部分斜拉桥施工力学性能分析

为了解多跨部分斜拉桥施工过程中结构力学性能的演变过程,从而对桥梁进行有效的施工控制,以开封黄河二桥主桥为例,采用有限元程序MIDAS Civil建立全桥有限元模型,进行施工过程仿真计算,分析其施工力学性能。分析结果表明,主梁成桥时压应力最大,次边跨初步和最终合龙对边塔塔底应力影响较大;中塔偏位较小,边塔在次边跨初步合龙阶段易产生较大纵向偏位;索力变化较小,可一次性张拉到位;桥梁整体稳定性较好;桥梁在各施工阶段的第1阶失稳均为桥塔面外反对称失稳。

Analysis of Mechanical Properties of Extradosed Bridge in Construction Process

To look into the development of structural mechanical properties of multi-span extradosed bridge in construction process,thus to carry out effective construction control of the bridge,the main bridge of the Second Kaifeng Huanghe River Bridge was taken as an example,the finite element program MIDAS Civil was used to set up the model for the whole bridge,the simulation calculation of the bridge in the construction process was made and the mechanical properties of the bridge were analyzed.The results of the calculation and analysis indicate that the compressive stress of the main girder reaches the greatest after completion of the bridge and the initial and final closure of the secondary side span has considerable influence on the stress in the side pylon base.The longitudinal displacement at the top of the middle pylon is little,but the top of the side pylon is prone to great longitudinal displacement at the stage of the initial closure of the secondary side span.The changing of stay cable forces is little and the cables can be tensioned in place in one time.The global stability of the whole bridge is good and at various construction stages,the first order instability of the bridge is all of the out-of-plane asymmetric instability of pylon.