In a Bar Bending Schedule (BBS), **Total Length** and **Weight** are crucial parameters for estimating the quantity of reinforcement steel required for a project. These parameters provide a clear understanding of the total steel needed, aiding in procurement and ensuring cost-effective material usage. This article explains how to calculate the total length and weight of bars, with examples.
The total length and weight are important because they:
The total length is calculated as:
Total Length = Length of Each Bar × Number of Bars
The weight of steel bars is calculated using the formula:
Weight (kg) = Total Length (m) × Unit Weight (kg/m)
The unit weight of steel bars is derived from their diameter using the formula:
Unit Weight (kg/m) = (d² / 162), where **d** is the bar diameter in millimeters.
Details:
Length of Each Bar = 6m
Number of Bars = 20
Diameter of Bar = 12mm
Total Length: 6 × 20 = 120m
Unit Weight: (12² / 162) = 0.888kg/m
Total Weight: 120 × 0.888 = 106.56kg
Example Entry in BBS Table:
| Bar Mark | Shape | Diameter (mm) | Length of Each Bar (m) | Number of Bars | Total Length (m) | Total Weight (kg) |
|---|---|---|---|---|---|---|
| S-12-01 | Straight | 12 | 6 | 20 | 120 | 106.56 |
Details:
Length of Each Stirrup = 1.744m
Number of Stirrups = 30
Diameter of Bar = 8mm
Total Length: 1.744 × 30 = 52.32m
Unit Weight: (8² / 162) = 0.395kg/m
Total Weight: 52.32 × 0.395 = 20.66kg
Example Entry in BBS Table:
| Bar Mark | Shape | Diameter (mm) | Length of Each Bar (m) | Number of Bars | Total Length (m) | Total Weight (kg) |
|---|---|---|---|---|---|---|
| ST-8-01 | Rectangular | 8 | 1.744 | 30 | 52.32 | 20.66 |
Details:
Length of Each Bar = 5.721m
Number of Bars = 15
Diameter of Bar = 16mm
Total Length: 5.721 × 15 = 85.815m
Unit Weight: (16² / 162) = 1.580kg/m
Total Weight: 85.815 × 1.580 = 135.59kg
Example Entry in BBS Table:
| Bar Mark | Shape | Diameter (mm) | Length of Each Bar (m) | Number of Bars | Total Length (m) | Total Weight (kg) |
|---|---|---|---|---|---|---|
| CB-16-02 | Cranked | 16 | 5.721 | 15 | 85.815 | 135.59 |
The total length and weight of reinforcement bars are essential parameters in a BBS, ensuring precise material estimation and efficient resource management. By following standard formulas, construction teams can reduce wastage, control costs, and maintain structural integrity.