Here’s the email from the Tennessee Department of Transportation sent along to media with a link to the video:
Near Smithville in DeKalb County, spans from the 1948 truss bridge on U.S. 70 over the Caney Fork River and Sligo Road were taken down today. TDOT is nearing completion of a $39 million project to replace the truss bridge with a new welded steel plate girder bridge. The new bridge was open to traffic in early August 2015. Demolition of the old bridge is an important phase in the project. The project is slated for total completion in June 2016, but it is very likely that it will be completed ahead of schedule.
If you keep watching after the first video, there are more afterwards.