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1、摘要本设计主要是关于预应力混凝土连续梁桥上部结构的设计。预应力混凝土连续梁桥以结构受力性好、变形小、伸缩缝少、行车平顺舒适、养护工程量小、抗震能力强等而成为最富有竞争力的主要桥型之一。设计桥梁跨度为30m+30m+30m+30m+30m,分为两幅设计,单幅为单箱单室,桥面总宽26m,双向4车道。主要采用现浇混凝土施工,按桥梁纵坡由低到高进行浇筑,一旦浇筑必须按每联连续浇筑,不得停歇。本桥设计分为双幅14联,按联施工。设计过程如下:首先,确定主梁主要构造及细部尺寸,它必须与桥梁的规定和施工保持一致,考虑到抗
2、弯刚度和抗扭刚度影响,设计采用箱型粱。主梁的高度呈成二次抛物线变化,因为二次抛物线近似于连续梁桥弯矩变化的曲线。其次,利用桥梁博士电子软件分析结构的总内力(包括恒载和活载的内力计算),用于计算内力组合结果也由桥梁博士电子软件计算而得,从而估算出纵向预应力筋的数目,然后再布置预应力钢丝束。再次,计算预应力损失及次内力,次内力包括先期恒载徐变次内力、先期预应力徐变次内力、后期合拢预应力索产生的弹性次内力、局部温度变化次内力。然后进一步进行截面强度验算,其中包括承载力极限状态和正常使用极限状态。在正常使用极限状
3、态验算中包括计算截面的混凝土法向应力验算、预应力钢筋中的拉应力验算、截面的主应力计算。最后,通过手算计算出桥面板及桥墩的形式及受力情况,最终整理成本桥设计的总体信息。关键词:预应力混凝土连续梁;后张法;现浇砼施工AbstractThegraduatedesignismainlyaboutthedesignofsuperstructureoflong-spanpre-stressedconcretecontinuousboxGirderBridge.Pre-stressedconcretecontinuou
4、sGirderBirdgebecomeoneofmainbridgetypesofthemostfullofcompletionabilitybecauseofsubjectingtothedintfunctionwiththestructuregood,havingthesmalldefomation,fewofcontroljoint,goingsmoothlycomfort,protectedtheamoutofengineeringsmallandhavingthepowerfullyabilit
5、yofcarthquakeproofandsoon.Fortimeandabilitylimited,thedesignofthesubstructure,transversepre-stressingandverticalpre-stressingisnotconsidered.Thespansofthebridgeare30m+30m+30m+30m+30mm,mainbeamisrespectivedesigned,eachsuithasoneboxoneroomandfourtrafficways
6、ofall,thewidthofthebridgesurfaceis26m.Themajorgirderappliescantileverhung-basketbearing,symmetricequilibriumconstruction.Thebridgedesignisdividedinto126unitsand48constructionsectionThedesignprocessisasfollows:First,makesurethemaingirderstructureofdetailsa
7、ndsize,itmustbewiththerulesandregulationsofthebridgeconstructionkeepsconsistent,consideringthebendingstiffnessandwrestresistanteffectstiffness,designUSESaboxbeams.Theheightofthemaingirderisintotwoparabolicchange,becausetwoparabolicapproximatecontinuousgir
8、derbridgebendingmomentthecurveofthechange.Secondly,theuseofbridgestructureanalysisofelectronicsoftwaredrtotalinternalforce(includingthedeadloadandliveloadofinternalforcecalculation),usedtocalculatethecombinationofin