Methodology for Evaluating the Seismic Vulnerability of Buildings and the Definition of Risk Scenarios in Urban Areas

The evaluation of building vulnerability is an essential part of any project looking at seismic risk on an urban scale. Hence of equal importance is the level of investigation which will give the results required within acceptable limits of time and cost. Varying procedures for the evaluation of building vulnerability have been devised to provide differing levels of information on the basis of the dimension and object of the study. Problems linked to seismic risk and policies aimed at reducing this risk must be studied with an overall perspective that takes into account: forecasting, damage prevention, emergencies and reconstruction which are interlinked. Everything that takes place in one phase is conditioned by what took place in the previous phase and will influence all of the following phases. Differing instruments and evaluation methods have been created for analyzing risk on a territorial scale in Italy, based on building type (level I analyses) or on factors conditioning building behaviour during an earthquake (level II analyses). Research aimed at reducing seismic risk, creating damage scenarios for urban planning and dealing with post-seismic emergencies requires more detailed information on seismic vulnerability than that provided by level I analyses. The study carried out by the ITC-CNR- L'Aquila focused on the historical centre of Sulmona. All of the buildings in the historical centre (approximately 1300) were evaluated using a brief form system. The data collected and the analyses performed are given on the right. The vulnerability of ordinary buildings was evaluated in order to construct damage scenarios for hypothetical macroseismic intensities. Damage is expressed as a percentage of the value of a new building.