The Hampton Roads Bridge-Tunnel Expansion includes building two new tunnels and trestle bridges to double the number of driving lanes.
To make way, another major part of the $3.9 billion project is taking down much of the decades-old infrastructure — and sending it to the bottom of the Chesapeake Bay.
“That means the bridge decks that you drive on every day, the beams that hold those bridge decks up and the foundations or piles that go down into the bay bottom,” said Ryan Banas, HRBT Expansion project director for the Virginia Department of Transportation.
By the end of the project next year, workers will have dismantled about 100,000 tons of concrete, or about 200 million pounds.
The HRBT builder is working with the state to use the hefty materials for a longstanding artificial reef program.
“We're able to upcycle some of that material that otherwise would just be demolished, very often put in landfills," Banas said. “And it gives us the ability to support wildlife habitat in our water.”
Taking junk to the reefs is also cheaper than other disposal methods, he said. (VDOT officials could not provide an estimate for exactly how much the project will save.)
Hunter Smith, artificial reef specialist for the Virginia Marine Resources Commission, said the reef program started in the 1960s and ‘70s as decommissioned World War II-era Liberty ships became available.
The agency now manages 23 reefs throughout the Chesapeake Bay and Atlantic coast.
“They're providing structure where the smallest microorganisms can attach,” Smith said. “That attracts the small bait fish, then the predatory fish, all the way up to the largest predatory fish. It kind of sparks the food chain.”
Black sea bass, flounder, red drum and tautog flock to the underwater concrete jungles.
That also attracts recreational anglers, who can use online maps or the VMRC Maps app to find reef locations for prime fishing.
The HRBT contractor has already delivered 951 tons of rubble to Bluefish Rock Reef, which is about 4 miles east of Buckroe Beach in Hampton, Smith said.
Demolition has been limited so far, but will pick up quickly over the next year as traffic fully shifts onto the new bridges, Banas said.
Officials load dismantled material onto a barge, which takes it offshore and uses a huge crane with a block and pulley system to lower it onto the bay floor. Each piece can weigh about 50,000 pounds.
Smith uses 3D imaging to make sure their placement adheres to certain restrictions, such as a 15-foot vertical clearance to prevent navigation hazards. It’s like a very heavy game of Tetris.
“With this stuff being really big, you’ve got to be careful. We can't just let it fall on top of each other.”
Most of VMRC’s artificial reefs are about a half-mile in diameter. Smith said ideally each site would be completely full, but it takes a long time to get enough materials, mostly donated from construction projects. Some sites last longer than others, depending on siltation on the bay bottom.
Once settled, the concrete should stay there for decades.
“You just put it down, and nature does the rest.”
