Obtaining a permanent repair by using GFRP in steel plates reformed by heat-treatment

• The formula is developed for heat-treated steel plates strengthened by GFRP.
• Heat treatment, one of the temporary retrofits proved to be used as permanent one.
• Strengthening heat treated steel members by GFRP is proved by Test and FEM.

Applying heat treatment to buckled steel construction elements especially at the time of disaster, are accepted as temporary repairs. This study aims to turn temporary retrofits applied to steel structural elements into permanent repairs using an additional operation. To this end, experimental and numerical investigations were conducted to remedy weaknesses observed in elements repaired with heat treatment by gluing fiber-reinforced polymer plates to them. Experimental and parametric studies show that a permanent repair can be achieved by affixing GFRP plates to locally buckled steel structures after heat treatment. In addition, a formula is presented to calculate the critical buckling stress in GFRP-reinforced steel plates based on the slenderness ratio.