Influence of Unreinforced Masonry Infill Panels on the Robustness of Multistory Buildings

AbstractThis paper investigates the contribution of unreinforced masonry infill panels to the robustness of composite steel framed buildings subject to sudden column loss. A previously developed multilevel robustness assessment approach is extended and used to establish the system pseudostatic capacity, which determines the level of gravity loading that could be sustained under sudden column loss without exceeding the system ductility limit. The infill panels are modeled according to the ultimate failure mode and confinement caused by the frame, where a simplified approach is proposed based on extracting the infill panel contribution in isolation of the surrounding frame. The developed modeling approach is applied to a 7-story building, where it is shown that accounting for infill panels can increase the structural resistance to sudden column loss significantly, thus avoiding disproportionate collapse in most cases.