公路桥梁钢筋混凝土构件的可靠度分析

A Reliability Analysis for the Reinforced Concret Components of Highway Bridge

本文参考有关统计资料,对我国新颁公路桥规JTJ023-85中钢筋混凝土构件承载能力的可靠指标进行了计算分析,并讨论了影响构件可靠度指标的几个主要因素。采用的方法是一种近似概率计算方法——一次二阶矩法,即只考虑随机变量的平均值和标准差两统计参数,对设计表达式进行线性化处理。结果表明,延性破坏构件在荷载组合G+Q_1下β平均值为3.6,在C+Q_2下β平均值为2.8;脆性破坏构件,则分别为4.1和3.3。这是新规范所反映的钢筋混凝土构件可靠度的基本水平。另外在某些荷载效应比值下提高了荷载安全系数和对脆性破坏构件考虑了工作条件系数,都较为合理。但构件在不同荷载情况下尚不能得到比较一致的可靠度。抗力和荷载效应的分项系数以及荷载的标准值还需进一步研讨。

We have analysed the reliability index of bearing capacity for some reinforced concret components of highway bridge designed according to the new Chinese Standard JIJ023-85, and also discussed some important effects that can effect the R. I. of components. An approximate probability-calculation method, i. e. the 1st degree-2nd order method was used. The main results are as following: The average β value for complex loading G+Q_1 and G+Q_2 under ductile failure are 3.6 and 2.8; while under brittle failure are 4.1 and 3.3. We believe that these value have reflected the general level of the new Chinese standard. Finally, some strong and weak points about this standard were discussed.