再生混凝土框架梁柱中节点抗震性能试验研究

Experimental study on seismic behavior of recycled aggregate concrete beam-column interior-joints

通过3个再生混凝土框架梁柱中节点试件在低周反复荷载下的加载试验,对其破坏形态、滞回性能、延性特征、刚度退化等进行了研究,为再生混凝土结构的工程应用提供试验依据和理论基础。研究结果表明:再生混凝土节点受力和破坏过程可分为初裂阶段、通裂阶段、极限阶段、破坏阶段;节点核心区剪切破坏时,混凝土多沿再生骨料新老砂浆界面呈酥松状破坏,表现出明显脆性性质;增加箍筋数量,可以提高节点核心区的受剪承载力;在核心区发生剪切破坏前,梁根部纵筋能够充分发挥变形能力,滞回曲线较为丰满;施加轴向压力,可延缓节点裂缝的开展,抑制梁纵筋黏结滑移,有助于提高试件的抗震性能;再生混凝土试件具有一定的延性和耗能能力,通过合理的设计可以用在抗震设防地区。

The low-cyclic reversed loading tests were carried out for three interior beam-column specimens made by recycled aggregate concrete（RAC）.The tests were designed to investigate the joint failure modes,hysteretic characteristics,ductility and stiffness degradation,for the purpose of providing experimental and theoretical background of recycled aggregate concrete structures.The results show that the mechanical and failure process of RAC frame joints can be divided into four stages： the initial cracking,the fully cracking,the ultimate and the failure stage.The shear failure occurs in the joint core area,which shows the obvious brittle damage along the recycled aggregate interface of old and new mortar.With the increase in the number of stirrups,the shear capacity of the core area are improved and the beam longitudinal reinforcement fully yields before the shear failure occurs in the joints.In addition,the hysteretic curve is more plump.The appropriate axial pressure can delay the development of cracks in the core area and restrain the beam reinforcement from bond slip.According to the test results,the recycled aggregate concrete elements show a good ductility and energy dissipation capacity.The RAC elements can be well applied in the earthquake fortification zone with a rational design.