Experimental investigation on seismic performance of embedded column base for circular CFST

Embedded column bases for concrete-filled steel tubes play an essential role in the structural safety of high-rise and super-high-rise buildings. However, the working mechanism and design methods of embedded column bases remain unclear. This paper presents an experimental investigation of five embedded column base specimens subjected to axial compression load and cyclic lateral load, to thoroughly reveal the seismic performance of such column bases with varied parameters. The failure modes, hysteretic curves, energy dissipation capacity, stiffness degradation, and strain developments were discussed. The test results revealed that increasing the embedded depth ratio and utilizing anti-punching shear reinforcements led to an improvement in the seismic performance of the embedded column base. Moreover, the axial load ratio only influenced the seismic performance of the column when the embedded depth was sufficient. Finally, a calculation method was proposed to determine the ultimate strength of the embedded column base. The method considered the resistances resulting from the horizontal interaction between the steel tube and foundation concrete, vertical interaction between the endplate and foundation concrete, and axial deformation of anchor bolts. The predicted results were found to agree well with the test results.