桥梁设计外文翻译---桥梁工程的发展概况.docx

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1、桥梁设计外文翻译-桥梁工程的发展概况 装订线 附录：外文翻译 Evolvement of bridge Engineering,brief review Among the early documented reviews of construction materials and structure types are the books of Marcus Vitruvios Pollio in the first century B.C.The basic principles of statics were developed by the Greeks , and were exem

2、plified in works and applications by Leonardo da Vinci,Cardeno,and Galileo.In the fifteenth and sixteenth century, engineers seemed to be unaware of this record , and relied solely on experience and tradition for building bridges and aqueducts .The state of the art changed rapidly toward the end of

3、the seventeenth century when Leibnitz, Newton, and Bernoulli introduced mathematical formulations. Published works by Lahire (1695)and Belidor (1792) about the theoretical analysis of structures provided the basis in the field of mechanics of materials . Kuzmanovic(1977) focuses on stone and wood as

4、 the first bridge-building materials. Iron was introduced during the transitional period from wood to steel .According to recent records , concrete was used in France as early as 1840 for a bridge 39 feet (12 m) long to span the Garoyne Canal at Grisoles, but reinforced concrete was not introduced i

5、n bridge construction until the beginning of this century . Prestressed concrete was first used in 1927. Stone bridges of the arch type (integrated superstructure and substructure) were constructed in Rome and other European cities in the middle ages . These arches were half-circular , with flat arc

6、hes beginning to dominate bridge work during the Renaissance period. This concept was markedly improved at the end of the eighteenth century and found structurally adequate to accommodate future railroad loads . In terms of analysis and use of materials , stone bridges have not changed much ,but the

7、 theoretical treatment was improved by introducing the pressure-line concept in the early 1670s(Lahire, 1695) . The arch theory was documented in model tests where typical failure modes were considered (Frezier,1739).Culmann(1851) introduced the elastic center method for fixed-end arches, and showed

8、 that three redundant parameters can be found by the use of three equations of coMPatibility. Wooden trusses were used in bridges during the sixteenth century when Palladio built triangular frames for bridge spans 10 feet long . This effort also focused on the three basic principles og bridge design

9、 : convenience(serviceability) ,appearance , and endurance(strength) . several timber truss bridges were constructed in western Europe beginning in the 1750s with spans up to 200 feet (61m) supported on stone 装订线substructures .Significant progress was possible in the United States and Russia during

10、the nineteenth century ,prompted by the need to cross major rivers and by an abundance of suitable timber . Favorable economic considerations included initial low cost and fast construction . The transition from wooden bridges to steel types probably did not begin until about 1840 ,although the firs

11、t documented use of iron in bridges was the chain bridge built in 1734 across the Oder River in Prussia . The first truss completely made of iron was in 1840 in the United States , followed by England in 1845 , Germany in 1853 , and Russia in 1857 . In 1840 , the first iron arch truss bridge was bui

12、lt across the Erie Canal at Utica . The Impetus of Analysis The theory of structures The theory of structures ,developed mainly in the ninetheenth century,focused on truss analysis, with the first book on bridges written in 1811. The Warren triangular truss was introduced in 1846 , supplemented by a

13、 method for calculating the correcet forces .I-beams fabricated from plates became popular in England and were used in short-span bridges. In 1866, Culmann explained the principles of cantilever truss bridges, and one year later the first cantilever bridge was built across the Main River in Hassfurt

14、, Germany, with a center span of 425 feet (130m) . The first cantilever bridge in the United States was built in 1875 across the Kentucky River.A most impressive railway cantilever bridge in the nineteenth century was the First of Forth bridge , built between 1883 and 1893 , with span magnitudes of

15、1711 feet (521.5m). At about the same time , structural steel was introduced as a prime material in bridge work , although its quality was often poor . Several early examples are the Eads bridge in St.Louis ; the Brooklyn bridge in New York ; and the Glasgow bridge in Missouri , all completed betwee

16、n 1874 and 1883. Among the analytical and design progress to be mentioned are the contributions of Maxwell , particularly for certain statically indeterminate trusses ; the books by Cremona (1872) on graphical statics; the force method redefined by Mohr; and the works by Clapeyron who introduced the

17、 three-moment equations. The Impetus of New Materials Since the beginning of the twentieth century , concrete has taken its place as one of the most useful and important structural materials . Because of the coMParative ease with which it can be molded into any desired shape , its structural uses ar

