再生混凝土框架结构抗震性能及其评价

Study and evaluation on the seismic performance of recycled aggregate concrete frame

通过三维6自由度振动台试验,得到再生混凝土框架结构的地震反应。基于实测地震反应的深入分析,发现在同一地震动输入下,各楼层的最大层剪力、最大倾覆力矩沿高度总体上呈递减趋势。随着地震动强度的增加,各楼层的层剪力、基底剪重比、倾覆力矩随之增大。通过对试验数据拟合,分别得到结构的剪力系数和动力放大系数计算公式。弹塑性阶段前期结构动力放大系数下降较快,而在弹塑性阶段的后期其下降速度趋于平缓。通过对试验模型结构整体和各层间滞回曲线、骨架曲线和特征参数的分析,建立再生混凝土框架结构整体和层间刚度退化四折线型恢复力模型。最后基于破损程度的分析,提出再生混凝土框架结构在不同破坏状态下的性能指标,并进一步采用变形和能量组合的双重破坏准则对再生混凝土框架结构进行了抗震能力评价。

Based on 3D 6-DOF shaking table tests, the seismic response of the recycled aggregate concrete （RAC） frame was recorded. The analysis results indicate that the maximum inter-storey shear force and the maximum overturning moment reduce proportionally along the height of the model under the same seismic wave, and the inter-storey shear force, the shear-weight ratio and the overturning moment of the model increase progressively with the increase of acceleration amplitude. The relationship between peak ground acceleration （PGA） and shear coefficient or the dynamic amplification factor may be obtained by the mathematical fitting of experimental results. The dynamic amplification factor decreases rapidly at the early elasto-plastic stage, but decreases slowly with the development of elasto-plasticity. A four- line restoring force model with degenerated stiffness is proposed based on the analyses of hysteretic curves, skeleton curve and characteristic parameters of the model structure. The earthquake damage level for RAC frame is preliminarily classified and the corresponding performance design index is proposed according to the experimental results. Furthermore, a two-parameter seismic to evaluate the seismic performance of damage model based on deformation and cumulative energy dissipation is suggested the RAC frame structure.