Analysis on FRP Strengthening of Cracked Steel Plates Considering Bonding Effect in Cracks

When Fiber Reinforced Polymer/Plastic (FRPs) are used to repair cracked steel plates, the bonding materials will be inevitably trapped into cracks. This phenomenon, however, has not been considered in the current theoretical analyses of most scholars. In this paper, a bridging force model was introduced to simulate the bonding materials between upper and lower surfaces of cracks. A finite element model was established for single-surface repairing of cracked steel plates, and the results were compared with the finite element calculation results without considering the bonding effect of binders inside cracks. Besides, the impact of bonding materials inside cracks upon FRP repairing of cracked steel plates was quantified. Results revealed that, in the case of short cracks, the error between two finite element calculations was slight; when the cracks were longer than 40 mm, the difference between calculated stress intensity factors (SIF), crack expansion displacements, and maximum out-of-plane displacements of steel plates were 20.61%, 77.14%, and 35.73% respectively; and the impact of bonding materials in the crack surfaces upon cracked steel plates cannot be ignored.