Investigation of the effect of underfloor leveling mortar on the behavior of anchorage bolts in steel column legs

A common situation in practice is that the gap between the column base plate and the reinforced concrete foundation at the junction of the steel column-reinforced concrete foundation is not filled with high-strength mortar. In this study, it was aimed to investigate the effect of leveling mortar under the base plate on the behavior of anchor bolts in steel column feet. This effect has been demonstrated comparatively by considering the cases of increasing the gap at different rates between the steel column base plate and the reinforced concrete foundation. The steel column-reinforced concrete foundation joint is numerically modeled with the help of ANSYS Workbench computer software based on the finite element method. In the numerical model, the material of the steel column, base plate, anchor rods and anchor bolts are assumed to be homogeneously isotropic. Nonlinear effects were also considered in the analyses. In the analyses, horizontal displacement was applied to the midpoint of the column and depending on the size of the gap left between the steel column base plate and the reinforced concrete foundation, the moment-rotation curves and the stresses in the anchor rods were obtained. As a result of this study, it was revealed that the gap between the steel column base plate and the reinforced concrete foundation, which is frequently encountered in applications, negatively affects the moment capacity of the joint.