The Army Corps of Engineers (Portland District) issued notice to proceed to Advanced American Construction, Inc. (AAC) on October 8, 2009 for the Downstream Gate and Friction Sheave Replacement at the John Day Dam navigational lock. John Day Dam is located on the Columbia River near Rufus, Oregon, 2 hours east of Portland. The weight of the downstream gate was in excess of 2 million pounds. AAC removed and replaced the downsteam gate in four sections each, using a 660 ton barge mounted crane. Once loaded, the derrick barge was transported upriver to the John Day Dam to begin work. Replacement of the downstream gate required a 14 week navigational lock closure that began December 10, 2010. Due to the necessity of the river being closed in order to complete this work, AAC crews worked double shifts six and seven days per week.
In addition to replacing the navigational lock gate, AAC’s contract included replacement of the full mechanical drive system. Work included jacking the two, 1 million pound counterweights, removal of the wire ropes and replacement of the friction sheaves with a 300 ton crane from the dam.