The following are the main reasons behind using ties in column.
- To hold the longitudinal bars in position in the forms while the concrete is being placed.
- Longitudinal bars are confined by transverse steel tie bars in order to maintain their positions.
- To prevent the highly stressed slender longitudinal bars from buckling outward by bursting the thin concrete cover.
- At the time of concreting it prevent movement of main reinforcement.
- In order to prevent buckling of column and bursting of lateral reinforcement into the concrete cover under the vertical forces (compression force) especially in the middle of the column by holding the longitudinal bars in position.
- It improves the ductility of column.
- It also improve dowel action of column reinforcement.
- The lateral ties also confined the concrete, thereby enhancing its compression load-bearing capacity.
