Revitalizing BC Place and installing one of the world's first fixed and retractable fabric roof was an exercise in heavy lifting that has earned PCL Constructors Westcoast Inc. a Silver Award of Excellence from the Vancouver Regional Construction Association in the category of General Contractor over $40 million.
“It was exciting to work with a lot of these large pieces of installation,” said PCL project director Andy Tallentire.
A total of 36, 50-metre tall masts, each weighing 250 tons, had to be placed with 36, 30-metre compression beams weighing 160-tons each, securing them.
The central node anchor for the roof cable consisted of two seven-inch thick steel plates, weighing 150 tons.
It was so large that its finials were left off passing it through the stadium’s largest door, which easily accommodates two tractor-trailers.
About 35 kilometres of cable support the roof and 1,000 pieces of secondary steel, weighing 18,000 tons.
The steel and post-tensioned, radial cable truss roof comprises both a fixed and retractable part.
The retractable roof was split into four sections for shipping to the site and each quarter, weighing 20-tons, was winched into place.
“There were 11 cranes on site at one time,” said Tallentire.
The tallest was an 11,000-ton crane with 300 feet of boom reach.
It arrived on the back of 70 trucks for on-site assembly.
The roof’s cable system grew into a virtual spider’s web.
Cranes had to strategically feed building material and parts throughout.
The 36 fabric panels making up the fixed roof had to be purpose-folded to fit through the maze.
“The biggest challenge was just the logistics and erecting these massive elements in a very small site. In the (stadium’s) bowl, the 11,000 ton crane could barely turn around,” said project superintendent Michael Halajian.
Moves were choreographed with the finesse of a ballet as men, equipment, and construction materials all shared space.
“We had spotters on the high towers, spotters on the ground and spotters at the higher elevations making sure that nothing that was airborne was snagged,” he said.
The masts, which sit like ribs on the crown, were fabricated in three sections to facilitate shipping and then joined at the erection site using a jig, said Halajian.
When the compression beams were placed, a crane had to lean the masts back to give the crews enough installation room.
In some areas, a crane or scaffold couldn’t facilitate construction.
PCL employed about 200 rope access workers, individuals whose only fall protection was tethered safety points.
“It is a specialty that is not acknowledged under WorkSafeBC,” said Halajian.
An engineered working plan for these rope access workers was developed to meet WorkSafeBC’s approval.
“These are highly-trained individuals and we could not have done the project without them.”
The roof components were fabricated throughout the world with PCL employing two quality control officers visiting and monitoring production facilities.
Nature and politics wreaked havoc.
In Thailand, civil unrest interrupted the steel fabrication, where Thai fabricators worked to Canadian Welding Bureau standards.
Airfreight from Europe ran into Iceland’s erupting volcano stalling delivery, while in Japan the tsunami caused problems.
“There were times we would be watching an event on television and wondering if our parts were going to get to the port,” said Halajian.
At the project’s end, a lesson was learned by many younger supervisors, said Halajian.
“Absolutely anything is possible if you put together a good team,” he said.
Crews double shifted and worked weekends to make it happen.
“We had foremen, who stayed on the job every day,” he said. “This was a once in a lifetime project to work on.”
The work was further complicated by BC Place’s interior renovation, which included seat replacement, new centre field, seismic dampers, complete replacement of the exterior glazing and doors, replacement of three of the older entrance gates.
The work also included the upgrading of the digital signage, installation of Wi-Fi and 3G and 4G wireless systems.
Panther Constructors also worked on the project, installing a dividing screen that separates the upper and lower seats.
The installation earned Panther a VRCA Gold Award of Excellence in the innovation’s category.
Exacting standards - measured in millimetres - had to be met by crews in many of the construction phases.
“When you look at the tolerances that had to be met, the thing came together more like a Swiss watch rather than a normal steel structure,” Halajian said.