Bridge Hunter indicates that 1977 is when the swing span was replaced by the lift span for navigational purposes. But a source indicates that it was added in 1955 to accommodate the barge traffic made possible by the building of the McNary Dam.
A BNSF bridge over the Columbia River also has swing and lift spans.
C Hanchey Flickr via Bridge Hunter, License: Creative Commons Attribution-NonCommercial (CC BY-NC) Burbank-Kennewick Railroad Bridge (Kennewick, Washington) Historic 1924 Burbank-Kennewick Railroad Bridge over the Columbia River between Kennewick, Benton County and Walla Walla County, Washington. The bridge is owned by the Union Pacific Railroad. The bridge has a vertical lift span for navigation with five Parker through truss approach spans (including an old swing span). |
Bridge Hunter has a good history by Richard Doody of the predecessor wooden bridge. After the pier work was done, the contractor estimated that it could build one of the thirteen spans every 6 days. That strikes me as awful fast. Back then the spans were probably built in place using falsework. I don't today's technique of building a span on a bank and then floating it into place had been developed.
A time-lapse video of the lift span going down
thebbz Photo via Bridge Hunter, Photo taken by Derrek Stewart, License: Creative Commons Attribution-Share-Alike (CC BY-SA) |
A time-lapse video of the lift span going down
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