Analisi di rischio a larga scala di ponti multicampata in c.a. con metodi agli spostamenti

In seismic countries, the managing authorities of road networks rely on risk assessment of bridges to decide retrofit intervention priorities on a regional scale. It is a current practice to assess seismic vulnerability in the form of fragility curves. The most extensively used tool currently available for the evaluation of vulnerability curves of large-scale systems is the Hazus methodology, which provides fragility curves for whole classes of structures, but shows deficiencies when applied to a community–specific database, where different typologies are represented. Given the large number of bridges in a regional scale road network, fragility curves have to be obtained by means of simplified and reliable numerical methods, time-history analyses being to date still very expensive in computational terms when applied in a probabilistic framework. In the last decade displacement-based (DB) methods have become increasingly established simplified assessment procedures. Present work reports on an extensive risk assessment study carried out on Northern-Italy’s Region of Veneto road system; the analysis focuses on one of the most typical bridge types of the network, multi-span RC bridges. Analytical fragility curves obtained with displacement-based approaches are proved to be sufficiently accurate. The curves obtained can be used as a reference for Italian and European RC multi-span concrete bridges.