Prediction of Site Characterization Based on Field Investigations and Empirical Correlations

Abstract

Significant damages of built environment recorded during past seismic events, closely linked to notable human and financial losses, have led to consideration of Romania’s capital city as one of the major earthquake-prone urban area worldwide. Strong historical ground shaking and extensive distribution of seismic networks have outlined that variability and specific parameters of layered unconsolidated sedimentary young deposits represents one of key component in site-response analysis. To predict seismic effects of near-surface soils, comprehensive surveys are needed for a realistic estimation of dynamic behaviour and site characterization. A large number of shallow and deep boreholes, standard penetration tests and non-invasive field techniques as down-hole and SASW measurements have been carried out in Bucharest sites. All the tests reported in the paper were performed at CNRRS (National Center for Seismic Risk Reduction) (now, Seismic Risk Assessment Research Center https://ccers.utcb.ro) and UTCB (Technical University of Civil Engineering of Bucharest). Shear wave velocities and penetration resistance have been set as main indicators in quantifying seismic properties. Empirical correlations to predict V_S from N-SPT test values were developed by using statistical methods. A comparative method between soil dynamic indexes determined by in situ investigation and the ones predicted using empirical models have been performed. The end-results can be considered as guidelines to predict the potential effect of site conditions on similar soil types, layer sequences and properties.