钢筋活性粉末混凝土框架节点抗震性能试验研究

Experimental research on the seismic performance of reinforced reactive powder concrete frame joints

活性粉末混凝土是一种具有超高强度、韧性和耐久性的水泥基复合材料,为了研究活性粉末混凝土框架节点的抗震性能,对4个活性粉末混凝土梁柱节点试件进行了低周反复荷载试验,研究了活性粉末混凝土梁柱节点的受剪破坏模式、承载力、滞回特性、延性、耗能、强度和刚度退化等抗震性能。结果表明:活性粉末混凝土框架节点具有较高的抗裂强度,节点区裂缝开展路径较多,多为细小裂缝,混凝土剥落较少,试件破坏时完整性较好;当达到最大荷载后,刚度退化和强度退化较为缓慢;节点的变形及耗能能力较强,试件破坏时的剪切变形为峰值荷载时变形的2.23~8.56倍,试件的平均等效黏滞阻尼系数为0.137,黏滞阻尼系数高于普通混凝土和高强混凝土节点。采用活性粉末混凝土可以改善框架节点的剪切延性和耗能能力等抗震性能,降低核心区箍筋率,便于施工。

To study the seismic behavior of frame joints made of reactive powder concrete with ultrahigh strength,toughness and durability,4reinforced reactive powder concrete beam-column joints were tested under cyclic loads simulated seismic load conditions.The failure patterns,seismic bearing capacity,hysteretic characteristics,ductility,energy dissipating,strength and rigidity degeneration of the reactive powder concrete frame joints were analyzed.The test results show that,the shear-cracking strength of the reactive powder concrete specimens is higher,and the development of surface crack exhibits the characteristics of multiple fine cracking and a little concrete spalling,and the specimens remain as an integral whole as the loading ends.The strength and rigidity degeneration rates are small.The deformation capacity and energy dissipation are well.When the failure is occurring,the shear deformation is the double of that under the peak load,and the averaging equivalent viscous damping coefficient of specimens is0.137,which is higher than the equivalent viscous damping coefficient of normal and high-strength concrete joints.The use of reactive powder concrete can improve the seismic performances of frame joints,including the shear ductility,energy dissipation capacity and so on,and reduce the stirrup ratio in joint core,which is conducive to the construction.