Study of economic design of wind-resistant cables for large-span pedestrian suspension bridges

The spatial wind-resistant cable is a common measure to improve the stiffness of large-span pedestrian suspension bridges. The amount of steel used in wind-resistant cables is generally high and can exceed 30% or even 60% of the steel used in the main cable, which significantly impacts the engineering cost. In order to design an economical and reasonable wind-resistant cable of pedestrian suspension bridges, this paper first analyzed the control index of static and dynamic properties in conjunction with the current domestic design codes, such as strength, stiffness, and wind resistance stability. Then, the design process was universally amplified in terms of general arrangement, static computation, and wind resistance stability analysis. This paper investigated the key technical points about the dig angle and rise-span ratio, initial cross section and tensioning force of wind-resistant cable, and the influence of dynamic property. A pedestrian suspension bridge with a main span of 300 m at a scenic canyon area was chosen as the project's background to demonstrate the process of wind-resistant cable design. According to the generic design process of multiple structure options, the horizontal angle of the wind-resistant cable was 30° with a span ratio of 1/12 by considering the results from finite element analysis of bridge structures and corresponding sectional model wind tunnel tests. The wind-resistant cable adopted wire rope with a diameter of 52 mm (6×55SWS+IWR), and the amount of steel used was approximately 58% of the main cable. The static design indices of the strength of the wind-resistant cable and the structural stiffness of the bridge structure, as well as the static wind stability and flutter stability, satisfy the specification requirements. The study can provide a reference for the design of similar projects in the future. © 2023, Central South University Press. All rights reserved.