How Do I make a toothpick bridge?
The Toothpick Bridge-Design The design relies on the four catenary arches to transfer the weight of a load to the four feet on each side of the bridge. They work in tandem like a regular truss with struts that connect the upper arches to the lower archs. The formula for a catenary arch is y=cosh(x). This ‘cosh’ function is the hyperbolic cosine. A sort of obscure trigonometric function used in non-euclidean geometry. Luckily, it’s on many hand-held calcualtors. A little Algebra… To normalize the function, we needed to use a particular part of the curve to get the height we wanted, and then magnify it to the size we wanted. This involve a little algebra. Essencially , the lower arch and upper arch are from the same function for a curve, only the upper arch uses slightly more of the curve ( to get the proper height ratio) and is therefore less ‘magnified’ A little Engineering… I recently decided to calculate the forces in the struts of a typical catenary truss. This page will give yo
