STIRRUPS USE IN CONSTRUCTION

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  What is stirrups?

These are steel bars that are tied perpendicular to main bars in columns and beams, mostly they are smaller in size when compared to main bars.

They are also called ties when used in column, they perform the same functions in beams and columns.

Purpose of stirrups in reinforced structural element.

 1. Prevent bulging out of main reinforcements in columns and beams.

Bulging out of reinforcements is the sideway displacement of bars perpendicular to a axial of structural member.



 2. Prevent movement of reinforcements during concreting.

Stirrups hold reinforcements in their position during concrete pouring and concrete vibrating, such that they maintains member cover and spacing between bars. 

 


 3. It provides resistance against shear and torsion.

Shear force is the one that acts or results perpendicular to axial loading, this force causes cut off of structural member mostly diagonally across it.

Concrete has limited shear strength depending to its characteristics strength, when the shear capacity of concrete is reached any excess shear stress should be taken by stirrups or shear links.



 

Main things required for proper stirrups system.


 1. 135-degree hook

  


 2. Proper hook length

 

 3. Proper stirrups diameter and spacing

The proper stirrups diameter and spacing are required so as to have link reinforcements system that will provide adequate strength against shear.

Stirrups Location and size.

The location (spacing between stirrups) and size of stirrups can be determined through design of beams against shear.


Stirrup Design procedures

 1. Determine shear values based on clear span and loadings.

 

 2.  Check if stirrups are required to support structure against shear.

 

 3. Determine the length of span over which stirrups are required.

 

 4. Determine shear reinforcements' area needed to provide required shear strength.

 

 5. Select size of stirrups, find the spacing required at critical section.

 

 6. Establish stirrups drawings per your standards-CODE



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