Research Initiation: Sensitivity Analysis and Failure Cost Design of Random Structural Systems in Load Space

评估结构可靠性的方法已经从构件发展到系统分析。利用非线性结构分析程序求出了荷载空间的极限状态和正常使用极限状态。通过在三维载荷空间中积分失效区域内载荷的联合密度函数来计算系统的失效概率。通过假设某些楼板荷载之间的正完全相关，可以将荷载空间的维度减少到三个。结构变异性由荷载空间中极限状态函数的随机化来模拟，不需要任何额外的结构分析。研究了失效概率对荷载和抗力变量的敏感性，指出了影响失效概率的重要因素。提出了一种系统的载荷空间设计方法，该方法基于单目标和多目标线性规划对失效模式和总期望费用最小化进行加权。结果是几个现实结构的未来(或失败)成本和初始成本之间的权衡曲线。

Methods of evaluating structural reliability have advanced from member to system analysis. A nonlinear structural analysis program is utilized to derive ultimate and serviceability limit states in load space. System probability of failure is computed by integration of the joint density function of applied loads in the failure region in a three-dimensional load space. The reduction of load space dimensions to three is possible by assumption of positive perfect correlation amongst certain floor loads. Structural variability is modeled by randomization of the limit state function in load space without requiring any additional structural analysis. Sensitivity of failure probability to load and resistance variables are studied and factors with significant contributions are noted. A systematic load space approach to design, based on applying weights to modes of failure and minimization of the total expected cost using single and multiobjective linear programming, is developed. Results are trade-off curves between future (or failure) cost and initial cost for several realistic structures.