By Tracy Record
West Seattle Blog editor
Many West Seattleites have become a lot more familiar with the First Avenue South Bridge in the almost four months since the West Seattle Bridge was suddenly shut down. With this week’s update on the West Seattle low bridge, some have asked about the condition of this bridge. As we’ve been previewing for weeks, it has some major work coming up: During 14 nights spread across three weeks, the northbound side will be closed for replacement of 14 of the bridge’s 96 deck panels.
The First Avenue South Bridge is actually two drawbridges – a little over half a mile long, built 40 years apart; northbound opened in 1956, southbound opened in 1996. And you should also keep in mind that it’s a state-owned-and-operated structure, so to find out more about the bridge itself, we talked with bridge-preservation engineer Evan Grimm at WSDOT (which has an FAQ page about the bridge here).
The state has ~3,000 bridges to maintain, and 40 inspectors who keep track of them – crawling under them, dangling off them, clipboards in hand. The bridges are routinely inspected every two years (that’s the federal standard, we’ve learned since the West Seattle Bridge closure). Bridges like this also get specialized inspections – underwater, for example, every five years. The state also has a full-time maintemance crew that Grimm says is “constantly out greasing gears, fixing broken wires,” etc., on bascule bridges. Even before the upcoming deck work, WSDOT was wrapping up a project upgrading mechanical and electrical equipment on the 1st Avenue South Bridge.
As for the project that starts this weekend to replace deck panels, Grimm says it’s necessary because some of the deteriorating panels are “giving us fits.” They’re trying to extend the life of the bridge – again, this is on the northbound side, now 64 years old, and Grimm notes that when it was built, they might have considered 75-80 years as a likely lifespan. “But as we look to the future, it might be a lot longer,” due in no small part to the cost of replacement.
Of those ~3,000 WSDOT bridges, by the way, only a handful are this type – primarily in Seattle and out in Aberdeen, Grimm noted. But he says with pride, this one is “a really cool bridge.”
WHAT YOU NEED TO KNOW ... about the upcoming work on the 1st Avenue South Bridge:
-Starts Sunday night (July 19th)
–(corrected) 10 pm-5 am each night of work
-Northbound full closure – you won’t be able to get onto NB 509/99 from the West Seattle/South Park onramps
-Southbound remains open
-14 nights of work are planned, Sundays-Thursdays (no work on Fridays or Saturdays)
-West Seattle low bridge is open to all traffic during those hours, and you can cross the Duwamish River via the South Park Bridge, too