Abstract
Elasto-plastic large deflection FEM analysis is carried out to investigate the ultimate strength and failure mode of two-hinge three-span suspension bridges consisting of cables, hangers, stiffened girders and towers with different combination of member safety factors. In many cases elastic buckling of tower occurs and leads to the collapse of the whole bridge system, accompanied by plasticity of hangers or cables at the ultimate stage in some cases, but a plastic hinge forms in the middle of tower and collapses the whole bridge system when residual stresses are introduced in the tower section. It is found from this parametric study that the safety factor of cables more significantly affects the ultimate strength of the system than other members.
