基于位移角的弯曲破坏RC抗震墙约束箍筋设计法

Corrective drift-based method of confining stirrups for reinforced concrete walls with flexure failure

研究表明,我国抗震规范中的钢筋混凝土抗震墙约束箍筋设计法无法量化位移角能力,使同一抗震等级下能达到的位移角不平衡。为了克服规范中的不足,提出了基于钢筋拉断破坏和混凝土压溃破坏两种破坏下基于量化位移角指标的约束箍筋设计法。基于该方法评估了现行中国规范不同抗震等级的剪力墙具有的位移角变形能力,结果表明中国规范在抗震等级为一级(9度)、一级(6、7、8度)、二三级时的位移角平均值分别在0.009、0.007、0.005左右。将以上3数据定量为中国规范三个抗震等级下的位移角设计指标,并利用本文提出的基于位移角的设计法对中国规范定性的基于轴压比设计法修改成定量的基于目标位移角设计法,量化了不同抗震等级的位移角能力,且克服了同一抗震等级时位移角不平衡的不合理性。

Research showed that the confining stirrup design method in Chinese seismic design code is not reasonable. The drift capacity of RC walls is different in the same seismic level in most cases. A new drift-based design method of confining stirrups is proposed. The new method both considers concrete compression failure and reinforcement fracture failure modes. Based on the new method,the drift capacity of RC walls designed according to Chinese code in three seismic design levels is evaluated. For walls with Seismic Grade I（ Intensity 9）,Grade I（ Intensity 6,7 or 8）,and Grade II or III of GB 50011-2010,the drift capacity can nearly get 0. 009,0. 007 and0. 005,which are defined as three drift indexes of three seismic levels. Using the proposed drift-based method and these three drift indexes,this paper modifies the Chinese method into quantitative drift-based method,which overcomes the disequilibrium of initial Chinese method.