Shear Strengthening of Reinforce Concrete (R.C) Beams Using Drilled Retrofitted Bars

Abstract

Shear retrofitting of beams has become crucial due to factors such as aging infrastructure, the implementation of new building codes, and shifts in the utility demands of structures. These considerations underline the necessity of reinforcing and enhancing the shear resistance of beams to ensure their continued stability, functionality, and longevity. The existing techniques offer limited in situ shear capacity enhancement which at times do not result in desired performance levels.

This study introduces an innovative approach aimed at enhancing the shear capacity of existing Reinforced Concrete (RC) beams. This was achieved through the strategic installation of externally drilled in post-retrofitted rebars, utilizing chemical grouting for optimal reinforcement. The investigation comprised an experimental phase and Numerical Modeling conducted in Abaqus. Five full-scale RC beams were subjected to testing, each exhibiting inclined and vertical orientations of retrofitted bars, while an unmodified reference beam served as the control section.

The experimental setup incorporated an array of instrumentation to capture key data, including strain measurements along the retrofitted bars, encompassing end slippage dynamics and vertical deflection. The outcomes demonstrated the efficacy of the proposed technique, which proved to be both cost-effective and logistically feasible for on-site implementation. Notably, the method led to a notable augmentation in the shear capacities of the RC beams, effectively shifting the failure mode towards flexural strength considerations. The findings also indicated the viability and suitability of the design.