Establishment of safety formats for dynamic nonlinear finite element analysis of a reinforced concrete structure under sudden load-bearing column removal

Abstract

This study establishes and evaluates three safety formats for nonlinear finite element analysis applied to the problem of progressive collapse of a reinforced concrete frame structure under the scenario of sudden removal of a load-bearing column. The considered safety formats include the partial factor method, the method of estimating the coefficient of variation, and the global resistance factor method. These formats are applied within the framework of a global resistance assessment approach to determine the design resistance of the structure. The three methods are applied to a reinforced concrete frame structure for comparative and critical analysis of the predicted structural resistance. The results show significant differences between the methods. The partial factor method and the global resistance factor method, each requiring a single nonlinear finite element analysis, provide a conservative estimate of the structural resistance, which is confirmed by the complete collapse of the examined frame in both cases. The method of estimating the coefficient of variation, based on two nonlinear finite element analyses with mean and characteristic values of material strengths, allows for a more detailed consideration of the variability of material properties. The obtained results demonstrate a significant difference in structural displacements depending on the level of material strength.