As part of Project HOPE, which provides advance hurricane and flood protection to the city of New Orleans, our team was selected to build the north and south floodwall structures. The project involved constructing a 7,500-linear-foot (lf) surge barrier from the Gulf Intracoastal Waterway (GIWW) through the marshes to Bayou Bienvenue and tying into an existing levee system at the Mississippi River Gulf Outlet Channel.
This entire project was unique, as a structure such as this had never been built before. The project garnered significant attention from the public because of the protection it provides from storms like Hurricane Katrina. Although it was a fast-track project, the notice to proceed was delayed for three months. To maintain the schedule, our team gathered resources from three industry-leading national companies, and hired and trained 330 craft employees in the first four to five months. In the end, more than 1 million man-hours were spent without a lost-time accident, with incident rates one-third of the national average, and the project was completed two months early.
An intricate trestle system was built through the marshes to provide a stable platform for construction of the surge barrier. The barrier wall included 1,271 66-inch concrete cylinder piles that were 144 lf long. They are supported by 645 36-inch steel pipe piles that are 248 lf long on a 1.5V:1H batter.
The wall is topped with precast concrete cap sections weighing between 95 and 100 tons. Cast in place closure pours were made between each precast segment. A cast in place parapet wall and guardrail were installed on top of the precast. The project included 35,560,000 pounds of reinforcing steel and 90,000 cubic yards of concrete. Heavy lift crane barges were used to install rebar cages into piles and set the large precast concrete wall modules that required threading over five vertical 20-inch-diameter pile-to-cap connector pipes and simultaneous connections to two batter piles.