Seismic Performances of Square HSC Columns Confined with High-Strength PC Rebar

This study focused on increasing the seismic performances of rectangular high strength concrete(HSC) columns by using ultra strength rebar as transverse reinforcements in order to enhance both seismic bearing and deformation capacity during earthquake ground motion.6 model tests,in which ultra strength rebar with the yield strength of 1420 MPa and high strength concrete with C60 and C90 grade are used,were carried out in the lab under the low circle repeated loading.The factors influenced the seismic performances of this kind of column were researched experimentally by using variable parameters such as axial compression ratios,stirrup reinforcements(index,space and type),and grades of longitudinal rebar and concrete.The failure mechanisms were experimentally clarified and the main parameters for strength and deformation of the columns were also determined empirically.An empirical formula represented the relationship of the displacement ductility,the compressive ratio and index of stirrup was derived numerically on the basis of the test data.The formula could be used to calculate the ductility of the column.The results of the test study showed that both bearing capacity and deformation ductility of the columns could be increased effectively by using ultra strength rebar as transverse reinforcement,confined HSC,and effective construction in details.