PITTSBURGH (KDKA) — Installation of the first part of the new Shaler Street Bridge is finally underway.

PennDOT crews are working around the clock to get the new span installed and get traffic moving again along the heavily-traveled area.

WATCH LIVE: Installation of part one begins —

Consider the numbers involved in moving a 70-foot concrete and steel bridge span: “essentially we’re moving around 300 tons plus the weight of the trailer,” says Patrick Heer of Mammoet International.

Instead of building the bridge from the ground up, PennDOT is instead installing it. They are calling the process “Innovative Bridge Moving Technology.”

Mammoet does this kind of work all over the world and brought in two trailers for this job. These are far from average trailers. Motorized, each one rolls on 48 very dense tires, in sync with each other at about seven-tenths of a mile an hour. You could easily outwalk this machine.

“To an untrained eye it would seem to be very delicate,” Heer says, “But actually the body itself is very rigid. What we have to make sure is everything is level and we don’t have any abrupt change in the direction or the speed of the transport.”

To assure a level ride, 2,500 tons of gravel were spread on Saw Mill Run after the Steelers crowd cleared through after Sunday’s game.

PennDOT Dist. 11 Assistant Executive for Construction Jason Zang says, “The gravel was grated to within a 16th of an inch elevation with GPS technology on the machines, then roller compacted, because if the roadway dropped in a place or the machine got stuck, you’re talking about a 270 ton bridge sitting on top of it kind of precariously, too. It’s very is high up.”

PennDOT District 11 Executive Cheryl Moon-Sirianni says this kind of “Rapid Bridge Construction,” while more expensive, is preferable to long term closures.

“A bridge like this where you can take a closure down from six months to a couple weeks– that’s definitely a plus,” she said.

If all goes as planned and the second span slips into place Tuesday as easily as the first span did Monday, Saw Mill Run is expected to reopen by Wednesday morning.

“Of course we’re a little worried everything goes into place, but if this works well, we’re going to be using technology like this on many of our bridges,” Cheryl Moon-Sirianni, PennDOT District 11 Executive, said.

KDKA has learned it’s a first for PennDOT. The technique is called a “Self-Propelled Modular Transporter.” By using it, they’ll be able to complete the work much quicker.

Caution tape and construction signs are up all over the area, and the pace of the work is slow but steady.

(Photo Credit: KDKA)

(Photo Credit: John Shumway/KDKA)

To make all of it happen, part of Route 19 – northbound and southbound – are closed until 6 a.m. Wednesday.

That means around 31,000 drivers a day are being detoured.

Here are the official detours drivers can follow:

Traveling North On Route 19:

  • Take the left-hand ramp to West 376/South 19 toward Carnegie/Airport
  • Turn right onto Woodville Avenue
  • Turn right onto Greentree Road
  • Greentree Road becomes Wabash Street
  • Turn right onto South Main Street
  • Follow South Main Street to the West End Circle
  • End detour

Traveling South On Route 19:

  • From the West End Circle, take Steuben Street
  • Turn left onto Short Street
  • Bear right onto South Main Street
  • Turn left onto Wabash Street
  • Wabash Street becomes Greentree Road
  • Turn left onto Woodville Avenue
  • Turn right onto the ramp to I-376 Parkway West
  • To continue to southbound Route 19, bear left toward South Truck 19/51 toward Uniontown
  • Stay left toward East 376/South 51 toward Uniontown
  • Take the South Truck 19/51 ramp (Exit 69B) toward Uniontown
  • End detour

The work is part of a $14.5 million improvement project.

Work on the bridge will last about two weeks.

Meanwhile, across town, PennDOT closed a couple of critical ramps today for 37 days. The closings are needed to give the contractor room to work on the CAP project.

The ramp from Bedford Avenue onto Southbound 579 is closed. That’s the ramp that carries daily commuters from the PPG Arena parking lots to the Liberty Bridge, Boulevard of the Allies and the Parkway East.

Also closed is the ramp from Seventh Avenue onto 579 between the federal building and steel tower.

Moon-Sirianni says, “We’re going to be apologizing for the next year and a half for all the inconveniences we’re going to put on the Penguins fans and folks traveling in and out of the city. We’re trying to minimize it but there will be more as we go on.”

Grant Street is expected to get much of the detoured traffic, “Grant Street is already busy at rush hour so we’ll be watching to see what we can do.”

Stay with KDKA for the latest on this developing story.