Parametric analyses on the initial stiffness of the SHS column base plate connections using FEM

Bolted Column Base Plate (BCBP) connections are widely used to connect steel columns to the concrete foundations. This paper conducts a parametric study on the initial stiffness of bolted base plate with Square Hollow Section (SHS) column connection, through an extended 3-D Finite Element Modeling (FEM). Different features of the connection such as material behavior, geometric details, typical contact phenomena and large displacements are also considered in the modeling. A comparison between experimental test and FEM is carried out to illustrate the ability of the numerical method to simulate the connection behavior. An analytical explanation on the initial stiffness of the connection is introduced. The parameters for numerical study were appointed and finally, using regression analysis, a power function describing the initial stiffness of the connection is obtained. The prediction equation has the ability to acquire initial stiffness of the SHS connections considering prying forces and there is also a reasonable accuracy in estimating SHS end-plate and base-plate bolted connections.