Strands of stay cable bridges on saddles with small radii - stresses, contact pressure and wire tip forces

• Applicant: Professor Dr.-Ing. Mike Schlaich
• Subject Area: Structural Engineering, Building Informatics and Construction Operation
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 255393138

Cables from parallel steel strands are often used in cable-stayed bridges and extradosed bridges. For some time now saddles are used instead of wedge anchors in the mast, because these are more robust. Within these saddles the wires are piped separately in channels through the mast. Currently, the dimensions of such saddles are still very large due to the lack of theoretical insight and because of conservative restrictions of the minimum cable bent radii. Saddles with substantially smaller radii are investigated at the Department of Conceptual and Structural Design of TU Berlin to make them even more compact, space-saving and cost-effective. In this project the stresses of the strands and the contact pressure distribution between the wire tip and saddle are studied experimentally, analytically and numerically focusing on in the edge region of the saddles. We will explore the mechanical basics and provide a simplified engineering model. Additionally, the influence of different materials and thicknesses of the strands support is considered. Tension elements with a well-defined moment of inertia such as steel bands are also examined to identify the influence of the bending stiffness of the strands with her slip of individual wires on the results. The numerical tests are performed with the method of finite elements.

• DFG Programme: Research Grants