Swinging bridge construction

A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its center of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right. Small swing bridges as found over canals may be pivoted only at one end, opening as would a gate, but require substantial underground structure to support the pivot. In its closed position, a swing bridge carrying a road or railway over a river or canal , for example, allows 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 horizontally about its pivot point.

Latest Issue. Past Issues. Overwashed and impassible in flood times, it was often supplemented by a swinging bridge—a narrow, spindly structure high above the water which, as the name implies, moved beneath the feet of its users. Rural swinging bridges were and still are vernacular architecture based on local knowledge and materials, but technically, they are suspension bridges just like the Golden Gate.

Print Article. Workers on the far bank of the Kootenai River downstream from Kootenai Falls drill holes in rock Thursday as part of the construction of a new swinging bridge just upstream. A sign points visitors to the swinging bridge that has spanned a stretch of the Kootenai River nearly continuously since the s.

A suspension bridge more precisely, suspended-deck suspension bridge is a type of bridge in which the deck the load-bearing portion is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early s. This type of bridge has cables suspended between towers , plus vertical suspender cables that carry the weight of the deck below, upon which traffic crosses. This arrangement allows the deck to be level or to arc upward for additional clearance.