Seismic Behavior of 3D Joint between Concrete Encased Steel Cross-Shaped Column and Steel Beam: Experimental Study

This paper presents an experimental study on the seismic performance of a three-dimensional (3D) joint between concrete encased steel cross-shaped (CESC) columns and steel beams. Cyclic loading test of five interior joints was performed to investigate failure modes, hysteretic behavior and strain distribution. Steel configuration, load ratio, and loading angle were considered. Seismic performance was evaluated based on peak load, stiffness degradation, energy dissipation, and ductility factor for these joints. The test results indicated that the seismic performance of joints with solid-web steel is much better than that of joints with T- and U-shaped steel trusses. The ultimate drift ratio of all joints was larger than the minimum limit of 1/50 in American and Chinese standards. The strain results showed that the influence of loading angle on the shear capacity of 3D joints cannot be ignored. Ultimately, because of the rhombic coordinate relationship between shear strength and loading angle, the formulas established in this paper can be adopted to assess the shear capacity of 3D joints between CESC columns and steel beams.