Proposing Formulas for the Parameters of Suspension Footbridge Hangers System to Eliminate Slackness, Overstress and Force Oscillations Problems

In suspension bridges both inclined and vertical hangers have their advantages and disadvantages. The inclined hangers are more prone to fatigue in comparison with vertical ones, but inclined hangers when encountering lateral loads (such as wind and earthquake loads) react better than vertical hangers. In some cases, some of the inclined hangers show slackness and some get too stressed. In this paper by using a new modification of the hangers system; while keeping the advantages of both systems, the disadvantages of both systems were resolved and slackness phenomenon was completely removed. The new arrangement of the hangers was formulated. Three different hangers systems were analyzed under nonlinear static analysis for symmetrical and asymmetrical live loads plus dead load. Results showed that the modified hangers system was improved considerably in comparison with vertical or inclined hangers.