Modelling Of Steel-Frp Single-Lap Joints Under Freeze-Thaw Cycling

Use of FRP as a repair system for steel structures is gaining worldwide recognition due to FRP's high strength to weight ratio, installation flexibility, and long term durability. However, the durability of adhesive bond between steel and FRP under extreme environmental conditions are still to be investigated thoroughly, and the influence of freeze-thaw cycles is a concern in this regard. A theoretical model is presented in this paper, which highlights the effects of freeze-thaw cycles on the interfacial stresses in steel-FRP single lap joint. The model accounts for the effect of moisture swelling, thermal expansion, and change in material properties due to freeze-thaw exposure. The model also accounts for the high order deformability of the adhesive layer in shear and through its thickness and allows for quantitative evaluation of the edge and interfacial shear and peeling stresses. The effects of different adhesive thickness profiles are also investigated, and the results are presented in terms of interfacial stresses.