寿命期内预应力混凝土连续梁体系可靠度分析

System reliability analysis of prestressed concrete continuous bridges in service life

摘要:

为了模拟氯离子侵蚀环境作用时寿命期内预应力混凝土桥梁的结构性能演变过程,建立了一种基于概率和有限元的寿命期内预应力混凝土桥梁性能演变分析方法.首先,明确了退化过程中的3个关键时刻并给出其计算公式;其次,在重点解决退化过程分析中的材料力学性能退化、截面面积削弱以及结构整体力学性能演变等问题模拟方法的基础上编写了耐久性分析程序CBDAS;最后,结合分析程序CBDAS、Monte-Carlo模拟以及体系可靠度分析程序建立了预应力混凝土桥梁时变体系可靠度分析方法.以一座预应力混凝土连续梁桥为对象,利用时变体系可靠度研究其在氯离子侵蚀作用时寿命期内的结构性能演变规律.

Abstract:

To evaluate the lifetime performance of prestressed concrete bridges exposed to chloride penetration environment,a probabilistic and finite element-based lifetime performance assessment approach for prestressed concrete bridges is proposed.Firstly,three critical times in the degradation process are discussed and their computing formulas are presented.Secondly,an analysis program named CBDAS(Concrete Bridge Durability Analysis System) is written based on the numerical simulation methods with respect to the deterioration of materials’ mechanical properties,reduction of sectional areas and variation of overall structural mechanics performance.Finally,the assessment method for calculating time-variant system reliability of prestressed concrete bridges is proposed associated with the analysis program CBDAS,Monte-Carlo simulation and analysis technique of the system reliability.The lifetime performance of a prestressed concrete continuous bridge under chloride penetration-induced corrosion is investigated by using the time-variant system reliability.