Numerical simulations of derived URM-RC buildings: assessment of strengthening interventions with RC

Abstract

The use of reinforced concrete (RC) in retrofitting interventions on existing unreinforced masonry (URM) buildings has been spreading all over the world since the beginning of the twentieth century. However, many of these mixed URM–RC buildings have revealed to be particularly vulnerable to seismic action, and their inherent complex structural behaviour is still understudied. In fact, the interaction effects from coupling RC structural elements to URM loadbearing walls is still a contentious issue for most of the research community. In this context, the present paper represents a steppingstone for the thorough understanding of the influence of strengthening interventions with RC in existing URM buildings, namely, regarding the addition of reinforcement layers on the horizontal diaphragms, and the insertion of ring beams at the roof level. This article describes a finite element nonlinear static analysis of a representative URM-RC building, before and after the introduction of the RC strengthening elements. The models used in these finite element-based analyses have been automatically created from BIM models correspondent to two full-scale prototype buildings (unstrengthened and strengthened configurations), analysed experimentally in a shaking table test campaign performed at the European Centre for Training and Research in Earthquake Engineering (EUCENTRE). The obtained results have been calibrated based on experimental results and compared with other numerical results obtained resorting to a macroelement-based model, found in the literature. As presented and discussed in this article, the refined finite element models have provided a better approximation of the experimental seismic behaviour of the building than the macroelement models. Plus, the refined finite element models have allowed to assess the influence of each strengthening element when applied separately.