Lateral bracing of beams provided by standing seam roof system: concepts and case study

摘要

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 metal building rafters against lateral torsional buckling, bottom flange braces provide torsional bracing to the rafter and the SSR system provides some lateral bracing. However, the degree to which the SSR system can restrain the rafter against lateral movement has not previously been studied. To quantify the in-plane strength and stiffness of the SSR system and identify how it can be used to provide lateral bracing to the rafter, an experimental testing program has been conducted on standing seam roof assemblies. In this paper, a method for using the experimental results in the calculations of required bracing for metal building rafters is described. A case study is also provided which demonstrates that the SSR roof can contribute to the bracing of rafters and may reduce spacing or size of discrete torsional braces.