大跨长联连续梁桥最大悬臂与成桥阶段稳定性分析

闽候新南港大桥主桥为70m+4×120m+70m连续梁桥,桥址处自然条件复杂。为确保该桥施工和建成运营后的抗风稳定性及安全性,采用有限元法对其主桥结构进行动力特性、最大悬臂阶段和成桥阶段的稳定性分析。结果表明:最大悬臂阶段结构稳定性最差(1阶纵向失稳特征值最小为39.13>5,满足规范要求),对结构稳定性起控制作用的是恒载,活载、风荷载等对桥梁最大悬臂状态的稳定性影响不大。

Stability Analysis of Long Span and Long Unit Continuous Girder Bridge in Longest Cantilever and Finished Bridge State

The main bridge of New Nangang Bridge in Minhou County is a(70 +4×120 +70) m continuous girder bridge and the enviornmental condition at the bridge site is complicated.To ensure the wind resistant stability and safety of the bridge during construction and in operation,the finite element method was applied to analyze the dynamic performance and the stability of the the main bridge structure in the longest cantilever state and finished bridge state.The results of analysis indicate that the bridge has the poorest structural stability in the longest cantilever state(the 1 order minimal longitudinal instability egienvalue is 39.13>5,which meets the code requirement),the dead load plays a dominated role in the control of structural stability,and the live load and wind load have little effect on the stability of the bridge in the longest cantilever state.