The Suspension Bridge Tower Cantilever Problem

A generalized theory is offered in this paper for the study of the behavior of suspension bridge towers under the action of forces in a plane parallel to the axis of the bridge.² Reduced to its essentials, the structure under consideration is a vertical cantilever, of variable cross section, with a fixed base. The top of the cantilever is free to rotate, and is deflected by means of a horizontal and a vertical load. The usual problem is to find the horizontal tower-top force required to produce a certain deflection in conjunction with a given vertical tower-top load. As soon as the horizontal force has been found, it is a simple matter to find any other properties of the deflected tower, such as the elastic curve or the stresses.