Reliability-Based Shear Design for Reinforced Concrete Beams with U-Wrap FRP Strengthening
The resistance factor in the draft version of Chinese Technical code for the application of fiber reinforced polymers in civil engineering for the shear-resistant design of reinforced concrete beams with U-wrap FRP strengthening is assessed from the probabilistic standpoint. The assessment using a resistance-factor-related computational uncertainty factor indicates that the average reliability indexes, for either unstrengthening or strengthening, increases at a slowing rate as load effect ratio increases from 0.10 to 2.5, and that the average reliability indexes for strengthened beams would dramatically decrease up to 19.2%~28.5% with the resistance factor specified in the code for U-wrap strengthening. A so-called reliability strengthening ratio is introduced to evaluate the change in average reliability index before and after strengthening with different resistance factors. A parametric study on this factor shows that if the reliability level in strengthened reinforced concrete beams is kept to be consistency with their corresponding unstrengthened beams, a value of 0.67 could be applied. The proposed relationship between reliability strengthening ratio and the resistance factor could be also used in personalized designs.
Jingsi Huo, Yan Xiao, Zongjin Li and Shuaib Ahmad
Z. He et al., "Reliability-Based Shear Design for Reinforced Concrete Beams with U-Wrap FRP Strengthening", Key Engineering Materials, Vols. 400-402, pp. 525-530, 2009