Multi-objective optimization-based reasonable finished state in long-span cable-stayed bridge considering counterweights

Abstract

Long-span cable-stayed bridges are typically required to place side-span counterweights to balance the self-weight in the middle of the span and prevent the bearings from negative reaction. This paper presents a novel method to optimize the reasonable finished state of long-span cable-stayed bridges considering cable forces and counterweights. The optimization scheme is formulated with the objective functions of the minimum bending energy and the minimum sum of counterweights, and the constraints, including bearing reactions, cable forces, bending moment of the structure, and counterweights, can be implemented flexibly. Then, a Pareto weighting coefficient method is proposed to solve the multi-objective model effectively and cheaply. Finally, a long-span cable-stayed bridge with a main span of 1088 m is considered as an application example to demonstrate the efficiency and accuracy of the proposed method. The results show that: the counterweights can be used not only to balance the negative reactions of the bearings, but also to cooperate with the cable forces to optimize the overall structural state more precisely. The proposed multi-objective optimization scheme is highly adaptable to design counterweights and cable forces of the reasonable finished state of long-span cable-stayed bridges. The proposed Pareto weighted coefficient method enjoys both computational efficiency and numerical stability considering traceable parameters and iterative processes, which can be used to solve various engineering multi-objective optimization problems.