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Photo courtesy of WACA
United Grainís cleaning tower in Vancouver, standing at more than 300 feet, is the tallest concrete slipform silo in North America.

United Grain Corp.

Location: Vancouver

Owner/developer: United Grain Corp.

Project team: Younglove Construction, general contractor and architect; Larson Engineering, structural engineer; Whitaker/Ellis Builders, concrete contractor; CalPortland, ready-mix supplier

United Grain Corp.ís Vancouver export terminal is the largest grain elevator on the West Coast. The $72 million project consists of a cleaning tower more than 300 feet tall and 26 new silos, adding a total of 66,000 metric tons of storage.

Auger cast piles required nearly 4,600 cubic yards of a 10-sack mix, and rebar was set for the mat foundation. A double mat of rebar was used to support the 26 silos that would be built on the slab. Five boom pumps were required to place the 400 cubic yards per hour supplied to the mat.

While the mat slab was being formed, the forms for the cleaning tower were completed, with the steel structure placed on top of the climbing form. Once this concrete pour started, the structure was elevated as the forms climbed on the concrete structure. This method saves the contractor from tying up the crane lifting the steel parts into place to build it 300 feet in the air.

The cleaning/shipping annex consisted of a four-pack of 35-foot-diameter silos slipped to a height of 176 feet, with two silos extending to 300 feet. This is the tallest concrete slipform silo in North America. Halfway up, the pump could no longer reach, so the crane placed the rest of the concrete. This placement took just about 10 days to top out, running continuously.

Once the cleaning tower was completed, the contractor did back-to-back concrete slips of two large annexes. The first was a 12-pack of 35-foot-diameter silos, each 125 feet high. The other was a 14-pack of 35-foot-diameter silos. Both consisted of over 5,000 cubic yards of concrete and a total of 2.25 million pounds of reinforcing steel.

Since the project was built in a secure area of the port, all drivers and quality control staff had to be issued Transportation Worker Identification Credential cards from the U.S. Department of Homeland Security.

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