八里湖大桥主梁施工模拟分析

Simulation Analysis of Construction of Main Girder of Bali Lake Bridge

八里湖大桥主桥为主跨132m的三塔部分斜拉桥,主梁采用C55混凝土双箱式边主梁型式(设纵、横向预应力),采用支架现浇法施工。先浇筑箱梁,然后挂设斜拉索(张拉20%索力),再张拉箱梁横向预应力。为了验证施工工序的合理性,利用ANSYS有限元程序建立16号墩两侧支架模型,模拟其施工过程,分析了横向预应力张拉和斜拉索挂设施工对支架钢管桩反力和箱梁应力的影响。结果表明,钢管桩反力和箱梁应力均满足规范要求,施工工序合理。

The main bridge of Bali Lake Bridge is a 3-pylon extradosed bridge with the main spans each being 132 m. The main girder of the bridge employed the C55 concrete double-box edge girders （provided with the longitudinal and transverse prestress） and was constructed on scaffoldings by the in-situ casting method. The concrete of the box girders was cast first, the stay cables were then installed （20% cable force was tensioned） and finally the transverse prestress of the girders was tensioned. To verify the rationality of the construction sequences of the bridge, the finite element program ANSYS was used to set up the model for the scaffoldings at both sides of Pier No. 16 and to simulate the construction process. The influences of the transverse prestress tensioning and the stay cable installing on the reaction forces of steel pipe piles of the scaffoldings and on the stress of the girders were analyzed. The results of the analysis prove that the reaction forces of the steel pipe piles and the stress of the girders can all satisfy the relevant requirements in the codes and the construction sequences are rational.