The Seismic Risk Of The Lifeline In Small Communes: The Cross-correlation Effects
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C. Vardanega, A. Raffetti & G. Valfrè
A significant part of the consequences of a severe earthquake in an urban area is related to the failure of the lifeline system. A systematic assessment of seismic risk, vulnerability, and criticality of lifelines in small communities (considering them both separately and from a systemic point of view) is performed. The risk is characterized by using functions related to the components of different lifelines. The approach allows the optimization of the use of economic limited resources in intervention to reduce risk. Given a set of remedial measures more expensive than the limited budget, the subset maximizing the risk reduction at the appropriate cost is selected. The developed methodology allows one to analyse the lifeline system characterized by the information related to vulnerability and to their functional model separately and as a whole. The definition of different reference earthquakes is also allowed. The information related to the vulnerability of the elements and to the seism is defined by means of probabilistic models. The present paper is organized as follows. After a brief introduction to the seismic risk associated to a system of lifelines, a synthetic description of the whole methodology adopted is given. In the second part of the paper the methodology developed to assess the risk due to cross-correlations effects between lifelines is described in detail. The problem is assessed from both structural and functional points of view. Results of the application of the whole methodology to test sites are also reported. This work is one of the outcomes of the activities promoted and directed by the Istituto Nazionale di Geofisica e Vulcanologia of Rome within the Programma Operativo di Ricerca per la Sismologia e l’Ingegneria Sismica (PRO.S.I.S.), aimed at assessing methods and instrumentations for the reduction of the seismic risk in Italy. Keywords: lifeline, seismic risk, cross-correlation, probabilistic approach.
lifeline, seismic risk, cross-correlation, probabilistic approach.