18、e almost 装订线unlimited . Wherever Portland cement and suitable aggregates are available , it can replace other materials for certain types of structures, such as bridge substructure and foundation elements . In addition , the introduction of reinforced concrete in multispan frames at the beginning of

19、 this century imposed new analytical requirements . Structures of a high order of redundancy could not be analyzed with the classical methods of the nineteenth century .The importance of joint rotation was already demonstrated by Manderla (1880) and Bendixen (1914) , who developed relationships betw

20、een joint moments and angular rotations from which the unknown moments can be obtained ,the so called slope-deflection method .More simplifications in frame analysis were made possible by the work of Calisev (1923) , who used successive approximations to reduce the system of equations to one simple

21、expression for each iteration step . This approach was further refined and integrated by Cross (1930) in what is known as the method of moment distribution . One of the most import important recent developments in the area of analytical procedures is the extension of design to cover the elastic-plas

22、tic range , also known as load factor or ultimate design. Plastic analysis was introduced with some practical observations by Tresca (1846) ; and was formulated by Saint-Venant (1870) , The concept of plasticity attracted researchers and engineers after World War , mainly in Germany , with the cente

23、r of activity shifting to England and the United States after World War .The probabilistic approach is a new design concept that is expected to replace the classical deterministic methodology. A main step forward was the 1969 addition of the Federal Highway Adiministration (FHWA)”Criteria for Reinfo

24、rced Concrete Bridge Members “ that covers strength and serviceability at ultimate design . This was prepared for use in conjunction with the 1969 American Association of State Highway Offficials (AASHO) Standard Specification, and was presented in a format that is readily adaptable to the developme

25、nt of ultimate design specifications .According to this document , the proportioning of reinforced concrete members ( including columns ) may be limited by various stages of behavior : elastic , cracked , and ultimate . Design axial loads , or design shears . Structural capacity is the reaction phas

26、e , and all calculated modified strength values derived from theoretical strengths are the capacity values , such as moment capacity ,axial load capacity ,or shear capacity .At serviceability states , investigations may also be necessary for deflections , maximum crack width , and fatigue . Bridge T

27、ypes 装订线 A notable bridge type is the suspension bridge , with the first example built in the United States in 1796. Problems of dynamic stability were investigated after the Tacoma bridge collapse , and this work led to significant theoretical contributions Steinman ( 1929 ) summarizes about 250 su

28、spension bridges built throughout the world between 1741 and 1928 . With the introduction of the interstate system and the need to provide structures at grade separations , certain bridge types have taken a strong place in bridge practice. These include concrete superstructures (slab ,T-beams,concre

29、te box girders ), steel beam and plate girders , steel box girders , composite construction , orthotropic plates , segmental construction , curved girders ,and cable-stayed bridges . Prefabricated members are given serious consideration , while interest in box sections remains strong . LOADS AND LOA

30、DING GROUPS The loads to be considered in the design of substructures and bridge foundations include loads and forces transmitted from the superstructure, and those acting directly on the substructure and foundation . AASHTO loads . Section 3 of AASHTO specifications summarizes the loads and forces

31、to be considered in the design of bridges (superstructure and substructure ) . Briefly , these are dead load ,live load , iMPact or dynamic effect of live load , wind load , and other forces such as longitudinal forces , centrifugal force ,thermal forces , earth pressure , buoyancy , shrinkage and l

32、ong term creep , rib shortening , erection stresses , ice and current pressure , collision force , and earthquake stresses .Besides these conventional loads that are generally quantified , AASHTO also recognizes indirect load effects such as friction at expansion bearings and stresses associated wit

33、h differential settlement of bridge components .The LRFD specifications divide loads into two distinct categories : permanent and transient . Permanent loads Dead Load : this includes the weight DC of all bridge components , appurtenances and utilities, wearing surface DW and future overlays , and e

34、arth fill EV. Both AASHTO and LRFD specifications give tables summarizing the unit weights of materials commonly used in bridge work . Transient Loads Vehicular Live Load (LL) Vehicle loading for short-span bridges :considerable effort has been made in the United States and Canada to develop a live

35、load model that can represent the highway 装订线loading more realistically than the H or the HS AASHTO models . The current AASHTO model is still the applicable loading. SizeEffectsandtheDynamicResponseofPlain Concrete Inthelastcoupleofdecades,therehaveb eennumerousreportsBa?ant1984;Carpinter i andChia

