Stress-strain model for high strength concrete confined by FRP

Abstract

Ductility of High Strength Concrete (HSC) columns can be increased by lateral confinement. The conventional confinement with steel reinforcement may not always be adequate to provide the ductility levels desired by the engineer. The lateral confinement by FRP can provide significantly higher confinement stresses than the conventional steel reinforcement, and convenient for repair applications. Confining pressure applied by FRP is a function of the lateral strain of concrete. Therefore information of axial stress, axial strain and lateral strain relationships of concrete is fundamental in the design of confinement. Many existing models are based on test results with low confining pressures which are not suitable for modelling FRP confined concrete. The authors present a model in this paper which is suitable for use in designing FRP confinement of concrete. Model results are compared with experimental results of FRP confined columns. The results demonstrate the model is suitable for this use.