Experimental investigation on light steel frames with single- and double-sided X-bracing

This paper explores the behaviour of light steel frames with bracing installed on one or both panel faces, for three full-scale panel specimens were tested under monotonic loads. It focuses on three key issues: (1) panel failure mode for the side in compression, (2) system friction, and (3) determining the horizontal panel displacement considering the solid body rotation. It was found from the test results that the failure mode was influenced by the use of double C- sections at the side in compression, as a single vertical C- would otherwise fail under minor axis flexural buckling. The presence of bracing on both sides and back-to-back vertical C- sections at the panel chord changed the failure mode to the holding-down device of the panel, with shear failure of its fixings due to uplift. Furthermore, the analysis of the results confirmed the presence of system friction which, if not considered, would result in overpredicting the panel stiffness. Finally, the elimination of solid body rotation from the panel deformation allowed for the calculation on the net panel stiffness, which matches the theoretically derived values.