Those engaged in this area of civil engineering may plan and develop community within a city, or entire cities. Such planning involves far more than engineering consideration; environmental, social, and economic factors in the use and development of land and natural resources are also key elements. These civil engineers coordinate planning of public works along with private development. They evaluate the kinds of facilities needed, including streets and highways, public transportation systems, airports, port facilities, water-supply and waste water-disposal systems, public buildings, parks, and recreational and other facilities to ensure social and economic as well as environmental well-being.社区和城市规划;从事土木工程这一方面的工程师可能规划和发展一个城市中的社区,或整个城市;此规划中所包括的远远不仅仅为工程因素,土地的开发使用和自然资源环境的,社会的和经济的因素也是主要的成分;这些土木工程师对公共建设工程的规划和私人建筑的发展进行协调;他们评估所需的设施,包括街道,公路,公共运输系统,机场,港口,给排水和污水处理系统,公共建筑,公园,和娱乐及其他设施以保证社会,经济和环境地协调发展; Photogrametry, surveying, and mapping. The civil engineers in this specialty precisely measure the Earth’s surface to obtain reliable information for locating and designing engineering projects. This practice often involves high-technology methods such as satellite and aerial surveying, and computer-processing of photographic imagery. Radio signal from satellites, scans by laser and sonic beams, are converted to maps to provide far more accurate measurements for boring tunnels, building highways and dams, plotting flood control and irrigation project, locating subsurface geologic formations that may affect a construction project, and a host of other building uses.摄影测量,测量学和地图绘制;在这一专业领域的土木工程师精确测量地球表面以获得可靠的信息来定位和设计工程项目;这一方面包括高工艺学方法,如卫星成相,航拍,和计算机成相;来自人造卫星的无线电信号,通过激光和音波柱扫描被转换为地图,为隧道钻孔,建造高速公路和大坝,绘制洪水控制和灌溉方案,定位可能影响建筑项目的地下岩石构成,以及许多其他建筑用途提供更精准的测量;Other specialties. Two additional civil engineering specialties that are not entirely within the scope of civil engineering but are essential to the discipline are engineering management and engineering teaching.其他的专门项目;还有两个并不完全在土木工程范围里面但对训练相当重要的附加的专门项目是工程管理和工程教学;Engineering management. Many civil engineers choose careers that eventually lead to management. Others are able to start their careers in management positions. The civilengineer-manager combines technical knowledge with an ability to organize and coordinate worker power, materials, machinery, and money. These engineers may work in government—municipal, county, state, or federal; in the . Army Corps of Engineers as military or civilian management engineers; or in semiautonomous regional or city authorities or similar organizations. They may also manage private engineering firms ranging in size from a few employees to hundreds.工程管理;许多土木工程师都选择最终通向管理的职业;其他则能让他们的事业从管理位置开始;土木工程管理者结合技术上的知识和一种组织能力来协调劳动力,材料,机械和钱;这些工程师可能工作在政府——市政、国家、州或联邦；在美国陆军军团作为军队或平民的管理工程师；或在半自治地区,城市主管当局或相似的组织;他们也可能管理规模为从几个到百个雇员的私营工程公司;Engineering teaching. The civil engineer who chooses a teaching career usually teaches both graduate and undergraduate students in technical specialties. Many teaching civil engineers engage in basic research that eventually leads to technical innovations in construction materials and methods. Many also serve as consultants on engineering projects, or on technical boards and commissions associated with major projects.工程教学;通常选择教学事业的土木工程师教授研究生和本科生技术上的专门项目;许多从事教学的土木工程师参与会导致建筑材料和施工方法技术革新的基础研究;多数也担任工程项目或技术领域的顾问,和主要项目的代理;。
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外文文献及翻译题目：沉埋隧道工程对环境的影响专业土木工程学生姓名李鹏班级BM土木071学号**********指导教师殷勇沉埋隧道工程对环境的影响摘要：一座沉埋隧道对环境的深远影响都与穿过水道的沉放管段有关。
隧道对这一地区内地下和地表水的影响在隧道设计和施工方法的选择中起最重要的作用。
最近在考虑的一个影响施工的问题是必须为隧道开挖的沟槽有可能出现被污染的泥土。
挖出与运送这些泥土至专门装备起来以便接收它们的存放地点的方法是一系列重要新技术和质量控制措施的环境问题。
最常见的是在任何建筑工程中都会遇到的环境问题，即噪音、灰尘以及交通阻塞。
本文对这些问题以及目前用于解决这些问题的技术和措施作了评述。
关键词：隧道环境沉埋隧道的特征一座沉埋隧道具有两项基本特征：它是某一地下结构场地的一部分，要在繁忙的交通条件下保证施工，而并不意味这个地区是被充分地利用了的。
因此，施工空间是很宝贵的。
