PSI - Issue 44

Gianluca Salamida et al. / Procedia Structural Integrity 44 (2023) 131–138 Gianluca Salamida et al. / Structural Integrity Procedia 00 (2022) 000–000

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3.2. Estimation of seismic damage scenarios

The following section describes the procedure used in this work to calculate damage scenarios. The scenario assessment is conducted considering the municipalities that fall within a certain distance from the epicentre of an event. Census data are used in order to obtain all the necessary information about the building stock; in particular, construction typology, number of storeys and geographical coordinates of each building within the municipalities under study are obtained. The damage scenarios are assessed using a Monte Carlo approach, involving a large number of simulations. First, the conditional distribution of the ground motion intensity is computed at the locations of buildings, defined form census data, as described by Buratti, Simoni and Mazzotti (submitted for publication). Then, simulations are run for each municipality and damage scenarios are estimated separately for masonry and reinforced concrete buildings. In each simulation IM values at the locations of buildings are drawn from the IM distribution, then a fragility model is randomly selected for each building from those appropriate, based on typology and number of storeys. At the end of the simulations, the damage scenario for the municipalities analysed is represented in the form of histogram, which expresses the percentages of buildings for the various damage levels. Furthermore, a damage map is produced, in which, for each census section, the percentage of buildings that have reached a certain damage level is shown. An example of a damage scenario is shown in Fig. 6, for the Emilia earthquake of 29 th May 2012, for thirteen municipalities around the epicentre. In the damage map, white areas within the considered municipalities represent uncensored agricultural areas. In addition, it is sometimes possible to note undamaged census sections, within others that have suffered damage: this happens when there are no buildings of the considered type in the scenario assessment within these areas.

Fig. 6. Seismic Scenarios Toolbox software interface: (left) damage map for damage level D4, in relation to masonry buildings and (right) damage scenario histogram for the 29 May 2012 Emilia earthquake (masonry buildings). 4. Conclusions The present paper presented two software tools developed in collaboration with the Emilia Romagna Civil protection agency: Ground Motion Analysis Toolbox and Seismic Scenarios Toolbox. With the former, it is possible to analyse accelerometric recordings and calculate a wide range of IMs, visualize response spectra in terms of acceleration, velocity and displacement, and compare them with those required by Italian regulations. A series of buildings representative of the territory of Emilia Romagna were studied by means of non-linear static analyses and, by applying simplified methods, the displacement demand of the structure can be calculated and then compared with the capacity. This tool makes possible to study the main characteristics of an earthquake and directly assess the response of certain building categories, both masonry and reinforced concrete, to accelerometric recordings. Finally, the Seismic Scenarios Toolbox software allows the calculation of shake-maps for various IMs; by combining these with census data and a series of fragility models, damage scenarios are calculated for masonry and RC buildings, within a Monte Carlo simulation approach. The software tools presented offer a contribution to the assessment of the seismic vulnerability of the existing building stock and, in the occurrence of an earthquake, can help the competent authorities to estimate the amount of damage to buildings and can provide useful suggestions in the early stages of emergency management.