Finite Element Analysis of Buckling Behavior for Cold-Formed Steel Hat Purlins with Openings

In urban building design, introducing openings in the webs of structural members allows the flexible installation of ductwork and piping. This study investigated the effects of the shape, location, and spacing of web openings on the buckling behavior of cold-formed steel hat purlins. Eigenvalue analysis shows that the existence of web openings reduced the buckling moment of a section by up to 24%. The shape and location of the web openings also affected the buckling behavior. In particular, the buckling moment decrease when the web opening was located at mid-span. It was found that, the buckling moment increase when the web opening spacing increases. The section with diamond web openings shows the highest buckling moment and the section with elongated circle openings shows the smallest buckling moment compared to other web opening shapes. The results of this study should provide guidance on hat purlins with openings design to meet structural performance requirements.