The Main Cables – Catenary Cables

Thus far, the main cables have been referred to as catenary cables. For a cable to assume the shape of a catenary, the load on the cable must be uniformly distributed. Under the spaced suspender loading, the shape is closer to a parabola. The difference between the two is very slight. Since the equation for a parabola is easier to work with, most engineers use the parabola equation in the design of simple suspension bridges. Since this case study is presented as a planning document, not an engineering text, the author has refrained from including design equations. However presenting some basic wire rope equations for a singlespan suspension bridge at this point has some value (see Figure 9).