SEISMIC DAMAGE ESTIMATION PROCEDURE FOR WATER SUPPLY PIPELINES

This paper presents a practical procedure for estimating damage to water pipes when an earthquake occurs. The procedure considers the pipe material, pipe diameter, ground condition and liquefaction condition as well as earthquake ground motion intensity. The standard fragility curve (damage ratio) is proposed as a function of peak ground acceleration based on the strong ground motion observation data of the 1995 Hyogoken-nanbu (Kobe) Earthquake and the damage data around the observation points. This standard fragility curve is modified by factors such as pipe material, pipe diameter, ground condition and liquefaction condition. These modification factors were determined mainly from a detailed analysis of damage to Ashiya and Nishinomiya cities caused by the 1995 Hyogoken-nanbu Earthquake. A 50-meter square mesh or grid system was adopted in this analysis in order to consider the micro land classification such as narrow valleys.