考虑安全性的桥梁主梁体系可靠性动态藤Copula预测

Dynamic Vine-Copula Prediction Approach of Bridge Girder System Reliability Considering Structural Safety

摘要:

为合理预测考虑安全性的在役桥梁主梁体系动态可靠性，利用危险监测点的动态极值应力信息，建立藤Copula技术与动态线性模型(DLM)贝叶斯递推过程相融合的贝叶斯动态藤Copula模型(BDVCM)，并结合一次二阶矩(FOSM)方法，实现危险监测点失效时变非线性相关的在役桥梁主梁体系动态可靠性预测。采用某桥主梁5个截面的动态监测极值应力数据进行验证分析，研究表明，考虑安全性的监测点失效时变非线性相关的桥梁体系动态可靠性预测值较不考虑监测点失效相关性所得结果大，说明不考虑失效动态非线性相关性所得结果偏保守。

关键词:结构工程;时变非线性相关性;贝叶斯动态藤Copula模型;一次二阶矩方法;动态可靠性

Abstract:

To reasonably predict safety-based dynamic reliability of the existing bridge girder system, the dynamic extreme stress data at the dangerous monitored points was adopted to build Bayesian dynamic vine- Copula model(BDVCM) through combining vine-Copula technique with Bayesian recursive processes about dynamic linear models(DLM), further, with first order second moment (FOSM) method, dynamic reliability of the bridge girder system considering time-variant nonlinear correlation of failure modes at the multiple dangerous monitored points was predicted. The dynamic monitored extreme stress data at five sections from a bridge girder was provided to illustrate the proposed model and method. The results show that predicted dynamic reliability of the bridge girder with considering the time-variant nonlinear correlation of failure modes at the multiple dangerous monitored points is bigger than that without considering the time-dependent nonlinear correlation of failure modes. It is illustrated that the predicted results without considering the time-variant nonlinear correlation of failure modes at the multiple dangerous monitored points are conservative.

Key words:structural engineering;time-variant nonlinear correlation;Bayesian dynamic vine-Copula model;first order second moment method;dynamic reliability