The objectives of this proposed research are to: (1) provide the effective guidance for repairs and rehabilitation of buried lifeline structures for seismic resistance; (2) provide technical information for realistic evaluation of the vulnerability of existing buried lifeline structures under various seismic environments; and (3) develop and document cost-effective methodologies for repairing and strengthening such vulnerable structures. Buried lifelines which include water, sewer, gas and oil pipelines have been damaged heavily by earthquakes including the 1985 Mexico City Earthquake, the 1987 Whittier, California Earthquake and the most recent Loma Prieta Earthquake of October 17, 1989. Existing buried lifelines are unsafe even under moderate earthquakes. Because of the importance of lifelines to the health, supply, and safety of the public, lifeline earthquake engineering needs greater attention. Since there is still no codified seismic provision to design buried lifelines, most water and sewer pipelines, including relatively new ones, have been built with minimum earthquake protection. Damages to water and sewer pipelines during earthquakes are unavoidable and economical loss can be substantial. Effective repair methods under emergency situations and for a permanent basis are to be addressed by this project. Due to the fact that the replacement of all existing water and sewer pipelines is very expensive, if not impossible, the development of effective rehabilitation techniques and strategies to be developed by the proposed research is urgently needed.
