Behaviour of low-strength reinforced concrete beam strengthened with deep embedment system

Abstract Conventional retrofitting methods such as external bonding and near-surface mounted techniques are not always feasible due to their reliance on the bond between the epoxy and the concrete surface, which can lead to structural failure. In response to this challenge, we suggest adopting a deep embedment (DE) system as a strengthening approach. This study examines the performance of low-strength reinforced concrete (RC) beams strengthened with steel DE bars. Two RC beams - one control and one strengthened - were constructed and tested under a four-point bending load system. The strengthened beam was enhanced with 8 mm steel bars embedded in the concrete beam’s core. The results revealed that the control beam collapsed owing to shear, while the strengthened beam experienced failure in flexural tension, with most cracks occurring in the flexural span. The presence of DE bars caused the failure mode of the control beam to shift from shear to flexural in the strengthened beam. Additionally, the maximum load sustained by the strengthened beam increased by 14% compared to the control beam, and the stiffness of the strengthened beam at the ultimate load was 2.45 times higher than that of the control beam.