Can you imagine a bridge that had the highest motor vehicle accident rate in Washington State? That was the First Avenue South Bridge. It is a pair of double-leaf bascule bridges. These bridges carry State Route 99 over the Duwamish River. The First Avenue South Bridge is about three miles south of downtown Seattle.
The present northbound span of the First Avenue South Bridge was built in 1956. It was built to connect the industrial areas northeast of the Duwamish. It also connects the residential neighborhoods to the south and southwest. Between 1996 and 1998, the drawspan was retrofitted. The approaches were completely demolished and rebuilt. The southbound span of the First Avenue South Bridge opened in February 1997. It carried traffic in both directions for two years. This allowed the northbound span to be rebuilt.
In 2001, the southbound span was damaged by the Nisqually earthquake. Its piers were knocked 3 inches out of alignment. It was closed briefly for repairs. Many West Seattleites have become more familiar with the First Avenue South Bridge. This happened since the West Seattle Bridge was suddenly shut down.
The First Avenue South Bridge is actually two drawbridges. They are a little over half a mile long. They were built 40 years apart. The northbound bridge opened in 1956. The southbound bridge opened in 1996. The state has about 3000 bridges to maintain. There are 40 inspectors who keep track of them. They crawl under them and dangle off them. The bridges are routinely inspected every two years. Bridges like this also get specialized inspections. This includes underwater inspections every five years. The state also has a full-time maintenance crew. They are constantly out greasing gears and fixing broken wires on bascule bridges.
WSDOT was wrapping up a project upgrading mechanical and electrical equipment on the First Avenue South Bridge. This was even before the upcoming deck work. Some of the deteriorating panels are giving the crew fits. They are trying to extend the life of the bridge. The First Avenue South Bridge is a really cool bridge. The northbound full closure allows the workers to replace the bridge deck.
So next time you cross the First Avenue South Bridge. Remember its history. Remember its importance to Seattle. Remember the work that keeps it going.