Effect of FRP-to-steel bonded joint configuration on interfacial stresses: finite element investigation

Externally bonded fibre-reinforced polymer (FRP) composites can be applied to strengthen and repair existing steel structures. In order to understand and quantify the behaviour of the bonded interface, researchers have conveniently tested FRP-to-steel joint assemblages. Both single- and double-shear joints of varying boundary conditions have been tested to date in which either the steel or FRP components have been loaded. In addition, the material and geometric properties of the joint materials have been varied and such variation in properties and test configuration will cause variation in the distribution and magnitude of interfacial stresses. This study presents the results of finite element simulations of the interfacial stresses of several FRP-to-steel joint configurations considered by researchers to date. Numerical simulations of interfacial stresses are also conducted on an FRP-strengthened I-beam and several key locations are examined in greater detail such as at the plate end, an intermediate fatigue induced crack, and a yielded zone. The beam stresses are compared with the stresses from the joint models and then joint configurations are identified which best capture the interfacial stress distributions at various positions along the length of the beam