Fort Kamehameha Sewer Outfall Extension

Location: Pearl Harbor, HI
Owner: NAVFAC - Pacific Division FY99 MCON P-497
Completion Date: January 1, 2003
Categories: Construction, Marine Pipelines
Healy Tibbitts Builders procured and installed 3,900 meters of 1.1 m diameter sewer outfall pipeline at the entrance to Pearl Harbor.  1,600 meters of nearshore HDPE pipeline was trenched through existing reef using a backhoe working from a temporary berm.  Pipe was joined onshore, pulled into the trench and backfilled with material from the berm.  800 meters of RCP pipeline were then installed by micro-tunneling from an offshore cofferdam jacking pit.  900 meters of HDPE pipe were laid in one string into an open-cut trench, and covered with articulated block mats and tremie concrete.  The final 600 meters of HDPE pipe and diffusers are being laid on concrete caps supported by underwater piles in depths up to 45m.  Offshore work, including construction of a temporary platform to support the micro-tunneling, was done by the derrick barges HT 538 and WEEKS 544.  The project team utilized their expertise and experience to implement a $750,000 value engineering proposal for the offshore pile supported section of the pipeline, resulting in schedule and cost savings. The offshore section involved diving to 150 feet.

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