OBSERVATIONS ON NONLINEAR DYNAMIC CHARACTERISTICS OF SUSPENSION BRIDGES

For most forms of loading static and dynamic response of a suspension bridge is modelled adequately by linear analysis. By examining the two principal non-linearities of inclined and vertical hanger suspension bridges the limitations of linear analyses are shown. The inclined hanger configuration is shown to be the more strongly non-linear. Some examples are given for simplified planar analyses of this type of bridge to large amplitude vehicular, random, sinusoidal and propagating earthquake excitation, showing that the effect only becomes significant when deflections approach the extent of cable sag due to cable elasticity.