它基本上是一预制结构。
最终将安装在河流或运河底部位置的隧道管段是在其它地方以非常接近工厂条件的方式筑造的，这种条件在现场和工地是不大可能达到的。
施工规划上的优点和将管段制造与工地准备分开进行在后勤上的优点是显而易见的，还有极易于实现有效的质量控制的优点。
隧道工点在环境上的影响同样也大大少于隧道完全都在现场施工的情况；如像空间的需求和施工运输，这两个问题就大大的缓和。
当然，这些优点的先决条件是有现成的可用于管段制造的适宜工地。
它必须满足一系列有关环境影响的条件。
在如荷兰这类人口密集的国家里，要找到合适的工地很不容易，而且很显然，一旦选定一可用位置，可多次使用就相当引人。
因此，隧道施工的总体规划是一个供讨论的普通主题。
两端的地下结构一座新隧道连结到原来既有的地下结构中去，往往实际上是取代一既有的跨越水域的设施，如轮渡或桥梁。
它也可为一既有隧道或桥梁的补充设施。
无论决定建造一新隧道的理由如何，它的位置将在很大程度上受到既有地下结构布置的制约，而且其施工设计也要满足现有交通运输只受最小程度干扰的要求。
这就意味着设计人员在隧道位置方面很少有选择的机会，因而不得不根据这一既定位置的条件和要求来修改隧道设计。
这一情形主要影响连接隧道本身的引道部分。
然而，因为引道由穿过含水地层的分段组成，就有可能要求用新的措施以控制引道建造基坑排水影响的范围。
引道沉埋隧道几乎总是位于沉积地带，在那里，隧道引道降到地下水位以下。
在其完成时，它们是不透水的结构，周围的地下水不能渗入，存在的仅是单纯结构性质的环境影响。
然而在施工期间，环境问题则起着重要的作用。
为了建造起结构物，必须开挖一施工基坑直至地下水位以下若干米的深处，传统施工方法要求在施工期中持续不断把水排干。
除非采取进一步的措施，否则排水势必降低周围地区的水位，而且会导致一系列不希望的后果。
沉陷将发生，周围楼房和建筑物的基础将受到影响，而且甚至深桩基础也将受到沉陷土体经磨擦传递至桩上的额外向下荷载。
由于沉陷而堤坝高程下沉，而且农业地区的排水水位将会受到影响。
还有可能造成一种性质完全不同的环境问题：施工区域内的泥土可能被污染。
在这种情况下，施工基坑的开挖就要求格外注意，而且如有可能，就要采用诸如将泥土与水混合后经管道水力输送的特别方法。
还必须有一个经批准能容纳被污染泥土的地方。
必须采取若干措施以防止由于抽、排水而造成被污染泥土迅速分布到大面积地面上。
在技术上，总是可能消除这些各种各样的影响。
然而，由于做起来极为复杂而且会花费大量资金和时间，因此，目前倾向于寻找尽最大可能在水下建造引道和隧道进口的方法。
最理想的是，排空施工基坑中的水应该是一排干整个引道又完全不影响周围地下水位的单项作业。
明显的结论就是尽可能将施工基坑设计成最终产品的一部分。
引道边墙可设计成像有不透水芯墙的堤坝，其形式有泥浆墙、塑料板围幕或是常见的钢钣桩墙。
对最后一种形式增加其挡土的功能，就可节省有价值的空间，而且可容易地达到在水下与不透水底板的连接。
底板可以用水下混凝土建成。
这种方法已发展到能控制其高程和表面平整，以致达到在引道完全排干以后，只需要较少的修整工作。
另一种方法是采用不透水的塑料板材，加镇重安放于水下以盖住基坑底部和边坡。
在荷兰，这种方法不仅用于隧道的引道，而且用于公络的凹槽段。
使用大面积的塑料板材，以泥土作镇重安放到水下，用在一主要公路交叉口起到了长期的良好效果，它表明此技术已经推广使用。
不久，荷兰的隧道引道可能会向人们展示有茂盛的绿色边坡，从而取代了灰色的混凝土竖墙。
引道也可在别处预制并以浮运构件的形式安装。
此种方法只需用疏浚船开挖沟槽而完全不必排水。
不过目前还没有能充分处理浮力作用和基础问题的适宜设计。
管段制造上述对地下水与引道开挖之间的关系的讨论大部分都可以同样的方式应用于制造管段临时场地的开挖。
昂贵的解决办法给工程带来不合理的负担。
而且，这个制造管段的场地必须多次被附近的开阔水域淹没并打开以使预制成的隧道管段运至船坞处以便为另一些管段让出地方。
很少会有足够大的地方可供一次制造所有的管段。
总之，由于选择制造管段船坞的位置不像选择隧道引道的位置那样要严格地用功能要求来决定，故选择制造管段船坞的位置具有可以灵活的优点。
因此，制造船坞也就可以允许使用传统的排水法，如果由于上面列出的理由认为不允许使用传统的排水法时，而船坞又不得不与周围地下水分隔开时，这种地方使用不透水塑料板法由于其费用低就具有明显的优点。
另一种不影响周围地下水位的排水方法是"抽水回灌法"此法乃将渗入基坑的水用泵排出，又用泵将这些水通过过滤井管回灌到水的来源区。
只要渗透速度不是太大而且可保持大致是个常数，这个排、灌时闭路循环就可以保持。
这个新的措施，现在正用在荷兰的一个扩大的引道施工坑，由于这个基坑又要作为制造管段的船坞故加以扩大。
基槽的建造沉埋隧道的构槽是用疏浚法开挖的。
在本文中，我们只强调用疏浚法开挖基槽的要求能达到极高的精确度，而且这个要求将决定最适合这一工作设备的类型。
鉴于严格的定位容差，最好采用锚定疏浚船或在定位桩上的疏浚设备。
不过，由于它们不能自由移动，就可能成为船只航运的障碍。
假如在浚挖区域有水流或浪潮的影响，浚挖的基槽就会成为水流携带或沿河底推移的沉积物的积存处。
如果基槽开挖后长期不放置管段，就会很快形成淤积。
在上述情况下，基槽开挖和隧道管段安装两工序的相隔时间必须越短越好，因而对这两道工序的安排都需格外准确，可以采用一种专门的设备于安装管段之前清理基槽。
在荷兰，这种操作目前已发展到用在东斯格尔迪特防风暴海浪堤坝的墩柱安装中达到很高精度。
疏浚搅起了河底沉积物，造成在一定时间一定区域的河水浑浊。
最终这些成为悬浮的细颗粒物质会散开并重新逐渐沉淀下来。
尽管这一过程对环境的影响有限，而且无害，但在一定范围内还是日益受到强烈的抨击。
如果要浚挖的泥土是已被污染的，事情就更为复杂化，因为在这种条件下，浚挖作业就会使污染扩散。
现在浚挖技术已发展到通过使用一种专门的汲泥头来消除这一影响。
采用从浮船上下悬帘幕将浚挖区域与周围完全隔开的方法也可减少污染扩散。
在这一方面的进一步发展目前大家都注意到，在荷兰大部分水道底部都含有被污染的沉积物已很明显，因而浚挖这些泥土必然要承担一些特别的环境要求。
当前，这些要求尚未统一形成，而是针对每一具体工程提出不同的要求。
希望这种拖延关键技术发展的混乱局面能迅速得以解决。
根据污染的类型和程度，可将被污染泥土分为1～4类。
对于浚挖泥土（包括浚挖过程中的工艺用水）的弃置都按分类受到严格的限制；尤其是3和4类泥土都必须与外界隔绝，而且在可能的情况下加以净化。
在鹿特丹地区，已建成了一座储放这些固体废物以及其它有害物质的中心堆集场。
此外，第4类浚挖弃土被放在临时的较小的堆集点，待其被净化后再转放至别的隔离存放处。
在没有这类设施的地方，就必须按浚挖工程建立这种堆放点。
这一措施很明显需要做大量的工作。
管段的运输和安装疏浚工作和对航运的阻碍都是管段运输和安装带来的环境问题。
要打开管段制船坞和加深船坞与安装点之间航道的浅水域就需要浚挖作业。
前面有关浚挖的一些论述也适用这一情况。
安装工序中有一特殊的方面有可能涉及隧道基槽的最后清理。
为了使清理和安装两工序间隔时间缩至最短，在管段安放到其最终位置底部回填砂之前已成功地采用了射水法清理隧道管段基底。
用强力射水把要清除的最后一层沉积物冲成悬浮物，随后被水流带走。
在管段离开制造船坞，锚泊在临时码头和离开临时码头，浮运至安装点以及安装期间都有可能阻碍航运。
只有最后一道工序才会造成航运在短期内临时完全中断或部分中断。
在这个方面，一座沉埋隧道穿过一条河流与穿过一条运河存在着差别。
在后一种情况下，由于没有水流影响，就使得在沉放和安装用可更好地控制管段。
这种控制上的有利，就允许沉埋管段隧道采用更长管段单元，但这必须有足够大的制造船坞。
所以在荷兰，以往绝大多数沉埋隧道的管段单元长度都在100～150m之间变化，在跨越阿姆斯特丹和海域间北海运河的赫姆隧道（Hemtunnel）工程中还用了长达268m的管段单元。
使用较长的管段单元减少了安装作业的次数，从而也就减缓了对航运的阻碍。
对于沉埋管段隧道工程来说，妨碍航运似乎很适合定为一环境问题，但并不是一个重大问题。
回填这道工序包括用砂回填管段基底部，回填塞槽，以及必要时于管段顶部建造一冲刷防护层。
回填材料必须是未被污染的。
作业船在隧道上面施工时将干扰航运。
不过，通过用安装在隧道管段内的设备进行部分作业，就能减少这类麻烦，譬如经穿过隧道底部的孔口泵送砂、水混合物来回填等。
这一系统已在荷兰成功地应用过。
运营和维修涉及隧道运营的主要环境问题是通风。
由于清洁隧道边墙和维修路面要阻碍车辆运行，它们必须在适宜的时间内快速进行。
平整光滑的壁面以及良好的表涂层有助于清洁作业，从而也减少了限制车辆通过隧道的时间。
路面的建造必须做到能尽可能减少日后的维修。