36、ia1997;Karihaloo 1999;Jenq andShah1985 aboutthespecimen sizeeffectsinquasi-brittle materials. Forthesematerials, Ba?antstatesthatthesourceofthe sizeeffectisamismatchbetweenthesizedependence ofthe energyreleaserateandtherateofener gyconsumedbyfractureBa?ant2000 .Whereasasignif icantportionoftheformer

37、in- creasesasthesquareofthespecimen size,thelatterincreases linearly. Thus,thereductioninthenominalstressisseenasa meansofcompensating forthisvariancebyreducingtheenergy releaserateofthespecimen.Unlikewithquasi-staticloading,thestudyofspecimensizeeffec tsinthedynamic domainhasnotreceived muchattenti

38、on. Suchattemptsareconfinedlargelytofiber-reinforcedpolymers Morton1998;Qianetal.1990;Liuetal.1998;Han1998.The datawithrespecttocement-basedmaterialsisextremelyscarceBa?antandGettu1992;Oh andChung1988;Krauthammeretal.2022;Elfahaletal.2022;BanthiaandBindiganavile 2022 and attentiontowardsimpactratesi

39、sveryrecent. Alackofdesign codesorevenastandardmethodforlaboratorytestinghinders ourabilitytocharacterize buildingmaterialsforconstructing impactandblastresistantfacilities.Moreover, impacttestingin- troducesseveralextraneousinfluencessuchastheinertiaBanthia etal.1987andtestmachineeffectsBanthiaandB

40、indiganavile2022.Perhapsthemostseriousi mpedimentis theinherentstress- ratesensitivityofcement-basedcomposites.Mortonstatesthatit isnotpossible toproduce anexactscalemodelforrate-sensitive materialsMorton1998.Further,thesuitabilityofknownscaling modelsunder dynamicrates isstillunder scrutiny.Inthisc

41、ontext, aspecialemphasismustbeassignedtoexplaining theissuesof scalingforcement-basedmaterialsunderhighstressrates. In thispaper,the sizeeffecton the impactresponseof concrete ispresentedthroughanassessment ofrecentlypublisheddataby thewritersandothers.Familiarscalinglawsdeveloped forquasi- staticlo

42、adingareexaminedinthecontextofdynamicstress rates. Thispaperdiscusses theinterplay betweenthespecimen size, matrixstrength,stressratesensitivity,andloadingconfiguration. 装订线 ScalingLawsforQuasi-BrittleSystems Itiswellknownthatthequasi-staticresponseofplainconcrete isaffectedbythesizeofthespecimen. E

43、videncegatheredover decadesrevealsastrongdependence onsizeforstructuralcon- cretebehaviorundercompressionSabnisandMirza1979,ten- sionBa?antetal.1991;vanMiera ndvanVliet2022,flexureW right1952;Ba?antandLi1995;Ju eshiandHui1997,shearBa?antandSun1987,andtorsion Zhouetal.1998.Three approachesdominatethe

44、studyofsizeeffectsinquasi-brittle ma- terialsBa?antandChen1997: 1. Thestatisticaltheoryofrandomstrength; 2. Thetheoryofstressredistributionandfractureenergyrelease causedbylargecracks;and 3. Thetheoryofcrackfractality. Ba?antsSizeEffectLawBa?ant1984 According toBa?ant,thesizee ffectinsolidsisasmooth

45、transi- tionfromthestrengthcriterionofplasticityapplicabletosmall sizespecimens tothecracksizedependenceoflinearelastic fracturemechanicsLEFM asseeninmuchlargerspecimens. Thefailurestressofaseriesofgeometricallysimilarspecimens ofconcreteisdescribedbythefollowinginfiniteseries: 122 12 N = Bf(+ 1 + A

46、 +A+ .) = d/d t - Multifractal ScalingLawCarpinteri andChiaia1997 Carpinteriand his associatesused the concept of self-similar morphologies withnonintegerdimensionscalledfractalstode- scribethemicrostructure ofquasi-brittlematerialssuchascon- crete.With anincreaseinthescale ofobservation,thetopologi

47、cal fractalityisthoughttovanish. 装订线 Asthemicrostructureofahetero- geneousmaterialremainsthesameregardless ofsize,theypro- posedthattheinfluence ofmacroscopicsizeonthemechanical propertieswasaresult oftheinteractionbetweenthedimension b andacharacteristiclength l ch forthespecimen.Onthebasisof thishypothesis,thefollowingmultifractalscalinglawMFSLwasproposed: 1/2 (1)ch u t l f b =+ where f t=asymptoticvalueofthenominalstrength u atinfinite sizes. AsopposedtoBSEL,MFSLappearstosuitunnotched speci