梁端塑性铰外移的型钢混凝土节点的抗震性能

通过对两个足尺节点试件的低周反复荷载试验,研究了梁端塑性铰外移的型钢混凝土节点的抗震性能.试件按“强节点”原则进行设计,对节点核心区附近梁端工字形型钢的上、下翼缘采取狗骨式削弱,并适当增加梁端根部到型钢翼缘最大削弱部位的纵向钢筋的配筋量.试验结果表明:两个节点试件的位移延性系数在5.27以上,均符合抗震设计的延性要求;在最大荷载时,两个试件的等效粘滞阻尼系数均超过0.30,耗能能力强.理论分析表明:在型钢混凝土节点中采用塑性铰外移的构造措施,不仅能够降低节点核心区所受的剪力以及梁柱连接焊缝的应力,而且能够增强节点试件在塑性铰区的转动能力和抗剪性能,从而提高节点的延性和耗能能力.

Seismic Behavior of Steel Reinforced Concrete Joints with Plastic Hinge Shifting Away from Beam End

The seismic behaviors of steel reinforced concrete joints with plastic hinge shifting away from the beam end were investigated based on the experimental results of 2 full-scale joint specimens under cyclic loading.In the investigation,the joints designed as strong connections were treated with dog-bone style weakening on the upper and below flanges of the H-type steel at the beam end near the joint core,and the longitudinal reinforcement ratio,which distributes from the root of beam end to the maximum weakened flange of the H-type steel,was properly increased.Experimental results show that the ductility factors of the 2 joint specimens are all more than 5.27,which meets the requirements of the ductile frame in seismic design,and that the equivalent viscous damping coefficients on the maximum load are all more than 0.30,which reveals quite high energy dissipation of the joints.Moreover,it is indicated from analyses that the constitution of plastic hinges for steel reinforced concrete joints can not only decrease the shear in the joint core and the stress of seam in the beam-column connection but also improve the rotation and shear capacities of plastic hinges in the beams,thus increasing the ductility and energy dissipation of the joints.