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

Activity Overview / Details

Students should take notes:

Share with students that bridge building has evolved over many centuries.  One of the simplest bridge designs is a truss bridge. Traditionally truss bridges are built with large wooden beams or also entirely of steel beams.  In earlier truss bridges wood beams were used most because of the abundancy of timber.  Wood also handles the two forces of  tension and compresion fairly well.  As steel became more available it provided better overall strength and longevity over wood.  What gives a truss its structural strength is not only the materials but also the geometry of the design.  The use of triangles allows the forces of compresion and Tension to be transfered through out the whole bridge.