EARTHQUAKE DAMAGE ESTIMATION AND DECISION-ANALYSIS FOR EMERGENCY SHUTOFF OF CITY GAS NETWORKS USING FUZZY SET-THEORY

Earthquake damage estimation for lifelines can be used for many purposes, for example, planning repair works or simulating network recovery. For gas networks, however, the issue is more crucial, as secondary disasters due to leaks are possible. If necessary, the,gas supply should be interrupted in heavily-damaged areas. Therefore, emergency shut-off decision is vital and earthquake damage estimation can be effectively used for a more reliable and swift decision-making. The system proposed in this paper uses fuzzy set theory to formalize knowledge acquired from experience and assess earthquake damage from ground conditions and ground motion characteristics. The results are obtained as fuzzy damage indices. Fuzzy decision analysis is then utilized to transform this imprecise information into a clear-cut decision on whether to cut or maintain the gas supply in a given area of the network.