August 18, 2010

PAVCO

The first of the 130-ton masts is lifted into position at BC Place Stadium.

Work begins on new retractable roof for BC Place Stadium

BRADLEY FEHR

Journal of Commerce editor

VANCOUVER

The new roof on BC Place Stadium is taking shape on Vancouver’s skyline. Construction crews recently started erecting the 36 masts that will ring the stadium and keep the new retractable roof in place.

“It’s one of the most complicated projects taken on in this community,” said David Podmore, chairman of BC Pavilion Corporation (PavCo), the Crown corporation that manages the stadium. “It’s a difficult project on a tight schedule.”

PCL Westcoast Constructor Inc. is the general contractor.

Each mast is about 50-meters long and weighs about 130 tons.

A massive crane is being used to put them in place. It can lift more than 1,100 tons, but has a capacity of 600 tons in its current configuration.

“It’s the largest crane I’ve seen,” Podmore said.

Eighty-five semi-trailers were needed to get the crane to jobsite.

Each mast will be assembled on site after arriving in three different pieces.

They are welded on a specially made machine that turns the mast, so the welding is done continuously.

Each of the masts will be erected in opposition.

“We’re really building 18 suspension bridges,” Podmore explained.

Temporary cables and supports are being used until the masts are attached to the center node, which itself weighs 120 tons.

The node sits 200 feet above the stadium floor, which is where it will be when the new roof is complete and is at the same height as the old inflatable roof. The node currently rests on a massive jacking tower that will be removed when the tensioning of the 90 mm (3.5 inch) cables, attaching the masts to the node, is complete.

The cables will be up to 366 metres in length and about 35 kilometres of the cable will be used for the project.

The 36 masts will be held together with compression beams, but won’t remain stationary.

“The stadium roof will float on the ring beam on a series of bearings,” Podmore said.

In order to do this, construction crews reinforced the ring beam that runs along the top of the stadium.

About 18,000 tons of steel will be used for the roof and its supports, which is roughly equivalent to the amount of steel used in the new Vancouver Convention Center.

With the tower out of the way and the tensioning done, the fabric will be put in place. The new retractable roof will open or close in 20 minutes and is expected to have a 40-year lifespan.

A similar roof exists on a stadium in Germany, but there are several important differences in the design and scope of the projects.

“The roof, when done, will be able to handle Vancouver snow loads,” Podmore said.

The BC Place roof has been designed to handle a snow load of up to seven million kilograms.

Podmore added that this roof is much larger than the similarly designed roofs that exist in Europe.

Work on the new stadium also includes installation of new lighting, a sound system and a centre-hung scoreboard.

So far the roof replacement is on schedule.

“Virtually all of the components for the building have been tendered,” Podmore said.

He added that most of the roof components are either fabricated and delivered or fabricated and on their way.

Seismic upgrades to the remainder of the stadium are being performed at the same time as the roof replacement and BC Place will be used as a regional emergency shelter after all the upgrades are complete.

PCL signed a $465 million fixed-price contract with PavCo, which includes $25 million for structural upgrades.

The entire budget for the project is $563 million, which includes interior renovations, new suites and redesigned space for vendors.

In May, the iconic air-supported roof was deflated and construction activity on the second phase started.

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