Response of concrete deep beams reinforced with GFRP bars around regions of discontinuity

This research aims to investigate the effectiveness of using glass fiber-reinforced polymer (GFRP) bars as internal shear reinforcement around openings in concrete deep beams. The study comprised laboratory testing, numerical simulation, and strut-and-tie modeling (STM). Four deep beams with a shear span-to-depth ratio of a/h = 0.8 were tested to failure. One beam did not include an opening to act as a benchmark. Three beams included a square opening in each shear span. The opening height was 20% of beam depth. Two different GFRP reinforcing configurations were used around the openings. The layouts of the GFRP reinforcement were based on two different strut-and-tie models. Shear reinforcement in the form of diagonal GFRP bars intersecting the bottom chord was more effective in improving the shear capacity than similar bars intersecting the top chord. Numerical predictions in terms of crack pattern and shear capacity were in good agreement with laboratory test results. The accuracy of the STM approach was examined by comparing its predictions with the laboratory test results.