Damage to water supply pipelines

Abstract

Earthquake damage to water supply pipelines during the 1995 Hyogoken-Nambu earthquake was investigated. An overview of the damage to water supply pipelines in the Hanshin area is presented and the relationship between the damage to water supply pipelines in Kobe city, geological features and damage to buildings is discussed. The damage is compared with that which occurred from past earthquakes. The study lead to the following conclusions. (1) The majority of failures occurred in pipelines of relatively small diameter. (2) The damage rates for asbestos cement pipe and vinyl pipe were high. The replacement of old pipe such as asbestos cement pipe is urgently required. (3) Joint separations were extensive. Joint separations for cast iron pipe occurred in the older lead and mechanical joints. (4) Liquefaction caused extensive damage to pipelines. The ductile cast iron pipelines with earthquake-proof joint did not suffer damage even in the liquefied area. The effect of earthquake proof joint was confirmed. (5) Since damage to the pipe fittings such as valves, hydrants, etc., was extensive, the strength of the pipe fittings should be improved.