大跨度连续钢系杆拱桥顶推施工临时结构优化设计

Optimum Design of Temporary Structures During Incremental Launching Construction of Long-span Continuous Steel Arch Bridge

以淮南孔李淮河大桥顶推施工为工程背景,对步履式顶推施工中的临时结构设计进行研究分析。应用有限元软件MIDAS建立有限元模型,对临时墩及墩旁托架的力学性能进行计算和分析,给出最优的临时墩布置方案;在该方案基础上建立有限元全桥模型,对步履式顶推施工过程进行仿真模拟,优化导梁长度及结构形式;在最优的临时墩布置及最佳导梁结构的基础上,结合现场实测结果,探究梁拱之间不同的临时撑杆结构形式对主桥及撑杆自身的影响。结果表明:针对淮南孔李淮河大桥顶推施工,临时墩布置宜采用方案2;选用45 m的钢箱梁时结构受力与变形最理想;在梁拱之间设置临时A撑可有效提高整体结构承载能力。

According to the experimental condition of Kongli Huai River bridge, the temporary structures during incremental launching construction are designed and optimized. Finite element software MIDAS is adopted to calculate and analyze the mechanical properties of temporary pier system, and then the best layout scheme of the temporary piers is proposed. Based on this layout scheme, the full-bridge finite-element model is developed to simulate the walking pile launching process. Length and structure form of the launching nose is optimized as well. Finally, the impacts of different strut structure form on itself and the whole bridge are discussed. The calculation results show that the second scheme fits best with the experimental condition of Kongli Huai River bridge. A 45 metres-long launching nose consists of steel box girder has minimum force and deformation. The struts can improve the structure strength during incremental launching construction.