Olmsted Locks and Dam

The Olmsted Locks and Dam project used a first-in-the-U.S. “in-the-wet” construction method to build two 110-by-1,200-foot locks and a dam system that includes tainter gates, boat-operated wickets and a fixed weir. Massive precast concrete shells, weighing up to 2,700 tons, were set on lifting frames and moved to the river for placement using a gantry crane, a track-mounted cradle and a catamaran barge.

Hillsdale Fabricators fabricated and erected structural steel for the complex lifting frames, the shells’ precast yard and the cradle system, along with thousands of pipe piles supporting the dam foundation. Lifting frame configurations varied by shell type, including frames measuring about 75 feet long by 100 feet wide and averaging 45 feet tall. Most steel was delivered by barge from Hillsdale Fabricators’ river facility on the Mississippi River in north St. Louis.