Assessing Geotechnical Hazards for Water Pipes with Uniform Confidence Level

A uniform confidence hazard evaluation provides a methodology to assess earthquake hazards so all pipes in a water system are designed consistent with their intended function and with a uniform confidence that design forces are greater than or equal to actual forces a pipe may experience during an earthquake. The method also provides design uniformity between different water systems. This paper summarizes: (1) how to define a pipe function in relation to its importance in aiding a community in post-earthquake recovery, and (2) how to identify transient, fault, landslide, and liquefaction induced lateral spreading ground movements with uniform confidence for pipeline design. The uniform confidence methodology is also useful for building and other infrastructure and lifeline systems designs.