Nonlinear static and dynamic assessment of the seismic performance of RC buildings considering the out-of-plane collapse of URM infills

In recent times, a significant interest in modelling the out-of-plane response of unreinforced masonry infills is growing. Such a response cannot be adequately assessed if the influence on it of the in-plane damage is neglected. In fact, past and recent experimental studies showed that the damage induced by the in-plane action can significantly affect the strength, stiffness and displacement capacity of infills. In this study, a recently-proposed modelling strategy is applied to account for the out-of-plane response and collapse of infills also considering the in-plane/out-of-plane interaction. Non-linear incremental dynamic analyses are performed on infilled reinforced concrete structures designed to Eurocodes to show how the out-of-plane collapse of infills and the in-plane/out-of-plane interaction effects can modify the seismic response of the case-study buildings. In addition, the seismic base acceleration and the in-plane displacement demand at which the first out-of-plane collapse of infills occurs are discussed and evaluated. The same evaluation is performed, in a simplified form, via non-linear static analyses. The results of both approaches are compared and discussed.