直接分析法在连续倒塌中的应用

THE APPLICATION OF DIRECT ANALYSIS METHOD IN PROGRESSIVE COLLAPSE

结构连续性倒塌分析中的核心问题主要有材料非线性、初始缺陷、动力效应和悬链线效应。结构的抗连续性倒塌性能设计验算主要采用构件拆除法,将关键竖向承载力构件拆除后检验结构的响应。结构整体分析可采用线性静力分析、非线性静力分析和非线性动力分析三种方法。采用基于非线性静力分析的直接分析法,在分析中直接考虑对结构响应有影响的因素,如材料非线性、初始几何缺陷、残余应力、节点连接刚度等,以整个结构体系为对象进行抗连续性倒塌分析。基于NIDA软件,通过一个算例体现了GSA和UFC规范中的构件拆除法的设计过程,并与传统的线性静力分析结果作比较。

The key issues in progressive collapse analysis include material nonlinearity,initial imperfections,dynamic effects and catenary effects. The structural stability analysis for progressive collapse resistance is mainly based on the alternative path method,and the response of the structure is checked after the removal of key vertical members. The global structural analysis can be performed by three methods,i. e. linear static analysis,nonlinear static analysis and nonlinear dynamic analysis. In this paper,the direct analysis method based on nonlinear static analysis is adopted to to consider the key factors affecting the structural behaviors,such as material nonlinearity,initial geometric imperfection,residual stress,joint stiffness,etc. Using software NIDA,this paper presents the analysis and design process of the alternative path method specified in the specification GSA and UFC via a worked example. The conventional linear analysis method is also used for comparison purpose.