Rigidity Selection for Mid-Tower of Three Tower Suspension Bridge

摘要

Comparing with normal two-tower suspension bridges, the whole stiffness of three-towersuspension bridges are relatively small,while the ratios of the deflection to span of these structuresare larger. The mid-tower stiffness of three-tower suspension bridge has great influence on themechanical behaviour of the whole bridge due to inner characteristics of this kind of bridges.Basing on some model experiments and related design specification, some design restrictions ofthree-tower suspension bridge, such as the deflection of the main span and the anti-slipping safetyfactor between the main cable and saddle of the mid-tower, are presented. Considering thesepractical restrictions and analytical results on the influence of the stiffness of the mid-tower to thewhole structures, the paper shows the reasonable range of mid-tower stiffness. A proper structuralstyle satisfying all of these restrictions is proposed at the end of this paper.