Rehabilitation of steel bridge girders through application of composite materials

A complete system approach to the rehabilitation of degraded steel bridge girders through the adhesive bonding of composite materials is presented and demonstrated considering a particular bridge girder removed from service in Pennsylvania as a case study. Issues of design, durability, field implementation, and affordability are addressed. The flexural characteristics of steel bridge girders are shown to be improved through testing of various reinforcement schemes on scale steel sections and testing of a selected scheme on the corroded bridge girder taken out of service. The stiffness of a degraded member is restored to its initial state and the load capacity of the member is increased significantly beyond the initial state. A methodology for selection of the most suitable adhesive based on the long-term durability for any particular rehabilitation scheme is developed and the results of the methodology are presented. The necessary surface treatments for the steel and the composite material are addressed as well as techniques for performing an accelerated cure through field heating methods. A case study was performed to examine the economic advantages of rehabilitation of the steel girders with graphite pultrusions vs. replacement of the girders.