Planning for More Resilient and Safer Cities: A New Methodology for Seismic Risk Assessment at the Urban Scale, Applied to a Case Study in Italy

Abstract

Recent seismic events and the damages related to them have highlighted the crucial role of urban planning in coping with the fragility and intrinsic vulnerability of cities. The paper presents a methodology for assessing seismic risk at an urban scale, expanding from a single-building investigation to an urban-scale analysis by adopting an empirical method for assessing the vulnerability of the urban fabric. Data collection and analysis have been conducted through the Geographic Information System (GIS). The methodology has been applied to the Italian city of Castelfranco Emilia, in the Emilia-Romagna region, where the current regional urban planning law is guiding municipalities towards the development of strategies mostly oriented toward the retrofit of the existing building stock and the overall regeneration of the urbanized territory, in accordance with the target of no net land take by 2050. The novelty of the method stands in the transposition of approaches born in the civil engineering and protection domains to the urban planning sphere, stressing the importance of developing urban planning instruments which are well-integrated with vulnerability assessments and, therefore, able to successfully incorporate risk considerations in the decision making.

EQ-DIRECTION Procedure towards an Improved Urban Seismic Resilience: Application to the Pilot Case Study of Sanremo Municipality

“…The total of the weights for each SE and SV is 1. Then, the values of the two scores (P i,sSE and P i,mSV ) are renormalized to be employed in Equation (1).…”

“…In order to evaluate these variables, it is necessary to define a small number of mechanical and geometrical parameters, assume a basic modal shape, and assign specific correction factors that are intended to account for the impacts of a wide variety of constructive and morphological details (such as the presence of tie-rods, ring beams, etc.). The fundamental steps for using such a mechanical model are as follows: (1) analyzing the data that are available from archives or site surveys, (2) defining all necessary parameters and factors in two directions (X and Y), (3) assessing the capacity curves, (4) defining the seismic demand by an Acceleration-Displacement Response Spectrum (ADRS), and (5) evaluating the value PGA LS of the PGA that generates any LS threshold using overdamped spectra [98]. In that way, the EAL may be computed as well.…”

“…Resilience and resilient thinking have gained attraction among decision-makers [1] as well as academics across disciplines, sectors, and different spatial-temporal scales as a way to survive in the uncertain, risky environment of today's world and deal with incremental unforeseen events of various natures (from natural hazards to terroristic attacks) [2,3]. According to [4], resilience can be defined as "the ability of a system, community or society exposed to hazards to resist, absorb, accommodate, adapt to, transform and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions through risk management".…”