Experimental analysis of strengthening solutions for the out-of-plane collapse of masonry infills in RC structures through textile reinforced mortars

Seismic events worldwide clearly showed that a crucial issue for life-safety and reduction of losses due to earthquakes for reinforced concrete (RC) buildings is related to the out-of-plane (OOP) collapse of infill masonry walls. In the literature, few studies addressed this paramount topic. This paper presents an experimental work about the assessment of possible strengthening solutions to prevent the out-of-plane collapse of masonry infills in RC buildings. Four nominally identical full-scale one-bay-one-story RC frames were built and infilled with a thin masonry wall made up of horizontal hollow clay bricks. The first specimen was representative of the as-built condition. The other specimens were strengthened against the out-of-plane collapse by means of Textile Reinforced Mortar (TRM) strengthening techniques based on the application of high-ductility or common mortar plaster and fiberglass reinforcing bidirectional nets, varying the TRM-to-RC frame connection's effectiveness. Tests consisted of a semi-cyclic history of imposed displacements in the OOP direction through small uniformly distributed pneumatic jacks. Experimental results are shown and compared to assess the effectiveness of the selected strengthening techniques and to provide a support towards the choice of the best strategies for future further investigations and applications.