Computer design of cold-formed C- and Z-section purlins

Cold-formed C- and Z-section purlins are typically used in roof and wall systems to support sheeting. In Australia and New Zealand, the design of cold-formed purlins is performed according to the Australian/New Zealand Cold-Formed Steel Structures Standards AS/NZS 4600. This standard is based on the specification of the American Iron and Steel Institute and incorporates rules for distortional buckling of both flexular and compression members and allows steels with yield stresses as high as 550 MPa to be used. A computer program PRFELB is developed for the limit design of cold-formed purlins to perform flexular-torsional buckling analysis and take account of the height of the load and of the restraining effects caused by bracing and roof sheeting.