Some Aspects of Seismic Risk Analysis of Underground Lifeline Systems

Abstract

The current state of the art of the seismic risk analysis for the underground lifeline systems, particularly for the water transmission network system, is reviewed. An emphasis in the review is placed on the analysis of major causes of system damages and on the procedures of the seismic design decision analysis unique to the underground lifeline systems. A methodology of the seismic risk analysis is then developed and an example analysis performed for a simplified version of the water transmission system in the City of Los Angeles indicating each step of the analysis and each assumption used therein. The example analysis has been carried through to the point where a sample of physically damaged network systems are simulated by means of a Monte Carlo technique. Eventually, a topological analysis should be applied to such a sample of damaged systems to estimate the probability of the original system becoming unserviceable immediately following an earthquake of a given intensity. Such probability values are vitally needed for the ultimate purpose of design decision analysis.