四级抗震等级时钢筋混凝土异形柱轴压比限值的研究

考虑到二、三级抗震等级时异形柱轴压比限值显著低于矩形柱轴压比限值的实际情况,需对四级抗震等级时异形柱轴压比限值问题进行深入研究。本文基于理论分析和非线性全过程分析,取曲率延性比μ_(φc)=6作为四级抗震等级时异形柱应具有的曲率延性水平,不仅可以保证异形柱具有与矩形柱相当的延性性能,而且满足抗震结构位移延性的需求;然后以此为标准,确定了四级抗震等级时异形柱的轴压比限值及相应的构造要求。本文研究成果将为工程设计中四级抗震等级时钢筋混凝土异形柱轴压比限值的确定提供参考,也为完善相关设计规范提供理论依据。

Research on limit values of axial compression ratios of specially shaped RC columns in case of 4th aseismic grade

Considering the fact that the limit values for axial compression ratios of specially shaped RC columns in case of 2nd and 3rd aseismic grades are much lower than those of the rectangular columns, it is necessary to make a thorough study on limit values for axial compression ratios of specially shaped RC columns in case of 4th aseismic grade. In this paper, based on the theoretical analysis and nonlinear analysis, the curvature ductility ratio 6 was taken as the curvature ductility level of specially shaped RC columns in case of 4th aseismic grade, which could assure that the specially shaped RC columns had the same ductility level as that of the rectangular RC columns and met the ductility requirements for aseismic structures. Then the limit values for axial compression ratios and the relevant construction requirements of the specially shaped RC columns in case of 4th aseismic grade were determined. Finally, the research results of the present paper will provide an important reference to determinate the limit values for axial compression ratios of the specially shaped RC columns in case of 4th aseismic grade as well as an important theoretical base to compile the related design code.