Ultimate tensile properties of bolted stiffened angle connections

In this paper, monotonic tensile tests were carried out on 20 bolted stiffened angle connections. The failure mode and ultimate tensile performance of the connections were studied in the terms of stiffened angle thickness, bolt pitch distribution, bolt diameter and preload. The test results show that the failure mode of the connection is closely related to the stiffness ratio between the bolt and stiffened angle. When this ratio was less than 1, the bolt fractured first, otherwise the stiffened angle fractured before the bolt. The fracture position of the stiffened angle was also different according to the different design parameters. The stiffened angle thickness has the most significant effect on the ultimate bearing capacity of the connection which increases with the increase in the thickness. The deformation capacity of the stiffened connection is closely related to the failure mode. Among the design parameters, horizontal bolt pitch has the most significant effect on the deformability of stiffened connection. The initial stiffness of the connection is positively correlated with stiffened angle thickness and bolt preload, but negatively correlated with bolt pitch distribution. Based on the test results and corresponding theoretical analysis, a mechanical model of the load-displacement curve for bolted stiffened angle connections is proposed and verified by the test results. The results show that the proposed model could well present the ultimate tensile properties of bolted stiffened angle connections.