基于振动台试验的预制再生混凝土框架后浇边节点分析

Analysis of Cast-in-situ Exterior Joints of Precast Recycled Aggregate Concrete Frame by Shaking Table Tests

通过振动台试验对预制再生混凝土框架不同楼层处的后浇边节点进行了抗震性能分析,对其破坏形态、滞回性能、延性特征、刚度退化等进行了研究,为采用后浇节点的预制再生混凝土结构的工程应用提供试验依据和理论基础,并对后浇节点的新旧混凝土叠合面这一薄弱环节提出了加强后浇节点抗震构造的设计建议。研究结果表明:再生混凝土后浇边节点破坏过程与普通混凝土边节点十分类似,可分为初裂阶段、通裂阶段、极限阶段、破坏阶段;再生混凝土边节点的延性等抗震性能仍满足相应抗震设防要求;再生混凝土框架边节点的抗剪承载力,可采用现行《混凝土结构设计规范》中节点抗剪承载力修正后的公式计算。

The shaking table test was carried out for cast-in-situ exterior joints in different floors of a precast frame made of recycled aggregate concrete （RAC）. The failure feature, the hysteretic behavior, the ductility characteristic and stiffness degradation under seismic waves were comparatively investigated, for the purpose of providing experimental and theoretical background of cast-in-situ joint in RAC structures. At last, some construction design recommendations were put forward to the weak surface between new and old concrete in the cast-in-situ joint. The research results show that failure process of cast-in-situ exterior joints with RAC is similar to that of conventional concrete, which can be divided into four stages： the initial cracking stage, the fully cracking stage, the ultimate stage and the failure stage. The seismic behaviors of exterior joints of RAC, including the ductility etc. , still meet the related requirements of earthquake- resistance design. The formula for calculating the shear capacity of exterior joints made of RAC is proposed and compared with the calculation formula in current Chinese Code for Design of Concrete Structures.