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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1. Introduction

Earthquakes in Italy in the last decade have had a major impact both in terms of human life and economic losses. The 2012 Emilia and the 2016 Central Italy earthquakes highlighted once more re the issue of seismic vulnerability of existing buildings. After these events several studies were conducted in order to classify the sources of vulnerability of buildings, with main reference to masonry (Penna et al. 2014) and precast reinforced concrete (RC) buildings (Savoia et al. 2017). With this perspective, various fragility models have been developed, Buratti et Al (2017) derived fragility models for precast RC industrial buildings; Ioannou et al. (2021) and Simoni et al. (2021) obtained fragility models for masonry buildings on the basis of observed damage data. Verderame et al. (2014) and Salamida and Buratti (2021) obtained fragility models for RC structures, based on numerical analyses. These studies, combined with prediction of the ground motion intensity allow to predict damage scenarios (Simoni et al. 2021). To make damage scenarios usable in the immediacy of a seismic event, two software tools, working in a Matlab ® framework, have been developed in collaboration with the Emilia Romagna Civil Protection Agency: Ground Motion Analysis Toolbox and Seismic Scenarios Toolbox. The former can be used to analyze accelerometric recordings, calculating a series of ground motion intensity measures, and to assess the expected potential damage, based on recordings, on a set of residential and hospitality building types. The latter make possible to calculate shake-maps for the stricken territory, using different IMs, and derive a seismic damage scenario. 2. Ground Motion Analysis Toolbox The software tool for the analysis of ground motion, Ground Motion Analysis Toolbox (GMAT), was created with the aim of providing an estimate of the potential effects of ground motions, in the immediacy of seismic events. This is done in the first stage by computing a series of ground motion Intensity Measures (IMs), then, for a more specific assessment of the effect the earthquake may have on existing buildings, it is possible to compare the capacity and demand in terms of displacement for a series of typical buildings, by applying appropriate simplified methods. GMAT allows to analyze the ground-motion recordings produced by the Italian National Accelerometric Network. Accelerograms are first filtered according the procedure described by Puglia et al. (2018), then a large set of IMs is calculated (Buratti 2012). A graphical interface allows the visualization of recordings in terms of acceleration, velocity and ground displacement, as well as in terms of pseudo-acceleration, pseudo-velocity and displacement response spectra. Acceleration spectra can provide insight about the potential impact that a ground motion can have on existing buildings. In this view, it is convenient to compare the spectra obtained from the recordings, with those prescribed by structural design codes. With this focus, spectra in terms of acceleration, velocity and displacement can be calculated following the procedure provided by the Italian Building Code (NTC 2018). These spectra can be displayed together with those obtained from station recordings, as shown in Fig. 1. Other ground motion characteristics that are assessed are energy spectra, the significant duration of each ground motion component and the presence of pulse-like features, investigated using the procedure developed by Baker (2007). 2.1. Analysis of Ground Motion intensities