Easy-to-Use Analytical Model of Compressive Arch Action of Bi-directional Primary RC Beams in Framed Structures Under Different Column Removal Scenarios

Compressive arch action (CAA) in the affected sub-structural beams has pivotal role in mitigating progressive collapse resulting from column failure due to blast events, and how to predict the enhancement effect of CAA becomes urgent. However, the existing analytical models were developed to predict CAA in one-way reinforced concrete (RC) beams but not applicable to bi-directional primary beam system in framed structures. This study presents a user-friendly analytical model to predict CAA in bi-directional primary beams in framed structures under different column removal scenarios, incorporating different design details and horizontal restraint conditions of the beams in two directions, as well as different column removal scenarios (CMS). To evaluate the validity of the analytical model, its predictions are contrasted with FEM simulations of typical bi-directional RC sub-assemblages with diverse design details. This comparison confirms that the model can achieve good precision in predicting resistance and displacement of CAA. Furthermore, parametrical investigations are carried out to examine how the varied boundary condition under different column removal scenario, and span difference of bi-directional primary beams affect the peak resistance of CAA.