Research On Bending Behavior And Theory Of Semi-rigid Bolted Base Connections Subjected To Minor-axial Bending Moment

In steel frame structural system,steel columns carry the self-weight and vertical loads(i.e.permanent and variable loads)of the structure and resist horizontal loads caused by wind or seismic forces,the failure of a few steel columns may lead to the destruction or even collapse of the entire structure.As an important component connecting the steel column and the foundation,the column foot is responsible for transmitting the vertical and horizontal loads borne by the steel column.The commonly used steel column foot joints are usually welded with the steel column and the bottom plate,but this connection method is not economical and cannot achieve rapid repair after damage.In addition,there are few theoretical studies on the performance of column foot joints in the weak axis direction.Based on the above reasons,this paper studies the weak axis performance of a new type of bolted column foot joint.The main research contents are as follows:(1)The current domestic and international research on column foot joints is summarized,and the content and research significance to be studied in this paper are put forward.(2)The quasi-static test in the weak axis direction of the new column foot joint was carried out,and the hysteresis curve,skeleton curve,energy dissipation,etc.of the specimen with different parameters were obtained.The influence of mechanical properties is small;the angle steel has plastic deformation,and the steel column remains elastic;the column foot joint has better bending resistance and energy dissipation capacity.(3)The mechanical simplified model of the new type of column foot joint is established,and the theoretical calculation formula of its weak axis direction is proposed.(4)The model of the new type of column foot joint is established with the help of ABAQUS finite element software.The simulation results show that the axial pressure,the thickness of the angle steel and the position of the bolts of the horizontal legs of the angle steel have a great influence on the performance of the joint,while the influence of bolt diameter of the horizontal leg of the angle steel and the friction coefficient can be neglected.(5)In order to explore the effect of the new bolted column foot joint on the overall seismic performance of the structure,this paper uses the OpenSees software to establish a two-story steel frame containing the column foot joint,and analyzes the maximum interstory displacement angle,the maximum residual interstory displacement angle,and the displacement time history curve.and other seismic responses,the results show that the frame containing this new type of column foot joint has good seismic performance。...