Innovative column base connections using welded anchor rods

Abstract Column base connections are crucial for the stability and integrity of steel structures. This study introduces a novel approach to enhance the overall performance of such connections, involving anchor rods welded beneath the base plate, capable of simultaneously withstanding tensile, compressive, and shear loads, as well as flexural moments. This innovative design aims to address the shortcomings of traditional connections, such as pinching hysteretic loops and uneven shear load distribution. A numerical study was carried out using the finite element method. Crucial parameters were involved in the numerical study such as concentric and eccentric layouts of anchor rods, varied loading regimes, and different levels of axial compressive loads. Numerical results revealed that utilizing welded anchor rods effectively eliminated pinching from hysteresis loops. Configurations featuring a concentric layout of anchor rods showed that the base plate's influence on cyclic behavior was minimal, functioning primarily as a linking tool between the anchor rods and the column. In the eccentric layout of anchor rods, the base plate had a more significant role. A positive correlation was observed between compressive load and both the initial stiffness and strength of the connection, which resulted from the prevention of rapid separation between the base plate and the grout, and delayed tensile engagement of anchor rods. The developed design criteria aligned well with numerical findings.