Seismic performance of high-strength concrete columns

This paper presents the experimental results of six scaled high-strength concrete columns with concrete compressive strengths of 76-86 MPa. Primary experimental parameters include axial loads ranging from 10 to 20% of column axial load-carrying capacity based on concrete gross section; longitudinal steel ratios of 2.46 to 3.53% of the gross sectional area; and volumetric ratios of transverse reinforcement ranging from 1.63 to 3.67%. Model columns with transverse reinforcement designed following the seismic provisions of current code developed sufficient ductility, with displacement ductility factors equal to or exceeding 6.0. The model columns designed with 50% of the transverse reinforcement required by current code also developed sufficient ductility when the axial load was 10% of its axial load-carrying capacity. Lateral load-carrying capacities of all the columns exceeded the flexural capacities calculated based on the equivalent concrete stress block used in current design code. Seismic shear strength of high-strength concrete columns was also examined, based on the test results and analytical approaches.