15WCEE Invited Paper (O'Rourke, et al.)
September 28, 2012
Lisbon - Portugal
Underground Lifeline System Performance during the Canterbury Earthquake Sequence
This paper explores key aspects of underground lifeline system performance, using data acquired after recent earthquakes in Christchurch, NZ. The paper examines the spatial distribution of peak ground velocity for the Mw 7.1 September 4, 2010, MW 6.2 February 22, 2011, and MW 6.0 June 13, 2011 earthquakes. Pipeline repairs throughout the water distribution system are evaluated in areas where liquefaction-induced permanent ground deformation was observed as well as areas affected principally by transient motion. Pipeline repair rates, expressed as repairs/km, for different types of pipe are evaluated relative to the estimated peak ground velocity outside liquefaction areas. Inside liquefaction areas, repair rates are assessed relative to differential settlement and lateral ground strain, calculated from high resolution LiDAR data acquired before and after each seismic event. Pipeline performance in the gas and water distribution systems is compared to show the influence of highly ductile polyethylene pipelines on system performance. Lessons learned regarding the earthquake performance of underground lifeline systems are summarized.