Development of pipe repairs using bonded metal plate – Part I: Shape factor, stiffness and surface treatment

Abstract This work aims to study the resistance of repairs with bonded plates in pipes with holes subjected to hydrostatic pressure. It is a promising alternative for application in low-risk repairs (up to 1 MPa). Due to the differences between the circumferential and transverse stresses in the pipes, the influence of the bonded plate area in the joint strength was evaluated, checking whether the shape factor occurs. The effect of plate thickness in the repair strength, besides the addition of silane on the plate surfaces, were also studied. Finally, considering a control plate based in the performed experiments, the surface treatment influence on the tubes was evaluated in the face of rupture pressure of the system. High hydrostatic resistance values were found, demonstrating the efficiency of the procedures used in the repair. The studies show little influence on the repair strength due to dimensions variation in different directions, and high influence on the surface treatment, stiffness and bonded area increase. The work aims to initiate the development of a new procedure for contingency repair with low risk.