Swingbridges of Southeast Texas
A swing bridge
is a bridge that has as its primary
structural support a vertical locating pin and support ring at or near to its
center, about which it can then pivot horizontally as shown in the animated
In its closed position, a swing bridge carrying a road over a river or canal, for example, allows road
traffic to cross. When a water vessel needs to pass the bridge, road traffic is
stopped (usually by traffic signals and barriers), and then motors rotate the
bridge approximately 90 degrees horizontally about its pivot point.*
- As this type requires no counterweights the complete weight is
significantly reduced as compared to other moveable bridges.
- Where sufficient channel is available to have individual traffic
directions on each side the likelihood of vessel-to-vessel collisions is
- The central support is often mounted upon a berm along the axis of the
watercourse, intended to protect the bridge from watercraft collisions when it
is opened. This artificial island forms an excellent construction area for
building the movable span as the
construction will not impede channel traffic.
- The central pier forms a hazard to navigation.
- Where a wide channel is not available a large portion of the bridge may be
over an area that would be easily spanned by other means.
- A wide channel will be reduced by the center pivot and foundation.
- When open, the bridge will have to maintain its own weight as a balanced
double cantilever, while when
closed and in use for traffic the live loads will be distributed as in a pair
of conventional truss bridges, which may require
additional stiffness in some members whose loading will be alternately in compression or tension.
- If struck from the water near the edge of the span, it may rotate enough
to cause safety problems (cf. Big Bayou
Conot train disaster).
*From Wikipedia, the free encyclopedia
TX12 Swingbridge over the Sabine River east of Deweyville
TX82 Swingbridge at Sabine Pass
TX87/73 Swingbridge between Bridge City and Orange
Round Bunch Road Swingbridge in Bridge City