Structural performance of differently confined and strengthened corroding reinforced concrete columns

• Effects of corrosion of confining reinforcement on columns behavior.
• Deformability got more severely deteriorated than strength.
• GFRP wraps far better than ferrocement jacketing for strengthening.
• Initial degree of confinement played a crucial role for behavioral improvement.

As earthquake resistant provisions have been taken for due consideration in recent codes only, the older reinforced concrete structures are, in fact, supposed to be constructed without ductile detailing. With ongoing corrosion of embedded rebars the strength and ductility of the structures get further sacrificed. An experimental investigation was undertaken for observing the effects of continuing corrosion process on the strength and ductility aspects of differently confined reinforced concrete short columns. Effect of subsequent strengthening on these degraded columns was also studied. The experimental program consisted of 53 small scale columns with variably confined sections subjected to accelerated corrosion tests. The structural response of under confined sections was observed to be substantially poorer than the properly confined sections, which further degrades considerably due to corrosion of embedded reinforcement. One set of corroded specimens was strengthened with ferrocement jacketing. On another set of degraded columns the glass fiber reinforced polymer (GFRP) wraps were used for strengthening. Quantification was made for the reduction of structural and ductility aspects of both types of columns having different confinement levels. The study emphasizes the immediate need for proper strengthening measures to be adopted for the existing corrosion experiencing structures for improving their much needed ductility considering any seismic event in the future.