The Buckling Behavior and Reliability Evaluation of a Cable-Stayed Bridge with Unique-Shaped Towers

Buckling is a significant concern for cable-stayed bridges that incorporate a large number of steel components, particularly those featuring unique-shaped towers that require further examination due to the intricate internal force and stress distribution. This paper investigates the buckling behavior of a cable-stayed bridge with inverted V-shaped towers. The cable tower is characterized by its unique design that consists of diagonal bracings and columns in a compression-bending state. A finite element model is established for the nonlinear buckling analysis of the bridge, revealing that the buckling failure mode of the bridge mainly concerns the tower columns that bear large bending moments and axial compressions. The buckling safety factors are analyzed under different loading conditions and design parameters, including the stiffening rib thickness, the width-to-thickness ratio, and the initial cable forces. It indicates that the design optimization can be achieved by using smaller and thinner ribs while maintaining the buckling safety factor above the required level in design specifications. Furthermore, the reliability evaluation of buckling safety is considered using Monte Carlo simulations, which incorporates the long-term effects of corrosion on steel components. Based on the identified buckling failure modes and safety factors, it suggests that the buckling resistance of the bridge is sufficient, though it can be further enhanced by using high-strength weathering steel on critical parts. Additionally, maintenance interventions are shown to be highly beneficial in improving the life-cycle performance of the structure.