Ties are utilized in the columns of reinforced concrete structures. Ties are used for several purposes. The primary justifications for using ties in the column are as follows.
To maintain the longitudinal bars’ alignment within the forms during the pouring of concrete.
To keep the thin concrete cover from bursting and the highly strained, thin longitudinal bars from buckling outward.
The use of ties in columns is covered under numerous civil engineering code rules. These code requirements must be understood by the design engineer when creating a concrete column.
Spiral reinforced concrete columns have a greater load capacity than linked columns. This phenomenon occurs because spirally reinforced columns exhibit higher toughness and ductility than tie-reinforced columns at modest load eccentricities.
Therefore, it is required of civil engineering experts to reinforce reinforced concrete columns with spiral reinforcement rather than ties whenever feasible.
Steel bars are bent into closed rings or loops that encircle the longitudinal bars to create column ties. To keep the ties in place, they are typically hooked around one of the major bars.
According to Eurocode 2 part 1-1, the distance between the ties cannot be greater than 12 times the minimum diameter of the longitudinal bars or 60% of the column’s lesser size.
The ties’ diameter shouldn’t be any smaller than 6 mm or less than one-fourth of the greatest longitudinal bar’s diameter.
In reinforced concrete construction, beam ties are frequently used, particularly for columns with square or rectangular cross sections.
Though not to the same extent as typical UK house construction, where walls on the inside and outside support the majority of the load. They are also utilized for circular cross-section columns; however, for optimal confinement and ductility, spiral reinforcement may be recommended in some situations.
A continuous helical bar with a consistent pitch is used to form the spiral reinforcement around the longitudinal bars. For columns with unique moment frames intended to withstand lateral forces from wind or earthquakes, beam ties are also utilized.