Reliability analysis of concrete haunched beams reinforced by fiber reinforced polymer (FRP) bars

Fiber reinforced polymer rebar (FRP) has an increasing demand and use worldwide due to its imperviousness to chemical attacks, along with its higher tensile strength, and lower weights compared to steel. The aim of this study is to investigate the flexural behavior of haunched beams reinforced with sand coated FRP rebar and conduct stochastic finite element analysis accordingly. In this thesis, for glass FRP three parameters had been taken into consideration, namely, concrete compressive strength, inclination angle, and reinforcement ratio, and for carbon FRP the effect of bond stress was considered as well. The study consists of two main phases. The first phase was comprised of ninety-six models. Results of the study were summarized in the form of load-deflection curves. The results indicated that there is increase in failure load along with lower deflection patterns for the beams having higher reinforcement ratio. Both load capacity and deflection were higher for the beams whose compressive strengths were high. Moreover, the inclination angle had no significant effect on most of the other parameters. In the second phase, stochastic finite element analysis was implemented via producing fifty simulations for each beam by Latin Hypercube Sampling technique in order to determine whose uncertainty is more important in terms of load capacities of the beams. As a result of the study, it was found that the uncertainty in beam thickness was the most sensitive parameter regarding load capacities of both prismatic and haunched beams.