Equivalent Model for Tower Design of Four-span Suspension Bridges

This study proposes a simplified equivalent model for the tower design of four-span suspension bridges under static loads. The model consists of towers and equivalent springs that replace the suspension cables. The stiffness of the equivalent springs is derived based on the parabolic configuration of the cable. For the analysis of the model, dead and live loads acting on the girders of each span are replaced with horizontal and vertical forces acting on the top of each tower. Then, the equivalent suspension bridge model is analyzed by solving the equations of the load- displacement relationships of the towers. Finally, an example model for a four-span suspension bridge is used for verification and the resultant values of the towers are compared by using the proposed method and finite element analysis.