Performance-based Seismic Risk Assessment of Urban Systems

Abstract

Disaster risk mitigation has become a global urgent need. Similarly to other natural hazards, earthquakes may cause significant damage on a large scale. In Europe and in other regions with dense urbanization, seismic events can heavily impact historical city centres due to the several structural fragilities. These centers are often part of the worldwide cultural heritage and their preservation is considered a strategic issue. Furthermore, earthquakes may have severe negative short-term economic effects on the impacted communities and adverse longer-term consequences for economic growth. For this reason, the development of an efficient approach for urban seismic risk assessment becomes essential. An original approach is proposed, based on performance concepts and multidisciplinary perspectives. The procedure is applied for validation to the city center of Concordia Sulla Secchia (Italy), damaged by the 2012 Pianura Padana Earthquake (PPE), comparing predicted damage scenarios with the actual post-seismic survey data.

Assessing community resilience, housing recovery and impact of mitigation strategies at the urban scale: a case study after the 2012 Northern Italy Earthquake

“…Indirect methods usually characterize the seismic response of buildings by dividing them into classes or assigning them a vulnerability index. In particular, seismic assessments based on the vulnerability index method proposed by the Italian "Gruppo Nazionale di Difesa dei Terremoti" (GNDT) (Gruppo Nazionale per la Difesa dai Terremoti 1994a) have been increasingly carried out in recent years (Vicente et al 2011;Ferreira et al 2013Ferreira et al , 2017Formisano et al 2015;Basaglia et al 2018;Cara et al 2018;Chieffo and Formisano 2019;Sbrogiò et al 2019). The GNDT method uses a form to assess the buildings' structural response based on 11 parameters.…”

“…In this paper, a recently proposed (Basaglia et al 2018) and already applied (Cara et al 2018) method is adopted. This method stems from the original GNDT form and include, for URM buildings, five additional parameters to include the effect of being in an aggregate sequence.…”

“…These parameters were already introduced in a previous study (Formisano et al 2015) but their scores and weights have been recalibrated as they were felt to be too conservative. The change was made by comparing the predicted damage to the one observed for Concordia sulla Secchia, a small Italian community hit by the 2012 NIE (Basaglia et al 2018). Given these additional parameters for URM buildings, the I V normalization is carried out using the following equations:…”

Geo-Hazard-Based Approach for the Estimation of Seismic Vulnerability and Damage Scenarios of the Old City of Senerchia (Avellino, Italy)

“…Thus, focusing at the urban scale, risk and age of the buildings are dependent on each other, since the site hazard induces significant consequences in term of expected losses. In fact, the seismic risk assessment on an urban scale implies the management of a large number of variables, such as different types of buildings, people, roads, etc., in order to know the expected damage probability due to earthquakes [7].…”

Seismic Risk Assessment and Mitigation at Emergency Limit Condition of Historical Buildings along Strategic Urban Roadways. Application to the “Antiga Esquerra de L’Eixample” Neighborhood of Barcelona

“…The damage grade of the chosen buildings, corresponding to the expected macro-seismic intensity in the city, is evaluated after having determined the vulnerability indexes by using the GDNT method (1986,1993,1999). Proper analytical functions are adopted to derive the macro-seismic vulnerability from the GNDT vulnerability indexes, making a clear distinction between masonry and reinforced concrete structures (Ferreira et al 2013, Basaglia et al 2018). The directional character of the seismic vulnerability of the buildings is explicitly taken into account within the vulnerability index method by using a novel elliptic interpolation (Basaglia et al 2016).…”