Four more West Seattle Bridge updates tonight, this time from West Seattle/South Park City Councilmember Lisa Herbold. They’re in her weekly newsletter (which is also online here); she begins with the stabilization-contractor announcement, reported here last night, and continues:
SDOT’s instrumentation consultant, BDI, measured crack depths on the sides of the box girders where they meet the deck and also used ultra-sonic pulse echo imaging and ground penetrating radar to help in understanding if there is any weakness in the steel rope that holds the bridge in compression.
On April 22, SDOT’s design consultant, WSP, provided an estimate of rate of crack growth as well as a critical failure projection. WSP also continues work on a decision tree to inform the question of whether or not to replace or repair the bridge.
SDOT also is installing additional structural health instrumentation (such as crack-width gauges, strain gauges and high-resolution cameras). This is mostly complete and will allow for a clearer definition of the condition of the bridge, and which path to pursue.
I’ve asked how the rate of crack growth informs the question of whether or not to replace or repair the bridge, and about the critical failure projection.
SDOT paved and reconfigured the 5-way intersection below the West Seattle Bridge last weekend; average daily traffic on the low bridge is down to 6,480 vehicles per day, approximately the same as the baseline. Here is the most recent traffic data we’ve received, with West Marginal and Idaho, and Highland Park and Marginal showing significantly higher than usual volumes:
SDOT has installed new controllers, added communications to signals, and tweaked signal timing in both the Roxbury and 35th corridors, and has upgraded these intersections over the past two weeks:
Chelan 5-Way Intersection
17th Ave SW & SW Roxbury St
16th Ave SW/Delridge & SW Roxbury St
15th Ave SW & SW Roxbury St
35th Ave SW & SW Thistle St
SDOT also noted they are planning to improve operations at the following intersections over the next few weeks:
30th Ave SW & SW Roxbury St
26th Ave SW & SW Roxbury St
20th Ave SW & SW Roxbury St
8th Ave SW & SW Roxbury St
35th Ave SW & SW Roxbury St
35th Ave SW & SW Barton St
35th Ave SW & SW Henderson St
35th Ave SW & SW Trenton St
16th Ave SW & SW Austin St
16th Ave SW & SW Holden St
35th Ave SW & SW Kenyon St
35th Ave SW & SW Holden St
35th Ave SW & SW Webster St
35th Ave SW & SW Myrtle St
35th Ave SW & SW Holly St
35th Ave SW & SW Morgan St
35th Ave SW & SW Raymond St
35th Ave SW & SW Findlay St
Changes include allowing SDOT to manage signals from a central location, rather than needing to go to the signal to manually make changes.
Town Hall Question Totals
For the Town Hall held last week, over 1000 questions and comments were submitted: 133 on the use of the lower bridge, 156 on traffic management, 212 on transit (including ferries), 63 on whether to repair or replace, 209 on process and oversight, and 254 on multiple subjects, or other items. My office is continuing to organize the suggestions.
Letter to Washington State Ferries
I sent a letter to Washington State Ferries, linked here, asking that they consider re-directing some of the ferry traffic from Vashon and/or Southworth, that usually travels to the Fauntleroy ferry dock, to Downtown Seattle instead; and that they consider trips from Fauntleroy to Downtown, and options suggested by the public.
The letter notes that during some previous years, for example 1981, 1993 and 2002, eastbound ferry traffic has been diverted to Downtown on a temporary basis. Thanks to the community members who assisted with this research.
SDOT info, meantime, is on the West Seattle High-Rise Bridge Safety Project website; our coverage since the bridge closure March 23rd is all archived here.