Dynamic analyses of steel-reinforced super high-strength concrete columns

Abstract

The dynamic behaviors of steel-reinforced super high-strength concrete columns under seismic loading were studied with a series of experiments. Thirteen specimens, with concrete strengths ranging from 94.9 to 105.4 MPa and shear-span ratios of 2.75, were manufactured. The axial load ratio and the stirrup reinforcement ratio were the main experimental variables affecting the dynamic behavior of the specimens. The columns under low cyclic lateral loading mainly failed in the flexural-shear mode. Shear force-displacement hysteretic curves and skeleton curves were drawn. The coefficients of the specimens  displacement ductility were calculated. Experimental results indicate that ductility decreases while the axial load ratio increases, but it increases when the stirrup reinforcement ratio increases. The limit values of the axial load ratio and the minimum stirrup reinforcement ratio of the columns were investigated to satisfy definite ductility requirements. These values were suggested as references of engineering applications and of the amendment of the current Chinese design code of steel reinforced concrete composite structures.