Buried tunnel project on the environmentAbstract: a deeply buried tunnel far-reaching impact on the environment through the waterways with the sinking pipe related. Under the tunnel on the mainland in the region and the impact of surface water in the tunnel design and construction method of choice to play the most important role. In considering the impact of the recent construction of a problem is the need to trench excavation for the tunnel may appear to be contaminated soil. And transporting the excavated soil up to the specialized equipment in order to receive their storage place is a series of important new technologies and quality control measures for environmental problems. The most common is in any construction project will encounter environmental problems, namely, noise, dust and traffic congestion. In this paper, these issues and the current technology to address these issues and measures are discussed.Key words: tunnel environmentCharacteristics of a Buried deeply buried tunnel tunnel has twofundamental characteristics: (1) It is part of an underground structure of the site, to ensure that heavy traffic conditions, construction, and does not mean that this area is full use of The. Therefore, the construction space is very valuable.Will eventually be installed in the location of the river or canal bottom section of tunnel is very close in other areas to build manufacturing plants, ways, and this condition is unlikely in the field and reached the site. The advantages of planning and construction of pipe manufacture and the site will be ready to separate from the logistical advantages are obvious, there are extremely easy to implement effective quality control advantages.Tunnel work site on the environmental impact is also considerably less than the construction of the tunnel fully all the circumstances at the scene; such as space requirements and construction of transport, these two issues is greatly easing.Of course, a prerequisite for these benefits is a ready-made for pipe suitable site. It must meet the conditions for a series of environmental impact. In the Netherlands such as densely populated countries, to find a suitable site is not easy, but it is clear that once selected an available position, can be used repeatedly for quite a draw a crowd. Therefore, the overall plan for the tunnel construction is a common topic for discussion.Both ends of the structure of a new underground tunnel link to the original structure to the existing underground, often in fact across the waters to replace an existing facility, such as ferry or bridge. It can also be a complement existing facilities in tunnels or bridges. Whether the decision to build a new tunnel the reason, its location will be in large part by the constraints of existing underground structure layout, and its construction design must also meet the existing transport only by the requirements of minimal interference. This means that the location in the tunnel area designers rarely have a choice, and thus havethe position according to the established conditions and requirements to modify the tunnel design.This situation mainly affects the approach roads connecting part of the tunnel itself. However, because the approach road through the water by the formation of sub-components, it may require new measures to control the approaches to the scope of the construction pit drainage impact.Buried Tunnel approach roads are almost always located in the deposition zone, where the tunnel approach road down to the groundwater level below. At its completion, they are impervious structure, the surrounding water can not penetrate, there's just the nature of the environmental impact of a simple structure.However, during construction, environmental issues will play an important role. To build from the structures, construction