The University of Sheffield
Department of Civil and Structural Engineering

Design Rules For Built-up Cold-formed Steel Structural Memberss

Supervisor: Dr Jurgen Becque

Cold-formed steel structural members have enjoyed an increasing popularity over recent years and offer various advantages over hot-rolled sections, such as a high strength-to-weight ratio, ease of transportation, handling and installation, and a straightforward and versatile manufacturing process.
While traditionally cold-formed steel elements have mainly been used as secondary load-bearing members such as roof purlins and cladding, new trends are emerging which increasingly feature cold-formed steel elements as primary load-bearing members. Examples are low- to mid-rise buildings constructed entirely from cold-formed steel and the development of cold-formed portal frame systems for industrial halls. To meet the increased load-carrying demands and at the same time make use of the benefits of increased cross-sectional symmetry, the members for these types of applications are typically built-up by connecting more basic shapes together using fasteners (bolts or sheet metal screws) or by spot-welding. Examples are back-to-back connected channel sections or lip-to-lip connected Z-sections. The behaviour of built-up sections, however, is far removed from that of the corresponding solid, continuously connected section, especially when cross-sectional instabilities such as local and distortional buckling are considered.
The aim of the project is to study the behaviour and capacity of built-up cold-formed steel members. Particular attention should be paid to the influence of the type and the spacing of the fasteners. The eventual goal is to propose design guidelines for these types of members, which at the moment are sorely lacking.

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