GPR surveys for the characterization of foundation plinths within a seismic vulnerability analysis

Abstract

We present the results of GPR surveys performed to identify the foundation plinths of 12 buildings of a school, whose presence is uncertain since the structural drawings were not available. Their effective characterization is an essential element within a study aimed at assessing the seismic vulnerability of the buildings, which are non-seismically designed structures, located in an area classified as a seismic zone after their construction. Through GPR profiles acquired by two 250 MHz antennas, both in reflection mode and in a WARR configuration, the actual geometry and depth of the building plinths were successfully identified, limiting the number of invasive tests necessary to validate the GPR data interpretation, thus enabling the choice of the most suitable sites that would not alter the serviceability of the structure. The collected data were also critically analysed with reference to local environmental noise that, if causing reflections superimposed on those of the subsoil, could undermine the success of the investigation. Due to the homogeneity of the ground, the processing and results relative to each pair of profiles carried out for all of these buildings is very similar, so the results concerning only two of them are reported. © 2013 Sinopec Geophysical Research Institute.