Since the 1930s, gantry cranes have moved equipment and lifted spillway gates to varying heights at Bonneville Dam.
The Corps mobilized some of the world’s largest mobile cranes to maneuver mammoth sections of old and new downstream navigation lock gates at several Columbia River dams in 2010. The cranes removed six old gate sections, offloaded new sections from floating barges and installed new pre-fabricated sections.
With a 200-foot main boom to balance and 250 tons to lift, the crane is stacked with 1.4 million pounds of counterweight during a job at John Day Dam.
In the Willamette Valley, Dexter Dam’s permanent gantry crane stands sentry as a mobile crane supports spillway gate repairs. The mobile crane lifts a new gate arm into place.
On the Oregon coast, mobile cranes moved enormous rocks to repair the cap of the Tillamook Jetty. These modern workhorses lugged rocks weighing up to 50 tons to build up a safer entrance to Tillamook Bay for maritime traffic.
With another in the background, a crane dredges sediment near Bonneville Dam. If not removed, sediment can enter a flow channel and settle inside the dam structure, where its removal is more difficult.
Gantry Cranes
Gantry cranes on the exterior decks of Corps powerhouses install and remove stoplogs for maintenance and lift spillway gates for repairs. The cranes move the length of the powerhouse on deck rails.
Water-filled bags hang from the John Day Dam gantry crane during a load test of its 50-ton capacity.
Bridge Cranes
Overhead bridge cranes travel the interior length of Corps powerhouses, mounted on parallel rails above the huge generators. A hoist, the lifting component of a crane, travels across the width of the bridge crane carrying loads and suspending multi-ton parts for maintenance and installation projects.
A smaller bridge crane with a capacity of 300 tons “flies a load” in Detroit Dam’s powerhouse.