钢纤维活性粉末混凝土梁柱中节点抗震性能试验研究

为研究钢纤维活性粉末混凝土梁柱中节点的抗震性能及受剪承载力，完成了8个钢纤维活性粉末混凝土梁柱中节点试件的拟静力试验，研究了钢筋强度、节点核心区配箍率、贯通节点的腰筋及柱内非角部钢筋对活性粉末混凝土梁柱中节点的破坏过程、破坏形态、受剪承载力、滞回特性、耗能、承载力和刚度退化等抗震性能的影响。结果表明，梁柱纵筋采用HRB600高强钢筋延缓了刚度退化速率，提高了试件的耗能能力；核心区箍筋配筋率的增大能够改善破坏阶段试件的承载力退化特性和耗能能力，节点核心区横向钢筋面积率为0~0.98%时，节点的受剪承载力和延性随横向钢筋面积率的增大而增大；贯通节点的梁内腰筋和柱内非角部钢筋均能够有效提高节点受剪承载力、延缓构件承载力的退化、提高其耗能能力。采用GB 50011—2010《建筑抗震设计规范》的受剪承载力公式，对于低配箍率节点承载力计算偏于保守，当面积配箍率大于0.98%时偏于不安全；ACI 352-02中公式的计算结果与试验值更接近，约有9%~46%的安全裕度。

Experimental study on seismic behavior of interior steel fiber reinforced RPC beam-column joints

In order to investigate the seismic behavior and shear bearing capacity of steel fiber reinforced reactive powder concrete (RPC) beam-column joints, quasi-static tests on eight RPC interior beam-column joints were carried out. The variables considered in test program included strength of reinforcement, stirrup ratio in joint core, and web rebars and vertical rebars across the joint core, and their influences on the failure mode, shear bearing capacity, hysteretic loops, energy dissipation, strength degeneration and rigidity degeneration behavior of the RPC joints were analyzed. The tests results indicate that the HRB600 longitudinal rebars in the beam mitigate the rigidity degeneration and improve the energy dissipating capacity of the specimen. An increase in stirrup ratio improves the strength degeneration and energy dissipating capacity of the specimen during the failure stages. As the transverse reinforcement ratio in joint core increases from 0 to 0.98%, the shear bearing capacity and ductility of the RPC joint increase. Web rebars and vertical rebars across the joint core improve the shear bearing capacity, strength degeneration and energy dissipation capacity of the specimen. Using the formula of GB 50011—2010 to calculate the shear bearing capacity leads to conservative results for RPC joints with a low stirrup ratio, but tends to be unsafe when the area stirrup ratio is greater than 0.98%. The predictions given by ACI 352-02 are closer to the test result compared to the GB 50011—2010 prediction, with a safety margin of 9%-46%.