新型柱间可更换耗能节点的全装配RC柱抗震性能试验

Seismic performance experimental research on a fully precast RC column with new replaceable energy-consuming joint between columns

为提高装配式结构的工业化程度和可修复能力,提出一种新型全装配钢筋混凝土(RC)柱间可更换耗能节点(RECJ),并将其应用到框架结构的底层柱。对两个采用RECJ连接的装配柱试件和一个整体现浇柱对比试件进行拟静力加载试验,长榫头试件在加载至1/25的层间位移角后更换受损的连接板,在同条件下进行加载,分析各试件的破坏形态、滞回曲线及骨架曲线特征、刚度及承载力的退化特征、延性及耗能能力、连接钢板及柱内钢筋应变变化等性能。结果表明:新型全装配框架底层柱的损伤及破坏主要集中在RECJ的连接钢板上,试件其他部位基本保持弹性;其滞回曲线呈梭形,形状饱满,耗能、延性及刚度退化性能明显优于全现浇对比柱;榫头长度较长的试件总体性能优于榫头较短试件,表现出更好的抗震性能,且具有与现浇柱等效的初始刚度和承载能力。RECJ在大震下可通过更换受损的连接板使结构快速恢复抗震性能。对RECJ的受力机制进行分析,并提出RECJ屈服阶段和峰值阶段的受弯承载力公式和转角变形,基于推导的公式得到骨架曲线模型。

In order to enhance the industrialization level and repairability of prefabricated structures,a novel fully precast reinforced concrete(RC) inter-column replaceable energy-consuming joint(RECJ) was proposed and applied to the ground floor columns of frame structures in this paper.A pseudo-static reciprocating loading test was carried out on two precast column specimens connected by RECJ and a cast in situ column comparison specimen.After loading the long tenon joint specimen to an interlayer displacement angle of 1/25,the damaged connecting plate was replaced and loaded under the same conditions.The specimens were then loaded under the same conditions.The performance analysis includes the failure mode,hysteresis curve,skeleton curve characteristics,degradation characteristic of stiffness and bearing capacity,ductility and the energy dissipation capacity as well as the strain changes of the connecting steel plate and the steel bar in the column.The results showed that the damage of the bottom column of the new fully precast frame are mainly concentrated on the connecting steel plate of RECJ,while other parts of the specimen remain largely elastic.In addition,the hysteresis curve of RECJ exhibits a full and plump shape,which indicates significant improvements in energy dissipation,ductility and stiffness degradation compared to the cast in situ comparison column.Overall,the specimens with longer tenon lengths outperform those with shorter tenons,which shows better seismic performance and equivalent initial stiffness and bearing capacity to the cast in situ column.RECJ can quickly restore seismic performance of the structure by replacing damaged connection plates during major earthquakes.The stress mechanism of RECJ was analyzed,and the bending bearing capacity formula and angular deformation of RECJ during the yield and peak stages were proposed.The skeleton curve model was obtained based on the derived formula.