Date:
Wednesday, February 15, 2006
Contact:
Harvey Coffman, Bridge Preservation Engineer, (360) 570-2556 (Olympia)
Melanie Coon, WSDOT Communications, (206) 440-4700 (Seattle)
SEATTLE – In the aftermath of the windstorm on February 4, WSDOT bridge inspectors have examined mechanical equipment for the drawspan (pdf 458kb) on the SR 520 Bridge and determined that a replacement must be made to the steel assembly that supports a guide roller under one corner of the east drawspan. The work will require inconveniences for drivers and also for vessel operators outlined in the schedule below.
The repair program was decided upon by WSDOT Bridge Preservation Engineer Harvey Coffman and the SR 520 bridge maintenance crew.
“After the storm, our inspection included the mechanical equipment as well as the pontoons and structures,” Coffman said. “In 1999, after a similar storm, we experienced damage to one of the vertical guides. Looking for the same kinds of problems this time, ultrasound testing results have turned up a small crack in a steel casting that holds one of the guide roller assemblies for the drawspan. If it isn’t fixed and the casting should fail, the drawspan will not operate smoothly. Worse, under traffic the drawspan pontoon may actually rock slightly so that drivers might think they hit something like a bad expansion joint where they transition back to the non-draw span portion of the bridge.
WSDOT has in stock a spare assembly weighing about 5 tons that will be readied for installation and moved to and installed on the bridge. The entire work program will be conducted over two workweeks, beginning on Monday, Feb. 13.
Short closures to vehicle traffic will be required in the early morning hours (between 2 and 4 a.m.) on Feb. 16 and Feb. 22.
The most important impact to traffic will be when the assembly is actually replaced. This will occur on the weekend of Feb. 25-26. The bridge will be closed to all vehicle traffic for 28 continuous hours from 6 a.m. Saturday, Feb. 25 to approximately 10 a.m. Sunday, Feb. 26. Westbound drivers will be diverted off at 92nd Avenue NE in Bellevue and eastbound drivers will be diverted off at Montlake Boulevard in Seattle.
“We know that many drivers needing to cross Lake Washington will have to go out of their way when the bridge is closed because of our work on the weekend of Feb. 25th and 26th,” Coffman said. “We regret the inconvenience to drivers, but fixing this mechanical assembly on the bridge is important to long term bridge performance. We’re glad that other minor damage caused during the windstorm, such as sheering of the locking hooks on the drawspan, is being repaired without impact on traffic.”
In addition, the drawspan will not open for vessels during the period beginning on Feb. 13 and lasting possibly until 10 a.m. on Sunday, Feb. 26. An official Notice to Mariners will be issued to and through the US Coast Guard.
The 2005 Transportation Partnership Act designated $500 million to the SR 520 Bridge Replacement Project. Additional funding is expected to be contributed through future toll revenues from the bridge and from proceeds of a regional transportation funding package to be presented for a future vote of the people. For more information on the SR 520 bridge replacement project, visit the project Web site at www.wsdot.wa.gov/projects/SR520Bridge.
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