Discrete Analysis Method for Suspension Bridges

Abstract

In the calculation of suspension bridges, the geometrically non-linear behaviour of the parabolic cable is the main problem. The linear methods of analysis suit only for small spans. A geometrically non-linear continual model is especially useful for classical loading cases - a uniformly distributed load on the whole or a half span. But the modern traffic models consist of concentrated and uniformly distributed loads. The discrete model of a suspension bridge allows us to apply all kinds of loads, such as distributed or concentrated ones. The simplest suspension bridge consists of a geometrically non- linear cable, connected by hangers with an elastic linear stiffening girder. Depending on the load case, the hangers may be unequally loaded; thus the cable may also be loaded by unequal concentrated forces. The assumptions of the discrete method described here are: linear elastic strain-stress dependence on the material and absence of horizontal displacements of hangers. Hangers elongation is taken into account. Some comparative numerical examples are presented.