高速铁路矮塔斜拉桥主梁局部受力行为分析

Local Analysis of the Main Girder of High-Speed Railway Low-pylon Cable-stayed Bridge

新建商丘至合肥至杭州铁路工程颍上特大桥在主梁斜拉索锚固区采用相比于隔板更为轻巧的横梁结构。针对这种新颖结构,为更好地了解其受力特性、优化构造细节,建立中支点至中跨跨中间的1/4主梁模型。模型考察主梁横梁局部应力,得到增设倒角可降低此处横向拉应力的结论。同时还关注腹板剪力分配,得到在无索区段中腹板承担较大剪力,有索区段相反的结论。最后通过索力作用下桥面板纵向应力分布模式,显示出索力在桥面板的传力路径,为结构局部优化、横向分析及结构配筋提供依据。

YinShang low-pylon cable-stayed bridge of Shangqiu-Hefei-Hangzhou railway Project uses thecrossbeam instead of the diaphragm to make the main beam lighter. Aiming at this new structure, a 1/4 main beam solid finite element model between medium support and middle stride is builtto better understand the mechanical characteristics and optimize structure details. The finite element model is employed to investigate the local stress of the crossbeam and the conclusion is reached that the chamfer can reduce transverse tension stress. The shearing force of the web plate is also addressed with the finding that the shearing force of the medium web in the section without cable is larger and the opposite is true in the section with cable. Finally, the path of cable force transferred on the deck is identified by the distribution of longitudinal stress under cable forces, which may provide reference for local structure optimization and the horizontal analysis as well as the design of reinforcement.