The spectral acceleration in the seismic vulnerability assessment of a historic masonry building. A comparison by using several approaches on a case study

This paper concerns the seismic vulnerability assessment of a historic masonry building by means of the spectral acceleration values detected with several approaches. This comparison is related to the particular geometrical-configuration of the case study, which makes the structure particularly prone to collapse mechanisms. These accelerations are evaluated in the static and dynamic nonlinear framework through the most common Finite Element Method (FEM) strategies employed by the scientific community. In particular, the nonlinear static analysis is performed by using a multi-control point pushover methodology allowing the detection of the most damaged areas in the building in which the nodes are located. The nonlinear dynamic analysis is performed by using an artificial accelerogram, and the damage cracks patterns are compared with the ones provided by the static approach. Afterward, a comparison between the spectral accelerations obtained with the FEM approaches and the limit analysis, according to the kinematic theorem, is proposed. This simplified analysis is used to investigate two of the most relevant out-of-plane failure mechanisms, previously highlighted by the global nonlinear investigations. The results show interesting aspects of the seismic resilience of the building, the San Fili Castle of Stignano, in the province of Reggio Calabria (southern Italy), which is strongly influenced by the absence of the box-like behavior.