建筑结构基于可靠指标的设计方法

RELIABILITY INDEX-BASED DESIGN FOR BUILDING STRUCTURE

按目前规范规定的分项系数进行结构设计时,不同荷载效应比下的可靠指标与目标可靠指标差别较大,并且规范没有建立分项系数与目标可靠指标的函数关系。针对这两个问题,提出了按设计值法确定分项系数的方法;优化分析了敏感性系数的取值,建立了分项系数与可变荷载效应标准值和永久荷载效应标准值比值的简化公式。研究表明,当敏感性系数表示为荷载效应比的关系式时,计算的可靠指标与目标可靠指标误差很小;每种可变荷载的组合系数可取为常数。

When designing a strurcture according to partial factor specified in the current standard,there are quite great differences between reliability index corresponding to each load effect ratio and target reliability index,and it does not establish the relationships between partial factors and target reliability index.To solve these two problems,the method of determining partial factor was developed in accordance with design value method.The values of sensitive coefficients were optimized and analyzed,thereby establishing the relationships between partial factors and the ratios of the nominal value of the variable load to that of permanent load.The research shows the error of the reliability index obtained and target reliability index reached the minimum as the sensitive coefficients were represented as functions of the ratios of the nominal value of the variable load to that of permanent load;the coefficient of combination of each variable load can be taken as a constant.