Biobjective Optimization of Cable Force for Concrete Cable-Stayed Bridges Considering the Requirements of the Serviceability and Ultimate Limit State

This study proposes an efficient biobjective cable force optimization strategy for concrete cable-stayed bridges aiming to maximize the safety of the structure under both the serviceability and ultimate limit state required by the design specifications. The multitude of potential load cases within limit states renders cable force optimization approaches challenged to fully satisfy code requirements, leading to encumbered complexity and computational expense. The proposed method utilized a load decoupling approach to separate the effects induced by the cable forces from other load effects to overcome this shortcoming. Furthermore, the relationship between the structural responses and cable forces was established explicitly using the influence matrix method, which aims to eliminate the finite-element method-based structural analysis in the iterations. A practical concrete cable-stayed bridge was utilized to examine the performance of the proposed method. The Pareto optimal fronts yielded by four different multiobjective optimization algorithms show a good agreement with each other, and all the computational time costs by them are less than 50 s for each run. The comparative analysis of different cable stretching plans demonstrates that optimizing the initial stretching cable forces and the final cable forces under the bridge finished state simultaneously can significantly improve the safety of cable-stayed bridges. The results also illustrate that the proposed strategy is a high-efficiency and specification-oriented cable force optimization solution for short-to-medium concrete cable-stayed bridges.