02.12.2006

Cracked crane

A tower crane has been discovered with large cracks in one of the vertical tubes of a tower section in Bellevue, Seattle only a city block from the scene of the fatal tower crane collapse in mid November.

The 100 metre high Liebherr crane was erected by the same company, Northwest Tower Crane Service of Tukwila and owned by Las Vegas based Coker Equipment.
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Steel Clamps and duck tape padding was used to "stabilise the crane"

The contractor Hanover Co and investigators from the state Department of Labor and Industries (L&I) are trying to figure out how the cracks occurred. A metallurgist X-rayed the section on Thursday and determined the cracks were serious enough that dismantling was necessary, the tower section will then be subjected to further tests.
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A Grove GMK450 with luffing jib was brought in from Ness crane for the inspections and clamping but Light stoped work on Friday night.

In the meantime steel collars have been fitted to the cracks, which appear to be in the vertical weld of one of the four main tubes, from spreading.

"I'm wondering why they weren't identified earlier," said Charles Lemon, crane-safety specialist for L&I. Still, I'm thankful that the employer found this before there was an accident."

After the accident on the 17th November Washington State inspectors visited the 13 other tower cranes in downtown Bellevue as a precaution. They reviewed contractors' maintenance records, took photos of each crane and apparently did not find anything untoward.
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A suspended platfrom was used to check the cracks and fit the clamps

The state governors office has advised crane owners and operators to perform a visual inspection of the their crane bases and towers for structural integrity problems, looking for cracks, cracked welds, stress fractures, chipped or flaking paint, loose bolts and rust spots.

“As part of any inspection of a work site involving cranes, L&I will look to see if an employer has fulfilled their responsibility to inspect the structures on a frequent and periodic basis”, the governor's statement said.