Lateral resistance performance evaluation of cold-formed steel zero-tolerance bolted moment-resisting frames

The experimental and analytical lateral load resisting behaviour of three cold-formed steel (CFS) moment-resisting frames with zero-tolerance bolted joints were investigated to understand the potential application of such joints in medium-span CFS portal frames. Strain gauge data were used to measure total longitudinal stresses in the column sections and were compared with analytical models. It was found that the bi-moment stress component was the second largest component after major-axis bending and can be analytically and conservatively estimated. The validity of the design approaches of monosymmetric and doubly symmetric back-to-back channel columns were also investigated. For the first time, the potential application of zero-tolerance jointed frames in medium-span CFS portal frames is demonstrated and conservative analysis and design approaches (monosymmetric) are employed.