池黄高铁三塔矮塔斜拉桥设计关键技术研究

Research on the Key Techniques for Design of Three-tower Extradosed Cable-stayed Bridge on Chizhou-Huangshan High-speed Railway

研究目的:矮塔斜拉桥具有结构刚度大、施工方便、经济性好、造型美观等优点,近年来在铁路桥梁中得到广泛使用。本文以池黄高铁大跨度三塔矮塔斜拉桥为背景,针对高速铁路桥梁特点,就结构体系、合理结构参数、斜拉索张拉方案等关键技术进行分析研究。研究结论:(1)高速铁路多塔矮塔斜拉桥结构体系选择的关键是既保证变形控制,同时减少温度力以及混凝土收缩徐变产生次内力的不利影响,采用刚构连续梁体系,辅以外伸跨,可以有效减小下部结构受力,同时满足刚度要求,结构经济合理;(2)边跨跨度和外伸跨跨度对主梁变形影响较小,塔高和无索区长度对主梁残余徐变变形影响较大;(3)斜拉索采用悬臂阶段和合龙后两次张拉,且二次张拉拉索在施工二恒之前,可有效控制主梁残余徐变变形;(4)本研究结论可为今后同类型桥梁设计提供参考。

Research purposes: Extradosed cable-stayed bridges have the advantages of high structural stiffness,convenient construction,good economics,and attractive appearance,which have been widely used in railway bridges in recent years. This paper takes the long-span three-tower extradosed cable-stayed bridge on Chizhou-Huangshan high-speed railway as the background,and studies key techniques such as the structural system,reasonable structural parameters,and stay cable tensioning schemes for the characteristics of high-speed railway bridges.Research conclusions:( 1) The key to selecting a structural system of a high-speed railway multi-tower extradosed cable-stayed bridge is to not only ensure the deformation control,but also reduce the adverse effects of secondary forces caused by temperature forces and concrete shrinkage and creep. Adopting a rigid-continuous girder system,supplemented with an outstretched span,can effectively reduce the stress on the substructure,meet the rigidity requirements,and the structure is economical and reasonable.( 2) Side span and outstretched span have little effect on the deformation of the beam. The height of the tower and the length of the cable-free zone have a great impact on the residual creep deformation of the main beam.( 3) The stay cable is tensioned twice after the cantilever stage and the full bridge closure,and the stay cable is tensioned for the second time before the secondary dead load,the residual creep deformation of the beam can be effectively controlled.( 4) The research conclusion can provide reference for the similar bridge in the future.