Posted November 26, 2016 | by Jessica Kirby, The Trowel
The Grasslands project in Regina, Saskatchewan, constructed by developer Devereaux, is a mixed-use retail and residential building responds to its context with beauty and contemprary style. The project is a non-combustible steel and concrete building complete with one level of underground parking that accommodates 53 vehicles, 23,000 square feet of main floor retail, and 62 luxury residential apartments spread over three floors.
Light-gauge steel stud bearing walls were used on the upper three levels with structural steel transfer beams above the main floor retail space. Cast-in-place concrete stair and elevator shafts were used for the building's lateral resistance, and the floor framing consists primarily of concrete filled deck supported by composite open-web steel joists.
Lochsa Engineering, engineer of record on the project, created the cold formed steel (CFS) fabrication shop drawings. The firm also completed structural design, which included augured concrete piles, cast-in-place concrete shearwalls, CFS bearing walls, and open web steel joist floor framing, said Lochsa principal, Jared Keller.
"For the CFS fabrication drawings, Lochsa co-ordinated with Fastwalls the location and cut length for every CFS component, including studs, tracks, and jambs, while considering shipping considerations for the pre-fabricated wall panels."
Driving challenges for Lochsa's scope of work on the project were the proposed construction schedule and fluctuating construction costs. Given the limited construction window for favourable conditions, the design of the building was split into various phases in order to remain in front of the contractors.
"This approach required Lochsa to submit an early foundation and structure package several months ahead of the other design team members," said Keller. "To minimize changes, additional co-ordination was necessary to try and minimize the impact of post-bid changes."
Fluctuating construction costs and labour availability also challenged the team, and there were multiple occasions in which Lochsa had to develop alternate plans to help bring the project back within budget, added Keller.
One of the project's unique features was its design with a mixture of traditional construction methods and prefabricated components. The hybrid approach helped shorten the construction window while allowing for more of the work to be fabricated off-site by steel stud framing company, Fastwalls.
"One of the project's unique features was its design with a mixture of traditional construction methods and prefabricated components."
The Nucor Ecospan composite floor joist system was also selected as a cost effective, simplified floor framing system capable of achieving a one-hour fire separation rating, said Keller.
Jim Freiberg, Ecospan sales representative, Mountain I North Central, said the floor system involves a steel, open web bar joist and structural metal deck, with a Shearflex® screw that connects the deck to the joists. Concrete is poured around the part of the fastener that protrudes above the deck, giving the floor its strength.
Given the project's two-year timeline, the Ecospan product was a logical fit. "We have a very simple assembly," said Freiberg. "You basically take an open web bar joist and one end bears on the outside bering Wall and the other on the inside corridor wall. When all the joists are in place, sheets of decking go over all of it, and that is a simple installation that someone with a carpentry background can achieve."
Because the job was pre-engineered, the Ecospan team had to fit its product into an earlier design that included plans for a different product. "There were some challenges, but we worked through those. Ecospan is relatively new to the Regina market so the people in the field had to be educated about what the installation looks like and how it fits together.
"We spent some time with them and team caught on quickly and mastered the process."
The labour force worked quickly and efficiently, flipping a floor about every week and a half. A significant help was the project's concrete subcontractor. "He was one of the best I've ever worked with," said Freiberg. "When he poured the concrete, the slab was all flat and level made the vertical construction go without a hitch because floors were level."
Another key to the project's success was the team's implementation of a simple framing system. "It goes outside wall to corridor wall, which allows the building to go up much faster than another system that would go from party wall to party wall."
Architect: Alton Tangedal Architect, Ltd.
Engineer of Record: Lochsa Engineering
Composite Flooring System: Nucor Ecospan
Pre-fabricated Steel Framing System: Fastwalls
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