of foundation must be excavated until the water table following a number of meters deep, the traditional construction method requires the construction period in the continuous draining of the water. Unless further measures, or drainage will definitely lower the water level in the surrounding area, and will lead to a series of undesirable consequences. Subsidence will occur, based on the surrounding buildings and structures will be affected, and even deep pile foundation soil settlement will also be passed by the friction down to the pile on the extra load. Subsidence and elevation of the dam sinking, and agricultural drainage water will be affected.May also result in a completely different nature of environmental problems: the construction area may be contaminated soil. In this case, the construction of the excavation pit special attention to requirements and, if possible, should be used, such as soil mixed with water and water transport by pipeline, special methods. There must also be able to accommodate an approved place of contaminated soil.Number of measures must be taken to prevent the pumping of contaminated water caused by the rapid distribution of the soil to a large area on the ground.Technically speaking, is always possible to eliminate the impact of these kinds. However, it is extremely complex and do take a lot of moneyand time, therefore, tend to look at present the greatest extent possible the construction of approach roads and tunnels in the water imported methods. Ideally, the empty pit in the construction of a drainage of water should be no impact on the approach roads and the surrounding groundwater single operation.The obvious conclusion is that as far as possible the construction pit designed as part of the final product.Approach a wall can be designed to image the wall of the dam impervious core in the form of a slurry wall, curtain or plastic sheet of steel sheet pile walls common. On the final form (steel sheet pile wall) (off panel through the use of heavy anchor piles and soil) to increase its retaining function, you can save valuable space and can be easily achieved in the water and impermeable floor connection.Water under the concrete floor can be built. This approach has been developed to control the elevation and surface roughness, which completely drained to the approach road after finishing requires less work.Another method is the use of impermeable plastic sheet, add water to the town of emphasis placed on the bottom and cover the pit slope. In the Netherlands, this approach not only for the tunnel approaches, and the groove for the public network segment.Use large plastic sheet, to the soil to the water for the town re-placed by a major highway intersection in the play a long-term good results, it shows that this technology has been widely used. Soon, the Netherlands, the tunnel approach roads may be to show a lush green slope, thereby replacing the gray concrete vertical wall.Approach can also be prefabricated elsewhere and in the form of installation of floating structures. This method only with trench excavation and dredging vessels do not have to drain. But not yet able to adequately address basic problems of buoyancy and appropriate design. Buried tunnel project on the environmentPipe manufacturing approaches to the excavation of underground water and the discussion of the relationship between the way the majority can be used to produce the same pipe excavation of the temporary venues.Expensive solution to bring an unreasonable burden to the project. Moreover, the manufacture of pipe near the site have repeatedly flooded the open waters and open to the precast tunnel segments into the transportation to the dock at the other pipe section in order to make room. Rarely a large enough place