The stiffness of beam-to-RHS joints with welded studs

The design of demountable bolted beam-to-column joints between structural open profiles as beams and structural hollow-section as columns (IR joints) is not easy. This is because placing bolts in the inner part of the hollow-section column is sometimes difficult or impossible due to their inaccessible interior. The research community has proposed some new types of I-beam to RHS column joints. Blind bolted angle connections, channel/angle connections or angle connections with welded studs are some examples. IR beam-to-column joints with welded studs is great of interest due to their easy on-site execution and their capacity to be disassembled, allowing the members of the joints to be removed, reused, and recycled, contributing to a more sustainable construction. Two analytical models for the stiffness estimation based on the component method are presented in this article. The analytical equations are tested against finite element simulations which has been previously validated through a comparison with the results from full-scale experimental tests. The experimental results were obtained in a vast campaign including single-side or double-side bolted beam-column joints. The results of the forty-nine geometries of beam to column joints analyzed in this paper show that stiffness can be estimated using the proposed analytical models with a reasonable level of accuracy. Finally, a simplified analytical equation to estimate the initial stiffness of the studied joints has been also proposed.