GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 2.2 320 ON-SITE OBSERVATIONS AND ANALYTICAL INTERPRETATIONS OF SOIL- STRUCTURE INTERACTION EFFECTS IN THE URBAN CENTER OF MATERA A. Piro 1 , N. Tragni 2 , F.de Silva 1 , F. Parisi 3 , M.R. Gallipoli 2 , F. Silvestri 1 1 Department of Civil, Architectural and Environmental Engineering, University of Napoli Federico II, Napoli, Italy 2 Italian National Research Council (CNR-IMAA), Tito Scalo, Italy 3 Department of Structures for Engineering and Architecture, University of Napoli Federico II, Napoli, Italy 1. Methodology Traditional analytical approaches (Veletsos and Meek, 1974; Maravas et al., 2014) to quickly estimate the modification of the structural period induced by a soft foundation soil are hard to be applied when the soil is layered and the geometry of the foundation or of the aboveground structure is irregular. To overcome such limitation, Piro et al. (2020) proposed the procedure summarised in the flowchart shown in Fig.1, based on ‘equivalent parameters’ which permit to extend the validity of the simple analytical formulations to complex soil-foundation configurations. The procedure derives from the comparison among the existing analytical approaches and the results of linear dynamic analyses on coupled SFS (soil-foundation-structure) systems, assuming alternative configurations of building basement (i.e. embedded floating foundation or underground storey), a variable number of storeys and different layered soil models. To apply the modified approach, it is necessary to know: • the embedment, D , and the width, B , of the foundation system; • the profile of the shear wave velocity, V S , and the mechanical properties (shear modulus, G , and mass density, ρ ) of the materials falling in the volume affected by the foundation motion extending down to a depth equal to 2b (indicated with A j in Fig.1); • the height, h , the width, b , and the fixed-base frequency, f 0 , of the structure. Fig. 1 - Flowchart of the methodology adopted in this work