Shear Behavior Of Anchor Bolt Connections In Exposed Steel Column Base

China’s steel structure design specifications stipulate that the anchor bolts of the column foot can not be sheared,which leads to the need to set the shear key for the exposed steel column foot.However,some international norms and studies believe that the anchor bolt can participate in the shear resistance of the steel column foot.Referring to of the exposed steel column bases joint used in the practical engineering,totally 19 specimens in 7 groups were tested to study the shear behavior of anchor bolt connection.Among the specimens,the diameter of the hole of base plate,the thickness of base plate,the diameter of anchor bolts and the yield strength of bolt material are changed.The test shows that,the anchor bolt connection has considerable shear resistance.There are three ultimate failure modes:shear failure of anchor bolt when reinforcement is sufficient,punching failure of concrete when reinforcement is insufficient,or both of them occur simultaneously.There are two types of load-relative displacement curves of anchor bolt connections,the main difference is whether there is a slip section.The length of the slip section is positively correlated with the difference between the diameter of the hole of base plat and the diameter of the anchor bolt,and is negatively correlated with the thickness of the base plate.For the yield shear bearing capacity of anchor bolt connection,this paper compares the experimental values with three existing theoretical models and gives the recommended formula.For the ultimate shear bearing capacity of anchor bolt connection,the anchor bolt section has both tensile force,shear force and bending moment in the ultimate state.In this paper,the relationship between tensile force,shear force and bending moment of anchor bolts under ultimate state is given,and the calculation model of ultimate shear capacity of three factors is proposed.It is found that in the ultimate state,the contribution of friction to the total shear capacity is generally 0.17-0.20,which is a relatively fixed interval.At the same time,the finite element model(ABAQUS modeling)of the steel column anchor connection is established,and the parameters of the test specimen are used as parameters.The failure mode of the specimens simulated by finite element modeling was analyzed,and the finite element load-relative displacement curves were compared with the experimental curves.Based on the post-processing ability of ABAQUS visualization,the deformation modes,force mechanism and shear resistance of each parameter at each stage of loading were further analyzed.The finite element simulation results are in good agreement with the experimental results.