2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference
Dr. Robert Driver, University of Alberta
Mr. Logan Callele, Waiward Steel Fabricators Ltd.
Dr. Bo Dowswell, ARC International, LLC
It is common for unstiffened wide-flange structural members to be loaded by an adjoining member through the flange. While many load types are readily accommodated by routine design, when the member is loaded torsionally the behaviour is complex and no widely accepted design rules exist. One common example occurs when handrail posts are attached to the top flange of a floor beam, where the horizontal design guard forces induce torsion in the beam. Another is encountered in industrial structures such as pipe racks where a beam that is rigidly connected to a column flange resists weak-axis bending, resulting from hydraulic pipeline forces, that in turn loads the column torsionally. Because of the lack of codified design criteria for cases where the torsional member is unstiffened, it is common to add full-depth stiffeners to transfer the forces to the entire cross-section. However, this adds considerable cost to the joint and is often unnecessary. Unstiffened members subjected to torsional moment through one flange engender phenomena of both single-flange torsion and web bending. Localized bending of the web at the web-to-flange junction and torsion of the flange connected directly to the member delivering the load constitute a complex shared force-resisting mechanism. This paper elaborates on the behaviour of unstiffened members subjected to torsional moment using finite element analysis. Characteristic behaviours of wide-flange members under this type of loading have been explored by conducting a comprehensive parametric study, varying parameters such as length of member, section depth, flange thickness, web thickness, and flange width.