Job To Dig Massive Port Of Miami Tunnel Starts Scratching The Surface

By Risa Polansky
After decades of planning, the Florida Department of Transportation is digging into the Port of Miami tunnels project, with environmental work underway and a groundbreaking set for May.

Miami Beach-goers now are getting a taste of what’s to come over the next four years of construction on the billion-dollar project, with rigs set up in the MacArthur Causeway’s median for soil exploration and some lanes closed as a result, Alice Bravo, district director of transportation systems development, told Miami commissioners last week.

But when it comes to equipment, this barely scratches the surface.

It’s going to take a boring machine 42 feet in diameter to dig the two tunnels under Biscayne Bay.

The tunnels are designed to divert cargo-truck traffic out of downtown by linking Watson Island to the seaport on Dodge Island.

Now, 13,000 vehicles enter the port daily, Ms. Bravo said.

"Most ports have a direct highway access, and improving access to the port has been a longstanding need" that officials have been evaluating since the late ’70s or early ’80s, Ms. Bravo said, before pegging tunnels as the best solution.

Each of the twin tubes is to be 41 feet in diameter.

At their lowest point, the tunnels are to hit 120 feet below sea level, she said.

The boring machine is to be lowered in segments from a cavern in the MacArthur median and assembled underground.

It’s to reemerge and be disassembled on Dodge Island, brought back, and sent down again to bore the second tunnel, Ms. Bravo said.

During the peak of construction, about 400 workers are to be on site.

As far as traffic impact, the project involves reconfiguring roads and widening the MacArthur, with a new lane planned for each direction.

In May the contractor is to start building a frontage road parallel to the causeway and begin work on the eastbound lanes to shift traffic there, she said.

Around September, work is to begin in the median between the bridge’s eastbound and westbound lanes, which will serve as the main construction staging area.

Three lanes in each direction must be open during peak traffic, Ms. Bravo said, but Beach comers and goers will encounter some temporary lane closures during off-peak hours.

"We’re getting very close to the point of groundbreaking," she told commissioners.

The big event is expected in May, with completion anticipated the same month four years later.

Contractor team Miami Access Tunnel — with French firm Bouygues Travaux Publics heading construction — is charged with designing, building, financing, operating and maintaining the project.

The state is to contribute $457 million, Miami-Dade County $402.5 million and the city $50 million.

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