A novel reinforcement method for carbon fiber reinforced plastic (CFRP) bolted joints is proposed considering the cylindrical stress fields around bolt holes. The C and R layers are circularly and radially steered reinforcing layers in the directions of the maximum tensile and maximum compressive stresses, respectively. The effects of the C and R layers on the bearing strength of CFRP bolted joints were investigated by conducting double lap shear tests. The tests showed that the C layer was effective at preventing the shear-out failure and increasing the bearing strength of joints during the ultimate stage of failure. By contrast, the R layer was effective at increasing the bearing strength of joints during the initial and ultimate stages of failure. The reinforcement mechanisms were also studied according to the local stress fields around the bolt joints.
