On the seismic response of buildings in aggregate: Analysis of a typical masonry building from Azores

In 1980, an earthquake of magnitude 7.2 ML caused severe damage to the existing buildings in some islands of the Azores Archipelago, Terceira being the most affected one. The traditional Azorean buildings are mostly made of rubble stone masonry walls and are often inserted in aggregates (or blocks), including adjacent buildings with different heights or/and different floor levels. This paper presents the results from the seismic performance-based assessment of a case study of such masonry building stock. The assessment was addressed to the global seismic response of the building, assumed to be governed by the in-plane capacity of the masonry walls, and taking into account the interaction with the adjacent buildings, shorter and with different floors heights. The global behavior was determined by nonlinear static analyses and the effects of some relevant modeling options were considered, including the analysis of the building either as an isolated structure and inserted in its aggregate. This study has shown the relevance of modeling the structure with the adjacent buildings' floors at their actual height to assess the real expected damage.