Sliding Resistance of Main Cables in Double-Cable Multispan Suspension Bridges

Abstract

Sliding resistance of the main cable is of the biggest concern when designing multispan suspension bridges. This paper presents a study on the layout form and sliding-resistance stability of the main cable in a double-cable multispan suspension bridge. It proposes a “top cable to bottom cable” layout, based on which analytical formulas for calculating the sliding-resistance coefficient of the double-cable have been derived. The formulas were verified by finite-element models (FEMs), and the results showed good agreement. The effects of major design parameters on the sliding resistance of the main cable were studied. Analysis shows that the top cable to bottom cable layout can effectively improve the sliding resistance of the main cable, and the bottom cable of the loaded span and the top cable of the unloaded span control the antisliding design of double cable; the sliding resistance of the main cable decreases along with an increase in the ratio of tower stiffness to cable stiffness; the influence of the sag-to-span ratio on the sliding resistance of the main cable is related to the tower stiffness; and the sliding resistance of the main cable increases with an increase in the ratio of dead load to live load.