Barnhart was recently hired for a project at the Holt Lock and Dam on the Black Warrior River in Alabama to remove and replace the lock’s lower mitre gate, our third lock replacement project in the past couple of years.
For the Holt project, two new gates were fabricated in Russellville, Alabama, and transported by barge to the site up the Black Warrior River. In the meantime, Barnhart was assembling a lift system that would span the width of the 150’ lock. The team brought in Big Al, their barge-mounted heavy lift crane, to set up the equipment.
Barnhart devised a system using a modular lift tower and two 8’ tall girders to span the lock in conjunction with a 500-ton hoist and slide system, which would maneuver the gates. Once the gates arrived, Barnhart lifted the two old gates from the pocket and downended them onto the barge for transport. Tugs were used to support the barge during this process.
The new gates were delivered to the hook of the hoist and upended using the 500-ton hoist. Each new gate weighed 375 tons, which was 35 tons more than the old gates. They were then set into the gate recesses on temporary stands, with each lift taking 3-4 hours. Barnhart’s part, from equipment set up and removal, took four days.
It took coordination among all the players, including Barnhart, the tug and barge company, the Corps of Engineers and the lock’s maintenance company, to successfully complete the project on time.
Watch this video of the process.