Landmark
Natchez Trace Parkway Bridge
Segmental concrete double arch spanning a wooded gorge without a single column touching the ground.
Location
About this audio guide
This guide to the Double Arch Bridge over Birdsong Hollow near Franklin, Tennessee traces how engineer Eugene Figg's team built the first segmentally cast concrete arch bridge in the United States, working outward from both hillsides with no support touching the valley floor below. It follows the choice to leave out the usual columns beneath the roadway, and what that meant for how the structure carries its own weight. Along the way it lingers on the strain gauges engineers embedded in the concrete to watch the arch behave under its own unusual load.
This audio guide was created using AI.