The standing seam roof (SSR) system is the most commonly used roof system for metal buildings due to its superior durability, water tightness, and energy efficiency. In this type of system, SSR panels attach to Z-shaped or C-shaped purlins with clips, and the purlins are in turn connected to rafters (i.e. roof beams). For the design of the rafters against lateral torsional buckling, bottom flange braces provide torsional bracing to the rafter and the SSR roof system provides some lateral bracing. However, the degree to which the SSR roof system can restrain the rafter against lateral movement, i.e. work as a diaphragm, has not previously been studied. To investigate the effects of different standing seam roof configurations (SSR panel type, clip type, thermal insulation, and purlin spacing) on the in-plane stiffness and strength of the SSR roof system, a total of 11 full-scale standing seam roof specimens were tested at Virginia Tech. Results showed that the in-plane load-deformation behavior of SSR systems was governed by clip deformations and that variations in the type of SSR panel or clip can have a major impact on the strength and stiffness of the specimens. These results can be used in the design of required bracing for metal building rafters, as they demonstrate that the SSR roof can contribute to bracing of the rafter and may reduce spacing or size of flange bracing. A final report is under review with industry and will soon be released.
This work was led by SDII Ph.D. student Gengrui Wei.