After 60 years of use, WSDOT contractors started to demolish the southern portion of the viaduct in October 2011, during the much anticipated “nine-day” viaduct closure. Rhine Demolition LLC was in charge of taking down the structure piece by piece, to protect the structures below and nearby.
Just about everything can be salvaged and recycled (how’s that for sustainable transportation?). Crews hauled several hundred truckloads of rubble to Terminal 25. The newly crushed concrete will be reused and incorporated into concrete for the new SR 99 tunnel, while the many tons of steel rebar will find new life through a local recycler.
As you can imagine, some of the additional advantages of recycling are savings in cost of materials and reduction in greenhouse gas emissions (since the materials were not taken to a remote site for disposal). 
SDOT also attempts to recycle whenever applicable. You may recall the story we blogged about King Street Station’s Jackson Plaza in June. We incorporated sustainable elements in the construction of the plaza, such as reusing the granite that was salvaged from an old building foundation.
King Street Station's Jackson Plaza