Geometric edge shape based optimization for interfacial shear stress reduction in fiber reinforced polymer plate retrofitted concrete beams

This paper focuses on the reduction of interfacial shear stresses when using bonded laminates in strengthening existing structures. The presence of high interfacial shear stresses that develop near the end of the composite known as edge effect may compromise the resistance to failure of the strengthened structure. It is known that the reduction in plate thickness decreases the magnitude of stress concentration at the plate extremities. Another way to tackle the problem is proper design of the plate end shape. In this regard in this paper, an analytical solution for reduction of interfacial shear tresses based on edge shape optimization is developed and extended by numerical modal analysis procedure of finite element method (FEM) in retrofitted concrete (RC) beam with fiber reinforced polymer (FRP) plate with different end shapes with different mechanical loading type. The approach allows selecting the proper configuration that reduces considerably the interfacial shear stress concentration.