大跨径连续箱梁桥稳定性分析

Stability analysis of long span continuous box girder bridge

为探讨大跨径连续箱梁桥稳定性的影响因素,以四川省虹云桥为研究对象进行抗倾覆稳定性验算,同时利用Midas/Civil程序软件建立有限元模型,对梁桥在最大悬臂阶段和成桥阶段不同荷载工况下的稳定性进行模拟分析,得到了结构各个工况下的屈曲模态和一阶稳定性系数。研究结果表明:该连续箱梁桥在最不利荷载工况下的抗倾覆稳定系数1.5;一阶稳定性系数91.2;其中,挂篮坠落产生的冲击荷载对结构的稳定性影响最大,直接导致结构在不同的荷载工况下一阶稳定性系数减少13.2%~15.4%。

In order to explore the factors that influence the construction phase stability of long-span continuous box girder bridge, the anti overturning stability was checked with research object of the rainbow bridge in Mianyang, Sichuan. At the same time, the finite element model was established by using Midas/Civil program software, the stability of the bridge under different load conditions in maximum cantilever stage and service stage was simulated and analyzed, and the buckling modes and the stability coefficients of the structure under different conditions were obtained. The analysis results show that the stability against overturning factor K of the continuous box girder bridge under the condition of the most unfavorable load is 1.5;the first-order stability coefficientγis 91.2. Among them, the impact load caused by hanging basket has the greatest influence on the stability of the structure, Among them, the impact load caused by the hanging basket has the greatest impact on the stability of the structure, directly leading to a 13. 2% - 15.4% reduction of first-order stability coefficient of the structure under different load conditions.