Interaction between infill walls and reinforced concrete frames after column removal

The progressive collapse resistance of reinforced concrete (RC) frames in which a middle column has been removed has been investigated by many researchers. However, previous experimental and computational studies have focused mainly on the catenary action provided by longitudinal reinforcement in the beams spanning the missing column. This study investigated the contribution of infill walls. Finite-element analysis was used after calibrating a reference model using test results reported by other researchers. Models were developed for a RC frame with and without infill walls. An equivalent strut was used in the infill walls to allow the removed column load to be transferred through the struts instead of developing catenary action in the beams. A simplified model of the progressive collapse resistance of frames with infill walls was then derived to estimate the peak strength provided by the infill wall under the scenario of middle-column removal.