Dec. 4, 2006
L&I advises checking tower cranes for water and ice damage
TUMWATER —Following last week’s structural damage that caused a Bellevue tower crane to be shut down and dismantled, the Department of Labor & Industries (L&I) is advising the construction industry to ensure that all tower cranes are checked for water and ice damage caused by recent harsh weather.
The preliminary investigation found that the likely cause of the structural cracks was water buildup in the legs of the cranes, coupled with the freezing temperatures. Unusually heavy rainfall in November could have filled the structure with water. The rainfall, followed by a sudden drop in temperature to well below freezing, accompanied by high wind, would have been sufficient to cause the retained water to freeze, causing expansion – and cracking – in the welds of the metal framework. The effect would be similar to water pipes bursting in freezing weather.
L&I is advising that all tower cranes in the state be checked to ensure they have good-sized “weep holes” and that the holes are open and draining properly.
The cause of the Nov. 16 tower-crane collapse has not yet been determined. The investigation is ongoing.
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For media information: Elaine Fischer, L&I, 360-902-5413 or nele235@LNI.wa.gov
