一种混凝土桥梁时变体系可靠度分析方法

An approach for evaluating time-variant system reliability of concrete bridges

提出一种基于有限单元法和Monte-Carlo模拟相结合的劣化环境作用时混凝土桥梁时变体系可靠度分析方法,明确并解决结构性能演变模拟和体系可靠度分析中的一些关键问题。根据已有研究成果中给出的基于有限元的分析方法利用FORTRAN 95编写分析程序——混凝土桥梁耐久性分析系统CBDAS来进行结构性能演变过程;提出一种基于结构超静定次数的体系失效模式确定方法,并利用MATLAB编写了分析程序SRMCS来计算结构的体系可靠度。结合结构性能演变模拟和体系可靠度分析给出混凝土桥梁时变体系可靠度的计算方法。最后,利用3个算例分别演示了程序CBDAS,SRMCS以及两者相结合时的分析功能。

A finite element- and Monte-Carlo simulation-based computational methodology was proposed to evaluate the time-variant system reliability of concrete bridges exposed to aggressive environments. Some essential ingredients involved in the simulation of the lifetime performance and the system reliability were figured out and solved. As for lifetime performance, based on the finite element-based method proposed in previous studies, a program named CBDAS （Concrete Bridge Durability Analysis System） was written in FORTRAN 95 to perform the time-variant performance assessment. In the case of system reliability, a technique for searching the structural failure modes based on the degree of static indeterminacy of the structure was presented, and a program named SRMCS （System Reliability by Monte-Carlo Simulations） was written in MATLAB to evaluate the structural system reliability. As a result, the computational methodology for computing the time-variant system reliability of concrete bridges was set up associated with the solutions of the lifetime performance and the system reliability. Finally, three numerical examples were illustrated to display the functions of CBDAS, SRMCS, and the combination of the two analysis tools.