for all of the pipe manufacturer.In short, the choice of the location of manufacturing pipe dock not chosen as the location of the tunnel approach roads to be strictly determined by functional requirements, so choose the location of manufacturing pipe dock with the advantages of flexibility. Therefore, the manufacture of docks will be allowed to use the traditional water method, if the reasons listed above that do not allow the use of traditional water law, and the dock had to separate from the surrounding water, this places impermeable plastic plate because of its low cost to have obvious advantages.Another does not affect the drainage around the water table is "pumping recharge Law" This law is the foundation of the water into the pump discharge and pump water through the filter of these tube wells to the water source recharge area. As long as the penetration rate is not too large and can be maintained roughly a constant, the row, when the closed-loop irrigation can be maintained. The new measures, now being expanded in the Netherlands approaches to the construction of a pit, but also because the foundation of the dock as the manufacture of pipe it to be expanded.Construction of foundation trench trough structure deeply buried tunnel excavation method is dredging. In this paper, we only stress the importance of dredging requirements of foundation trench excavation method can achieve high accuracy, and this requires that the work will determine the most suitable type of device. Given the strict positioning tolerances, preferably dredging boat anchor or pile in positioning the dredging equipment. However, because they can not move freely, it could become an obstacle to shipping vessels.If there is water in the dredging area, or the wave of the impact of dredging will become the base slot to carry water along the bottom or盐城工学院本科毕业生毕业设计说明书2010sediment accumulation over the place. If the foundation trench excavation in place pipe for long periods, it will soon form a deposition. In these circumstances, the base section of tank excavation and tunnel installation of the interval between the two processes must be as short as possible, and thus the arrangement of the two procedure are to be particularly accurate, you can use a special device to clean the base before the installation of pipe slot. In the Netherlands, this operation has been developed to be used in the East (Eastern Scheldt) anti-dam pier storm waves reach a very high precision installation.Dredging stir up the river sediments, resulting in a certain time a certain area of the water turbidity. Eventually become a suspended fine particles of these substances will spread out and gradually settle down again. Although this process had limited impact on the environment, and harmless, but in a certain range or the increasingly strong criticism.If you want to have dredged soil is contaminated, it is even more complicated, because in such conditions, the dredging operation will cause the spread of contamination. Dredging technology has now developed to the drain by using a special mud head to eliminate this effect. Under the floating boat by hanging curtains from the dredging area will be completely separated from the surrounding method may also reduce the spread of pollution.Further development in this regard we have taken note of the current, most waterways in the Netherlands contain contaminated bottom sediments have been very clear, so dredging the mud is bound to take some special environmental requirements.Currently, these requirements have not been unified to form, but made different for each specific project requirements. Hope that this delay in the development of key technologies of the chaos can be quickly resolved.According to the type and extent of