Moment capacity of eaves brackets of cold-formed steel portal frames

Abstract

The strength and stiffness of cold-formed steel portal frames are heavily related to the performance of their joints; these joints are normally formed through brackets, bolted to the webs of channels. Previous research in the literature has considered the strength of the apex bracket, and design equations proposed to predict its moment capacity. No similar research, however, has been undertaken for the eaves bracket. In the literature, the only design guidance found is a design chart, limited to eaves joints fully restrained against lateral torsional buckling, for use under a closing moment and an eaves bracket details having a stiffener along its hypotenuses. This paper describes a finite element study comprising 7,560 models, that addresses all these limitations. Unified equations are presented that can be used for the design of eaves brackets in practical partially restrained eaves joints, as found in New Zealand practice, both closing and opening moments, and different arrangements of stiffeners in the detail of the eaves bracket.