September 10, 2010

Saskatchewan bridge reopens after crane mishap

RICHARD GILBERT

staff writer

A bridge in southwest Saskatchewan has been repaired and re-opened to traffic, after it partially collapsed under the weight of a construction crane that is being used to rebuild the structure.

“We were two weeks into the project and a heavy crane was on site,” said Kirsten Leatherdale, communications branch manager with the Saskatchewan ministry of highways and infrastructure.

“Where the crane was placed on the bridge was not strong enough to support the crane. So, it ended up on the bank of the lake and partially in the water.”

A piece of the bridge on Highway 2, about 30 kilometres north of Moose Jaw, gave way and caused it to topple into Buffalo Pound Lake early on Aug. 28.

The crane was preparing to drive a steel pile when two concrete girders became overloaded and collapsed.

The crane operator was unharmed, but was forced to jump to safety.

The rest of the construction crew on the bridge ran to safety before the crane fell.

“The removal of the crane allowed for work to begin immediately on the repair of the timber piers that support the girders and the replacement of the concrete girders,” Leatherdale said

“This work has been inspected by an independent consulting engineer to confirm that the repair is safe, secure and sufficient to accommodate all highway traffic prior to the detour being removed.”

The contractor dragged the crane from shallow water using two excavators on Aug. 30.

It’s believed a small amount of oil may have leaked into Buffalo Pound Lake, which is a source of drinking water for Moose Jaw and Regina. The water has been tested and the leak has not been confirmed.

“Containment booms made of synthetic fabric were strung across the water on both sides of the bridge within an hour of the accident, and a vacuum truck was brought on site to mitigate any possible water contamination,” said Leatherdale.

Engineers are still investigating the cause of the partial collapse, which is considered to be dangerous by provincial Occupational Health and Safety (OH&S).

“When this type of incident happens, the employer, contractor and owner all share the duty to investigate and make a determination,” said Jennifer Fabian, OH&S director of safety services.

“They must look at cause and determine the appropriate remedial action to prevent its occurrence.

“We will follow up on the employer’s investigation because it is based on an engineer’s report. If this is inadequate, we will undertake our own investigation.”

Rehabilitation work to replace the 45-metre timber and concrete structure began earlier in the month.

Vehicles are once again moving through the construction zone on the northbound lane of the bridge.

The timber and concrete structure, which was built in 1963, will be replaced by a steel and concrete bridge.

The total cost is about $2.2 million.

“The bridge had been inspected in 2007 and again in 2009 and, although the structure was determined safe for motorists, the bridge had been proactively identified for replacement,” said Leatherdale.

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