Evaluation of flexural resistance of compression yielded concrete beams reinforced with fibre reinforced polymers

Concrete elements reinforced with fibre reinforced polymers (FRPs) have been increasingly applied in civil engineering structures. However, these structural elements are usually suffering from brittle failure caused by either concrete crushing or the sudden rupture of FRP. To solve this common issue, a compression yielding (CY) mechanism was recently developed with the aim of enhancing the ductile behaviour of FRP-reinforced concrete beams. In the present study, the flexural resistance of FRP-reinforced concrete beam with a CY block in the compression zone (CY beam) is analysed, and a closed-form solution is derived for the moment capacity of CY beam. The influence of the uncertainties of the mechanical properties of CY material on the flexural resistance of CY beam are quantified. Engineering reliability analysis is then conducted to obtain the reduction factor for CY beam under different load combinations. A reduction factor of 0.75 for building structural members and 0.70 for bridge structural members are recommended for engineering design. In addition, a reduction factor table is provided considering a wider range of statistical parameters.