The construction of a new Ship Collision Protection System, part of the Capital Improvement Program, began last summer on the Delaware Memorial Bridge after a decade of planning.
If construction stays on schedule, the system should be installed by September 2025.
According to the Delaware River and Bridge Authority (DRBA), the work will cost approximately $93 million. A $22.25 million grant from the U.S. Department of Transportation (USDOT) and bond issuances will fund most of the project.
The bridge sees over 100,000 vehicles cross the bridge daily, according to the DRBA. To protect those travelers from ship collisions, engineers have designed stone-filled cylinders called "dolphins" to reinforce the piers supporting the bridge. DRBA plans to build eight of these dolphins, each of which measure 80 feet in diameter and takes about three months to build.
The frames of the dolphins are made of steel piles driven into the riverbed. Then, in order to fill the cylinders, construction workers have installed long wick drains into the river bottom. As they pack in the sand and, later, stones, the drains act like straws and draw out the water to the surface. It's a laborious process, Meconi said, but an effective one.
Once the dolphins are completely filled, a cap will be placed over the top. The dolphin will then be ready to serve as a sort of airbag.
The installation of dolphins to prevent collapse in the case of a collision is not the only investment DRBA is making towards the safety of the Delaware Memorial Bridge.
The bridge is regularly inspected by engineers, according to DRBA, and millions are invested every year to maintain the bridge. This includes everything from painting the steel to protect it from corrosion to dehumidifying the bridge's main cables.
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Source: Delaware Online
