Essay On Truss Bridges

Truss bridges are recognizable because of their numerous, relatively small interconnected triangles. This framework of triangles is used for is strength to withstand tension and compression forces. They are considered a light-weight yet a very stiff form of construction. At first they were built of wood, then with the discovery of welding they began to build then using iron, then steel. Occasionally, a combination of the materials may be used. There are actually 30 different kinds of truss bridges. Truss bridges were commonly built before the 1930’s. They are considered expensive to build today and are considered to be labor intensive and costly to maintain. Truss bridges are frequently found to be used for railroad bridges and typical spans can range from 40m to 500m.

Suspension bridges can reach lengths
They are built using cantilevers; horizontal structures that are only supported on the ends. These bridges are anchored securely on one side, in order to hold up the necessary weight on the opposite side, which is freestanding. Cantilevers must also withstand tension in the upper supports and compression in the lower supports. With proper materials and engineering, cantilever bridges can span over about 1,500 feet.
Cable-stayed bridges look similar to suspension bridges, but support the weight load very differently. They are similar in the way that they both have towers, and the roadways are hung from cables, but are different in the way the cables are connected to the towers. In cable-stayed bridges, the cables are attached to the towers, which support the weight load. Unlike suspension bridges, in which the cables ride freely across the towers. For medium-length distances, 500 to 2,800 feet, cable-stayed bridges are quickly becoming bridges of choice because they require less cable, and the are quicker to