孟州黄河公路大桥组合梁整孔架设受力分析

孟州黄河公路大桥主桥为19孔80 m钢-混组合梁桥,组合梁由单箱单室槽形钢梁与预制桥面板通过焊钉结合而成,针对该桥特点,提出采用架桥机安装整孔钢梁,并在桥面板与钢梁结合前采用架桥机对钢梁施加吊拉力的方法施工。为验证该施工方案的可行性和实施效果,开展了施工阶段的受力分析和实桥试验。结果表明:利用架桥机在桥面板与钢梁结合前施加吊拉力,能大幅降低钢梁应力,同时增加跨中区域桥面板的压应力储备;考虑架桥机和钢-混组合梁一体化设计时,架桥机对该桥施加的吊拉力最优值取1300 kN;除个别测点误差较大外,各施工阶段应力和挠度实测值与理论计算值基本吻合,趋势一致,且整孔架设钢梁具有预制化程度高、作业效率高等优点。

Analysis of Load Bearing Behavior of Composite Girder of Mengzhou Huanghe River Highway Bridge Erected by Full-Span Method

The main bridge of Mengzhou Huanghe River Highway Bridge is a steel-concrete composite girder bridge consisting of 19 spans of 80 m.Steel trough girders and precast prestressed concrete slabs that form the superstructure are connected by shear studs.To suit the characteristics of the bridge,a full-span erection of steel girders using gantry crane was proposed,and before the connection of the steel girders and the deck slabs,the steel girders were applied with lifting tension by the gantry crane.The load bearing behavior of the girders during construction was analyzed and field test was conducted,to verify the applicability and efficiency of the construction method.The results show that with the lifting tension applied by the gantry crane,the stresses in the steel girders were greatly reduced,and the compressive stresses in the midspan deck slabs were increased.The lifting tension was set at 1300 kN,considering the existence of optimum values during the integral design of the gantry crane and the steel-concrete composite girder.Except for the measurement points with great errors,the measured stresses and deflections in the construction stage were in good agreement with the theoretical values,with constant trend.In the full-span construction,the prefabrication degree of the components as well as construction efficiency is high.