November 23, 2009

Geotechnical engineering

Sinkhole halts construction on Calgary emergency operations centre

RICHARD GILBERT

staff writer

A sinkhole next to the active construction site of Calgary’s new emergency operations centre has stopped work on the project.

“In terms of the situation we have before us, we were under construction and the excavation has been completed,” said Sharon Purvis, director of corporate properties and buildings for the city of Calgary.

“We put our supporting walls in and the shotcrete was applied. We started with the foundation at one point around the bottom and noticed some shifting. So we looked for a void.”

During the night of Nov. 11, a separation between the asphalt on First Street was noticed. The next day, the road slumped for 25 metres.

“We took measures by spraying gravel against the east wall to stabilize it against any movement,” said Purvis. “We finished spaying the three quarter inch crushed gravel on Nov. 16.”

The city has closed First Street between Fifth and Sixth avenues until engineers can determine what caused the metre-deep sinkhole and determine how to fix it.

Purvis said the city will continue to monitor the road and an adjacent building.

“We have been shooting or surveying the building directly east of the site and there has been no movement to date,” he said. “We have pre-excavation data, which is being compared with new data daily. We are also undertaking visual inspections.”

If the city does not find any further movement, work will resume on the east side of the site.

The owner of the three-storey apartment building adjacent to the site expressed concern that the project is threatening his property.

In a CBC story, he said several new cracks have been noticed in the foundation of his building and the ground around it has sunk by half an inch.

The city began construction on the new Emergency Operations Centre in June. The 53,000 square foot building is being built primarily underground. It is designed to serve as a self-sustaining command centre for members of more than 30 partner agencies during a disaster or major emergency.

The $54 million facility, which will be home to staff of the Calgary Emergency Management Agency, is expected to open in early 2012.

In the last year, at least three massive sinkholes have developed under roads or parking lots adjacent to a suspended condominium construction project in downtown Calgary.

Print | Email | Comment