How to Calculate the Cutting Length of Rectangular Stirrups in Beam and Column | Stirrups Cut Length | Cutting Length Formula | Hook Length and Bond Length for Stirrups:
In this article we will discuss about the Cutting Length Of Rectangular Stirrups | Stirrups Cut Length | Cutting Length formula | Hook Length for Stirrups | Bond Length for Stirrups | Bar Bending Schedule | Circular Stirrups | Diamond Stirrups | Square Stirrups | Triangular Stirrups | Helical Stirrups | 2 4 6 Legged Stirrups
Cutting length of rectangular stirrup means its length and weight calculation is very easy and simple. The bar bending schedule is very important in every construction work. Without known the proper length and proper quantity of the stirrups, it is very difficult to do the construction work properly.
Cutting length of the stirrup is very important because in every beam we use stirrups and the mean is the most important member in the construction buildings.
In this article, we are going to discuss the rectangular stirrup cutting length calculation in detail. Before going for calculation lets clear the following basic concepts.
Steps involved in finding the cutting length of stirrups:
- Look at the size of column or beam from drawings
- Adopt Dia of the bar (generally 8mm Dia is used for stirrups)
- Deduct the concrete cover or clear cover
- Find the total outer length of stirrup after deducting concrete cover. Stirrups Cut Length
- Add the length of the hook to the length of the stirrup
- Deduct the length of bends
- Use below formula to find the total cutting length of stirrups. Bond Length for Stirrups
What is Bar Bending Schedule?
Bar Bending Schedule, commonly referred to as “BBS” is a comprehensive list that describes the location, mark, type, size, length and number, and bending details of each bar or fabric in a Reinforcement Drawing of a Structure.
This process of listing the location, type and size, number of and all other details is called “Scheduling”. In context of Reinforcement bars, it is called bar scheduling. In short, Bar Bending Schedule is a way of organizing rebars for each structural unit, giving detailed reinforcement requirements. Stirrups Cut Length
Calculate Cutting Length Of Rectangular Stirrups | Cutting Length Of Stirrups:
We will give you here some useful guidelines to compute the cutting length of different types of square, rectangular and circular stirrups in three steps. Also, you will learn what are the required clear cover, bend deduction as well as hook length for stirrups.
Below are the details of actual increase in steel if it bends : Bond Length for Stirrups
Bend Elongation in steel
450 Bend – 1d elongation
900 Bend – 2d elongation
1350 Bend – 3d elongation
Elongation means the mechanical property of metal. It is the degree to which a material is likely to be delivered, expanded, or compressed before rupture. It refers to a point between tensile strength and yield strength and is demonstrated as a percentage of the original length. Circular Stirrups | Diamond Stirrups | Square Stirrups | Triangular Stirrups | Helical Stirrups | 2 4 6 Legged Stirrups
below is the desired hook length in stirrups :
Usually, the length fluctuates among 9d to 12; here d denotes diameter in mm.
Given below, the desired clear cover in column :-
Column – 25 mm to 40 mm
25 mm is taken when the diameter of prime reinforcement is equivalent to 12 mm.
40 mm is taken when the diameter of prime reinforcement is greater than 12 mm
The clear cover stands for the spacing among the exterior surface of steel and concrete.
While going to determine the cutting length of stirrups, always make calculation in center to center distance of stirrup. Circular Stirrups | Diamond Stirrups | Square Stirrups | Triangular Stirrups | Helical Stirrups | 2 4 6 Legged Stirrups
Cutting Length Formula for Rectangular Stirrups:
Cutting length of rectangular stirrups can be determined with the following formula :-
2 (A+B) + (2 x 12D) – (2 x 3D + 3 x 2D)
Here, A+B denotes center to center (c/c) dimension
2 x 12D denotes two hooks with 12D as length
2 x 3D + 3 x 2D denotes elongation of steel
2 x 3D means two stirrups with bend elongation in 1350
3 x 2D means 3 bends with bend elongation in 900
After putting all the values, we get 1104 mm
Watch the above video to learn more,
Why hook is provided in stirrups:
Hook is provided in stirrups for the following reasons:
- To prevent from buckling of column.
