Effect of the different data survey scale on assessment of seismic exposure and vulnerability of the historic center of Caltabellotta

Abstract

The results of the prediction of exposure and seismic vulnerability for the buildings of the historic center of Caltabellotta, obtained with databases of different levels of accuracy, are compared. In particular, the results obtained on the basis of the estimation of the characteristics and of the distribution of the typologies derived from the filling in of the CARTIS sheets on a sector scale are compared with those obtained through a survey from the outside to a building scale. In this latter area, indicators contained in the CARTIS are suitably supplemented with those available in the literature, partly modified to adapt them to the local reality. The vulnerability is evaluated on the basis of the RISK-UE method, using suitably adapted values of the vulnerability modifiers. In the application of the procedure, the difficulties emerged in the recognition and attribution of the typology of masonry in the presence of plastered buildings are highlighted. In this context, a typological investigation is developed which, starting from the survey and the material classification of the buildings with exposed faces, and retracing the possible transformation processes that the structural housing units have completed, formulating two simplified criteria for the attribution of material properties. to the buildings plastered according to the plano-altimetric characteristics and the elevation of the buildings. The outcomes prove the accuracy of the procedure based on survey at the sector scale.