John J. Audubon BridgeOverview
When it opened in 2011, the John James Audubon Bridge in Louisiana became North America’s longest cable stayed bridge, with towers of height 164 yards (150m), a main span of 527 yards (482m) and an overall length of 4,295 yards (3,927m). The new bridge carries four lanes of traffic 22 yards (20m) above the Mississippi River, replacing the existing unreliable ferry service. It is the only Mississippi crossing between Natchez and Baton Rouge, a distance of apporximately 93 miles (150km).
TENSA®FINGER sliding finger joints of Type GF and Type RSFD were selected to fulfil the requirements of both the client and the designer. Finger joints were preferred by the client for their low maintenance demands, and the choice of type of finger joint resulted from the movement demands of the bridge at each joint location. Cantilever finger joints of type RSFD were chosen to facilitate the smaller movements of 12 inches (310mm) at one bridge axis, while sliding finger joints of type GF were chosen for the bridge axes requiring movements of 28 inches (710mm) and 49 inches (1,240mm) respectively. The joints of type GF feature sliding support for the ends of the finger plates which span across the bridge gap, and a downward pre-tensioning of the finger plates to ensure that they remain in contact with the sliding surface below. Weighing in at 24 tonnes each, the joints allowing movement of 49 inches (1,240mm) are the largest sliding finger joints of their type ever manufactured.
TENSA®FINGER type GF and RSFD
Movements between 310 and 1‘240 mm
New Orleans, Louisiana