What are stirrups?
Stirrups is a closed ring-shaped steel embedded between the concrete of frame structural member like, beam, column etc is known as stirrups.
Stirrups are made by bending the steel rebar three times or more to make a close ring. The shape of stirrups may be triangular, rectangular, square, circular, spiral, or diamonds. The most used stirrup in the construction lines for the square and rectangular columns is rectangular, square, or diamond stirrups.
What is the purpose of stirrups in reinforced concrete beams ?
There is very important role of stirrups in beam or column. The stirrups are used for the following reason given below.
- Stirrups are used to resist the lateral shear stress in the RCC Structure.
- They are used to resist the diagonal tension stress in the RCC Structure.
- They are used to prevent from buckling of compressive stress-bearing structures like columns, struts, etc.
What is the hook in stirrups? How much should be hook length?
Hook length is the extended part of the stirrups from the peripheral boundary toward the inner direction is known as hook length. The hook length is provided at least 9d in the column or beam. Where d is the diameter of the stirrups.
The bending of hook length should be a minimum of 135°. Hook lengths are provided in columns to increase the bonding between concrete and stirrups to provide better shear resistance.
Type of stirrups
A) Accoding to Shape of Stirrups.
- Square stirrups
- Rectangular Stirrups
- Triangular Stirrups
- Circular stirrups
- Hellical stirrups
- Diamond stirrups
B) According to the nature of the stirrups
- Single legged stirrups
- Two legged stirrups
- Three legged stirrups
- Four legged stirrups
- Five legged stirrups
- Six legged stirrups
- Seven legged stirrups
- Eight legged stirrups
1) Single-legged stirrups
The stirrups standing on a single leg is known as single-legged stirrups.
2) Two-legged stirrups
The stirrups standing on two leg is known as two-legged stirrups.
3) Three-legged stirrups
The stirrups standing on three legs is known as three-legged stirrups.
4) Four-legged stirrups
The stirrups standing on four legs is known as four-legged stirrups.
5) Five-legged stirrups
The stirrups standing on five legs is known as five-legged stirrups.
6) Six-legged stirrups
The stirrups standing on six legs is known as six-legged stirrups.
7) Seven-legged stirrups
The stirrups standing on seven legs is known as seven-legged stirrups.
8) Eight-Legged Stirrups
The stirrups standing on eight legs is known as eight-legged stirrups.
Hence, these are the types of stirrups depending on different shapes and nature.
Suitable diameter of stirrups
The diameter of the stirrups to be used in the RCC structure depends upon the shear stress applied to the structure. There is not a fixed diameter of the stirrups. But generally, for residential buildings, the suitable size of stirrups varies from 6 mm to 10 mm.
For commercial and important buildings like hospitals, shopping malls should use stirrups above 8 mm. The size of such types of stirrups may vary from 9 mm, 10 mm.
Difference between stirrups and ties
The function of both stirrups and ties in the RCC structure is the same and provided for the same purpose but the difference is that stirrups are used in horizontal members-like columns and ties are used in the vertical member-like columns.
What is double stirrups? How to provide double stirrups?
Double stirrups are nothing but providing two stirrups of different shapes or the same shape interlinking the different longitudinal bars in the column or beam is known as double stirrups. Double stirrups are generally provided in columns.
Generally, double stirrups are provided one after another with no spacing between them. They are mostly provided in rectangular or square columns. The shape combination of stirrups used for double stirrups is rectangular and diamond or square and diamond or square and rectangular.