The University of Sheffield
Department of Civil and Structural Engineering

Design Rules For Thin-walled Structural Elements Subject To Coupled Instabilities

Supervisor: Dr Jurgen Becque

Thin-walled steel structural members are employed in a wide range of applications, such as roof purlins, stud walls, storage racks, wall and roof cladding, and more recently even as primary members (beams and columns) in low-rise buildings. Because of their limited thickness these members can be produced on an industrial scale by cold-rolling. In many cases thin-walled steel is able to offer economical structural solutions through a high strength-to-weight ratio, ease of transportation and installation and a straightforward production process. However, the reduced wall thickness makes cold-formed steel members susceptible to a number of cross-sectional instabilities which are not typically encountered in hot-rolled members, such as local and distortional buckling modes. These instabilities may also interact with each other and with the overall column or beam instabilities, which makes the study of the stability of thin-walled steel members a very complex field and one in need of further research.
Current design rules for thin-walled steel around the world are typically based on the effective width concept, which leads to lengthy and complex calculations, while its predictions are not necessarily safe or accurate. The lack of economical, efficient design rules constitutes a substantial impediment to the further development of the field, both from a scientific and an economic/industrial perspective.
The aim of the research is to develop safe, easy-to-use design rules for thin-walled steel structural members, based on the numerous experimental data available in literature. Some promising advances have already been made in this regard through the Direct Strength Method and the research aims to further develop this concept.

This project is NOT FUNDED, although Departmental/University scholarships are available for applicants who can demonstrate strong evidence of research potential.