What is a Toothpick Bridge?

A toothpick bridge is a simplified demonstration of the mathematics involved with full scale bridges. The forces involved with toothpick bridges exemplifies the forces that are involved in Truss bridges built today.

Through experiments and testing, you can reproduce the forces of a full scale bridge by building a toothpick bridge. These forces include:

Compression: Compresion is the downward force placed on a beam. For example, if you take a short straw pinch it in the middle, it flats out. If you hold it length wise between your finger tips and press, it takes a significant amount of pressure before the straw finally folds. That force is called compression.

Tension: Tension is a force that pulls. For example, if you took a toothpick and tried to pull each end until the toockpick broke, it would take a lot of force. That force is tension.

Torsion: Torsion is twisting. Twisting a toothpick to make it break is easier than pulling it apart (tension). Not all toothpicks are the same and different forces on the torsion will break different toothpicks.

Shear: Shearing is two opposing forces pushing on the same point. For example, if you hold a piece of wood with both hands next to each other, and push up with one hand and down with the other, you are applying shear to that piece of wood. Shear usually occurs horizontally, and not vertically.

Site Design and Owner

This site is owned and designed by Robert Christiansen. Robert Christiansen is a 25-year veteran of the technology industry. Robert Christiansen was co-founder, Director, and COO of Prepaid Card Holdings, Inc. and its operating subsidiary Bank Freedom (www.bankfreedom.com), providing branded and private-label prepaid debit card solutions nationally. Prior to joining prepaid Card Holdings and Bank Freedom, Robert Christiansen operated several successful Internet retail operations (including this one!). In 1999, Robert Christiansen launched the Southern California operations of All Covered, Inc, a professional consulting company focused on small business technology services. Mr. Christiansen went on to manage the western region of All Covered and was instrumental in developing the repeatable success of the business model. From 1987 to 1998 Mr. Christiansen held various positions at Artios Corp including VP of Consulting Services and Manager of R&D of software development for the international paper industry. Mr. Christiansen studied Computer Science and Mathematics at California State University at Chico.