连续梁桥悬臂施工倾覆稳定安全系数研究

Study on Overturning Stability Safety Factor in Cantilever Construction of Continuous Girder Bridge

连续梁桥在悬臂施工期间的稳定性通常采用安全系数来保证,但是安全系数的取值均是依据设计者的经验而定,无法考虑参数随机性的影响。首先介绍了一种基于可靠度反分析理论的安全系数确定方法,然后以一个算例验证了该方法的效率和精度,最后对国内一座连续梁桥悬臂施工整体稳定安全系数进行评估。计算结果表明,参数的随机性会对连续梁桥悬臂施工整体倾覆稳定安全系数产生较大影响,忽略参数随机性的影响会导致过高地估计连续梁桥悬臂施工整体倾覆稳定安全系数。

The stability of continuous girder bridge is guaranteed commonly by the safety factors in the cantilever construction. But the value of safety factor is determined by the designers according to the experience. It is hard to consider the influence of factor randomness. The article introduces a safety factor determination method based on the reliability back-analysis method, verifies the efficiency and accuracy of this method by a numerical example, and evaluates the overall stability safety factor in the cantilever construction of a continuous girder bridge in China. The calculation result shows that the factor randomness will greatly influence the overall overturning stability safety factors in the cantilever construction of continuous girder bridge. The neglect of factor randomness influence will result in the over-estimation of overall overturning stability safety factor in the cantilever construction of continuous girder bridge.