某大跨度悬索桥桥塔施工过程数值模拟分析

Numerical simulation analysis of construction process of a suspension bridge tower

某两塔单跨钢桁梁悬索桥,其桥塔为牌楼造型门式框架结构,塔柱施工采用液压爬模施工,下横梁采用支架现浇法施工,在工序上采用"先塔后梁"的异步施工方法。为确保桥塔在施工过程安全、合理,采用有限元软件MIDAS/Civil建立桥塔有限元模型,对桥塔施工过程进行模拟分析。结果表明:在桥塔施工过程中,塔底截面未出现名义拉应力,预应力的张拉、支架的拆除以及主动横撑的设置都会对塔柱受力有较大的影响;塔柱施工过程中3道临时主动横撑减小了斜塔柱根部混凝土开裂的可能,保证塔柱与横梁异步施工过程中塔柱的线形和应力满足设计与施工要求。

The pylon of a two-story single-span steel truss suspension bridge is a archway gantry frame structure. The tower column construction adopts hydraulic climbing formwork construction,the lower beam is constructed by bracket castin-place method,and the asynchronous construction method of'first tower back beam'is adopted in the process. In order to ensure the safety and reasonableness of the construction process,the finite element model of the pylon was established by the finite element software MIDAS/Civil,and the construction process of the pylon was simulated. The results show that during the construction of the pylon,the prestressed tension,the removal of the bracket and the setting of the active bracing will have a great influence on the force of the tower column;the nominal tensile stress does not appear in the bottom section of the whole construction process. The three temporary active cross braces during the construction of the tower column reduce the possibility of concrete cracking at the root of the inclined tower column,and ensure that the line shape and stress of the tower column meet the design and construction requirements during the asynchronous construction process of the tower column and the beam.