Limit Analysis for Triumphal Arches in Masonry Churches: Case Study from L'Aquila 2009 and Central Italy 2016-17 Earthquakes

The protection and conservation of historical monumental assets is a priority for contemporary societies. As it is widely recognized, historical masonry buildings (and in particular masonry churches) are unable to adequately withstand horizontal actions and generally suffer heavy damage if struck by a seismic event. Although a correct evaluation of their seismic capacity is necessary in order to preventively plan retrofitting interventions, the complexity of the constructions and the uncertainties in material modelling make it difficult to fully understand the behaviour of masonry churches. In this context, the macro-element approach is largely applied and confirmed by the partial collapses observed after the last seismic events. In this paper, a simplified procedure based on the limit analysis is introduced to evaluate the seismic capacity of triumphal arches, considered as part of the most vulnerable macro-elements in masonry churches. Triumphal arches from churches affected by the L'Aquila (2009) and Central-Italy (201617) earthquakes have been investigated by means of a linear kinematic approach, defining the possible positions of the non-dissipative hinges through step-by-step numerical analyses. The obtained results, finally, have been compared with the damage scenario observed in the considered triumphal arches, aimed at evaluating the effectiveness of the proposed procedure.