The parkade for the 351 Water Street building is already completely constructed.
Now it needs to be assembled.
The newest office tower in St. John’s is being constructed partially with a method that hasn’t been done in this province before, says building owner East Port’s vice-president, Judy Wall. The building is being constructed with precast concrete slabs built offsite.
“Which means it’s made in a factory in a controlled environment so it’s premade, it’s prestressed. Because it’s done under strict, interior, controlled environment conditions, you’re left with a very good product,” Wall said.
Precast concrete requires less maintenance, lasts longer, and looks better, said Wall, who bases her assesment on a parkade East Port built on the Halifax harbourfront in 1985.
“If you walk through that parked now, it is still in excellent shape compared to a cast-in-place or steel structure.”
Wall said the St. John’s building will see the same benefits.
“Because it’s prestressed you don’t see cracking and you don’t see wear and you don’t see the sort of things you’d see in cast-in-place concrete over time.”
With those advantages come some logistical challenges in getting the pre-cast concrete slabs, which can weigh upwards of 45,000 pounds, to the site.
When those pieces are made in another province, the challenges become even greater.
Once the decision was made to build the parkade with premade pieces, instead of the more common method of pouring concrete into forms on site, East Port had to find somebody to do the work.
They looked around Newfoundland first, said Wall, but didn’t find a company doing precast on the scale required for this project.
“The issue was that there wasn’t a plant in St. John’s. We did look to see if we could get even some of it at least done here but you’ve got to have the casting beds and it has to be in an enclosed area.”
In the end, East Port chose to go with Nova Scotia-based company Strescon, because it has the facilities and the experience to complete the job, said Wall.
Once made, the pieces were then shipped on trailers through Oceanex to a yard in Mount Pearl that East Port used to hold the pieces until they were needed.
Adding to the complication was Strescon’s desire to build all sizes of each piece before moving onto the next, and East Port’s desire to have the pieces arranged in the holding yard in a way that made sense for construction.
Each piece had its own detailed drawing.
“There were something like, I believe, 200 pages of detail drawings for that garage because each piece, even if they look exactly the same, there are subtle differences,” said Wall.
The pieces, and putting them together, could be compared to building something with LEGO pieces, with the notable difference of each piece not being exactly the same.
“Because each piece could be slightly different, it would be like trying to put LEGO together with 1,089 pieces and having to keep track of which piece went where so in other words you couldn’t just take an eight-piece red LEGO block and put it anywhere,” Wall said.
The process was “incredibly challenging,” said Wall, who has been impressed with the quality of work from each contractor.
Once all the pieces were made and delivered, they were then brought onto the site as needed, where they are assembled by American Steel & Precast Erectors, a company based in New Hampshire.
The use of an American company came after looking for a local firm to do the work, said Wall, adding that Strescon declined an offer to do the installation work.
Strescon recommended ASPE, who had the required experience.
East Port has attempted to use Newfoundland labour wherever possible, said Wall, and ASPE has hired local workers who they’ve since trained.
The parkade construction is ahead of schedule, partly because the weather has co-operated, said Wall.
Construction on the parkade is expected to be completed in June, with the rest of the building using a steel and cast concrete building method.
St. John’s newest office building, 351 Water Street, has an opening date of April, 2014.