CALIBRATION OF THE AISI R-FACTOR DESIGN APPROACH FOR PURLINS USING AUSTRALIAN TEST DATA

The design procedure for purlins under wind uplift in Clause C3.1.3 of the American Iron and Steel Institute Specification (AISI) is based o n the use of reduction factors (R-factors) to allow for flexural-torsi onal behaviour of purlins with screw-fastened sheeting. The paper desc ribes the calibration of the R-factors as specified in Clause 3.1.3 of the American Iron and Steel Institute Specification (1991) for simply supported and continuous span purlins under wind uplift and downwards loading. The calibration is based on tests performed in the vacuum te st rig at the University of Sydney. The calibration is performed for p urlins both unbraced and with bracing. This calibration is more genera l than that in the AISI Specification since the AISI values were only computed for purlins without bracing.