contamination, contaminated soil can be divided into 1 to 4 classes. For dredging mud (including dredging process water in the process) and disposal are subject to strict restrictions by category; particular, 3 and 4 the soil must be isolated,- 11 -沉埋隧道工程对环境的影响and in possible to be purified.In the Rotterdam area, has built a store of these solid waste and other hazardous substances the center of the dump site. In addition, Type 4 is placed in temporary dredging spoil heap smaller point, let it be purified and then transferred to another isolated place repository. Place in the absence of such facilities to be established by dredging this dump sites. This measure is a clear need to do a lot of work.Transportation and installation of pipe work and dredging the shipping obstacles to transport and install pipe sections are brought about environmental problems. To open the pipe system and installation of marinas and docks to deepen the shallow waters between the points need to channel dredging operations. Some of the previous discussion about dredging also apply to this situation.The installation procedures in a particular area may involve the end of the tunnel-based clean-up slot. To make clean-up and installation of the two processes reduce to a minimum interval of time, placed in the pipe to its final position before the bottom of the sand filling has been successfully used to shoot clean water law section of the base tunnel. With a powerful water jet to remove the last layer of the sediment washed into the suspension, followed by water flow away.Left in the pipe manufacturing dock, anchored at the temporary terminal and leave the temporary pier, floating point and transported to the installation during installation are likely to hinder shipping. Only the last one caused by the shipping process will complete in the short term temporary interruption or partial interruption.In this respect, a deeply buried tunnel across a river and there are differences across a canal. In the latter case, the absence of flow effects to make the sinking and installation of pipe can be better controlled. The advantage of this control to allow the use of more deeply buried sections of the tunnel tube pipe unit, but it must be large enough to create dock.Therefore, in the Netherlands, in the past most deeply buried pipe unit length of the tunnel are varied between 100 ~ 150m, crossing the North- 12 -盐城工学院本科毕业生毕业设计说明书2010Sea Canal between Amsterdam and the Trondheim area tunnel (Hemtunnel) project has also used the unit for up to 268m of pipe . Use a longer pipe unit reduces the number of installation, which will slow down the barriers to shipping.Buried pipe for the tunnel project, it seems to impede the shipping for the environment as a problem, but not a major problem.This process includes filling with sand filling pipe at the base, back to the filling tank, and, if necessary in the pipe at the top of the construction of a scour protection layer.Backfill material must be uncontaminated. Ship in the tunnel construction work will interfere with the above shipping. However, by using a pipe installed in the tunnel were part of the operation of equipment, we can reduce such problems, for example, through the tunnel at the bottom of the holes by pumping sand and water mixture to backfilling. This system has been successfully applied in the Netherlands.Tunnel operation and maintenance operations involving major environmental issue is ventilation.Cleaning and maintenance of the tunnel wall to obstruct the road vehicle operation, they must be in the appropriate period of time quickly. Smooth wall and good coating helps to clean the operating table, thus reducing the time limit traffic through the tunnel.Road construction must be done to minimize future maintenance.- 13 -。