连续梁倒拆施工倾覆稳定性的体系可靠度方法

System Reliability Method to Analyze Overturning Stability of Demolition Construction of Continuous Beam Bridges

针对连续梁双悬臂挂篮逆施工顺序拆除施工的纵向倾覆稳定性,采用可靠度方法对其进行安全评价.提出因果链模式的体系可靠度方法,推导拓展了全概率公式的应用范围,并据此推导了因果链模式体系可靠度计算公式,计算结果和串并联联接模式很好吻合.推导拓展了贝叶斯公式的应用范围,分析得出导致体系失效最主要的失效模式.对最主要的失效模式进行了参数敏感性分析,得出可以指导拆除施工抗倾覆问题的结论,即吊索强度、根数和钢管桩强度以及切割不对称误差对拆除体系倾覆安全可靠度影响非常大.

The overturning stability of cantilever beam bridges in demolition process was assessed by the method of reliability, the causality-chains method of system reliability was proposed, and the application of total probability formula was developed. Moreover, the system reliability formula of causality-chains was derived with the developed total probability formula, and the calculated results by the formula were found to be well anastomosed with the series parallel connection. Furthermore, the application of Bayes formula was developed, by which the most important failure mode was analyzed. The sensitivity of parameters of the most important failure mode was analyzed. It is concluded that the lifting rope strength, rope number and temporary support strength have a significant influence on the overturning stability of the demolition system.