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)

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

Happy Learning 🙂