Numerical study on enhancing shear performance of RC beams with external aluminum alloy plates bonded using steel anchors

This article compromises a three-dimensional numerical study using the Abaqus program to investigate the behavior of reinforced concrete (RC) beams externally strengthened in shear using aluminum alloy (AA) plates bonded using steel anchors. Based on previous experimental tests, a numerical validation study was conducted in two parts. The first part aims to model the interaction behavior using different bonding methods between steel plates and the surface of the RC beams, whether using epoxy adhesive only, using steel anchors only, or using a dual system between them. The second part aims to model the performance of shear-defected RC beams that externally strengthened by AA plates using epoxy adhesive. To take into account debonding collapse due to epoxy adhesive bonding, the interaction between the AA plates and beam surface was simulated with a cohesive-damage interaction. Comparing the numerical results with previous experimental studies shows the success of the numerical model in simulating the performance of different bonding methods, as well as the behavior of the RC beams defective in shear and strengthened by AA plates, which qualifies it to study some additional variables. From the study it was found that by using only epoxy adhesive, the strengthening technique using an AA plate over the entire shear span zone (AASP method) was capable of increasing the ultimate capacity of the defective beam by 104%, which represents 77% of the load of the non-defective beam. It has also been demonstrated that AA plates are susceptible to collapse by out-of-plane buckling when bonded using steel anchors only. By using a dual system for bonding the AA plates consisting of epoxy adhesive and steel anchors, AASP method was capable of increasing the ultimate capacity of the defective beam by 164% and change its failure pattern to the preferred ductile bending pattern.