Seismic fragility curves for the Italian RC residential buildings based on non-linear dynamic analyses

Abstract

In the present paper, Fragility Curves (FCs) of Reinforced Concrete (RC) structural types representative of the existing Italian building stock have been derived through an analytical approach. The proposed methodology is based on Non-Linear Dynamic Analyses (NLDAs) encompassing all the steps required to bring about reliable as well realistic fragility results. First, prototype building types have been selected by considering the main attributes affecting the seismic vulnerability of existing RC buildings, that is: age of construction (i.e. '50s, '70s and '90s), number of storeys (i.e. 2, 4 and 6 storeys), arrangement in elevation of infills (i.e. Bare-, Infilled-, Pilotis-frame) and design level (i.e. seismic or gravity loads). A simulated design has been used for detailing the building types at hand, whose non-linear dynamic response has been computed by using a large set of signals. The signals have been purposely selected in order to approach the elastic design spectra provided in the Italian seismic code for different return periods, being able to take into account also record-to-record variability and soil-amplification effects. A specific relationship between the considered engineering demand parameter (i.e. inter-storey drift ratio) and all damage levels proposed in the EMS-98 scale have been defined on the basis of empirical data and expert judgement. A set of FCs in terms of peak ground acceleration are finally derived and compared to point out the role of the considered vulnerability attributes.

Energy-based modelling of in-plane fragility curves for the 2D ultimate capacity of Italian masonry buildings

“…Analytical methods for seismic fragility curves have also been proposed for different typologies of buildings, in particular, for Reinforced Concrete (RC). The most common approaches are based on non-linear dynamic analyses (Folić and Čokić, 2021;Manfredi et al, 2022;Ruggieri et al, 2022). The proposed methods often require a relevant modelling effort in defining the geometry and a high computational effort to solve the numerical problem.…”

Effect of Retrofit Interventions on Seismic Fragility of Italian Residential Masonry Buildings

“…In those works, six fragility models were developed, derived by means of mechanical models [14,15], using empirical approaches [16][17][18], or empirical-heuristic methodologies [19]. In the literature, it is possible to find many other methods for assessing both large-scale and building scale seismic vulnerability [20][21][22][23], but the above-mentioned approaches are very well suited to applications at territorial scales thanks to the definition of macro-typologies of buildings on the basis of available census data [24].…”