Key Bridge (Washington, D.C.)
The Francis Scott Key Bridge, more commonly known as the Key Bridge, is a six-lane reinforced concrete arch bridge carrying U.S. Route 29 (US 29) across the Potomac River between the Rosslyn neighborhood of Arlington County, Virginia, and the Georgetown neighborhood of Washington, D.C. Completed in 1923, it is Washington's oldest surviving road bridge across the Potomac River.
Key Bridge (Washington, D.C.)
Key Bridge under construction, c. 1920
Southern terminus of Key Bridge and remaining pier and abutment of Aqueduct Bridge (2005)
Panoramic view of Key Bridge in 2013.
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct may be made from a series of arches, although other more economical structures are typically used today.
A double-arch stone bridge in Nagasaki, Japan
The Roman Alcántara Bridge, Spain (built 103-106 AD)
The Anji Bridge, 6–7th century AD
Segovia Aqueduct (c. 100 AD)