框架柱塑性铰区基于延性的抗剪承载力研究

Experimental Study on Shear Capacity of Concrete Columns Within Plastic Hinge Region Based on Ductility Design

为防止钢筋混凝土框架柱发生脆性破坏,实现中、强地震作用下所期待的延性破坏,对10个框架中柱构件进行了反复荷载作用下塑性铰形成后的抗剪性能试验研究。从混凝土及箍筋应力水平等条件出发,提出纵筋屈服后框架柱破坏形态的分类标准;研究纵筋屈服后箍筋与混凝土各自的抗剪贡献,回归得出构件在不同位移延性时箍筋及混凝土抗剪贡献的计算公式;以试验为依据研究了框架柱塑性铰区域混凝土抗剪承载力的退化过程及剪切受力机理,对不同延性需求的构件给出不同的抗剪承载力计算公式,弥补我国现行规范未明确剪切抗力与不同延性需求之间定量关系的缺陷。

In order to prevent serious brittle shear failure of reinforced concrete frame columns,and to realize the expected ductile failure under the middle-strong earthquake,an experiment of 10 reinforced concrete frame column specimens for shear capacity is carried out under cyclic load.From the stress levels of concrete and stirrups,the classfication criteria of failure types for frame columns is proposed.The contribution of stirrups and concrete is also studied after the yield of longitudinal reinforcement,and the formulas for the shear contribution of the stirrups and concrete in different displacement ductility are all gained.The degradation process and shear mechanism of concrete shear capacity within the plastic hinge zone are all studied in detail.Based on the ductile design,the formula for the shear capacity of reinforced concrete columns is supposed under the seismic loading to make up the shortcuts of GB50010—2002.