Finite Element Modeling of RC Beam Column Sub-assemblages Subjected to Column Loss Scenario

Abstract

Progressive collapse is a situation where a failure of whole or large part of a structure occurs that has been initiated by failure of a relatively small part of the structure such as failure of any primary structural element. When a vertical load carrying element, typically a column is lost, the loads that are supposed to pass through lost column need to be safely transferred to the adjacent elements to prevent progressive collapse. This paper presents a computational investigation on failure modes and structural behavior of RC beam column sub-assemblages subjected to progressive collapse. For this purpose six finite element models are developed in ABAQUS, each comprising two span beams and three columns and the mechanism of progressive collapse resistance in middle column missing scenario is analyzed under mid span point loading in different stages of deflections. The finite element models are validated by comparing the results with the experimental results in literature. Good agreement is observed, which validates the capability of models to predict the structural behavior of RC beam column sub-assemblages in progressive collapse event with satisfactory accuracy, in spite of performing costly, time consuming non repeatable experimental works. Moreover, a parametric study is performed to examine the effects of beam top longitudinal rebar ratio, beam bottom longitudinal rebar ratio and beam span-to-height ratio on the global structural behavior of beam-column sub-assemblages. Structures with higher energy absorption capacity boost progressive collapse resistance mechanism. Hence energy absorption capacity of finite element models are compared and discussed.

Keywords: Finite element, Beam-column sub-assemblage, Progressive collapse, Compressive arch action, Catenary action.