Seismic risk assessment of lifelines in Bucharest

Abstract

This study is focused on the seismic risk assessment of lifelines from Bucharest, the capital city of Romania. The damage sustained by the lifelines in Bucharest during the major Vrancea intermediate-depth event of March 1977 is presented. The seismic exposure for the gas, electricity, sewage and water networks is evaluated using publicly available information collected from various sources. The seismic fragility is evaluated using the recommendations of the SYNER-G research project. Finally, seismic risk metrics, in terms of repair rates and probabilities associated with various damage states are evaluated using a Monte Carlo simulated earthquake catalogue for the Vrancea intermediate depth seismic source. The impact of considering the spatial correlation of ground motions and of the anchoring of the elements in the stations for the gas, electricity and water systems is also evaluated in this study. The largest mean probabilities associated with the moderate, extensive and complete damage states for Mw 7 and Mw 7.5 earthquake scenarios are obtained for the components of the electricity distribution system, namely electric substations and small generation plants. In addition, it has been also observed that the mean repair rate for the gas pipe network is smaller as compared to the water and sewage systems.