Seismic Fragility of Code-conforming Italian Buildings Based on SDoF Approximation

The paper presents and discusses seismic fragility functions of code-conforming buildings in Italy. The structures under consideration are taken from those considered by a large Italian research project (RINTC), aiming at evaluating the seismic reliability of new-design buildings. Design refers to a variety of structural typologies (i.e. un-reinforced masonry, reinforced concrete, steel, and precast concrete buildings) and configurations (e.g. number of stories, floor plan, and the presence of infills), as well as to sites with different hazard levels and local site conditions. The seismic fragility of the structures is evaluated via multiple-stripe nonlinear dynamic analysis using the equivalent-single-degree-of-freedom (ESDoF) systems calibrated based on pushover analysis of the three-dimensional structural models. The seismic response of the ESDoF models is also validated in terms of demand-capacity ratio and risk of failure compared to those of the three-dimensional structural models. Along with providing fragility curves for the buildings located at high-hazard sites, the study discusses the issues that significantly affect the fragility assessment for those located at low-to-mid hazard sites.