Low-cycle fatigue behavior of corroded and CFRP-wrapped reinforced concrete columns

• Cumulative seismic damage of columns with or without corrosion was studied.
• The effect of using CFRP wraps on seismic behavior of columns was evaluated.
• Cyclic loads with constant amplitudes and variable amplitudes were applied.
• Steel corrosion significantly reduces low-cycle fatigue life of columns.
• The seismic damage indexes of columns with or without corrosion were estimated.

An experimental study was taken to investigate the cumulative seismic damage of reinforced concrete columns with or without steel corrosion and to evaluate the effect of using CFRP wraps on the seismic behavior of the columns. Eleven identical rectangular reinforced concrete columns were constructed and tested under standard cyclic loads with variable drift amplitudes or low-cycle fatigue loads at different constant drift amplitudes. The column models included five un-corroded columns and six columns corroded using an external current method. Test results indicate that steel corrosion reduces the strength, ductility, low-cycle fatigue life, and cumulative energy dissipation capacity of reinforced concrete columns under cyclic loads, whereas the use of CFRP wraps greatly improves the above-mentioned behavior except the strength of un-corroded and corroded columns. The corroded column with a steel corrosion level of about 10% and retrofitted using CFRP wraps exhibited lower loading capacity but much better ductility and cumulative energy dissipation capacity than un-corroded columns. The seismic damage indexes of the columns with or without steel corrosion were also estimated based on the Park–Ang damage model and the relationships between damage indexes and experimental observations were discussed.