Quasi-Balanced Failure Approach for Evaluating Moment Capacity of FRP Underreinforced Concrete Beams

Abstract

Failure of concrete beam sections underreinforced with fiber-reinforced polymer (FRP) is initiated by FRP rupture before concrete crushing. In such a case, the typical rectangular stress block based on the balanced failure mechanism may not apply. In the present study, rigorous sectional analyses are performed implementing existing concrete stress-strain models for a wide range of values of design parameters. Based on the results of the numerical analyses, the variation of parameters of equivalent stress block of concrete was investigated, and an alternative, yet simple, design method for evaluating moment-carrying capacity of FRP underreinforced concrete beam using quasi-balanced failure approach was developed. The proposed design method was verified by comparing the predicted moment-carrying capacity with existing test results.