Optimum crossing cable system in multi-span cable-stayed bridges

This paper presents a strategy to optimize the cable system of multi-span cable-stayed bridges with crossing stay cables. A general approach to minimize the steel volume in cables is performed considering number of cables, cable anchor positions on the deck, cable area and prestressing forces as design variables. Each cable anchor position is associated to an independent design variable allowing overlapping stay cables as well as different spacing along the deck. As the number of cables can vary throughout the bridge, the final design could have different number of cables on each side of the same tower. The possibility of designing a non-conventional cable arrangement leads to significant reductions in cable steel while satisfying structural design constraints. The Queensferry Crossing (UK) was chosen as a real application example to verify the capabilities of the proposed methodology.