Experimental analysis of Textile Reinforced Mortars strengthening strategies against the out-of-plane collapse of masonry infill walls

Out-of-plane (OOP) collapse of masonry infill panels in existing reinforced concrete (RC) buildings due to seismic events is a key issue for life safety and seismic economic loss estimation. Few studies in the literature deal with this topic and, above all, with possible strengthening strategies against the OOP collapse. This work presents the main results of an experimental campaign about different strengthening solutions to mitigate the OOP collapse of masonry infills in RC buildings. The investigated strengthening techniques were based on the application of a thin mortar plaster and fiber-reinforced polymer nets with different connection typologies with the surrounding RC frame. The specimens were realized with traditional horizontal hollow clay bricks and were tested through the application of a semi-cyclic OOP displacement pattern by means of uniformly distributed small pneumatic jacks. Tests data and results are presented and commented in terms of OOP force-displacement responses and damage evolution. Details about the effectiveness of each retrofitting solution are provided and compared to support the selection of the best strategy for future applications.