不同设计使用年限下实用设计表达式系数的求解

Solution on the Coefficients of Design Formulation for the Pragmatic Usage Under Different Design Working Lives

基于可靠度分析理论以及荷载标准值等数据的调整,分别运用JCSS法与Monte Carlo法计算出运用于结构领域的新的目标可靠指标并依据不同可变荷载的概率统计模型计算出对应于不同设计使用年限的调整系数及数理统计参数。以最小二乘法为准则,借助Matlab里的数学算子,分别采用穷举优化搜索法和极值理论求解法计算出实用设计表达式中荷载分项系数及结构重要性系数,并计算出标准值等数据调整前后的单构件的相对误差增量。从工程实际应用出发,在荷载、抗力分项系数均按现行规范采用的情况下,计算出能同时体现不同安全等级与设计使用年限的结构重要性系数,并分析了现行规范中采用的结构重要性系数取值对应的包络范围,对今后结构设计提供参考借鉴。

Based on the reliability analysis theory and the adjusted characteristic values of an action,the new target reliability index,which is applied in structure area,is calculated using the JCSS method and Monte Carlo method.Moreover,the adjustment factors and mathematical statistics parameters corresponding to different design working lives are computed according to different probability distribution models of variable actions.Especially,in theoretical analysis,based on the least square method,the partial factors of safety for load and the coefficients for importance of structures were developed by using the method of enumeration in association with optimization search and the method of extremum theory respectively with the function of Matlab.The relative error increments of the single component are then solved before and after the adjustment of the data（e.g.characteristic values）.As for practical applications,the different coefficients for importance of structures corresponding to different levels of safety and design working lives under various situations are obtained when the partial safety factor for load and the partial safety factor for resistance meet the requirements of the current standard.Finally,the application envelops of different coefficients for importance of structures are analyzed for the future structure design.