Gushing in from all corners, all sides, the country's most massive concrete pour ever streamed into Calgary's Bow tower site downtown Saturday, marking the start of construction for what will be the tallest building in Western Canada.

More than 68 trucks delivering enough concrete for 2,800 home foundations made their way through downtown streets starting Friday and continuing into this afternoon as part of the first stage of the new headquarters for Encana Corp.

The 36-hour continuous run of concrete, involving more than 500 workers, shatters previous Calgary records, including pours for the Calgary Tower and Stampede Corral.

"There has never been a base of a building (in Canada) that's actually this big and this deep," said Michael Brown, associate vice-president for Matthews Development, builder for the project.
Not only is it the largest pour to happen on Canadian soil, but it is the third largest in the world, behind the Howard Hughes Center in Los Angeles and the Al Durrah Tower in Dubai.

To fill the 2,787 square metre base more than 1,000 truckloads of concrete were used, pouring more than 14,000 cubic metres of concrete into the six storey hole. Although it is expected to dry in a few days, crews will stay off for a couple of weeks "just to be safe," said Brown.

A huge amount of concrete is needed to ensure a solid base for the building, said Brown.
Because the building is very tall and very large, many things were considered in the three months it took to plan the pour, including the consistency of the ground under the foundation.

As well, planners had to figure out the best way to bring the concrete into downtown, including co-ordinating timing of the trucks so the concrete remained at a proper consistency and workers could manage continuous pouring.

Once the foundation has dried, steel columns will be erected, forming the skeleton of the 58-storey building. From there, construction of a six-storey underground parkade will begin.
The first floor of the building is expected to be built by the beginning of October, and from there crews will build one floor per week. The exterior construction is expected to take until fall 2009, and Brown says the entire project will be finished sometime in 2011. 

"When you build a building of this magnitude you have a number of milestones. Today is probably one of the bigger milestones we are going to achieve this year," said Brown.

With a price tag of over $10 million, this weekend's pour is small portion of the $1 billion needed for the exterior construction. An additional $1.5 billion will go inside the building in the form of mechanics and furnishings.
"This is a very important building for downtown Calgary," said mayor Dave Bronconnier, who was at the site Saturday morning.
"It's a huge part of our heritage and history."
And despite speculation the construction will interfere with this year's Stampede parade, Bronconnier said 6th Avenue will reopen by early July and "the parade will go as scheduled without question."

Since the closure of 6th Avenue last August, to make way for excavation of the tower, commuters have run into traffic jams downtown. And while the city can't promise that roads won't need to be closed as the tower is built, they will make sure to let people know early and often said Colleen Brown, communications advisor for traffic engineering for the City of Calgary.

"We don't necessarily know what closures will happen," she said.
"For now we are recommending that people avoid the area as much as they can."
As far as noise, Calgarians won't have to deal with the extreme levels caused by the pour, but can expect the regular sounds that would come from  any construction site, said Kerry Gillis, senior vice president of operations for Ledcor Construction, the construction manager for the project.

"Unfortunately there's not much we can do about the noise," he said.
Kerry said the unique shape of the tower will help minimize its environmental footprint. Lots of windows will ensure maximum daylight and environmentally friendly electrical and mechanical fixtures will be installed.
"If you have those green attributes it saves you money in your operating costs," he said.
The tower is sure to be a sight once completed, said Michael Brown.

The square-footage of the building, makes it 30 to 60 percent bigger than most other buildings in downtown Calgary.
 

"It's going to redefine the Calgary skyline," he said.