Robustness of Multistory Buildings with Masonry Infill

Abstract

This paper investigates the influence of unreinforced masonry panels on the robustness of multistory buildings under sudden column loss scenarios. A recently developed multilevel framework is employed to evaluate the resistance to progressive collapse under such scenarios, which is applied in this paper at story level allowing for the resistance of the floor system and the infill panels. The response of various structural components under pushdown deformation is obtained using high-fidelity finite-element analysis, where an accurate mesoscale description is utilized for the masonry infill, elastoplastic beam-column elements are used for the floor system, and component-based nonlinear mechanical models are employed for the joints. This methodology is applied to a 7-story composite steel-concrete benchmark building, where it is established that the use of masonry infill panels for exterior cladding can considerably increase progressive collapse resistance, even in the case of perforated walls. Furthermore, the results indicate that the maximum dynamic deformations under sudden column loss are relatively small due to the significant resistance of the infill, which is particularly relevant when considering the retrofitting of structures affected by column loss.