长悬臂状态下连续刚构桥墩身的双重非线性稳定分析

Double Oonlinear Stability Analysis of Pier Body of Continuous Rigid Frame Bridge Under Long Cantilever Condition

对于跨越山涧的高耸连续刚构桥而言,其稳定性问题尤其重要。以某墩高为60 m的空心薄壁墩连续刚构桥为例,利用有限元软件ANSYS,对该桥最长悬臂阶段墩身进行双重非线性稳定性分析。结果表明,在双重非线性稳定分析中仅考虑挂篮施工机具的动力效应,破坏处在墩内壁,靠近墩底变截面的位置,属于小偏压破坏;双非线性稳定安全系数比几何非线性分析结果降低47%,证明材料非线性占主导作用;考虑初始缺陷的双非线性稳定安全系数较理想状态分析结果的降低程度随缺陷加大而增加,但墩顶纵向位移及破坏时受力情况同理想状态差不多。

For high-rise continuous rigid frame bridges that span mountain streams,the stability issue is particularly important.Taking a continuous rigid frame bridge with a hollow thin-walled pier of 60 meters in height as an example and 7 using the finite element software ANSYS,the double nonlinear stability analysis of the pier at the longest cantilever stage of the bridge is performed.The results show that in the dual nonlinear stability analysis,only the dynamic effect of the hanging basket construction equipment is considered,and the damage is located on the inner wall of the pier,near the variable cross-section of the pier bottom,which is a small bias failure;the dual nonlinear stability safety factor ratio geometric nonlinear analysis The result is reduced by 47%,which proves that the material nonlinearity plays a dominant role;the double nonlinear stability safety factor considering the initial defects is lower than that in the ideal state,and the degree of decrease increases with the increase of defects,but the longitudinal displacement of the pier top and the force when it fails are nearly the same as the ideal state.