The Columbia River is a major highway for migrating fish. Each year, tens of millions of five different species of migrating salmon and steelhead pass through the Rocky Reach Dam. The Juvenile Fish Bypass structure helps young salmon and steelhead quickly and safely pass downstream through the 48-year-old dam.
Constructed entirely between migration cycles of these endangered fish species, TBI employed innovative construction methodologies and aggressive project scheduling to dodge physical constraints and numerous commercial deadlines, completing the facility prior to the arrival of the 2003 migrating season. The difficulties created by the inordinate pace of construction in such a confined workspace, combined with the enormous startup mobilization effort, presented significant challenges.
The contract needed to be complete by May 1, 2003 (395 calendar days after the bid opening) with a limitation that prohibited work on the actual site until September 15, 2003. In essence, the majority of the $40 million price tag was to be spent in the last seven months of the contract. The mobilization and startup activities to meet the schedule were unprecedented. By August 2002—four months after the bid date—the job site had received and assembled four crawler cranes, one ringer crane, a floating dry dock, three crane barges, two dive barges, two floating pile templates, two inland tugboats, and several materials barges. In all, more than 150 truckloads of specialized equipment and supplies were shipped from across the United States over a six-week period.
During construction, the team faced engineering challenges such as the installation of deep water drilled shaft foundations in extremely hard bedrock; off-site fabrication of a floating pump station with subsequent transportationIcontrolled ballasting of the structure on a prepared site; off-site preassembly and on-site erection of large steel modules with a portable floating derrick barge; and managing the erection of over 2,600 tons of light framed structural steel and mechanical members with a diving team at water depths exceeding 100 feet.