A bascule bridge (also referred to as a drawbridge or a lifting bridge ) is a moveable bridge with a counterweight that continuously balances a span , or leaf, throughout its upward swing to provide clearance for boat traffic. It may be single- or double-leafed.
5-649: The bridge unofficially known as the Alva Bridge is a small two-lane drawbridge located in Alva, Florida . The bridge is 21 feet tall and it is one of four vehicle drawbridges in Lee County . The bridge carries Broadway over the Caloosahatchee River . The first bridge at this site was a small swing bridge constructed in 1903, and it was the closest bridge to Fort Myers up until 1924. In 1925,
10-404: The adoption of steam power in the 1850s, very long, heavy spans could not be moved quickly enough for practical application. There are three types of bascule bridge and the counterweights to the span may be located above or below the bridge deck. The fixed- trunnion (sometimes a "Chicago" bascule) rotates around a large axle that raises the span(s). The Chicago bascule name derives from
15-560: The current drawbridge, a bascule-type bridge which opened in 1969, after three years of construction. Bascule bridge The name comes from the French term for balance scale , which employs the same principle. Bascule bridges are the most common type of movable span because they open quickly and require relatively little energy to operate, while providing the possibility for unlimited vertical clearance for marine traffic. Bascule bridges have been in use since ancient times, but until
20-457: The location where it is widely used, and is a refinement by Joseph Strauss of the fixed-trunnion. The rolling lift trunnion (sometimes a "Scherzer" rolling lift), raises the span by rolling on a track resembling a rocking-chair base. The "Scherzer" rolling lift is a refinement patented in 1893 by American engineer William Donald Scherzer . The rarer Rall type combines rolling lift with longitudinal motion on trunnions when opening. It
25-564: The original bridge was replaced with a new swing bridge . The old swing bridge was then dismantled and taken to Matlacha, Florida , where it operated as the Matlacha Pass Bridge for a year before being destroyed by a hurricane . The new swing bridge operated until 1966, when it was destroyed by a barge transporting rocket parts to the Kennedy Space Center . The second swing bridge then had to be replaced by
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