摘要毕业设计主要是关于小跨度预应力混凝土简支箱梁桥上部结构的设计。预应力混凝土简支箱梁桥以结构受力性能好、变形小、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。受时间和个人能力的限制，本次毕业设计没有具体涉及到下部结构。设计桥梁标准跨度为40m,横向布置4片箱梁，桥面宽为13m，设计车道数为3车道。基础形式采用钻孔灌注桩。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，考虑到抗弯刚度及抗扭刚度的影响，设计采用箱形梁。顶板厚度沿全桥不变为0.18m,底板厚度在跨中为0.18m，端部为0.25m。其次，计算桥梁结构总的内力(包括恒载和活载的内力计算)。然后进行内力组合，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，计算后张法中各个阶段的预应力损失。最后进一步进行截面强度的验算，其中包括承载能力极限状态和正常使用极限状态。在正常使用极限状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，预应力阶段和使用阶段主梁截面的强度和变形验算、锚固区局部强度验算和挠度的计算。设计最后结合本桥的特点编制施工方案，主要包括上部结构施工，下部结构基础和墩身的施工工艺等。关键词预应力混凝土简支箱梁桥、预应力损失、施工方案ABSTRACTGraduationismainlyonsmall-spanprestressedconcreteboxgirderbridgestructuredesign.Prestressedconcreteboxgirderbridgewithgoodmechanicalpropertiesofthestructure,deformationissmall,thedrivingcomfortcomfortable,asmallamountofmaintenanceengineering,seismicandstrongabilitytobecomethemostcompetitiveoneofthemainbridge.Andpersonalcapacitybythetimeconstraints,thisgraduationdesignisnotspecificallyrelatedtothelowerpartofthestructure.symmetricalSpanbridgedesignstandardsforthe40m,transversestandardspanbridgefourpieces,bridgethewidthof13m,designforthreelaneslanenumber.symmetricalbalancepouringconcrete.Designprocessisasfollows：First,thebeamsofthemainstructureandthesize,itmustcorrespondwiththeprovisionsofthebridgeandworkingtogethertoresistandstiffnessandtoturnthestiffnessofthedesignadoptstheboxgirder.Thethicknessofthewholebridgeis0.18m,floorthicknessinthecrossfor0.18m,endsfor0.25m.Thesecondstepistoanalyzeinternalgrossforceofthestructures(includingdeadloadandlivedload),theinternalforcecompositioncanbedonebyusingthecomputeresults.Accordingtotheinternalforcecomposited,theevaluatedamountoflongitudinaltendonscanbeworkedout,thenwecandistributethetendonstothebridge.Again,afterthecalculationofthelawofthestagesinprestressed.Thelaststepsischeckingthemaincrosssection.theworkincludestheload-caringcapacityultimatestateandthenormalserviceabilityultimatestateaswellasthemainsection,sbeingoutofshape.Prestressedandusesthestageofthebeamintensityofthesectionalandotheraddend,fixingthelocalstrengthandtheaddendelements.Thisdesignisalladesigndrawingacomputer-aideddesigningdrawupdocuments,typesetting,acomputerandprintoutthepapers.KeyWordsPrestressedconcreteboxgirderbridge；prestressloss；Constructionscheme目录摘要......................................................................1ABSTRACT...................................................................2第一部分预应力混凝土箱形梁桥设计.........................................1一、工程概况...........................................................1二、方案比选...........................................................11.桥梁设计原则......................................................12.各种桥梁的特点....................................................23.方案比选.................
