Bar Bending Schedule for Slab

Before diving into the topic, I hope you read the basic topics that we have covered already

• Difference between one way slab and two way slab
• Difference between Main Bars & Distribution Bars
• Why is the Crank rod provided?
• What is development length and lap length?

The above posts help a lot to understand the topic much better.

One way Slab Reinforcement Details

From Drawing (Given Data)

• Slab Size = 6000 x 2500 x 150
• 10mm Main Bars @ 150mm c/c spacing
• 8mm Distribution Bars @ 150mm c/c Spacing
• Slab thickness is 150 mm
• Top Extra Bars – 8mm @ 150 c/c
• Beam Cover – 25 mm

Bar Bending Schedule for One Way Slab

Step 1 – Find out the total Number of Main Bars & Distribution Bars

• Number of Main Bars = (Length of Longer Side / Spacing) + 1 = (6000/150)+1 = 41 Numbers

• Number of Distribution Bars = (Length of Shorter Side / Spacing) + 1 = (2500/150)+1 = 18 Numbers

Step 2 – Find Out the Cutting Length of Bars (Main bar & Distribution bar)

 

• Cutting Length of Bar = Clear Span (Lclear) + (2 x Beam Width) – (2 x Concrete Cover) + (1 x Inclined Length) – (45° bend x 2)

Therefore, Inclined Length D = 0.42 x d

Where, D = Slab thickness – 2 x Clear Cover – Bar Dia = 150-(2*25)-10 = 90 mm

Inclined Length = 0.42 X 90 = 37.8 mm

• Cutting Length of Main Bar =  Clear Span (Lclear) + (2 x Beam Width) – (2 x Con. Cover) + (1 x Inclined Length) – (45° bend x 2)

= 2500+(2*240)-(2*25)+37.8-20 = 2947.8 mm = 2.95 m

• Cutting Length of Distribution Bar =  Clear Span (Lclear) – (2 x Con. Cover)= 6000 – 50 = 5950 mm or 5.95 m

Step 3 – Find out the number of Top Extra Rods (for L/4 length)

• Number of Top Bars  = Crank Length (L/4) / Spacing + 1 = ((2500/4)/150)+1 x 2 side = 10 Numbers
• Cutting Length of Top Bars = Same cutting length as distribution bars (5.95 m)

Description	Dia of Bar	No of Bars	Cutting Length (m)	Steel weight per metre	Qty (Kg)
Main Bar	10	41	2.95	0.62	74.98 Kg
Distribution Bars	8	18	5.95	0.40	42.84 Kg
Top Extra Bars	10	10	5.95	0.62	36.89 Kg
Total					154.71 Kg

For steel, calculation refer – How to calculate the weight of steel bars? post

Two Way Slab Reinforcement Details

 

From Drawing

• Slab size – 6000 x 5400 x 150
• 10mm Main Bars @ 150mm C/C spacing
• 10mm Distribution Bars @ 200mm C/C Spacing
• Development Length L_d = 40d
• Top Extra Bar 8mm @ 150 mm c/c (both direction)

Bar Bending Schedule for Two Way Slab

Step 1 – Find out the Total Number of Main Bars & Distribution Bars

• Number of Main Bars = (Length of Longer Side / Spacing) + 1 = (6000/150)+1 = 41 Numbers

• Number of Distribution Bars = (Length of Shorter Side / Spacing) + 1 = (5400/150)+1 = 28 Numbers

Step 2 – Find Out the Cutting Length of Bars

• Cutting Length of Bar = Clear Span (Lclear) + (2 x Beam Width) – (2 x Con. Cover) + (1 x Inclined Length) – (45° bend x 2)

Therefore, Inclined Length D = 0.42 x d

Where, D = Slab thickness – 2 Side Clear Cover – Bar Dia = 150 – (2*25) – 10 = 90 mm

Inclined Length = 0.42 X 90 = 37.8 mm

• Cutting Length of Main Bar = Clear Span (Lclear) + (2 x Beam Width) – (2 x Con. Cover) + (1 x Inclined Length) – (45° bend x 2)

where 45° bend = 1 d

= 5400 + (2*240) -(2*25) + 37.8 – (10*2) = 5847.8 mm = 5.85 m

• Cutting Length of Distribution Bar = Clear Span (Lclear) + (2 x Beam Width) – (2 x Con. Cover) + (1 x Inclined Length) – (45° bend x 2)

= 6000 + (2*240) -(2*25) + 37.8 – (10*2) = 6447.8 mm or 6.45 m

Step 3 – Top Extra Rods

a) Number of Top Bars (Longer & Shorter Side)

• Number of Top Bars (Longer Side) = Crank Length (L/5)/ Spacing = (5400/5)/150 = 7.2 = 7 No.s x 2 side = 14 No.s
• Number of Top Bars (Shorter Side) = Crank Length (L/5)/ Spacing = (6000/5)/150 = 8 = 8 No.s x 2 side = 16 No.s

b) Cutting length of Top Bars (Longer & Shorter Side)

• Cutting Length of Top Bars (Longer Side) = 6000 + (2 x L_d) = 6000 + (2 x 40 x 10) = 6800 mm or 6.8 m
• Cutting Length of Top Bars (shorter Side) = 5400 + (2 x L_d) = 5400 + (2 x 40 x 10) = 6200 mm or 6.2 m

Description	Dia of Bar	No of Bars	Cutting Length	Steel weight Per Metre	Total Qty (Kg)
Main Bar	10	41	5.85	0.62	148.71
Distribution Bars	10	28	6.45	0.62	111.97
Top Bar (Shorter Side Extra Rod)	10	16	6.2	0.62	61.50
Top Bar (Longer Side Extra Rod)	10	14	6.8	0.62	59.02
Total					381 Kg

Happy Learning 🙂