After encountering a brief mention of “Fauntleroy Bridge seismic work” on a city page listing future projects, we checked with SDOT to see what that’s about. Here’s the explanation of what’s on the drawing board for a half-mile section at the southwest end of the West Seattle Bridge, from SDOT communications director Rick Sheridan:

This work will upgrade the Fauntleroy Expressway Bridge, which spans over SW Admiral Way, Harbor Ave SW, SW Avalon Way, SW Manning St., and local railroad tracks that access the adjacent steel mill. This reinforced concrete bridge is approximately 2527 feet long and carries traffic between the West Seattle Freeway and Fauntleroy Way SW.

The city completed a first phase of seismic retrofit work in the mid 1990s. This covered widening and strengthening bridge supports, and tying bridge segments together over the supports. The project you referenced is a second phase of work. This will upgrade the structure to prevent a collapse during a 1000 year seismic event, which is the new national design standard.

We have identified the bridge weaknesses that need to be retrofitted to meet this new standard. A consultant contract is being negotiated to design and detail the retrofit work. Construction is tentatively scheduled to begin in early 2010.