CURVATURE DUCTILITY ANALYSIS OF HIGH PERFORMANCE CONCRETE SHEAR WALL IN PERFORMANCE-BASED SEISMIC DESIGN
According to the characteristics of shear wall cross sections,a new piecewise confining stirrup is suggested to improve the curvature ductility of high performance concrete shear walls.Based on the section property and special configuration of the stirrup,the effects of piecewise confining stirrup on the curvature ductility of high performance concrete shear walls are analyzed and calculation formulas used for evaluating the yielding and ultimate curvatures for the cross section of shear walls with piecewise confining stirrup are derived.The relationship between the depth of compression zone and the curvature ductility is analyzed and the relationship between the curvature ductility of shear wall cross section and the amount of confinement reinforcement is derived.Case studies and sample analysis show that the effect of confining stirrup on the ultimate curvature for the cross section of shear walls is much more significant than that on the yielding curvature.The curvature ductility for the cross section of shear walls is related to the axial compressive ratio,the amount and range of confinement reinforcement,and the design parameters of confined concrete core at the end of section.