Earthquake Damage Estimation and Rehabilitation Prioritization of Buried Lifelines

Abstract

This chapter provides a scheme/guideline showing the priority for rehabilitation of buried pipelines of any existing system. The strategy is based on various several important factors such as pipeline damage probability, rehabilitation cost, and rehabilitation rate (e.g. km/day), pipeline importance factor, and total funds available. Buried water, sewer, and gas pipelines have been damaged heavily by earthquakes including the Northridge earthquake of January 17, 1994. Many of them were built several decades ago without seismic consideration; hence, are unsafe even under moderate earthquakes. However, pipeline rehabilitation is costly and it is impossible to rehabilitate all pipelines in a system in a short time with insufficient manpower, equipment, materials, and funds. Seismic rehabilitation or retrofit is a cost-effective way to prevent pipeline damage caused by future earthquakes. The strategy to establish priorities for rehabilitating buried pipelines requires the following tasks: (1) Evaluating the damage probability of buried pipe links using a probability-based earthquake damage estimation model (EDEM); (2) calculating the node weights of the system; (3) calculating the pipe link weights of the network based on a cost or a time factor; (4) generalizing the source expansion tree; and (5) setting the priorities based on the generalized link weight, which is defined as the summation of node weights for the nodes served by the pipe link.