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Preparation of Bar-Bending Schedule:

Updated: Nov 21, 2022

What Bar Bending Schedule Means (BBS) ?

A Reinforcement Drawing is a reference drawing of a Structure's Bar Bending

Schedule, or "BBS" it is a detailed list that specifies the location, mark, type, size,

length, and number of each rebar or fabric as well as its length and number and

bending details.

"Scheduling" is the process of outlining the location of rebar, the kind of rebar, its

size or diameter, the quantity, and every other detail. Bar-bending scheduling is used

in the context of reinforcement bars. The Bar Bending Schedule, which provides

specific reinforcing requirements, is a method of ordering rebar’s for each structural

unit.


General guidelines to be followed in preparing BBS:

  1. The bars should be assembled together for each structural unit, such as a beam, column, footings etc., according to general criteria it should be followed at the time of preparing BBS.

  2. The bars in a building structure ought to be mentioned floor by floor.

  3. Schedules should not be included in the detailed reinforcement drawings but should be provided separately as A4 sheets for cutting and bending reasons.

  4. The bar and fabric schedule forms, as well as the shapes of the bar, should all adhere to IS 456:2000 and BS 8666.

  5. Generally it is preferred to list bars in ascending numerical order.

  6. A specific group or set of bars with specific length, size, shape, and type utilized at work must be specifically referred to by the bar mark reference on the label that is joined to a bundle of bars.

  7. This is crucial because a reference to a bar mark might then mentioned to a group of bar features. Additionally, this helps steel workers and fixers in keeping track of the kind and quantity of bars required to finish a project job.

Advantages of Preparing BBS

  • Calculation of steel reinforcement quantities of various diameters and grades is simplified.

  • A schedule of bars makes it simple to get ideas for various bar diameters, bends, and lengths.

  • The bar bending schedule is highly useful when inspecting the reinforcement on a construction site.

  • Additionally, it aids in reducing misunderstanding on the construction site.

  • It offers the precise amount of steel needed for the job, allowing for the optimization of reinforcement in the event of cost overruns.

  • Site engineers may easily check and confirm the cutting length and bar bending while conducting site inspections thanks to the bar bending schedule.

  • These bar schedules make it simple to create the construction bills at the conclusion of the entire project.

Bar bending Schedule is used by following people:

  1. Quantity Surveyor.

  2. Detailed Estimator.

  3. Person authorized for purchase and order work.

  4. Person Analyzing the drawings.

  5. Steel Fixer on Site.

  6. Site Engineer and Clients Consultant Engineer.

A quantity surveyor is in charge of project costs and operation estimation. High

levels of precision are necessary for this kind of surveying. The quantity surveyor

can shorten the amount of bars needed for each bar type using the bar bending

schedule.

This leads to an estimation of the quantity of steel, which gives requirement of the

cost needs for steel work. Therefore, the contractor who places the order for the

reinforcements also uses this schedule. And the weight of the purchased steel

determines the unit cost of steel.

To ensure that the reinforcing work on the job site is in accordance with the design

requirements as shown in the plans, the clerk of works and other inspectors consult

the BBS. The steel fixers use it as a point of reference personally. They can quickly

record the quantity and kind of rebar required for a structural unit.

In short, the Bar Bending Schedule incorporates all relevant reinforcement-related

data utilized by experts at various construction-related phases, from procurement of

material to completion of project.


Steps to prepare BBS

Necessary required data

  1. Bar mark reference/ Bar number

  2. Diameter of bar

  3. Shape of Bar

  4. Centre to Centre Spacing between bars

  5. Length of bar

  6. Cutting length of bar

  7. Number of bars

The structural unit's reinforcing drawings contain the majority of the data present in a

BBS. By simply looking at the drawings, which contain precise dimensioning, bar

shape, diameter, length, and spacing are directly entered into the schedule.



Number of bars:


For example, the spacing of the stirrups is 180mmc/c and the length along which

they are placed is 5000 mm, we can calculate the number of bars by the formula

below.


[ length / Spacing] +1 = Number of bars

= [ 5000 / 180] +1 = 28.77

In this case we have to round off the figure to 29.

Hence, we require 29 number of stirrups


Cutting Length:

We must keep in mind that steel is ductile by nature and can elongate. As a result,

adding bends or hooks increases the length of a bar. Therefore, some reductions are

required to make up for this lengthening.


Cutting Length= True length of bar + Number of bends – Deductions for predicted

elongation.


For 45 degree

Cutting length= Total length of bar - 1 x Dia of bar x No of bends

For 90 degree

Cutting length = Total length – 2 x Dia of bar x No of bends.



For Stirrups:

90-degree hook:

Length of stirrup = (2a + 2b) + 20xdia

135-degree hook:

Length of stirrup = (2a + 2b) + 24xdia

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