Parametric Study of Steel Column-Base Connection Subjected to Bidirectional Bending and Axial Compression

Abstract

Column base plate connection is one of the most critical structural components of steel momentresisting frames which acts as a transfer medium to transmit the reaction forces, shear and moments from the entire building into the foundation. Failure of these base plate connections is critical since it can result in the collapse of the entire structure. Very often these base plates experience bidirectional lateral loadings from natural events such as wind and earthquake. Previous studies considered uniaxial lateral loading combined with axial load but do not provide any guidelines for exposed column base plate connections under axial load and biaxial lateral loading. This study aims to develop an accurate nonlinear finite element (FE) model of exposed column-base connections under combined axial load and bi-axial lateral loading using general purpose finite element software ABAQUS. The developed model is validated against experimental results under monotonic and cyclic loading considering both geometric and material nonlinearities to check the accuracy of the model. After validation, a bidirectional symmetric lateral loading combined with constant axial compressive load is applied in the developed model to analyze the response of the column-base plate connections. Further, the effects of three different parameters of column base plate connection such as base plate thickness, base plate yield strength, and anchor rod diameter are investigated through parametric study. Results show that higher value of base plate thickness and anchor rod diameter significantly affect both the stiffness and strength of column base connections. It also demonstrates that base plate yield strength has no significant influence on column base connections.