钢箱梁步履式顶推施工力学行为分析

Analysis of Mechanical Behavior of Steel BoxGirder Walking Jacking Construction

以广东省江门市一座在建斜拉-异形拱混合结构桥梁为研究背景,采用MIDAS/Civil建立有限元模型,模拟钢箱梁顶推施工过程,对顶推过程中钢箱梁、导梁的应力和变形以及顶推支墩受力情况进行分析,并绘制极值包络图;对最大支反力作用下关键部位的局部稳定性进行分析。结果表明:步履式顶推施工工艺能够满足钢箱梁的安装要求;导梁及钢箱梁的变形和最大应力均出现在工况四,即钢箱梁前端顶推至倒数第二个桥墩时,且均未超过控制限值;导梁和钢箱梁关键部位的局部稳定性满足规范要求。分析过程确保了钢箱梁顺利施工。

Based on the research background of a hybrid cable-stayed-special-shaped arch bridge under construction in Jiangmen City,Guangdong Province,MIDAS/Civil finite element model was established to simulate the construction process of steel box girder pusher.The stress and deformation of steel box girder and guide beam,the stress of the jacking piers during jacking process were analyzed,and the envelope diagram of extreme value is drawn.The local stability of key parts under the action of maximum support reaction is analyzed.The results show that the construction technology of walking type pushing can satisfy the installation of steel box girder.The deformation and maximum stress of the guide beam and the steel box beam and the maximum support reaction of the jacking pier all occur in the fourth working condition,that is,when the front end of the steel box beam is pushed to the penultimate pier,and they do not exceed the control limit.The local stability of the key parts of the guide beam and steel box beam meets the requirements of the code.The analysis process ensures the successful construction of the steel box grider.