CASCADE LOCKS — Most Oregonians know it for its fish ladder and its role in Oregon’s hydropower history, but Bonneville Dam is also home to the one of the world’s few concrete swing bridges. All 4 million pounds of it.
Installed in the early 1990s and measuring about 186 feet, the swing bridge stretches across the navigation channel and opens for tugboat traffic. If the bridge goes out of commission, so does all the upper Columbia barge traffic.
The swing bridge, and other dam bridges across the state, are swinging easier these days, thanks to some innovative self-lubricating bearings made by Eugene-based Columbia Industrial Products (CIP).
The bearings, or wear pads, that the bridge rests on are no small engineering feat. Originally made from bronze or brass, the bearings required oil for lubrication, something that quickly became an environmental issue since the bearings are located near or in water. For eight years the U.S. Army Corps of Engineers sponsored a worldwide testing program to encourage development of cleaner, more cost-effective bearings. CIP’s bearings, made of polyester textiles and resins, emerged as the best product because it needed no exterior lubricant. CIP is now a $2.3 million business.
The new bearings, installed during the annual weeklong lock outage in March, create less friction than previous models and have their own internal lubrication, making them more environmentally friendly. These multi-tasking wonders keep the bridge, and the river traffic, moving.
— Colleen Moran