Los Angeles water pipeline system response to the 1994 Northridge earthquake

ABSTRACT

Damage caused by the 1994 Northridge earthquake (Mw=6.7) to transmisin, trunk, and distribution pipelines operated by the Los Angeles Department of Water and Power and the Metropolitan Water District is summarized. The locations of trunk line [pipeline diameter>/610mm (24in.)] repairs are discussed relative to earthquake intensity, and the repair rate (repairs/km) is evaluated according to pipe composition. Repairs in both the trunk and distribution pipelines are summarized according to pipe composition and size. A simplified analytical model for assessing the potential damage to buried pipelines from traveling ground, wave effects is proposed. The model utilizes measured or estimated values of peak particle velocity, which affects ground strain, and predominant period, which affects wavelength, to develop pipeline seismic response diagrams that correctly predict damage to modern steel trunk lines during the 1994 Northridge and 1985 Michoacan earthquakes.(AU)