Design considerations for prefabricated composite jackets for structural repair: parametric investigation and case study

Prefabricated fiber-reinforced polymer (FRP) repair systems are becoming popular for structural repair because FRPs superior resistance to corrosion and weathering. Several parameters impact the effectiveness of this type of repair, including the structural continuity provided by the joining system and grout properties. This study numerically investigated the effects of these critical design parameters to generate new knowledge and understand fundamental structural behaviour of a prefabricated composite repair system. The results reveal that the effective transverse tensile strength of FRP joint should be as low as 20% of the jacket strength for structural repairs. Moreover, grout stiffness dictated the stress transfer between the core and outer jacket. Increasing the compressive strength of the grout delayed grout cracking and degradation, accompanied by a rapid increase in FRP joint strain. Lastly, numerical simulation of a corroded steel column in an actual bridge shows that the application of the FRP jacket improves the strength capacity by 320%, which is 85% higher than that of the conventional FRP repair system. This study provides useful information for optimally designing and effectively using prefabricated composite jackets for structural repairs.