GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 2.1 327 observations is the greatest for all cited events, and fragility curves depending on material types (masonry or RC buildings), number of storeys and topography influence are available. Comparison between Japanese empirical fragility curves (Suppasri et al., 2013) for masonry and RC buildings (Fig. 2) shows that for low damage levels material type influence is negligible, while for high damage levels RC buildings show a better response than masonry structures. For the definition of mechanical fragility curves, the empirical damage levels are considered for both masonry and RC structures and compared with the failure mechanisms given by the mechanical models. Fig. 2 - Japanese empirical fragility curves for masonry (M) and RC (C) buildings. Damage analysis for residential buildings. At present, the analysis of the coastal building stock is limited to areas where tsunami inundation is expected. These areas are defined according to New-Zeland guidelines “ DGL 08-16 ”, where potentially inundated areas can be evaluated assuming a simple attenuation law, that every meter of wave height along the coast corresponds to 200 m of inland inundation distance, in an hypothetical horizontal surface condition and without considering any obstacle to the wave flux. Different attenuation laws can be considered, such as constant or energetic approaches ( Energy Grade Lines Method introduced in ASCE 7-16 ). To establish the areas where data for vulnerability analysis have to be collected, an inundation depth of 25 m is assumed at the coastline, considering the worst scenario in accordance with hazard maps provided by TSUMAPS project. Coast areas are then further subdivided, based on a variable size grid (Fig. 3) that is scaled based on the buildings density expected in the census area of interest. Once defined an inundation depth for a given coast line, according to a large scale approach, it is assumed that the water flow develops mono-directionally inland. Every grid is integrated with available information on topographic elevation obtained from Digital Terrain Models ( DTM ), hence comparing topographic elevations with expected inundation depth profiles from the coastal line to the inland. Conclusions. The main aim of this research is to improve the knowledge on the structural vulnerability of existing masonry and RC residential buildings built along the Italian coast under tsunami loads, by using a large scale approach. The first step here presented is aimed at deepening the state of art review from international papers, design codes and guidelines, to understand how to estimate tsunami vulnerability. Japanese guideline ensures the best approach for large scale analyses due to its low knowledge level implicitly required.