Cyclic performance of CFST column-to-steel beam joints with a novel grooved end-plate connection

End-plate connections are widely used in steel structures for their semi-rigid behavior, yet conventional designs suffer from end-plate warping, bolt slippage, and limited stiffness. This study proposes an innovative grooved end-plate (GEP) joint for concrete-filled steel tubular column-to-H-beam connections. Three GEP joints and one conventional end plate (OEP) joint were tested under cyclic loading and analyzed via finite element modeling. Results reveal that GEP joints increase rotational stiffness by 29.7% and ultimate bearing capacity by 6.9% compared to OEP joint, failure modes shift from end-plate warping in OEPs to controlled weld tearing in GEPs. Hysteresis curves exhibit spindle-shaped loops without pinching, confirming stable energy dissipation. Parametric studies identify an optimal side extension length of half the column width, balancing stiffness gains with acceptable ductility loss. This work advances semi-rigid joint design by integrating geometric innovation with seismic resilience, providing practical guidelines for high-rise and modular steel structures.