现浇预应力混凝土连续箱梁桥的施

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1、现浇预应力混凝土连续箱梁桥的施工1.工程概况桐寨铺互通A匝道桥（AK0+605.496匝道桥）全长256m，上部采用4*20+(20+2*25+20)+4*20m跨径组合，其中第二联为三室等截面预应力混凝土箱形连续梁，第一、三联为三室等截面钢筋混凝土箱形连续梁，梁宽15.5m，梁高1.3m。2.支架施工2.1支架基础桥下地表平坦，承台基坑采用灰土分层夯实填筑后，在支架搭设范围内填筑不小于50㎝厚的灰土，然后浇筑10㎝厚的砼基础。2.2支架塔设上部箱梁施工采用（碗扣式）钢管支架作为支撑，承重部分由纵向和横向的工字钢组成，组合钢管支架采用工字钢联成

2、整体，横向设剪力撑，使其连成一体。根据支架实际的纵向和横向间距布设，考虑施工的恒载，活载计算支架的承载力，验算其稳定性。2.3支架预拱度设计与拱度计算公式为f=f1+f2+f3，其中f1:地基弹性变形，f2:支架弹性变形，f3：梁体挠度。f2=σL/E计算，f3根据施工经验取20m跨径为2cm，25m跨径为2.5cm。预拱度最大值设置在梁的跨中位置，并按抛物线形成进行分配，算得各点处的预拱度值后，通过支架上的砂筒对底模进行调整。25Cr-13Nitypeoraweldingmaterialwithhighnickelcontent.Lowtem

3、peraturesteels,austeniticstainlesssteelandheat-resistantcorrosion-resistanthighalloysteelsandausteniticandnon-austenitedissimilarsteelweldedjointsshallcomplywiththefollowingrequirements:toensurepenetrationandfusionundergoodconditions,lowcurrent,short-arc,weldingspeedandmuchf

4、asterweldingprocessandinterpasstemperatureshouldbecontrolled.Highcorrosionresistanceperformanceofdouble-sidedweldedwelds,weldedlayerincontactwithcorrosivemediafinallywelded.Lowtemperaturesteelwelding,suitableforthesurfaceoftheweldbeadannealing.Check6.6.16.6weldinginspectionb

5、eforeweldingmaterialandweldingmaterials,mustbecarriedoutaccordingtostandardacceptance,unqualifiedpersonsmaybeused.Groupbeforethedimensionsofvariouspartsofthemainstructure,Groovesizes,andgroovedsurfaceforinspection.WeldingGrooveandGrooveonbothsidesshouldbecheckedbeforetheclea

6、ningquality.Checktheweldingbeforeweldingconditionsareconsistentwiththeprescribedconditions,andweldingequipment.Thedryingandcleaningofweldingmaterialstoconfirmthatitmeetstherequirements.6.6.2intermediateweldinginspectiontackweldingaftertheskullshouldbeclearedcheckstoweldingth

7、edefectsfoundshallberemovedbeforetheycan.Multi-layerweldingweldingaftertheeachfloorshouldimmediatelycleanthelayers,andVisualinspection,founddefectsinweldedtoeliminatebeforetheycanproceedtothenextlevel.Tointerrupttheweldingseam,shouldbecleanedandcheckedbeforecontinuingtoweldt

8、oeliminateweldingdefectsfoundbytherear.6.6.3checkafterweldingseamsshallbewe