PIPELINES HANGING FROM BRIDGES – UNIQUE DESIGN PROBLEMSTO OVERCOME, UNIQUE SOLUTIONS TO CONSTRUCT

摘要

The Golden State Water Company (GSWC) serves more than 1 in 20 Californiansrnwith drinking water, which is a total of over 1.5 million customers. They serve arndiverse number of water systems located all over the state, including SouthernrnCalifornia. The Central District includes the cities of Bell and Bell Gardens. The tworncities have diverse sources of supply including surface supplies and somerngroundwater. In order to improve the water supply reliability of both systems,rnGSWC decided to construct a 12-inch main connecting the two distribution systems.rnThe distance between the systems is about 1,400 feet (ft); however, it includes severalrndaunting obstacles. A long bridge across the Los Angeles River and another bridgernacross the 710 freeway are between the two water systems, along with a multitude ofrnutilities including gas, petroleum, communication ducts, water mains, and storm andrnsanitary sewers. Permits must be obtained from the California Department ofrnTransportation (Caltrans), the statewide transportation agency, both cities, and severalrnutilities with prior rights-of-way.rnDuring 2007 and 2008, a pipeline design was prepared that included special featuresrnto overcome the multitude of obstacles. During late 2008 and early 2009, the pipelinernwas constructed. This paper documents the design decisions that were made and thernresulting construction that implemented the design features. Some of the importantrndecisions that will be discussed include:rn1. Pipe material selection, for buried segments as well as suspended segmentsrnhanging from the two bridges.rn2. Design and construction of a 450-ft pipeline span across the Los Angeles Riverrnbridge taking advantage of a corridor currently used by a large telephone duct andrna gas pipeline, while avoiding these utilitiesrn3. Design and construction of a 150-ft pipeline span across the 710 freeway, one ofrnSouthern California’s busiest truck routes out of the Long Beach Harbor, so that