An optimization-based approach is proposed to assist in the design of under-deck cable-stayed concrete bridges. This strategy combines a convex optimization algorithm with a multi-start procedure to obtain local optimum solutions and the best of which is selected as the optimum design. The finite element method is used for the three-dimensional analysis considering dead load and road traffic live load, geometrical nonlinearities and time-dependent effects. The design is posed as a multi-objective optimization problem with objectives of minimum cost, deflections and stresses considering service and strength criteria defined according to the Eurocodes provisions. This minimax optimization problem is solved indirectly by minimizing a convex scalar function obtained via an entropy-based approach. The discrete direct method is used for sensitivity analysis, providing the algorithm with the structural response to changes in the design variables. The design variables are the under-deck cables cross-sectional areas and prestressing forces, the deck and struts sizes, the length and number of struts. Numerical examples concerning the optimization of a single-span real-sized under-deck cable-stayed concrete bridge illustrate the features and applicability of the proposed approach. Optimum solutions with minimum cost and high efficiency of the cable-staying system are obtained.

中文翻译：

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桥面下斜拉混凝土桥的优化

提出了一种基于优化的方法来辅助桥面下斜拉混凝土桥的设计。该策略将凸优化算法与多启动过程相结合以获得局部最优解，并选择其中最好的作为最优设计。有限元方法用于考虑恒载和道路交通活载、几何非线性和瞬态效应的三维分析。该设计被提出为多目标优化问题，其目标是最小成本、挠度和应力，并考虑根据欧洲规范规定定义的服务和强度标准。通过最小化基于熵的方法获得的凸标量函数来间接解决该极小极大优化问题。采用离散直接法进行敏感性分析，为算法提供对设计变量变化的结构响应。设计变量包括甲板下缆索横截面积和预应力、甲板和支柱尺寸、支柱长度和数量。有关单跨实际尺寸的桥面下斜拉混凝土桥优化的数值实例说明了该方法的特点和适用性。获得了斜拉系统成本最低、效率最高的最优解决方案。