Numerical evolution of Reinforced Concrete Beam-Column Subassemblages under Progressive Collapse

Progressive collapse of building structures typically occurs when an abnormal loading condition causes a sudden loss in the structural capacity of one or more critical members, which leads to a chain reaction of failure and ultimately catastrophic collapse (Tohihi et al, 2014). In this research, based on alternative load path (ALP) approach, with using three-dimension (3D) finite element (FE) method, numerical studies were conducted for investigation progressive collapse resistance of beam-column joints in reinforced concrete (RC) frame under loss of exterior ground column. The paper presents a simple and reliable FE model that predicted the nonlinear load-deflection response of tested RC joints conducted by other researchers. Experimental models including two set of interior and exterior subassemblages were analysis under monotonic loading to simulate gravity load on the damaged frame after a blast. In the numerical simulations, the nonlinear behavior of materials was modeled by appropriate constitutive laws. The comparisons between numerical and experimental responses highlighted the reliability of proposed FE model. In addition, a parametric study is conducted using the validated models to investigate effect of slab on the behavior of the subassemblages and the transverse reinforcement ratio and slab effects on performance of substructures that covering both the interior and exterior joints.