Ultimate tensile behavior of bolted stiffened T-stub connections in progressive collapse resistance

This paper investigates the ultimate tensile behavior of the bolted stiffened T-stub connections using experi-mental, numerical, and analytical methods. The monotonic tensile tests were carried out on sixteen bolted stiffened T-stub connections with different parameters to investigate the failure mode, yield line distribution, and key mechanical properties of them. The results showed that the distribution pattern of the yield line along the center of the bolt holes changed with the increase of the stiffened T-stub thickness and the longitudinal bolt pitch. The effect of the longitudinal bolt pitch on the ultimate strength of the connection was non-monotonic. Finite element models of the bolted stiffened T-stub connections were established and validated to conduct the parametric analysis. The simulation results showed that increasing the thickness ratio between the vertical plate and the horizontal plate could improve the ultimate strength of the connection. Based on the experimental and parametric studies, the prediction methods for the ultimate strength and initial stiffness of the stiffened T-stub connections with or without bolt pretension were proposed and validated against the experimental data and other prediction methods.