How WSDOT preps its bridges for winter

Thursday, November 6, 2014by  Jon Osterberg

 Just as you winterize your home, Northwest landmarks get prepped for winter, too.

 That includes the Tacoma Narrows Bridge and the Hood Canal Floating Bridge, vital links between Pugetopolis and the Kitsap and Olympic peninsulas.

 The Narrows Bridge absorbs some serious winter weather. Need proof? Just search for “Galloping Gertie bridge” online and you’ll find the infamous film of the first Narrows Bridge collapsing into the water on Nov. 7, 1940, during a windstorm.

 (Drivers, rest easy: the current Narrows and Hood Canal bridges are much improved and safe.)
 Barbara LaBoe, who works in communications at the Washington State Department of Transportation (WSDOT), shared how WSDOT protects those bridges.

 Maintenance crews seal deck joints on the Narrows Bridge to prevent chlorides from seeping into the substructure. Otherwise, concrete and steel can deteriorate. Chlorides commonly come from salt water. They also come from deicing salts, but salt is not used on the Narrows Bridge. Instead, crews use CF7, a clear liquid anti-icer and deicer that works to -25° F.

 Workers sweep the bridge every six weeks, and they periodically check water collectors to make sure they’re clear of debris. Two WSDOT employees regularly work staggered night shifts to monitor the bridge.

 The Hood Canal Bridge, like the Tacoma Narrows Bridge, replaces a structure that collapsed in a windstorm. If you were born before man stepped onto the moon, you might recall that on Feb. 13, 1979, an 80-mph tempest and 15-foot waves blasted the bridge until it broke apart, its pontoons filled with water, and it sank.

The rebuilt bridge opened in October 1982. As a precaution it’s now closed to traffic during sustained winds of 40 mph or more.

 LaBoe said the Hood Canal Bridge is manned weekdays year-round by a crew that continually conducts preventive and corrective maintenance. Before fall, workers check the pumps that suck water from the float cells, clean drains and catch basins, and coat the drive-gear track to prevent corrosion. They also winterize the bridge’s maintenance boats, motors, and safety equipment.

 Do you have occasional fire drills at your job or school? For WSDOT it’s much the same, but instead of fire drills, they practice emergency bad-weather bridge closures and “storm evacuations,” where traffic is shut down and workers withdraw from the bridge.

 Like the Narrows Bridge, WSDOT applies liquid formula to the Hood Canal Bridge before ice forms to maintain a safe road surface. The bridge receives WSDOT’s highest priority of all roads in the nearby area, with the goal to keep its lanes bare and wet even in snow and ice.

 Watch for a future story in this series that looks at how WSDOT maintains a 3,620-foot-long mountain overpass in the winter.​​

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