基于不确定性的钢框架结构抗连续倒塌评估

PROBABILISTIC EVALUATION OF PROGRESSIVE COLLAPSE RESISTANCE OF STEEL FRAME STRUCTURE BASED ON THE UNCERTAINTY ANALYSIS

为评估钢框架结构的抗连续倒塌性能,考虑了结构初始破坏位置和材料参数不确定性,建立了随机Pushdown非线性评估方法。选用重要性抽样、分层拉丁超立方抽样技术与MATLAB中MBC标准模型工具箱相结合,设计了100组评估样本模型。采用ABAQUS对其进行有限元分析,基于对数正态分布模式,得到了失效区域外荷载级数K与梁柱塑性转角θ的结构倒塌超越概率函数。采用美国规范DoD2016和FEMA-356中以梁柱塑性转角θ对结构破坏程度的划分标准,分别提取结构的各个性能水平的超越概率,绘制结构的倒塌易损性曲线,建立了概率评估系统,为钢框架结构的抗连续倒塌失效概率评估提供参考依据。

To evaluate the progressive collapse resistance of steel frame structure,considering the uncertainty of the initial failure location of structures and the material parameters,the stochastic nonlinear evaluation method(pushdown)was established.The importance sampling,hierarchical Latin hypercube sampling techniques and the MBC standard model toolbox in MATLAB were used to design the evaluation model and 100 groups of evaluation models were formed.Using the finite element analysis method and based on the lognormal distribution,the transcendental probability function of progressive collapse of structure with increasing coefficient K and plastic rotations angleθwas derived.Using the criterion of the degree of structural damage caused by the beam-column plastic angleθin the DoD 2016 and FEMA-356,the exceeding probability of each performance level of the structure was obtained.The collapse vulnerability curve was derived through the plastic rotations angleθin the DoD 2016&FEMA-356.This evaluation method could provide a reference for the failure probability evaluation of progressive collapse of steel frame structures.