Seismic performance analysis of exposed column-base connections along minor axis

Abstract

Steel frame structures often use exposed column-base plate connections. Studies on such connections have mainly focused on the mechanical properties along the strong axis. Thus, the seismic performance evaluation for the weak axis direction, which may cause insufficient structural safety, has been underestimated. The present study discusses the results of eight cyclic loading tests along the minor axis of exposed column-base plate connections. Then, the effects of the axial compression ratio, the size of the column section, the diameter and the arrangement of anchor bolts, the thickness of the base plate, and any stiffeners on the connection's seismic performance are quantified. It was found that the failure mode is breaking of the anchor bolts except for two specimens with torn welding lines. Also, all hysteretic curves are the slip type with the highest ductility coefficient of 10.49. The experimental results are used to build a numerical model based on the finite element method. Also, the stiffness calculation formula for the weak axis direction is derived using the component method. In addition, a technique for predicting a column's moment-rotation curve is proposed. It will be shown that the results of this technique agree well with those of the finite element model and with the experimental data.