The new bridge ship-collision protection system project consists of the installation of eight stone filled “dolphin” cylinders, each measuring 80 ft. in diameter. (Delaware River and Bay Authority photo)
Construction on the new Delaware Memorial Bridge Protection System is under way, a $93 million effort designed to limit damage to each of the two spans' tower structures as a result of strikes from large, wayward ships and vessels. The work is expected to be complete in September 2025.
That was the word July 26 from Delaware River and Bay Authority (DRBA) officials who said the project is partially funded by a $22.25 million U.S. Department of Transportation (DOT) Better Utilizing Investment to Leverage Development (BUILD) grant.
"The Delaware Memorial Bridge is a vital transportation link in the [Interstate 295] north-south corridor and millions of people rely on it to move products, visit family, or commute to work on a daily basis," Thomas J. Cook, DRBA's executive director, said in a news release. "The current bridge tower pier protection systems are original to each span and today's tankers and ships are bigger and faster than those of the 1950s and 1960s.
"Our goal is to take preemptive measures to prevent a commercial vessel from striking one of the bridge towers, which could cause significant damage to the bridge infrastructure and disruptions to interstate travel," he added.
The first of the two structures that make up the Delaware Memorial Bridge was opened in August 1951, followed by a second span in September 1968. Together, the two bridges, each more than 10,700 ft. long, provide eight travel lanes of I-295/U.S. 40 between New Castle County, Del., south of Wilmington, to Pennsville Township in New Jersey.
How is the Bridge Protection System Installed?
The new bridge ship-collision protection system project consists of the installation of eight stone filled "dolphin" cylinders, each measuring 80 ft. in diameter. Four cells will be installed at the piers supporting both the eastern and western towers and be located a minimum of 443 ft. from the edge of the Delaware River's 800-ft.-wide channel.
Earlier in July, the contractor, R.E. Pierson Construction Co. of Pilesgrove Township, N.J., began to construct a 360-ft. temporary trestle from the Delaware shoreline south of the New Jersey bound bridge to transport materials and personnel to barges.
Cranes carried by large barges will mobilize at the site near the Delaware tower structures and get set to install long wick drains into the river bottom, which will act like straws by enabling water to travel to the surface as the 80-ft.-diameter cells are filled with sand and stone. As the soft material compresses from the weight, the water contained within the framework is squeezed out and up.
In addition, a barge loaded with 115-ft.-long sheet piling will arrive from Louisiana for installation at the site, the DRBA noted.
The process takes approximately three months for each cell to be completed, and will be repeated seven times to construct each of the solid-fill dolphin cells.
If the Delaware Memorial Bridge was being constructed today, the installation of a similar protection system on the dual-span suspension bridge's towers would be a requirement for the project to proceed, the two-state agency noted.
"This innovative Ship Collision Protection System at the base of the bridge tower structures will better protect the structural integrity of the bridges in the event of a ship collision," the DRBA said in its news release.
The authority, a bi-state governmental agency created by a compact between Delaware and New Jersey in 1962, owns and operates the Delaware Memorial Bridge, the Cape May- Lewes Ferry and the Forts Ferry Crossing.
The DRBA also manages corporate and aviation properties through its economic development powers — two airports in New Jersey (Millville and Cape May), as well as three more in Delaware (the New Castle Airport, Civil Air Terminal and Delaware Airpark).
All DRBA operating revenues are generated through the bridge, ferry and airport facilities.
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