Rehabilitation of steel bridge members with FRP composite materials

This dissertation consists of five papers, which presents the results of research on the application of FRP composites on the strengthening steel bridge structures. In particular, the work focuses on both rehabilitation of steel bridge girders (flexural members), and steel bridge columns (compression members) with FRP composite materials.; The first paper focuses on the flexural steel member strengthening. Based on the experimental results, it is clear that an increase in stiffness and ultimate load capacity of corroded steel members can be achieved from the application of CFRP laminates to the tension flange of corroded steel members. Peel off of FRP laminates was the observed failure mode of the retrofitted beams.; The second through fifth papers investigate the feasibility of retrofitting of compression loaded steel members using FRP composite pipes filled with expansive light-weight concrete. First, a high-expansion light-weight concrete was investigated. Second, the local bond-slip relationship between steel and this type of concrete was developed. Finally, a FRP retrofit method was proposed for corroded steel bridge columns, and deficient steel columns were strengthened using this retrofit technology. Test results indicated that a restoration of ultimate load capacity of a deficient steel column with the proposed FRP retrofit technology is attainable. Also design guidelines were developed for the retrofit of stocky and slender columns.