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Attempts have been made to increase the safety of bridges with pin and hanger assemblies by adding some form of redundancy to the assembly. Retrofits that add redundancy to pin and hanger assemblies include adding a "catcher's mitt"—a short steel beam attached to the bottom of the cantilevered girder that extends out beneath the suspended girder to "catch" the suspended girder should ...
The bridge may be stiffened by the addition of cables that do not bear the primary structural or live loads and so may be relatively light. These also add stability in wind. An example is the 220-meter-long (720 ft) bridge across the river Drac at Lac de Monteynard-Avignonet: this bridge has stabilizing cables below and to the side of the deck.
The narrow section at mid-span gives the bridge profile a slight arch shape making this design particularly useful when large headroom is required. The profile also makes the bridge more architecturally pleasing than a beam bridge. Rigid-frame design may be the most efficient bridge type for spans between 35 and 80 feet (11 and 24 m). [5]
A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers).For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel, or box girders built from prestressed concrete.
The (non-modular) box girder bridge was a popular choice during the roadbuilding expansion of the 1960s, especially in the West, and many new bridge projects were in progress simultaneously. A serious blow to this use was a sequence of three serious disasters, when new bridges collapsed in 1970 ( West Gate Bridge and Cleddau Bridge ) and 1971 ...
The earliest beam bridges were simple logs that sat across streams and similar simple structures. In modern times, beam bridges can range from small, wooden beams to large, steel boxes. The vertical force on the bridge becomes a shear and flexural load on the beam which is transferred down its length to the substructures on either side [27 ...
In a plate girder bridge, the plate girders are typically I-beams made up from separate structural steel plates (rather than rolled as a single cross-section), which are welded or, in older bridges, bolted or riveted together to form the vertical web and horizontal flanges of the beam. In some cases, the plate girders may be formed in a Z-shape ...
According to the company, Zometool was primarily designed for kids. Zometool has also been used in other fields including mathematics and physics. For example, aperiodic tilings such as Penrose tilings can be modeled using Zometool. The learning tool was designed by inventor-designer Steve Baer, his wife Holly and others.