- The main requirement for safety against bond failure is to provide a sufficient extension of the length of the bar beyond the point where the steel is required to develop its yield stress and this length must be at least equal to its development length. However, if the actual available length is inadequate for full development, special anchorages must be provided, such as cogs or hooks or mechanical end plates.
- Hooks are provided for to resist seismic movement.
- To prevent concrete from splitting outward.
- It prevent slippage of steel from the concrete.
- To Keep longitudinal steel bars in position and hold steel tightly.
Advantages of Bar Bending Schedule:
Bar bending schedule provides details of reinforcement cutting and bending length. Advantages of bar bending schedule is when used along with reinforcement detailed drawing improves the quality of construction, cost and time saving for concrete construction works.
Advantages of bar bending schedule in concrete construction are:
1. When Bar bending schedule is available, cutting and bending of reinforcement can be done at factory and transported to site. This increases faster execution at site and reduces construction time and cost due to less requirement of workers for bar bending. Bar bending also avoids the wastage of steel reinforcement (5 to 10%) and thus saves project cost. Circular Stirrups | Diamond Stirrups | Square Stirrups | Triangular Stirrups | Helical Stirrups | 2 4 6 Legged Stirrups
2. Using bar bending schedule for when used for Fe500, it saves 10% more steel reinforcement compared to fe415.
3. It improves the quality control at site as reinforcement is provided as per bar bending schedule which is prepared using the provisions of respective detailing standard codes.
4. It provides the better estimation of reinforcement steel requirement for each and every structural member which can be used to compute overall reinforcement requirement for entire project.
5. It provides better stock management for reinforcement. Steel requirement for next phase of construction can be estimated with accuracy and procurement can be done. This prevents stocking of extra steel reinforcement at site for longer time, preventing corrosion of reinforcement in case of coastal areas. It also prevents shortage of reinforcement for ongoing work by accurate estimation and thus concrete construction works can proceed smoothly.
6. Bar bending schedule is very much useful during auditing of reinforcement and provides checks on theft and pilferage.
7. Bar bending schedule can be used for reinforcement cutting, bending and making skeleton of structural member before it can be placed at the required position. Other activities such as excavation, PCC etc can proceed parallel with this activity. So, overall project activity management becomes easy and reduces time of construction. It becomes helpful in preventing any damages due to construction time overrun. Circular Stirrups | Diamond Stirrups | Square Stirrups | Triangular Stirrups | Helical Stirrups | 2 4 6 Legged Stirrups
8. It provides benchmarks for quantity and quality requirements for reinforcement and concrete works.
9. Bar bending schedule provides the steel quantity requirement much accurately and thus provides an option to optimize the design in case of cost overrun.
10. It becomes easy for site engineers to verify and approve the bar bending and cutting length during inspection before placement of concrete with the use of bar bending schedule and helps in better quality control.
11. It enables easy and fast preparation of bills of construction works for clients and contractors.
12. The quantity of reinforcement to be used is calculated using engineering formulas and standard codes, so there is no option for approximate estimation of steel reinforcement.
13. With the use of bar bending schedule, mechanization of cutting and bending of reinforcement can be done, again reducing the cost and time of project and dependency on skilled labor requirement. It also improves the reliability on accuracy of bar cutting and bending.
14. When mechanized bar cutting and bending is used, the cost of reinforced concrete work per unit reduces and helps in cost optimization of construction project.
Full article on Cutting Length Of Rectangular Stirrups | Stirrups Cut Length | Cutting Length formula | Hook Length for Stirrups | Bond Length for Stirrups | Bar Bending Schedule. Thank you for the full reading of this article in “The Civil Engineering” platform in English. If you find this post helpful, then help others by sharing it on social media. For More detail please see the above video tutorial further you have any question regarding article please tell me in comments.