湛河斜靠式拱桥考虑吊杆破断时的稳定性能分析

Stability analysis of the Zhanhe double X-arch bridge considering suspender fracture

以跨越平顶山市湛河的斜靠式拱桥为工程实例,采用有限元程序MIDAS/Civil建立该拱桥空间有限元计算模型,考虑不同的吊杆破断情况,进行斜靠式拱桥空间稳定性能分析,对比斜靠式拱桥不同吊杆破断情况与吊杆完好状态下的桥梁稳定性能计算结果。得出结论:各工况对应的桥梁第1阶稳定系数在7.10～7.34之间,满足一般拱桥稳定系数大于4～5的要求;吊杆破断对该桥梁的低阶失稳模态几乎没有影响,失稳形式主要表现为拱肋的面外扭转失稳;主拱吊杆破断对桥梁稳定系数影响较大,稳定拱吊杆破断对桥梁稳定系数影响较小。计算结果对正确认识斜靠式拱桥在不同吊杆破断状态下的稳定性能以及进行斜靠式拱桥的科学维护,具有重要的理论意义及工程实用价值。

Based on the example of the Zhanhe bridge—a double X-arch bridge across the Zhanhe River in Pingdingshan City,the bridge＇s spatial finite element model was built by the FEM software MIDAS/Civil.The bridge＇s spatial stability under different suspender fracture had been calculated.By comparing the bridge＇s spatial stability in health state and in suspender fracture state,it can be concluded：The bridge＇s first stability coefficient under all load cases are between 7.10 and 7.34,meet the standard requirement that arch bridge＇s stability coefficient must exceed 4 to 5.There is almost no effect caused by suspender fracture to the bridge＇s lower unstable modals.The bridge＇s unstable shapes are mainly shown out-plane torsional unstability of the arch rib.The main arch suspender fracture has great effect to the bridge＇s stability coefficients,and the stable arch suspender fracture has little effect to the bridge＇s stability coefficients.These conclusions have great theoretical meaning and practical value for understanding correctly the structural stability of double X-arch bridge in different suspender fracture states and also for the bridge＇s scientific maintenance.