Creating a Bar Bending Schedule (BBS) for a Reinforced Cement Concrete (RCC) sunshade is essential for accurate construction planning. This guide helps calculate the cutting length and weight of reinforcement bars used in a typical window projection.

Given Data for the Sunshade Design

• Sunshade Length: 1500 mm
• Sunshade Width: 900 mm
• Sunshade Thickness (Front): 75 mm
• Lintel Beam Width: 230 mm
• Lintel Beam Depth: 350 mm
• Main Bars: 10 mm Ø @ 150 mm c/c
• Distribution Bars: 8 mm Ø @ 150 mm c/c
• Sunshade Clear Cover: 20 mm
• Lintel Beam Cover: 25 mm

Cutting Length Calculations

Main Bar Cutting Length

The cutting length of the main bar includes straight lengths and bend allowances:

= [{sunshade thickness – (2nos. × cover)} + (sunshade width – cover) + {2nos.×  (lintel width – cover)} + 100mm. + (100mm. – lintel cover) – (3nos. × 90° bend.) ]

= [{75 – (2 × 20)} + (900 – 20) + {2 × (230 – 20)} + 100 + (100 – 25) – (3 × 2 × 10)] = [35 + 880 + 420 + 100 + 75 – 60] = 1450 mm
= 1.45 meters

Distribution Bar Cutting Length

= 1500 – (2 × 20)
= 1500 – 40
= 1460 mm
= 1.46 meters

Number of Bars Required

Number of Main Bars

= [{1500 - (2 × 20)} ÷ 150] + 1
= [1460 ÷ 150] + 1
= 9.73 + 1 = 10.73 ≈ 11 bars

Number of Distribution Bars

= [{900 - 20 - 10} ÷ 150] + 1
= [870 ÷ 150] + 1
= 5.8 + 1 = 6.8 ≈ 7 bars

Weight of Steel Reinforcement

Main Bar Weight Calculation

Formula:
Weight (kg) = (D² × L × N) / 162

Where:

• D = Diameter of bar (mm)
• L = Length of bar (m)
• N = Number of bars

= (10² × 1.45 × 11) / 162
= (100 × 1.45 × 11) / 162
= 1595 / 162 ≈ 9.85 kg

Distribution Bar Weight Calculation

= (8² × 1.46 × 7) / 162
= (64 × 1.46 × 7) / 162
= 653.12 / 162 ≈ 4.03 kg

Summary Table

Click Here To See How To Calculate The Cutting Length Of Chair Bar In Footings (Step-by-Step Guide)