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

Abstract

This article compromises a three-dimensional numerical study employing the Abaqus program to investigate the behavior of reinforced concrete (RC) beams externally strengthened in shear using aluminum alloy (AA) plates bonded utilizing steel anchors. Based on previous experimental tests, a numerical validation study was conducted in two parts. The first part modeled the interaction behavior using different bonding methods between steel plates and the surface of the RC beams, whether utilizing epoxy adhesive only, steel anchors only, or a dual system between them. The second part modeled the performance of shear-defected RC beams that externally strengthened by the 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 defected in shear and strengthened by the AA plates, which qualified it to study some additional variables. From the study it was found that by utilizing only epoxy adhesive, the strengthening technique using the AA plate over the entire shear span zone (AASP method) was capable of increasing the ultimate capacity of the defected beam by 104%, which represents 77% of the load of the non-defected beam. It was also demonstrated that the AA plates were susceptible to collapse by the out-of-plane buckling when bonded using the steel anchors only. By utilizing a dual system for bonding the AA plates consisting of epoxy adhesive and steel anchors, the AASP method was capable of enhancing the ultimate capacity of the defected beam by 164% and changing its failure pattern to the preferred ductile bending pattern.