Geotechnical site classification and Croatian National Annex for Eurocode 8

Abstract

One of the challenging tasks for Croatian accession to the European Union is the completion of the National Annex to Eurocode 8 (EC 8) that calls for the development of national seismic hazard maps. These maps need to be developed for several return periods (probabilities of exceedance) and should consider both bedrock and soil conditions. The latter is especially challenging as it calls for site characterization at a microzonation level, i.e., site characterization based upon V_S,30, SPT blowcounts, and undrained shear strength, information available only in the departments of Public Works of major cities. In this paper, the authors discuss several shortcomings associated with the EC 8 ground type definitions and propose their revision. The authors also present the ongoing work for preparation of the Croatian National Annex to EC 8 and explain the rationale for the improvement of EC 8 ground type definitions.