INNER HARBOR NAVIGATION CANAL FLOODWALLS

New Orleans, Louisiana

The IHNC Floodwall joint venture project is a 1.5-mile floodwall across the northern end of Lake Borgne, where the Inner Harbor Navigation Canal enters the harbor just east of New Orleans. This project is an essential component of the extensive New Orleans hurricane flood protection program that was implemented by the Corps of Engineers.

The floodwall consists of 66-inch-diameter cylindrical concrete piling 144-foot long, driven side by side, with only a six-inch gap, for the entire length of the wall. Truncated 18-inch concrete filler pile are installed in the interstices of the cylinder pile, and the space is grouted down to a bearing layer below the seabed.

This wall of piling is braced by 245-foot-long 36-inch steel pipe pile, battered at a 2:1 slope spaced at 12-foot centers. The vertical wall and battered pile are connected by precast concrete caps that are post-tensioned to the pile. Cast in place concrete ties the precast sections together and a cast in place parapet wall tops out the floodwall at +26 mean sea level. The 36-inch and 66-inch pile required cleanout for internal reinforced concrete placement as part of the structure connection. The wall was constructed by multiple crane barges, and a continuous trestle and track system with self-propelled work platforms for pile driving, drilling, and grouting operations that advanced along the wall. Prior to the project, Massman Construction Co. individually performed a total of 13 load tests on the 66-inch cylindrical concrete pile, 36-inch steel pipe pile, and 24-inch square concrete pile to provide geotechnical data to the designer for the floodwall final design. Two multi-use reaction frames were designed to provide jacking loads on the piling in excess of 600 tons.