Repairing concrete column cracks and damages is essential. The column concrete damages are becoming critical in mass structures like shopping malls, commercial buildings. To carry out the column repair identify the axial dead load, live load, and horizontal load.
Repairing concrete columns are two category
- Surface or cosmetic – covers local deterioration
- structural repair – strengthens the affected columns.
Repairing Concrete Methods for cracks and damages
1. Unloading Columns
unloading the column is necessary. Entire cross-section of the repair column is capable of carrying the reintroduce design load. Without unloading, new repair does not carry any load. Drying shrinkage of new material reduces the share of the load.
2. Redistribution of the Load
In corrosion of reinforcement and concrete deterioration, Redistribute a load of column concrete with alternative supports for repair.
3. Supplemental Reinforcing Steel
The supplemental vertical bar to fix outside the original cage with extra ties. Provide adequate cover and Place Apartment’s bars outside the tie bars to increase column dimensions. Use Hairpin ties, of stainless steel laterally to support the supplemental bars. Column ties cannot disturb at the repair of the longitudinal bars as it causes buckling.
4. Concrete Removal
Remove concrete within a column cage and unload the column. If not, the longitudinal bars are buckle and compression failure of column take place.
5. Corroded Reinforcing Steel
It’s not necessary to remove the corrode reinforcing bar with the reduce cross-sectional area if the loss is supplement with additional reinforcing bars. The partially corrode reinforcing bars are thoroughly clean by sandblasting to obtain the bare metal. The bars with excessive corrosion is replacing with fresh reinforcement having full laps on both sides.
6. Corroded Ties
Replace the corrode ties by adding stainless steel hairpin ties that are anchor into the concrete. It is often necessary to deposit extra material around columns to provide an adequate cover over the supplemental ties.
7. Low-strength Concrete
Where the concrete strength is low, resulting in insufficient load-carrying capacity, several alternatives are available:
- Shore the column and remove and replace the in-place concrete.
- Shore column and increase the size of the column to reduce bending stresses, and increase confinement on placed weak concrete.
- Wrap the column with carbon- or glass-reinforced plastic.
- Install a supplemental column.