Case Study - Seismic Experiences, New Zealand

Overview

Functioning pipeline systems are a cornerstone of urban human communities, to bring in the clean water on demand for drinking, washing and sanitary needs, and in turn remove the used water from drains, waste and storm water sources. If the pipe system is suddenly rendered non-functional, such as by seismic event, critical disruption of the community and public health danger can result. Of the many requirements for design carried by pipeline systems, seismic events impose arguably the most challenging of all demands on a buried pipeline asset. These include the extreme ground forces, with the variable ground movements that are possible, and the paramount need to restore function to damaged pipe systems, particularly drinking water pipes, as quickly as possible. Pipe system design, materials, installation methods, repair methodologies and practical implications of operation are all directly affected by seismic activity. This paper includes first-hand observations and experiences, specific to pipeline systems in New Zealand seismic events, covering a 28 year period, from 1987 to 2015, (Table 1) including the Edgecumbe earthquake of 1987, the Thompson Sound earthquake near Te Anau of 2000, the Christchurch/Canterbury area earthquakes during 2010 to 2012, and the Eketahuna earthquake of 2014. These events provide us with a unique opportunity to practically evaluate the seismic performance of pipe materials and joint systems, that either survived, were damaged and repaired, or were totally destroyed and abandoned, during New Zealand seismic events. This paper presents conclusions and recommendations from lessons learned during these events.