Robust and reliable optimization of wind-excited cable-stayed masts

Deterministic optimization methods have been widely used in the design of structures in order to reduce costs and improve the structural performance. However, it is well known that uncertainties related to design, construction and loading can lead to suboptimal performance of the system, especially for wind sensitive slender structures that show a behavior highly dependent on dynamic properties and loading. For these reasons, optimization methods under uncertainties have gained an increasing importance as they are powerful tools for providing robust, reliable and cost-effective designs. Two are the main objectives of the paper: the first is to propose an optimization framework for cable-stayed masts, subjected to wind load, taking into account the uncertainties on the characteristics of the structure and on the wind excitation. The procedure provides both reliability and robustness and can tackle all the peculiarity of wind exposed slender structures, like geometric non-linearity, uncertainty in the loads definition, uncertainty in cable prestress and dynamics. The second goal is to compare robust and reliable solutions and highlight the differences in terms of performance and safety levels.