Effect of Confining Layers of Steel Straps Confined High-Strength Concrete Cylinder under Uniaxial Cyclic Compression

The remarkable advantages and promising increment in concrete ultimate capacity as well as ductility by using steel straps as lateral confinement has brought the steel strapping tensioning technique (SSTT) as one of the most affordable confining technique in market. A number of studies have been reported the behaviour of SSTT-confined concrete under uniaxial monotonic compression loading but none of any study addressed the uniaxial cyclic response of such confinement. In this paper, twenty-one high-strength concrete cylinder specimens with diameter of 150 mm and 300 mm in height were cast, laterally pre-tensioned with steel strap in different confining layers and tested to failure under uniaxial cyclic and monotonic compression loading. A number of conclusions to be drawn from experimental results including the tangential validation of stress-strain curve for uniaxial monotonic and cyclic loading, independency of plastic strain to the amount of confining layers, the disagreement of uniqueness concept on the repeated uniaxial unloading and reloading cycles, and the promising effect of confining layers and loading patterns to the ultimate capacity of SSTT confinement. A plastic strain model is proposed and compared with existing plastic strain models. The result proved that SSTT confinement able to secure the lowest plastic strain among the others existing confinement method.