1. Troop 8 Truss Presentation

2. What are Trusses? A truss is a type of framework, usually comprising straight struts and ties, which is designed to be stiff. This is achieved by the inclusion of a sufficient number of triangles. Some or all of the joints may be fixed rather than pinned, but the main contribution to the stiffness is provided by the triangulation. Before steel became an economically useful material, trusses were made of wood or iron.

3. Examples of Trusses?

4. Why Triangles? A triangle is the only rigid shape that can be made with pinned joints - so there is only one set of angles that will go with a given set of sides. Stable With Applied Force Unstable with Applied Force

5. Plank Bridge? Bridges experience two forces – compression (push together) and tension (pull apart). All materials have compression strengths and tensile strengths. Consider the beam bridge with a load – i.e. your weight. The weight causes the beam to bend. There is a compression force on the top and a tension force on the bottom. A truss adds rigidity to the beam, therefore, increasing it’s ability to dissipate the compression and tension forces

6. Bridge Shapes?

7. Bridge Shapes? (Continued)