Evaluation of rating factors for steel cable-stayed bridges using load and resistant factor rating

Abstract

Since the girders and towers in cable-stayed bridges are subjected to bending moments as well as axial forces, the conventional load rating equation, which considers single force effect only, cannot be used to evaluate the load carrying capacity of cable-stayed bridges. The load rating equations for components in cable-stayed bridges have not currently been established yet. This paper proposes load rating equations for girders and towers in cable-stayed bridges using the interaction equations for beam-column members. Moving load analyses are performed for the cases of maximum axial compressive force, maximum positive moment and maximum negative moment for each component in cable-stayed bridges, and detailed procedures to apply proposed equations are presented. The Dolsan Grand Bridge is used to verify the validity of the proposed equations. The conventional load rating equation overestimates the rating factors of girders and towers in the Dolsan Grand Bridge, whereas proposed equations properly reflect the axial-flexural interaction behavior of girders and towers in cable-stayed bridges.