钢筋混凝土异形截面框架柱轴压比限值的研究

迄今为止,尚未见到国内外对于高抗震等级时异形柱的轴压比限值的研究报道,而且国家相关规范修订后,二、三级抗震等级时异形柱的轴压比限值需要相应修改,因此有必要系统地研究各抗震等级时钢筋混凝土异形柱的轴压比限值．理论分析表明：为使一、二、三、四级抗震等级时异形柱框架结构具有适当的位移延性水平,柱的曲率延性比应分别达到12、10、8和6：以此为标准,通过对异形柱曲率延性全过程非线性分析,从而确定各抗震等级时异形柱的轴压比限值及对箍筋间距与纵筋直径比s／d、箍筋直径d的相应要求．

A Research on Limited Value of Axial Compression Ratio of Arbitrarily Shaped RC Columns

The information concerning the research on limited value for axial compression ratio of arbitrarily shaped RC columns in the case of high seismic fortification grade hasn't been found yet so far. Considering the fact that the related National Design Codes have been changed, the limited value for axial compression ratio of arbitrarily shaped RC columns in the case of 2~(nd) and 3~(rd) seismic fortification grades also needs changing. Therefore, it is necessary to make a systematical study on the limited value for axial compression ratio of arbitrarily shaped RC columns in the case of every seismic fortification grade. The theoretical analyses show that 12,10,8 and 6 are taken as the values of curvature ductility ratio of arbitrarily shaped RC columns respectively in the case of 1~(st) , 2~(nd), 3~(rd) and 4~(th) seismic fortification grades, which assures that the arbitrarily shaped RC columns meet the displacement ductility requirements for seismic structures. Then the limited value for axial compression ratio of the arbitrarily shaped RC columns in the case of every seismic fortification grade is determined on the basis of its nonlinear analysis of curvature ductility, and the requirements for the ratio of stirrup spacing to the diameter of longitudinal bar, s/d, and the diameter of stirrup, d_v are met.