Effect of Geometric Properties a nd Initial Imperfections on the Rotational Stiffness of Stainless Steel Bolted Connections

The initial imperfections in bolted end-plate connections are mainly induced by residual deformation from welding. Three typical initial imperfections, namely V-shape, C-shape, and W-shape have been identified based on field studies in the literature regarding geometrical imperfection shapes in extended bolted end-plate connections. This study explores the effect of C-shape and V-shape imperfections on the rotational stiffness of stainless-steel end-plate connections, specifically focusing on connections with six bolts. A validated numerical model was used to investigate the impact of initial imperfection on rotational stiffness. The results indicate that the initial rotational stiffness of the connection decreases with an increase in initial imperfection. Further, the V-shape has the least influence, while the C-shape significantly influences the initial rotational stiffness. For V-shape imperfections, its influence on the stiffness of the connections is negligible as long as the imperfection is limited to the criterion of (end plate depth)/300. In the case of a C-shape imperfection, its influence on the rotational stiffness would be substantial, even if it satisfies the requirement of the imperfection limit. According to the results, even the presence of a 0.5 mm C-shaped imperfection decreased the rotational stiffness by 8.9%. These results are useful for maintaining fabrication tolerance for connections.