Numerical modeling for connections of staggered single channel rafters in double-bay cold-formed steel portal frames

Previous work on double-bay cold-formed steel portal frames has shown that it is possible to have internal eaves connection with staggered single channel cold-formed rafters. The rafters and the column are bolted back-to-back at the eaves joint so as to counterbalance the forces in the connected elements. Experiments have shown that sufficient ductility to generate enough plastic rotation at the joint is not achieved. To understand the elastic and inelastic behaviour of this connection, a numerical model is introduced in this study. This numerical model, which has been tested against previous experimental data, gives good agreement with regards to mode and location of the failure, moment-rotation and moment-curvature response of the tested frame. This model facilitates a better understanding of the behaviour of this connection configuration, which will probably result in a wider application of cold-formed steel portal frames.