GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 Site-dependency of fragility funcHons M. Fasan 1 , C. Bedon 1 , F. Romanelli 2 1 University of Trieste, Department of Engineering and Architecture 2 University of Trieste, Department of Mathema9cs and Geosciences IntroducHon This work focuses on invesCgaCng the potenCal impact of site condiCons on fragility curves, considering factors like source effects, wave propagaCon, and local site characterisCcs. UClizing physics-based numerical simulaCons, the study examines a hypotheCcal site using a single seismic source with varied crustal and straCgraphic models. Through nonlinear dynamic analyses the response of a reinforced concrete frame structure is assessed, leading to the evaluaCon of fragility curves using the cloud analysis method. The study emphasizes the frequently overlooked impact of crustal models through comparisons among curves for various configuraCons. The primary objecCve is to comprehend physical parameter influences on the seismic response of buildings in a hypotheCcal semng. Methodology The methodology of this study delves into ground shaking simulaCon and seismic source modeling to explore the factors affecCng seismic responses. Ground shaking, influenced by rupture processes, rupture propagaCon, and slip distribuCon on the fault plane, exhibits high variability in expected acceleraCon. SyntheCc accelerograms are computed through the tensor product of earthquake source representaCon and Green's funcCon of the medium, considering local site effects and crustal layer characterisCcs (Chieffo et al., 2021; Hassan et al., 2020). The simulaCons encompass a hypotheCcal seismic scenario, evaluaCng various configuraCons by employing two realisCc deep crustal models (propagaCon effects) and two local straCgraphic models (site effects, within the same category according to EC8). The earthquake source is modeled as a distributed slip field on the fault surface, employing a Monte Carlo approach to account for spaCotemporal variability in rupture evoluCon. Seismogram calculaCons use two techniques, Modal SummaCon (MS) and Discrete Wave Number (DWN), ensuring accurate simulaCon of ground moCon under different condiCons. The limitaCon to a maximum frequency of 10 Hz is a compromise for simulaCon accuracy, available informaCon, and computaCon Cme. The fragility curves in this study are derived through the "cloud" methodology, employing unscaled signals and assuming a linear correlaCon between the logarithms of signal intensity