All the gate work at Dalles Dam had to happen in 13 weeks during the worst winter in over three decades.
Dalles Dam navigational lock gate replacement/modifications
Location: The Dalles, Oregon
General contractor: Northbank Civil and Marine
Owner/developer: U. S. Army Corps of Engineers
This $14 million project was to fabricate a new 225,000-pound upstream navigational lock gate and replace the existing upstream gate, trunnions, anchorages, seals and hoist machinery.
It also included replacing the gudgeon arms that support the downstream miter gate. Prior to removing the existing arms, each 1 million-pound gate leaf had to be jacked, cribbed and tied back to the existing navlock walls.
After installing the new gudgeon arms, the tension diagonals were readjusted and all seal surfaces were adjusted. All the electrical wiring and controls were replaced and upgraded throughout the entire lock system.
This work included removing existing medium voltage switchgear, transformers and cabling, followed by installation of new redundant systems selected to improve reliability of the lock.
All on-site gate work had to happen within an incredibly short 13-week navigational lock outage during the worst winter in over three decades.