John Day Lock & Dam Gate & Sheave Replacement

Project Description

AAC plans to remove and replace the existing downstream gate in four sections each, using a 660 ton barge mounted crane. Assembly of the derrick crane will occur at AAC’s Linnton facility located on the Willamette River and will then bemoved to Columbia Business Park in Vancouver, WA toload thenew gate sections being fabricated by Oregon Iron Works. Thederrickwill then be transported upriver to the dam to begin work.Replacement of thedownstream gate will require a 14 week navigational lock closure scheduled to begin December 10, 2010. Due to the necessity of the river being closed in order to complete this work, AAC crews will work double shifts six and seven days per week. AAC’s contract includes replacement of the full mechanical drive system. Work will include jacking the two, 1 million pound counterweights to remove tension from the 32 wire ropes. The wire ropes will then be removed from the 18’ diameter steel sheave to allow for its removal. After the sheaves are replaced AAC will completely replace the gearing, bearings, electric motors and brakes that operate the gate.

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