Preliminary Study on the Impact of the Introduction of an Updated Seismic Hazard Model for Italy

Abstract

A new hazard model for Italy has recently been proposed; hazard maps have been produced for various return periods, allowing the values of peak ground acceleration (PGA) and spectral accelerations for response periods up to 2 s to be interpolated for each of the 8,101 Italian municipalities. The new model allows for a more refined definition of the hazard in each municipality as compared to the current use of a fixed spectral shape anchored to upper bound 475-year PGA values and scaling factors for different return periods. The aim of this work is to investigate, in a preliminary fashion, the implications that the adoption of the new return-period dependent hazard maps would have on design and assessment of structures. To this end, the seismic performance of reinforced concrete frames of varying height is evaluated assuming they were located in each of the 8,101 municipalities in Italy and the results obtained with the current and the new hazard model are compared. The new model is shown to result in lower seismic risk in the majority of the municipalities.

Keywords:

• Seismic Hazard
• Response Spectra
• Vulnerability Assessment
• Risk Assessment
• Reinforced Concrete Buildings
• Italy

Acknowledgments

The authors acknowledge the financial support provided by the Italian Department of Civil Protection (DPC – Dipartimento della Protezione Civile), through the financing of the INGV-DPC 2004-06 applied research program, under the framework of which this work has been partially funded (as part of Sub-Project S1 activities). The authors would also like to thank two anonymous reviewers for their useful comments which helped to greatly improve the article.

Notes

¹All references to the “current code” in this article refer to OPCM [2003] with the use of the ground motion parameters of the four zones, and not to any subsequent updates introduced to the aforementioned code.

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CEN [2004] Eurocode 8, Design of Structures for Earthquake Resistance, Comité Européen de Normalisation, Brussels.

Ordinanza del Presidente del Consiglio dei Ministri n, 3274 del 20 Marzo 2003, [2003] “Primi elementi in materia di criteri generali per la classificazione sismica del territorio nazionale e di normative tecniche per le costruzioni in zona sismica,” G.U. n. 72 del 8–5–2003. (In Italian).