Pictures 1 Bridgeport Swing Span Railroad Bridge, Bridgeport Alabama
1980 General close-up view of the swing span bridge in the close position, looking upriver. The pivot/center pier is positioned in the center of Tennessee River. Note: Each arm of the continuous swing span acts as simple spans. The total span over four (4) supports is partially continuous-- the middle panel at the center pier is continuous for bending moments, but discontinuous for shears.
1980 Aerial view of the entire bridge crossing the Tennessee River looking up river. The swing bridge, when open, permits river navigational traffic to ply the river. Construction of a replacement bridge, to be located 93.27 feet down river, has now started.
1980 A general elevation view of the entire railroad bridge crossing the Tennessee River with the center/pivot pier of the 364' - 0-1/2' swing bridge positioned in the center of the river. With the bridge in the open position, navigational river traffic can continue down river by going through a 145-foot horizontal opening on each side of the pivot pier, provided the opening provides the necessary clearance required. Note: The two (2) middle supports on the center/pivot round pier.
1980 Close-up view under the track at the center/pivot pier showing the system of distributing girders which transfer all the load of the swing span, both dead, live load, wind, etc., onto the circular drum, thence to the rim bearing 40 20-inch diameter wheels. Note: The track timber ties supported on the bottom truss chord of the swing span truss.
1980 Detailed view top of center/pivot pier. The swing span revolves on a cylindrical drum, supported by 40 20-inch diameter steel wheels running on a circular track, the truss loads being delivered to the drum by a system of distributing girder. Note the circular gear anchored to the top pier. Two (2) powered pinion gears, electric driven, turn the swing span bridge on the 25'-5' diameter circular track as the wheels and drum rotate.
1980 Detail of center of swing span rotation. Forty (40) rods radiate out from a center cap stand (like spokes on a bicycle) and hold 40 20-inch diameter wheels onto a rim bearing circular track on which they roll when swing span is opened and closed.