Reliability-based design of FRP shear strengthened reinforced concrete Beams: Guidelines assessment and calibration

Possessing a more complicated mechanism and catastrophic brittle collapse mode, it is necessary to investigate the reliability level of design guidelines for concrete structures shear strengthened with fiber reinforced polymer (FRP). In this paper, six guidelines have been appraised based on the philosophy of load and resistance factor design approach. First, the model error of shear capacity prediction was identified. Subsequently, the reliability index was estimated, followed by the calibration of FRP design factors and a comparison of the design economy. The results show that: (1) For U-jacketing and fully wrapping, the Chinese guideline is the most accurate. For side bonding, both Chinese and American guidelines show a satisfying prediction. (2) The reliability index for Ujacketing is generally larger than that for side bonding and smaller than fully wrapping. (3) The Australian guideline provides the largest reliability indexes for U-jacketing and side bonding, while the British guideline provides the largest reliability indexes for fully wrapping. (4) Besides the reliability level, the design economy also relies on the sensitivity of ss to design factors. For U-jacketing, CIDAR shows the best economy, followed by CSA and fib. For fully wrapping, TR shows the best economy, followed by CIDAR and ACI for ss T < 3.5.