Research On Seismic Performance Of RC Frame Column With Dense Stirrups And High Axial Compression Ratio

Seismic performance of reinforced concrete frame columns with dense stirrupsand high axial compression ratio is investigated experimentally in the thesis.Two columns with dense stirrups and one contrastive column are tested underlow cyclic loading with high axial compression ratio to investigate the columns’seismic behavior. The main test parameter is the pattern of stirrup densification. Theprimary seismic performance indexes including failure mode,hystereticcharacteristics,skeleton curve,ductility,stiffness degradation and energy dissipationcapacity are discussed. The following conclusions can be made based on the results ofthis investigation:(a) Seismic performance of reinforced concrete frame column with high axialcompression ratio is improved significantly by the use of dense stirrups.(b) The failure form of RC frame column could be modified by using densestirrups,because the concrete is in a state of triaxial compression and the developmentof oblique cracks can also be inhibited.(c) The initial stiffness of RC frame column is not affected by the use of densestirrups. At the same time,the horizontal bearing capacity and the ductility of columnare enhanced.(d) The stiffness degradation of RC frame column with dense stirrups isrestrained and the bearing capacity of RC frame column is stable even though thehorizontal displacement of column is large.(e) The energy dissipation capacity of RC frame column columns with densestirrups is obviously better than the contrastive column.The FEM models of the RC frame columns with and without dense stirrups areestablished and the elastic-plastic analysis is carried out using versatile FEMsofeware-MSC.marc. The comparison between the FEM analysis and experimentalresults indicates that: the calculated hysteretic curve and skeleton curve have a goodagreement with the experimental results. The seismic performance of RC framecolumns with dense stirrups and higher axial compression ratio is discussed based onthe reasonable FEM analysis. The seismic performance and ductility of RC framecolumns are getting worse with the increase of axial compression ratio.