Abstract Reinforced concrete (RC) beams often suffer from reduced shear capacity due to overloading or environmental deterioration, posing a significant challenge for maintaining structural safety and serviceability. Various strengthening techniques have been proposed in practice, including externally bonded (EB) laminates and near-surface mounted (NSM), to enhance the shear performance of damaged RC beams. However, these methods face limitations, such as susceptibility to debonding, limited effectiveness for heavily damaged beams, and uneven stress distribution. The present study investigates a novel shear strengthening technique known as embedded through-section (ETS) CFRP bars, which involves drilling holes through the beam section and inserting CFRP bars bonded with adhesives. The ETS technique effectively mitigates the debonding problem associated with conventional FRP strengthening methods. This research evaluates the shear efficiency of ETS-strengthened RC beams with 50% and 70% pre-damage under monotonic and repeated loading, considering the effect of CFRP bar location (centre vs. near longitudinal reinforcement) and inclination angle (45° vs. 90°). The results showed that embedding CFRP bars at 45° and near the longitudinal reinforcement significantly enhances shear capacity, with increases up to 63.66% for beams damaged under repeated loads, providing new insights for effective rehabilitation of damaged RC structures.
Hadi et al. (2026) studied this question.