You're right.. this bridge was closed in 1999 when the new Brewster Bridge was built the same year, a half-mile downriver. You can see the new bridge in the distance through the trees to the left in the Street View.
I was shocked to find the calcium carbonate deposits forming stalagmites and stalactites underneath the beams. It is absolutely fascinating. This is the second bridge in East Tennessee where I have found those deposits forming. I thought those were common only in caves, not in the open.
Notice the pier construction. That's how you can tell a bridge built back in the day by the state highway department. The piers are always rounded with notches and groves every few feet.
I think the concrete bridges are just as historic as the steel trusses, but I'm more partial to trusses!
PS Based on Historical Imagery in Google Earth, this bridge was likely open until at least 1998. The new bridge wasn't built until some time between 98 and 07
I find abandoned concrete bridges to actually be as interesting as abandoned through-truss bridges. Thanks for this add, Calvin!