Analytical Model for Frictional Resistance between Cable and Saddle of Suspension Bridges Equipped with Vertical Friction Plates

For multispan suspension bridges, frictional resistance between the main cables and the saddles is essential for counterpoising unbalanced cable tension between different spans. The use of friction plates in saddles is one of the most common methods for increasing frictional resistance, and the corresponding evaluation method is vital for the design of suspension bridges. In this study, an analytical model for the calculation of frictional resistance between cables and saddles is presented. Large-scale model tests were performed to simulate the realistic friction conditions of a typical multispan suspension bridge in China, namely the Yingwuzhou Yangtze River Bridge, to validate the model. The main components of frictional resistance were analyzed, and the effects of vertical friction plates in enhancing frictional resistance were investigated by model tests and theoretical analyses. The results indicate that the presented analytical model provides an effective and feasible tool for evaluating the total frictional resistance and the contribution of friction plates in practice. The main components of total frictional resistance, including the frictions at the base and side contact interfaces between the cable and the saddle trough, are quantified, proving the former to be dominant. The parameter analyses reveal that the frictional resistance can be increased by 57% by incorporating six vertical friction plates for the actual saddle.