Advanced numerical prediction of unreinforced U-shaped masonry walls loaded out-of-plane

The seismic vulnerability of unreinforced masonry structures is a relevant topic as they stand for one of the most typical building typologies in the world. Despite the effort carried out by researchers, further experimental campaigns can help to increase the level of knowledge on the most frequent collapse mechanism and to suggest the most adequate reinforcement technique for the specific case. In this context, we address here a study on a mixed construction technique, in particular a type of building with masonry walls and concrete slabs, the so-called “Placa” buildings. Such buildings are typical of the Lisbon region and were mainly erected from 1930 to 1960. In this period, there was low awareness about the effects of adding heavy slabs to the global and local behavior of masonry structures. The seismic vulnerability of such structures is high, which is relevant in a medium-high seismic hazard region such as Lisbon. An experimental campaign will be performed at the University of Minho. The set-up comprises a U-shaped brick wall tested subjected to an out-of-plane load and three tests are planned to perform: an unreinforced and two (different) reinforced configurations. In this paper, sensitivity analyses concerning the unreinforced wall are shown. The primary goal is the identification of the correct set-up that would allow the exploitation of the energy at the orthogonal connection without leading to undesirable rocking phenomena of the wall. In such a way, the subsequent application of the reinforcement will have a major role in vulnerability reduction.