中文摘要：

为了给大节段钢箱梁的制造及整孔吊装施工控制提供技术依据,针对温度梯度变化对等跨径等截面连续钢箱梁制作及架设过程中由于线形变化而引起的匹配焊接的问题,以港珠澳大桥工程中深水区非通航孔桥的钢箱梁桥为研究背景,选取海中等宽段桥梁的大节段钢箱梁进行研究。采用有限元程序MIDAS/Civil建立了大节段钢箱梁的空间梁单元数值模型,依据桥位区实测钢箱梁结构竖向温度变化规律,拟合了温度梯度曲线模式,研究了不同竖向温度梯度温差模式对大节段钢箱梁架设时焊接端口的梁端正、负夹角的影响规律及修正方法;探讨了借助温度梯度对梁端夹角的影响,不采用额外调整措施的最佳焊接时机。研究结果表明：竖向温度梯度对大节段焊接合龙部位两节段间的梁端夹角有显著影响,无论采用规范温度模式还是实测拟合温度模式,产生的梁端夹角均有数值过大而影响焊接工作正常进行的可能;温度梯度产生的梁端夹角,既可通过钢箱梁制造时预留空间,焊接时根据现场温差进行配切消除,亦可选择最佳焊接时机消除温度梯度对梁端夹角的影响,直接完成焊接;不同钢箱梁大节段应选择在不同的顶、底板温差时段进行焊接;研究成果成功地指导了港珠澳大桥钢箱梁制作、吊装施工。

英文摘要：

To provide technical basis for prefabrication and integral hoisting construction control of large segment steel box girder,aimed at the problem of matching welding leaded erection line change which is influenced by temperature variation in production and construction process of continuous steel box girder with equal span and section,box girder bridge with non-navigable spans of Hong Kong-Zhuhai-Macao Bridge over deep water was used as background and the large segment girder with equal-width bridge in the middle of sea was selected and investigated.Finite element program MIDAS/Civil was used to establish the spatial beam element numerical model oflarge sections of bridge steel box girder.According to the vertical temperature variation of steel box girder measured in situ,temperature gradient model was fitted.The influence law and correction method of different modes of vertical temperature gradient on positive and negative angles of welding port were investigated in construction process.The best welding time without extra adjustment measures were also discussed with the help of the influence of temperature gradient on the angles of beam end.The results show that,angles of beam end caused by temperature gradient lead to remarkable influences on the section between two welding parts in closure segments zone.No matter in standard temperature mode or measured fitting temperature model,the angles of beam end caused by temperature gradient may be too big which affects the normal welding work.The angles of beam end can be eliminated by cutting steel box girder in situ according to the temperature distribution,which is reserved in production process.The best welding time also can be selected to eliminate the influence of temperature gradient on the angles of beam end for direct welding.Different welding temperature ranges of top steel box girder and bottom steel box girder should be taken for different segments.The research results effectively guide the steel box girder fabrication and hoisting construction of Hong Kong-Z