Truss Bridges

There are 4 different, basic types of truss bridges: Warren, Pratt, Howe and K Truss.
 (In order, below.)

Structural Analysis

A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to loads. Truss bridges are one of the oldest types of modern bridges. The basic types of truss bridges are shown below. There are over 27 different types of Truss Bridges but the are the four most common used.

Basic Warren Truss Bridge

Red represents tension, blue represents compression, and green is no load.
Picture

Basic Howe Truss Bridge

Picture

Basic Pratt Truss Bridge

Red represents tension, blue represents compression, and green is no load.
Picture

Basic K-Truss Bridge

Picture

These pictures show how weight or load is distributed throughout a Truss bridge. A Truss Bridge is designed to distribute weight through different beams within triangular shapes. This is done so that the tension is distributed to the middle of the bridge and the  compression to the ends of the bridge. This makes the bridge much stronger. In all of these pictures you can see how load is distributed.  

Design your own Truss Bridge

To design a truss bridge of your own go to http://www.jhu.edu/virtlab/bridge/bridge.htm. I challenge you to design the four types of bridges listed above. 

If you would like to learn more...