Experimental study on seismic performance of precast concrete column-steel beam joints connected by tie-bar
In order to give full play to the construction performance of assembled structures as well as to improve the seismic performance of reinforced concrete column-steel beam nodes(RCS),a prefabricated concrete column-steel beam tensile reinforcement connection joint is proposed.The effects of the diameter of the tension reinforcement,the relative position of the tension reinforcement and the steel beam flange,and the form of the steel beam flange on the seismic performance of the joint were investigated through low-cycle reciprocating loading tests on six joints.The results show that:the damage mode of the joint is beam end bending damage and node area connection damage,which is mainly manifested by steel girder flange flexure,steel girder flange tearing,dehiscence of tension reinforcement,steel sleeve tearing,tie-bar unholding and steel sleeve detached from concrete column;Fuller shape of the load-displacement hysteresis curve at the beam end,the stiffness degradation curve is relatively smooth,the displacement ductility coefficient is between 3.30 and 5.52,and the equivalent viscous damping coefficient is between 0.15 and 0.30.The joint has a good plasticity,and it has a good performance.The joint s have good plastic deformation capacity and seismic performance;with the increase of the diameter of the tie bars and plug weld holes,the load carrying capacity and energy dissipation capacity of the joints are improved,the load carrying capacity,ductility and energy dissipation of the joints are reduced when the tie bars are arranged in the inner side of the flange of the steel girder,and the load carrying capacity of the non-strengthened flange is significantly reduced,but the ductility is improved.The finite element calculation model of this kind of nodal specimen was established,and the relevant influencing factors such as axial compression ratio and steel sleeve thickness were studied in depth.The results show that:with the increase of axial compression ratio from 0.2 to 0.7,the joint bearing capacity increases slightly by 8.8％;the joint bearing capacity is significantly improved by 65.1％with the increase of the thickness of the steel sleeve from 10 mm to 20 mm in the core area;the extension height of the steel sleeve in the core area does not have much effect on the joint bearing capacity;the ratio of tie-bar tensile strength to the steel girder flange tensile strength is less than 1.0,the joint bearing capacity is significantly improved with the increase of the ratio,and the increase in joint bearing capacity slows down with the increase of ratio greater than 1.0,and the increase of joint bearing capacity hardly increases with the increase of ratio greater than 1.5.
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