A synthetic formulation for the Italian seismic hazard and code implications for the seismic risk

Abstract The paper contains two parts. In the first one, the seismic hazard on the Italian territory, as given by the current Italian structural design code, published in 2008, is discussed. Hazard curves, given by the Italian code in a tabular form, are fitted with a single non-linear model and it is shown that a more compact, simple and user-ready territorial hazard description can be applied. The model is valid for both the bedrock and the surface seismic hazards, and is accurate. The surface seismic hazard is computed with a local amplification mapping, which is now well detailed over the entire territory. Departing from these results, in the second part the territorial seismic risk for the ultimate limit state is computed via a parametric fragility curve. From the results, it can be inferred that the codes need further factors calibration, with the aims of guaranteeing both territorially uniform reliability levels, and the traditionally assumed target reliability levels, e.g. those stated in the Eurocodes.