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Posted 12/4/2012

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By Diana Fredlund
Portland District Public Affairs Office


PORTLAND, ORE. – Portland District personnel are preparing for emergency repairs to one of the downstream miter gates at The Dalles navigation lock between Dec. 5 and Dec. 7. 

 “We determined that one bushing on the downstream gate was deteriorating so quickly that without intervention it would result in a catastrophic failure,” said Frank Salber, The Dalles Dam maintenance manager.  “The bushing just was not going to last until our regular maintenance outage in March.”  Bushings are placed between the gate hinge and the support pin, which allow the lock gates to smoothly swing open and closed.

 Engineers, mechanics and other staff found an innovative way to replace the failing bushing on the upper hinge: machinists are creating some ingenious tools and fabricating replacement parts that will be used during the repair.

 Custom tools are often needed at a large multipurpose facility like The Dalles Dam, Salber said.  “Our craftsmen are very good at building special tooling to perform unusual tasks. In this case we have built a hydraulically actuated device for turning a very large turnbuckle.”

 “Normally, a repair like this would require dewatering the lock, devising a means to support and manipulate the 800,000 pound gate and remove the pin to get at the bushing – a process that might take a month or longer,” said Mike Colesar, The Dalles Dam engineering manager.  “We believe we can safely keep the gate from moving with water pressure alone, allowing us to loosen the anchors and replace the bushing without removing the pin.  It required some out-of-the-box thinking to find this much faster and cheaper method.”

Innovation and ingenuity are valuable tools the Corps is using to keep river traffic flowing.  Whether it’s designing just the right tool for the job or a new way to use it, skilled craftsmen and mechanics at The Dalles Dam make it possible to find solutions that are as free-flowing as the river should be.

The Dalles