冻融循环下钢筋混凝土框架梁柱中节点抗震性能试验研究  

Experiment study on seismic behaviors of RC beam-column joints after freeze-thaw cycles

作　　者：郑捷[1] 董立国[1] 秦卿[1] 郑山锁[1] 汪锋[1] 

机构地区：[1]西安建筑科技大学建筑设计研究院,陕西西安710055

出　　处：《建筑结构学报》2016年第10期73-81,共9页Journal of Building Structures

基　　金："十二五"国家科技支撑计划(2013BAJ08B03);国家自然科学基金项目(51678475);教育部高等学校博士学科点专项科研基金项目(20136120110003)

摘　　要：通过6个不同冻融循环次数和轴压比的RC框架中节点梁柱组合体试件的低周反复加载试验,研究冻融循环次数和轴压比变化对节点核心区和梁柱组合体破坏模式、水平承载力、变形及耗能能力等抗震性能指标的影响。结果表明:随着冻融循环次数的增加,混凝土力学性能劣化,贯穿节点的梁端纵筋与混凝土之间的黏结强度显著退化,使得通过"斜压杆机构"与"桁架机构"传入节点核心区的剪力比例发生变化,导致低周反复荷载作用下节点核心区破坏模式发生转变,承载力降低,组合体耗能能力下降,延性稍有增大;当剪压比较大时,轴压比的增大使经冻融循环后的节点承载力降低,延性和耗能能力均出现不同程度的下降;冻融循环次数增加,由节点核心区剪切变形引起的柱顶水平位移在总柱顶水平位移中所占的比例增大。In order to study seismic behaviors of RC frame beam-column joints,such as failure mode,horizontal bearing capacity,deformation capacity and energy-dissipating capacity under different freeze-thaw cycles and axial compression ratio,quasi-static tests were carried out for six interior beam-column joints of RC frame with different freeze-thaw cycles and axial compression ratios. The results show that with increasing of freeze-thaw cycles,not only the mechanical performance of concrete is degenerated,but also the bond performance between longitudinal bar and concrete in the beam end is attenuated significantly,leading to the change of shear force ratio of RC frame beamcolumn joints through the force transfer according to the ‘diagonal compression strut model＇and ‘truss model＇. As a result the failure mode of RC frame beam-column joints is transformed,the ultimate strength and energy dissipation ability are reduced,while the ductility is increased slightly. With increasing of axial compression ratio,the bearing capacity,ductility and energy-dissipating capacity of the RC frame beam-column joints are decreased under high shearcompression ratio. With increasing of freeze-thaw cycles,the percentage of column top lateral displacement caused by the beam-column joint core shear deformation in the total column top lateral displacement is increased.

关 键 词：RC框架梁柱节点 冻融循环 轴压比 低周反复荷载试验 抗震性能 

分 类 号：TU375.403[建筑科学—结构工程]