Abstract
The catastrophic collapse of the Twin-towers has further prompted structural engineers to understand and investigate the progressive collapse of multi-story buildings. This paper aims to simulate the response of reinforced concrete (RC) special moment resisting frame (SMRF) assemblies under column-loss scenarios through nonlinear finite element (FE) modeling. Besides the modeling of nonlinear rate dependent material behavior, bond-slip effects at the concrete-to-steel rebar interface have been considered. The FE model was calibrated against a scaled, single-story, two-bay by one-bay, RC SMRF model specimen with reinforcement detailing conforming to ACI 318-11 code. The specimen was tested under a middle column removal scenario. The calibrated FE model was subsequently employed for some parametric studies of interest wherein the effect of different parameters such as: type of assembly, column continuity, development of beam rebars at exterior joints, applied axial loads on columns and beam continuity at exterior joints, on the behavior of SMRF under a middle column removal scenario was studied. A simple procedure is also proposed for the progressive collapse assessment of RC SMRFs caused by sudden column removal.