Downtown block party
New transit terminal going together like LEGO blocks
For school-aged “engineers,” it can be a challenge to build something using a Meccano set or LEGO blocks.
But that’s nothing compared to the planning and attention to detail involved in creating a blocklong building, using pre-cast concrete components in a congested downtown locale.
But Mark Timmins has done it all before. Now he’s overseeing work on the City’s new regional transit terminal and parkade structure. Workers are rapidly putting it together, piece by piece.
“There’s over 400 pieces,” says Timmins, site superintendent for the contractor, Graham.
And they’re large, some of them as heavy as 25,000 or 35,000 pounds. They range from the vertical pillars that show how tall the building will be, to the “double T” panels that become the parkade floor. Exterior panels — many of them featuring a brick-like facade — and concrete stairwells are also part of the mix.
Based on the design of JMAA Architects in Red Deer, the prestressed concrete elements were pre-cast in Calgary. But day after day, they’ve been arriving at the 5 Avenue South construction site here — almost like clockwork.
Timmins explains the pre-cast order was being completed as subcontractors were onsite here, creating the footings and foundation for the $17-million project. But then the pieces were trucked to a large “lay down” site just east of Lethbridge.
And as the massive, 350-tonne crawler crane is lifting one part into place, a flatbed truck rolls in with the next piece.
“It’s all co-ordinated,” the construction superintendent says. “We average 10 to 15 pieces a day.”
At that rate, all the precast could be in place by month’s end.
Then the crane will be dismantled and the building will be hoarded and heated to allow interior construction to proceed through the winter.
While the 293-stall parkade will be substantially in place, Timmins says the project also includes office space, passenger waiting areas, an elevator and other passenger amenities.
That means people in the electrical, plumbing, heating and other trades will be arriving as the structural workers finish off. The project’s target date for completion is “early 2019.”
“There is still a lot of work to be done,” he adds.
But construction has gone much faster, Timmins says, because it called for pre-cast. Once the concrete panels are in place, he adds, connecting steel plates cast into the concrete are welded to the next component.
Large concrete structures using the conventional pour-in-place approach often take longer, Timmins points out, because they need more onsite workers and supervisors. This phase, he says, requires just 15 experienced workers.
Another consideration, he adds: Rain or cold weather may also hamper projects using the older approach, using concrete mix trucks and plywood forms. On the other hand, Timmins says strong winds can put an end to crane work that day. So far, “windy Lethbridge” has seen just one day lost on this job.
Graham is a Calgary-based construction solutions partner with projects throughout North America, and it’s Canada’s sixth largest construction company.
Now as the heavy lifting nears an end, the superintendent says he’s pleased with the project — and the comments from “sidewalk superintendents.”
People are happy to see brick veneer as part of the exterior finish, he says. It was selected to complement the brick used on many nearby buildings downtown. “That’s a nice feature,” he says. The facility will also boost the number of downtown parking spaces, he observes, while providing a more comfortable off-street area for Lethbridge Transit passengers.
But for now, Timmins is enjoying the public’s response to this significant addition to our downtown facilities.
“It’s certainly created a lot of excitement for the public walking by,” he says.
And not a few onlookers have compared it to Lego.