Non-linear shape-finding analysis of a self-anchored suspension bridge

A non-linear shape-finding analysis is proposed for a self-anchored suspension bridge, the Yongjong Grand Bridge, the main cable of which is three-dimensional in shape. The proposed procedure consists of two successive steps of non-linear analysis. The first step focuses on the cable-only system and the second on the total bridge system. A trial profile of a three-dimensional main cable was calculated based on the conventional method utilizing a simplified force equilibrium at each node of the main cable. The non-linear analysis is then repeated for this cable-only system until the profile converges to the target configuration that satisfies the vertical design sag at the mid-point of the main span. Even when the best efforts were made to determine the configuration of the cable-only system, the initial deformation of the stiffening truss is not avoidable due to the huge axial force that originates from the main cable. Therefore, the initial frame forces are predicted and included in calculating the unbalance loads for the nonlinear analysis of the total bridge system so as to prevent dead load deformation. The possible differences between the conventional and the proposed method are examined through numerical applications. (C) 2002 Elsevier Science Ltd. All rights reserved.