钢筋套筒灌浆连接装配式剪力墙结构三层足尺模型子结构拟动力试验

Pseudo-dynamic substructure test on a 3-story full-scale model of prefabricated concrete shear wall structure with rebars splicing by grout sleeves

为研究钢筋套筒灌浆连接装配式剪力墙结构的抗震性能,完成了1个3层足尺模型在不同强度地震作用下的子结构拟动力试验,观察其破坏现象,研究其滞回特性、变形能力、刚度退化和钢筋屈服次序等。结果表明:试验模型的破坏集中在地震作用方向的连梁和窗下墙,连梁以弯曲破坏为主,窗下墙为剪切破坏,首层墙肢出现轻微的弯曲破坏;试验过程中,连梁纵筋、墙肢竖向钢筋及连梁箍筋依次受拉屈服,试验模型实现了"强墙肢弱连梁"及连梁"强剪弱弯"的设计目标;8度多遇、设防和罕遇地震以及9度罕遇地震作用下,试验模型的抗侧刚度分别降低约5%、20%、60%和80%,对应的最大层间位移角分别为1/3 341、1/899、1/268和1/111,以层间位移角为参数,结构的破坏程度分别为完好、轻微损坏、中等破坏和倒塌;"预制底板出筋"和"预制底板不出筋"的双向叠合楼板均具有良好的整体性和平面内刚度,均可起到水平刚性隔板作用;墙体一字形截面竖向后浇段采用由2根U形钢筋组成的封闭箍代替普通箍筋具有可行性;预制夹心保温外墙的内、外叶墙之间连接可靠,外叶墙不参与结构受力,结构设计时可不考虑外叶墙的作用。

To study the seismic behavior of the prefabricated concrete shear wall structure with rebars splicing by grout sleeves,pseudo-dynamic substructure test on a 3-story full-scale model was performed under the excitation of earthquake record. The cracks and damage phenomena of the test model were observed. Further analysis was conducted to investigate the seismic behavior,such as the hysteretic characteristic,deformation capacity,stiffness degradation and rebar yield order. The results indicate that cracks and damage of the test model center on the coupling beams and the window belly walls in the earthquake excitation direction,characterized by bending failure in the coupling beams,shear failure in the window belly walls and slight bending failure in the wall piers. The longitudinal rebars of coupling beams,the vertical rebars of wall piers and the stirrups of coupling beams yield in turn,which indicates that the design concepts ‘strong wall pier,weak coupling beam ＇and ‘strong shear,weak bending ＇of coupling beam are achieved. Under frequent earthquake,design earthquake and rare earthquake of seismic fortification intensities eight,and rare earthquake of seismic fortification intensity nine,the lateral stiffness of the test model decreases about 5%,20%,60% and 80%,respectively,compared with the initial stiffness. The maximum interstory drift ratios are 1 /3 341,1 /899,1 /268 and 1 /111 respectively under the same load conditions,which shows that the damage extent of the test model is no damage,slight damage,moderate damage and collapse,respectively. Since the concrete superposition two-way floor slabs with rebars or no rebar protruding from precast bottom slab both are of good integrity and adequate in-plane stiffness,both types of superposition floor slab can be considered as a rigid diaphragm. It is feasible by using two U-shaped rebars to form a closed stirrup instead of the ordinary stirrup in the rectangular vertical post-casting section between two precast shear walls. The connection between inner wythe and outer wythe of the precast concrete sandwich insulation wall is reliable. As the outer wythe does not participate in bearing loads,the contribution of the outer wythe can be neglected in the structural design.