Water Pipe Replacement: Seismic and Aging

Ƞ This paper presents a model to allow a utility to develop a cost effective long term program to replace older water pipes with new, seismic resistant water pipes. Prior and after the recent 2010 Chile, 2010 Christchurch, 2011 Christchurch and 2011 Japan earthquakes, the various water utilities had opportunities to replace some water pipes with new seismic resistant pipes, either HDPE or DI with special joints; or make repairs with cut-in PVC or DI or steel pipes. In the post-earthquake rush to restore water service, most repairs were made as simply and as fast as could be done; meaning that many of the repaired pipes will break again in future earthquakes. We learn from these earthquakes that the time to make seismic upgrade is not right after the earthquake; but instead, seismic upgrades must be factored into long term (typically 10 to 50 year) capital improvement plans.