装配整体式钢筋混凝土框架中节点地震损伤试验研究

EXPERIMENTAL STUDY ON SEISMIC DAMAGE OF INTERIOR JOINTS IN INTEGRALLY PREFABRICATED REINFORCED CONCRETE FRAMES

为研究装配整体式钢筋混凝土框架中节点地震损伤特性,对1根现浇节点试件和3根不同轴压比的装配整体式节点试件开展了拟静力试验,观测其损伤破坏过程,分析其荷载-变形及刚度退化等力学性能,并对轴压比的影响进行比较。最后,运用修正的Park-Ang损伤指数模型探讨轴压比、混凝土强度、箍筋特征值和纵向配筋率等参数对节点损伤的影响规律,并对装配整体式钢筋混凝土框架中节点全过程损伤进行定量分析及划分损伤等级。结果表明:该装配整体式钢筋混凝土框架中节点经历了五个破坏阶段,其中梁端和下柱接缝处为薄弱部位;轴压比增大会加速节点损伤,混凝土强度、箍筋特征值、纵向钢筋配筋率的提高,均能明显减缓节点损伤;采用的损伤指数模型可较好反映试验节点的地震损伤情况。

In order to study seismic damage of interior joints in integrally prefabricated reinforced concrete frames,quasi-static tests were conclucted on one cast-in-place joint and three integrally prefabricated joints with different axial compression ratios.The damage process was observed and the mechanical properties of load-deformation and stiffness degradation were analyzed.Besides,the effects of axial compression ratios were compared.Finally,the modified Park-Ang’s damaged index model was used to discuss the influences such as axial compression ratios,concrete strength,stirrup eigenvalues and longitudinal reinforcement ratios on joint damage,and the total process damage of joints was quantitatively analyzed and classified.The results showed that the joints in the integrally prefabricated reinforced concrete frame under low cyclic loading went through five damaged stages in the test,in which the joints between beam ends and lower columns were the weak parts.The larger axial compression ratios could accelerate the joints damage.The increase of concrete strength,stirrup eigenvalues and longitudinal reinforcement ratios could obviously slow down the joint damage.The damaged index model used in the paper could better reflect the seismic damage of the tested joints.