June 6, 2012

Hybrid steel system checks in at Winnipeg airport hotel

RAYMOND SC WAN ARCHITECT

The Grand Hotel in Winnipeg is an example of the first large application, in Western Canada, of a hybrid structural system which uses Deltabeam.

DON PROCTER

correspondent

A seven-storey hotel being constructed at Winnipeg's James Armstrong Richardson International Airport is the first sizable application in Western Canada of a hybrid structural system consisting of a trapezoidal-shaped steel beam called Deltabeam connected to precast hollow-core concrete slabs.

Deltabeams are manufactured by Peikko Canada Inc., a Quebec City-based steel engineering and manufacturing company.

“Each floor has over 25 beams — each 22 feet long,” explains Mark Johanson, Peikko’s marketing director.

The hybrid system is one of several on the market.

Peikko engineer Guy Bernuy says one of the reasons the Deltabeam/hollow-core system was specified for the Grand Airport Hotel is that it eliminates obstructions in lower floors.

“The Deltabeams supported by columns create a column-supported flat floor. It allows for flexibility in the use of the space, especially on the lower floors,” says Bernuy.

Deltabeam offers architects design flexibility because a steel section can be added to the bottom plate for esthetic purposes, Johanson adds.

The idea behind the hybrid structural system is to create a slim floor. Eight-inch precast concrete hollow-core slabs match the depth of the Deltabeams.

The system costs less than conventional cast-in-place concrete partly because of speed of erection, says Johanson, adding that on some projects it erects in half the time.

One beam can be erected and installed in as little as a minute because the beams don’t require on-site welding or bolting. They are simply dropped onto the connection, which is welded onto a steel column or casted in a precast concrete column, says Johanson.

“Compared to a steel structure, it offers a slimmer floor and uses up less space (up to two feet less per floor because there is no downstanding beam) so heating and cooling costs will be lower and the height of building can be smaller.”

“Another benefit,” adds Johanson, “is you don’t need to break the top extremities of the hollow core to place concrete because the beam’s trapezoidal design accommodates the concrete.

“The beam disappears into the structure,” he says, noting that only the 3/8”-thick bottom flange remains visible.

Another plus is the installation of the beams can be adjusted up to a 1/2” in either direction because of the way the connections are detailed.

The hybrid system also is easy to sound-proof with a layer of acoustic insulation or sound dampening material under the one-inch topping (poured-in-place concrete) over each floor slab.

The new breed of hybrid systems is lighter than cast-in-place concrete structures. Peikko’s Deltabeam and the hollow-core precast slabs, for instance, weigh up to 30 per cent less. The plus is that columns, footings and foundations can be smaller. Johanson credits the project’s architect Raymond SC Wan Architect of Winnipeg for specifying the unconventional system for the hotel.

While Peikko uses more Deltabeams per floor at the Winnipeg airport than at any other structure in its portfolio, the company is involved in other notable projects.

The 30-storey Renaissance II condo tower in London, Ont., is a case in point.

The tower might be the tallest residential precast concrete building in North America when it is capped off this summer, says Johanson.

Specifying the hybrid structural system for that tower has contributed to cutting six months off the construction schedule, he says.

Furthermore, the tower has been erected with half the labor required for the twin condo tower constructed with a Hambro steel composite floor system. “Reducing risk management is a big plus there because fewer workers are required.”

The hybrid system’s future looks bright — particularly in the high-rise market, says Johanson. “It is where we want to focus over the next four or five years.”>

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