Next week, SDOT plans a “deck scan” of the Spokane Street Viaduct – that’s the section of the West Seattle Bridge that’s still open, east of 99. The announcement explains, “A deck scan is one way we understand the condition and performance of our streets and bridges to keep them safe and durable. … Our contractor will be conducting the deck scan to identify any potential defects with the following tools: A sound scan that uses sophisticated audio equipment to listen to the road with an array of microphones. The scan notes changes in acoustic response as it drives over the roadway, which helps us identify spots on the concrete deck that may result into future potholes. … Ground penetrating radar (that) uses electromagnetic waves to locate potential concrete delamination – or a layer of unbonded concrete – on the deck. Finally, we’ll use an overhead 4K camera to complete infrared imaging to take an in-depth view of the surface of the roadway.” This work won’t close the SSV but will lead to slowdowns, 7 am-5 pm Monday (August 30th) through Friday (September 3rd) next week. SDOT says a deck scan also is planned for “closed portions of the West Seattle Bridge and streets and ramps leading to it.” The north half of the Spokane Street Viaduct is less than a decade old, completed in 2012.
West Seattle, Washington