In-plane seismic fragility models for clay masonry infills in reinforced concrete frames

Abstract

This study aims at deriving multi-damage state fragility functions/curves for clay masonry infills in low-to-medium-rise reinforced concrete frames designed according to a performance-based seismic design methodology. Different structural archetypes were identified and modelled numerically by means of distributed plasticity approaches in order to undertake multi-stripe nonlinear dynamic analysis and derive seismic lognormal fragility models through regression analysis. Both infilled and bare frame configurations were simulated and compared together, providing fragility curves corresponding to immediate occupancy, damage prevention, and, ultimately, life safety limit states, all of which can be integrated in general frameworks for seismic risk/loss assessment and management. To this end, fragility models are given in terms of three different intensity measures, namely peak ground acceleration, peak floor acceleration, and peak floor spectral acceleration, considering also two different methods for the calculation of the probability of occurrence/exceedance of a certain damage state, namely building-wise and storey-wise approaches.