Shear strength and behavior of steel fiber reinforced concrete columns under seismic loading

The benefits of using steel fiber to reinforce concrete columns are investigated to improve on the brittle column behavior of the columns during seismic excitation. Eight specimens for performance test are prepared and used to evaluate the steel fiber reinforcing effect on shear strength and behavior of the reinforced concrete columns. The variables used in this study are the volume fractions of steel fiber (i.e., 0.0%, 1.0%, 1.5%, and 2.0%) and the nominal ratios of shear reinforcement (i.e., 0.26% and 0.21%). From the test results, it is found that the maximum enhancement of the shear capacity is achieved with 1.5% of steel fiber volume fraction. To predict the maximum shear strength of steel fiber reinforced columns, Hirosawa and Priestley's proposed shear strength equations, ACI (American Concrete Institute) 318-99, AIJ MB (Architectural Institute of Japan Modified B method), and NZS (New Zealand Standard) 3101's shear strength equations were reviewed and applied. From the parametric and regression analysis, the Priestley equation is modified to include the steel fiber reinforcing effect. Finally, the proposed equation is presented to predict the shear capacity of steel fiber reinforced concrete. (C) 2006 Elsevier Ltd. All rights reserved.