预制混凝土柱-钢梁对拉钢筋连接节点抗震性能试验研究

Experimental study on seismic performance of precast concrete column-steel beam joints connected by tie-bar

为充分发挥装配式结构的施工优越性以及改善钢筋混凝土柱-钢梁节点(RCS)的抗震性能,提出一种预制混凝土柱-钢梁对拉钢筋连接节点。通过对6个节点试件的低周往复加载试验,研究了对拉钢筋直径、对拉钢筋与钢梁翼缘相对位置以及钢梁翼缘形式对节点抗震性能的影响。结果表明:节点试件破坏模式为梁端弯曲破坏和节点区连接破坏,主要表现为柱钢梁翼缘屈曲、钢梁翼缘撕裂、对拉钢筋断裂、钢套筒撕裂、对拉钢筋脱孔和钢套筒与混凝土柱脱空;梁端荷载-位移的滞回曲线形状较为饱满,刚度退化曲线较为平缓,位移延性系数在3.30~5.52之间,等效黏滞阻尼系数在0.15~0.30之间,节点具有较好的塑性变形能力和抗震性能;随着对拉钢筋和塞焊孔的直径增大,节点试件的承载力和耗能能力有所提高;对拉钢筋布置在钢梁翼缘内侧,节点试件的承载力、延性和耗能均有所降低,非加强翼缘节点试件的承载力显著降低,但延性有所提高。在试验基础上,建立了该种节点的有限元分析模型,对轴压比、钢套筒厚度等相关影响因素进行了研究。结果表明:随着轴压比的增大(由0.2增大到0.7),节点承载力有小幅增加8.8%;节点承载力随着核心区钢套筒厚度的增大(由10 mm增大到20 mm)有明显提高,增大了65.1%;核心区钢套筒延伸高度对节点的承载力影响不大;对拉钢筋与钢梁翼缘抗拉力比值小于1.0时,节点承载力随比值提高大幅提升,比值大于1.0时,节点承载力增加有所放缓,而比值大于1.5后,节点承载力几乎不再增长。

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 10mm to 20mm 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.