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A Truss bridge is a bridge which usually provides support through the use of triangles. The triangle is the shape of choice since it cannot be distorted when stress is applied to the bridge. The bridge is formed by two chords, the lengths for the top and bottom. Some Truss bridges also have only one chord, which is the roadway.

There are several general patterns of Truss bridges. They all have one thing in common: They use triangles (although that is not necessarily a requirement for a Truss bridge).

One of the more basic Truss bridges is the Kingpost. It consists of a large triangle over a short span. It had a middle section running down it to move the force.

If there's a Kingpost, there has to be a Queenpost. The Queenpost has a trapezoidal shape, with two members supporting the slanted posts. As such, it needs a top chord to connect them.

Many modern bridges are based off of the Warren Truss, which also has a trapezoidal shape. This bridge features many supports at alternating angles. It usually spans anywhere from 50 to 100 meters.

The Pratt Truss similar to the Warren Truss, except that all of the inner supports are facing one direction. Usually the support members are thinner, resulting in a more economic design.

The Howe Truss is on the opposite end of the budget spectrum. This is a bridge in which the outer supports are similar to those of the Pratt Truss, yet in the middle, the supports cross to make an X. Its use is rarely seen.

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