Part of Lesson Plan: Bridge Building Concepts/ Design: Truss Bridges part 1 of 4

Activity Overview / Details

Show students a diagram of a variety of truss bridges. On a piece of graph paper, have students sketch a truss design from the slide or have them design and draw their own.  (10min)

Students should take notes:

Explain that a truss works to hold up a bridge by transferring the weight that is on top of a bridge up through the vertical posts and down through the 45 degree braces until the force reaches the abutements (the stone or cement ends of the river shore). The force is then absorbed into the earth. If the bridge does not have this triangular design, all the force of the weight becomes concentrated on a particular part of the bridge and the stress may break it.