Repair of corroded and buckled short steel columns using concrete-filled GFRP jackets

Many bridges and structures in the United States that are supported on steel columns or piles exhibit inadequate strength due to increasing load demand or aging due to corrosion, or both. The combination of increased load demand and reduction of capacity due to corrosion-induced section loss can lead to unexpected buckling of the piles. This paper investigates the effectiveness of a glass fiber reinforced polymer (GFRP)-based technique for rapid retrofit of buckled steel piles or columns. The system consists of a GFRP jacket, which is formed on-site and subsequently filled with an expansive concrete. Thirteen-buckled short steel columns with varying degrees of section loss were repaired and tested to failure under axial compression. The research results indicate that the repair system restored the capacity of the buckled columns to between 69% and 104% of the capacity of the undamaged control column. Further the repaired piles exhibited a hardening response in the non-linear range rather than the sudden loss of capacity and softening response that is characteristically associated with buckling of steel columns. The findings suggest that installation of concrete-filled GFRP jackets can be an effective technique to rapidly repair corroded and buckled short steel columns or piles.