Load-deflection behaviour of sleeved joints in modified Z purlin system

The nonlinear rotational behaviour of bolted joints in the cold-formed steel purlin system is normally approximated to a linear theoretical model. Based on the experimental and numerical results, this paper employs a new method to obtain the nonlinear flexural rigidity of the sleeved connections for deflection analysis. Two equations are proposed to predict the moment resistance and the effective flexural rigidity ratio respectively, for the sleeved modified Z connections with different configurations. The nonlinear load-deflection behaviour of sleeved connections can then be predicted using these equations.