波形钢腹板矮塔斜拉桥整体稳定性分析

摘要

To examine the integral stability of the new type of composite girder bridge,like the extradosed bridge with corrugated steel webs,an extradosed bridge with corrugated steel webs, with four spans of 58 m,118 m,188 m,and 108 m,was taken as the study background.According to the load bearing behaviors of the box girder with corrugated steel webs,the MIDAS Civil soft-ware was used to establish the link element model of the bridge.The calculation results were com-pared with the results gained by the combined spatial block and cell element model,to verify the efficiency of the link element model,based on which the link element model was used to calculate the integral stability of the overall bridge.The results of the calculation show that the dead load is the main factor leading to structural instability and the first order instability mode is the in-plane buckling instability of the main piers.The first order of instability mode induced by wind loads is mainly the in-plane symmetrical bending instability and in-plane asymmetrical bending instability, with big stability coefficient.The minimum value of the elastic stability coefficient of the bridge is 19.79,and the integral instability mode of the bridge is close to the instability mode of the contin-uous rigid-frame bridge with high-rise piers.When the geometrical non-linearity is taken into ac-count,the minimum value of the stability coefficient is 19.4,the stability of the bridge meets the requirements of the design code and the bridge will not come across instability damage during its operation period.%为了解波形钢腹板矮塔斜拉桥新型组合结构桥梁的整体稳定特性,以跨径(58+118+188+108)m的某波形钢腹板矮塔斜拉桥为背景,根据波形钢腹板箱梁的力学行为特点,利用MIDAS Civil软件建立该桥杆系单元模型,对比ANSYS软件建立的空间块体板壳组合单元模型的计算结果,验证了杆系单元模型的有效性,在此基础上采用杆系模型计算全桥的整体稳定性.计算结果表明:恒载是桥梁重要的失稳因素,引起的第1阶失稳模态为面内主墩屈曲失稳;风荷载单独作用引起的第1阶失稳模态主要是面内对称弯曲失稳和面内反对称弯曲失稳,稳定系数较大;桥梁的弹性稳定系数最小值为19.79;桥梁结构整体失稳模态接近于高墩连续刚构桥的失稳模态;考虑几何非线性后稳定系数最小值为19.4,桥梁结构稳定性满足桥梁设计规范要求,该桥在运营阶段不会发生失稳破坏.