Development of Prediction Methods for the Lateral Anchorage Requirements in Metal Building Roof Systems

Abstract

Metal building roof systems with C- or Z-section purlins require restraint to resist lateral forces developed within the roof system under gravity loads. The currently available procedures for predicting these forces have been shown to be inaccurate for sloped roofs and difficult to apply to roof configurations with multiple points of anchorage. A new method has been developed that builds on the previous research and accurately addresses roof slope as well as the use of multiple anchorage devices of finite stiffness. The development of this method relied on a stiffness model, similar to that used by previous researchers, which was updated and calibrated to the results of recently completed tests. The calculation procedure explicitly addresses the location and stiffness of anchorage devices as well as the inherent stiffness of the purlin system to accurately distribute the anchorage forces.