Basic knowledge about Reinforcement Steel works done at Construction Project
Concrete Cover for Reinforcement
Concrete cover is also called clear cover for reinforcement. and it is the distance b/w steel surface and nearest outer surface of concrete structure.
Concrete cover for different RCC members
Pile = 75 mm
Pile cap =75 mm
Footing = 75 mm
Column below ground = 65 mm
Column above ground = 40 mm
Shear wall below ground = 65 mm
Shear wall above ground = 40 mm
Beam below ground = 65 mm
Beam above ground = 40 mm
Slab below ground = 50 mm
Slab above ground = 20 mm
Stair = 20
Unit Weight of Steel bar
ø 6 mm bar = 0.067 kg/ft = 0.222 Kg/meter
ø 8 mm bar = 0.120 kg/ft = 0.395 Kg/meter
ø 10 mm bar = 0.188 kg/ft = 0.617 Kg/meter
ø 12 mm bar = 0.270 kg/ft = 0.888 Kg/meter
ø 16 mm bar = 0.481 kg/ft = 1.580 Kg/meter
ø 20 mm bar = 0.752 kg/ft = 2.470 Kg/meter
ø 25 mm bar = 1.173 kg/ft = 3.850 Kg/meter
ø 28 mm bar = 1.472 kg/ft = 4.830 Kg/meter
ø 32 mm bar = 1.923 kg/ft = 6.310 Kg/meter
ø 36 mm bar = 2.435 kg/ft = 7.990 Kg/meter
ø 40 mm bar = 3.005 kg/ft = 9.860 Kg/meter
Lap in compression zone:
Steel should be lapping for compression zone with 40d, where 'd' is dia of steel bar
Lapping for Tension
Steel should be lapping for tension zone with 50d where 'd' is dia of steel bar
Lapping of the bars should be done as per lap length shown on Structural Drawing only, above value can be used in case where details not available, lapping of bars depends on the grade of concrete and bond stress.
For higher diameter reinforcement steel bars like above ø 36 mm, lapping of bar is done by coupler or welding in case of lapping normally, additional spiral reinforcement should be fixed around it.
Binding Wire Requirement
For binding one ton of reinforcement steel bars 7 kg to 13 kg binding wire is required depending on the quantum of steel provided in member.
Standard length of Reinforcement steel bars
Reinforcement steel bars comes in standard length of 40 feet or 12 meter.
Minimum Longitudinal Bar in a Column
Use Minimum 4 No’s of steel in Square column and 6 No’s for circular column
Placing 1st Stirrup:
Place 1st stirrup with the spacing of 2 inches or at cover of that member, whichever is less.
Hook’s Angle of Stirrup
Stirrup’s hook angle should be 135° to resist the lateral forces of earthquake.
Bend for Vertical Bar of Column
Remember that vertical column bars are called longitudinal bars, and bend is provide at one end of longitudinal bar with the angle of 90 degree and then length should be not less than 18 inches.
End Hook for Longitudinal Bar of Beam
Column end hook angel should be with 90 degree
Hook’s Length of Stirrup:
The stirrup hook length should be not less than 5 inches / 120 mm or use this formula = 12d where 'd' is dia of steel bar which used for stirrup.
Maximum Lap in a Zone
Don’t use more than 50% lapping zone in any RCC structure.
Bent Up bar
Provide bent up bar near at support of slab and beam.
Concrete Cover for Reinforcement
Concrete cover is also called clear cover for reinforcement. and it is the distance b/w steel surface and nearest outer surface of concrete structure.
Concrete cover for different RCC members
Pile = 75 mm
Pile cap =75 mm
Footing = 75 mm
Column below ground = 65 mm
Column above ground = 40 mm
Shear wall below ground = 65 mm
Shear wall above ground = 40 mm
Beam below ground = 65 mm
Beam above ground = 40 mm
Slab below ground = 50 mm
Slab above ground = 20 mm
Stair = 20
Unit Weight of Steel bar
ø 6 mm bar = 0.067 kg/ft = 0.222 Kg/meter
ø 8 mm bar = 0.120 kg/ft = 0.395 Kg/meter
ø 10 mm bar = 0.188 kg/ft = 0.617 Kg/meter
ø 12 mm bar = 0.270 kg/ft = 0.888 Kg/meter
ø 16 mm bar = 0.481 kg/ft = 1.580 Kg/meter
ø 20 mm bar = 0.752 kg/ft = 2.470 Kg/meter
ø 25 mm bar = 1.173 kg/ft = 3.850 Kg/meter
ø 28 mm bar = 1.472 kg/ft = 4.830 Kg/meter
ø 32 mm bar = 1.923 kg/ft = 6.310 Kg/meter
ø 36 mm bar = 2.435 kg/ft = 7.990 Kg/meter
ø 40 mm bar = 3.005 kg/ft = 9.860 Kg/meter
Lap in compression zone:
Steel should be lapping for compression zone with 40d, where 'd' is dia of steel bar
Lapping for Tension
Steel should be lapping for tension zone with 50d where 'd' is dia of steel bar
Lapping of the bars should be done as per lap length shown on Structural Drawing only, above value can be used in case where details not available, lapping of bars depends on the grade of concrete and bond stress.
For higher diameter reinforcement steel bars like above ø 36 mm, lapping of bar is done by coupler or welding in case of lapping normally, additional spiral reinforcement should be fixed around it.
Binding Wire Requirement
For binding one ton of reinforcement steel bars 7 kg to 13 kg binding wire is required depending on the quantum of steel provided in member.
Standard length of Reinforcement steel bars
Reinforcement steel bars comes in standard length of 40 feet or 12 meter.
Minimum Longitudinal Bar in a Column
Use Minimum 4 No’s of steel in Square column and 6 No’s for circular column
Placing 1st Stirrup:
Place 1st stirrup with the spacing of 2 inches or at cover of that member, whichever is less.
Hook’s Angle of Stirrup
Stirrup’s hook angle should be 135° to resist the lateral forces of earthquake.
Bend for Vertical Bar of Column
Remember that vertical column bars are called longitudinal bars, and bend is provide at one end of longitudinal bar with the angle of 90 degree and then length should be not less than 18 inches.
End Hook for Longitudinal Bar of Beam
Column end hook angel should be with 90 degree
Hook’s Length of Stirrup:
The stirrup hook length should be not less than 5 inches / 120 mm or use this formula = 12d where 'd' is dia of steel bar which used for stirrup.
Maximum Lap in a Zone
Don’t use more than 50% lapping zone in any RCC structure.
Bent Up bar
Provide bent up bar near at support of slab and beam.
