Digging machine 'Harriet' finishes first tunnel at PortMiami
Updated On: Aug 01 2012 10:58:29 AM EDT
An enormous drill named "Harriet" reached the turnaround point at Dodge Island Tuesday morning, signaling the completion of the first of two tunnels connecting downtown Miami to the Port of Miami.
Despite intense, sweltering heat spirits were high at PortMiami as Harriet, the massive tunnel-boring machine, burst through the concrete wall.
There was a party atmosphere as confetti shot up into the sky cascading on the dozens of workers eager to watch the historic moment firsthand.
Harriet traveled 4,000 feet to get here which is the halfway point for the first of its kind project.
In an instant, history was made. And when Harriet's cutter head burst through the concrete, engineers watched in awe.
The men who navigated Harriet under Biscayne Bay spoke with Local 10's Christina Vazquez and told her that what impressed them the most was the machine's ability to travel 4,000 feet and hit its mark spot on.
"Some of the challenges were keeping up with the distances in the tunnel, keeping our sites at equal distance," said Robert Loane. "In the turn it was a little bit tough."
With no GPS underground, the surveyors relied on a specialized laser.
"The laser, which works on the speed of light, gives you the distance and the compass gives you the angle," said Mael Le Coq. "I was a bit nervous, because you never know."
"I'll celebrate a little bit tonight," said Loane. "I can't go too crazy though. I have to work tomorrow."
With the eastbound lanes of the new tunnel now complete it will take two to three month to turn the large machine around so it can begin boring back under Biscayne Bay to create the westbound lanes.
When complete in 2014, the tunnel will help ease traffic in Downtown Miami providing a direct link for cargo trucks to travel from the Port to I-95.
Port Director Bill Johnson said in coordination with other improvement projects, to include the deepwater dredge, it will make Port Miami attractive to new companies out of Asia.
The completion date dovetails with the current expansion project at the Panama Canal which will allow for larger cargo ships to pass through.
Johnson said Port Miami will be in position to process those larger loads once all the projects are complete.
Harriet is more than a football field and a half long and weighs 6.5 million pounds. The machine is several stories high.
"Instead of looking at this like a machine, this is a complete factory," said Herrenknecht Project Manager Aaron Scarfia.
"This is the piece that actually is going to scrape against the ground," said Scarfia, referring to the machine's cutter head.
The cutter head will drill through rock with the help of 266 cutting knives and 34 cutter discs.
"As you're cutting through the ground, these [cutter discs] will rotate and cut the dirt," said Scarfia.
- VIDEO: How "Harriet" works
Crews use foam to turn the soil they dig up into putty, which is carted off on the conveyor belt above the MacArthur Causeway. The belt can remove 2,000 tons of material per hour.
"It's just fascinating that you can stand in one place and see what's functioning on the entire machine," Scarfia said of the control room.
The tunnel itself is made up of rings, which are placed one at a time. Each ring is made up of eight concrete segments. Those segments weigh 25,000 pounds, and measure 14-feet long, 5-feet wide and 2-feet deep.
The construction crews plan on using 12,000 concrete segments.
Thrust cylinders propel the machine forward, and brushes leave grease to seal the edges of the concrete.
During an emergency, the 16 person crew takes refuge in a small bunker. Inside, communication devices give them access to the outside world to call for help.
It will take about two to three months for Harriet to come out of the tunnel. At that point, it will be turned around and start the westbound tunnel back to Miami.
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