Study on the initial stiffness of blind bolted T-stub connections

The bolted T-stub has been recognized as a fundamental model for the idealization of the tension zone performance of the bolted endplate moment resisting connection. Analytical models to predict the initial stiffness of blind bolted T-stub connections are presented in this paper. A particular locus is set on the contribution of the Hollobolt flaring sleeve and the tube face to the initial stiffness of the connections for which relevant design equations are compared and developed. The analytical models have been used to evaluate the initial stiffness of the T-stub assembly and the T-stub to square hollow section. Along with theoretical studies leading to analytical models, finite element models have been developed based on the previous experimental data. The accuracy and further improvement of the proposed models have been discussed.