Efficient shear retrofitting of reinforced concrete beams using prestressed deep embedded bars

The Deep Embedment (DE) technique is a promising reinforced concrete (RC) shear strengthening scheme. When compared with the other retrofitting systems, the DE approach is impressive in many ways. Particularly, since the DE element is installed to the beam core, the truss mechanism is enhanced and that enables achieving high shear enhancements. Due to the internal application of the DE reinforcement, steel can also be utilized as the retrofitting material without reservations on corrosion. It is however identified that the tensile capacity of the DE bar is partially utilized. In this context, the potential of using prestress in the DE system as an improvement was explored through a non-linear numerical study and an experimental study. Two DE reinforcement types of normal steel and high-tensile steel were considered and the prestress level was set to 40%. Both approaches showed that the use of prestress in the DE system was capable of enhancing the beam shear capacity significantly, where the extra strength gain in one case was almost 26%. The serviceability performance of the beams was also improved due to the prestress application. Meanwhile, the numerical predictions showed good correlations with the global and local behaviours of the experimental beams.