Based on reliability theory and single beam nominal invalidation probability, through analyzing the system probability could be calculated. First,for the bridges of transverse connection with no damage,the paper got system reliability with the weighted sum method,by using weight that calculated from invalid index. Second,for the bridges of transverse connection with some damage,according to model test of 5 pieces of T-beam,the system reliability was translated to the product of invalidation coefficient and single beam nominal invalidation probability on the base of transverse load-distributing influence lines. Finally, calculation formula (a, =0. 0l2n2x -0. 075nx +0. 518x +0. 210n +0. 490)of validation coefficient was derived from analyzing rules of the validation coefficient, and, system reliability was calculated quantitatively. Because the method is simple and objective, and the computational amount is small, it has made a further research for system reliability.%目的 计算梁式桥体系可靠度,为桥梁体系可靠度的进一步发展及体系层次的评定奠定基础.方法 在梁式桥单梁失效概率基础上,研究多片梁在横向连接不同损伤情况下的关系.在横向连接无损伤状况下,采用失效指标法求取权值,然后加权求取体系可靠度进而计算体系可靠度.结果 以最大横向分布影响线为基础,把体系失效概率分离为失效系数和单梁名义失效率的乘积进行计算,分析得到了失效系数的规律,推导出了失效系数计算公式α1=0.012n2x -0.075nx +0.518x +0.210n +0.490.结论 将体系可靠度分离为失效系数和单梁名义失效概率,进一步明确了体系可靠度的概念,相对以往方法计算量小,具有较强的操作性.
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