Suchergebnisse

Abstract Florence is known all over the word for its historical and monumental buildings; however, most part of residential buildings have been made in the XX century, and they present all the critical issues proper of recent housing. Florence is one of the first Italian cities to have experienced the public housing. Its public housing population consists mostly of masonry buildings, and it does not comply the requirements provided by the current seismic legislation. This work is aimed at evaluating the seismic performance of a masonry building-type belonging to the public housing population of Florence. A typical public housing intervention, consisting of 18 masonry buildings, has been assumed as case-study. The seismic input has been described according to the Italian Code prescriptions, by considering the effective soil stratigraphy, and considering the effective mechanical properties of each layer. The seismic performance of the case-studies has been checked by performing a nonlinear static analysis. The results are expressed in terms of seismic performance, defined as the ratio between the seismic capacity and the corresponding demand. The obtained results evidenced the role of the building features on the seismic assessment of the buildings.

The seismic excitation at the surface can be determined through Site Response Analyses (SRA) as to account for the specific soil properties of the site. However, the obtained results are largely affected by the model choice and setting, and by the depth of the considered soil layer. This paper proposes a refined 3D analytical approach, by the application of OPENSEES platform. A preliminary analysis has been performed to check the model adequacy as regards the mesh geometry and the boundary conditions. After the model setting, a SRA has been performed on various soil profiles, differing for the shear velocity and representing the different soil classes as proposed by the Eurocode 8 (EC8). Three levels of seismic hazard have been considered. The seismic input at the bedrock has been represented consequently, through as much ensembles of seven ground motions each, spectrum-compatible to the elastic spectra provided by EC8 for the soil-type A (bedrock). Special attention has been paid to the role of the considered soil depth on the evaluation of the surface seismic input. Different values of depth have been considered for each soil type and seismic intensity, in order to check its effect on the obtained results.