Robustness of steel moment frames against progressive collapse by means of plastic limit analysis

Abstract

Purpose Progressive collapse refers to a phenomenon, in which local damage in a primary structural component leads to total or partial structural system failure, without any proportionality between the initial and final damage. Robustness is a measure that demonstrates the strength of a structure to resist progressive collapse. Static pushdown and nonlinear dynamic analysis were two main procedures to calculate the capacity of structures to resist progressive collapse. According to previous works, static analysis would lead to inaccurate results. Meanwhile, capacity analysis by dynamic analysis needs several reruns and encountering numerical instability is inevitable. The purpose of this paper is to present the formulation of a solution procedure to determine robustness of steel moment resisting frames, using plastic limit analysis (PLA). Design/methodology/approach This formulation utilizes simplex optimization to solve the problem. Static pushdown and incremental dynamic methods are used for verification. Findings The results obtained from PLA have good agreement with incremental analysis results. While incremental dynamic analysis is a very demanding method, PLA can be utilized as an alternative method. Originality/value The formulation of progressive collapse resistance of steel moment frames by means of PLA is not proposed in previous research works.