A methodology for the seismic vulnerability assessment of load-bearing masonry buildings in Malta

Abstract

Since the last major earthquake which hit the Maltese Islands on the 11th January 1693, significant urban areas have been built up. The urban environment consists of a large variety of building types, from different time periods, with varying characteristics. These characteristics contribute towards the vulnerability of the individual building and the aggregate of buildings in a block Such characteristics, including materials, structural systems, building height and layout, position in a block and building ground interface, all contribute to the structural performance of a building in case of an earthquake. The Faculty for the Built Environment at the University of Malta has carried out a thorough study of the identification and the definition of indicators based on the characteristics of the contemporary loadbearing masonry building typology present in the Maltese Islands, which can lead to an evaluation of the vulnerability of such structures and the built environment to seismic action in areas which have developed in the last 50 to 60 years, when such a building typology became prevalent The methodology developed draws on other methodologies employed within other countries and on the experiences of regions with a high incidence of earthquakes, where such methodologies have been well calibrated However the methods employed in other countries cannot be directly transposed to the local building stock due to inherent variations in local building typologies which need to be taken into account. This, together with the knowledge that, in the vast majority of cases, residential buildings falling under this construction typology in the Maltese Islands, have not been constructed in accordance with any seismic design codes, in addition to the consideration of the high probability of occurrence of a major seismic event if a 475 year period is taken into account, stresses the necessity of the development of a seismic vulnerability assessment methodology for use in the case of contemporary loadbearing masonry buildings.