空心薄壁高墩连续刚构桥全过程稳定分析

为更好地保障高墩连续刚构桥施工安全，以石川河特大桥为工程背景，通过有限元仿真的方法对空心薄壁高墩连续刚构桥展开了复杂工况下的全过程稳定分析，得到了第一阶屈曲特征值和屈曲模态，并对混凝土强度、桥墩高度及高墩壁厚进行了参数敏感性研究。结果表明：只考虑几何非线性，最大悬臂状态的稳定系数为20.39，而考虑双重非线性的稳定系数为6.12，分别较第一类静力稳定降低了16.5%和74.9%；就石川河特大桥15#墩而言，屈曲模态为纵桥向失稳，高墩的破坏属于小偏压破坏，破坏截面发生在距墩底h/8―h/7左右的区域；随着桥墩高度增加，桥梁的稳定性逐渐减小且减小的速率逐渐降低，而混凝土强度和高墩壁厚对高墩稳定性影响不大。可见考虑复杂工况的全过程稳定分析具有更好的实际意义。

Whole process stability analysis of continuous rigid frame bridge with hollow thin wall and high pier

In order to better ensure the construction safety of high pier continuous rigid frame bridge, taking Shichuanhe bridge as the engineering background, the whole process stability analysis of hollow thin-walled high pier continuous rigid frame bridge under complex working conditions is carried out by finite element simulation method, the first-order buckling eigenvalue and bending mode are obtained, and the parameter sensitivity of concrete strength, pier height and high pier wall thickness are studied. The results show that: considering only geometric nonlinearity, the stability coefficient of the maximum cantilever state is 20.39, while the stability coefficient of the double nonlinearity is 6.12, which is 16.5% and 74.9% lower than the first kind of static stability, respectively; As far as the 15# pier of Shichuanhe bridge is concerned, the buckling mode is longitudinal instability. The failure of high pier belongs to small eccentric compression, and the failure section occurs in the area about h/8-h/7 from the bottom of pier; With the increase of pier height, the stability of the bridge gradually decreases and the decreasing rate gradually decreases, while the concrete strength and high pier wall thickness have little effect on the stability of the high pier. It can be seen that the whole process stability analysis considering complex conditions has better practical significance.