Post-buckling resistance of gusset plate connections: Behaviour, strength, and design considerations

• The compressive behaviour of gusset plate connections has been investigated.
• Focus is given to their post-buckling resistance and behaviour.
• The numerical modelling strategy was validated using existing test results.
• Extensive parametric studies have been undertaken.
• Two curve fitting-based design approaches were finally proposed.

This paper presents a numerical study on the buckling behaviour of gusset plate connections under compression. The main focus is given to the post-buckling resistance of relatively slender gusset plate connections, cases which are commonly found in thin gusset plates in light-weighted structures, and also potentially, as driven by the recent development in steel manufacture industry, in high-strength steel (HSS) gusset plates. The numerical modelling strategy was carefully validated using the results of eight full scale tests previously conducted by the authors and co-workers, and an extensive parametric study was subsequently performed covering a reasonably wide range of geometric configurations and material properties of practical gusset plate connections. Stable post-buckling equilibrium paths were observed for the models with relatively thin gusset plates, and the use of HSS further promotes remarkable post-buckling resistance. The influences of initial imperfection and material strain hardening on the buckling behaviour of gusset plate connections have also been discussed in detail. Based on the results from the numerical study, two design approaches were proposed, namely, Column Buckling Approach, which is based on a modified column analogy from the current design practice, and Plate Buckling Approach, which is based on a plate analogy and modified Winter formulae. While both methods can be used by practicing engineers, the latter may take account of the plate action of gusset plates in a more reasonable manner, and it is also more consistent with the common design rules for plated structures.