Flexural strength and ductility performance of high-strength reinforced concrete columns

Abstract

Flexural strength and ductility performance of high-strength reinforced concrete (HSRC) columns containing transverse reinforcement designed according to the shear resistance requirement of BS 8110 and a new proposed equation have been investigated experimentally. Six HSRC columns with common dimensions were constructed and tested under various compressive axial load levels as well as reversed cyclic inelastic displacement excursions. The actual flexural strengths obtained from the experimental tests were compared to the theoretical strengths based on the equivalent rectangular concrete stress block of BS 8110, from which the strength enhancement ratios were studied. Depending on the compressive axial load levels, HSRC columns designed according to BS 8110 can exhibit behaviour from very brittle to moderately ductile. To improve the ductility performance of HSRC columns, a theoretical equation previously proposed by the authors was adopted for the design of transverse reinforcement in three of the HSRC columns. It was observed from the experimental results that columns with transverse reinforcement designed according to the proposed equation could reach curvature ductility close to 10, which is considered as the measure for limited ductility.