How is Column Crank Length Calculated?
The crank length of a column reinforcement bar is calculated by adding the diameter of the bar to the clear cover requirement. The clear cover is the distance between the surface of the concrete and the reinforcement bar. It is important to provide sufficient clear cover to protect the reinforcement bar from corrosion and to ensure that it has adequate bond strength with the concrete.

The crank length of a column reinforcement bar is calculated as the sum of the following:
- The diameter of the reinforcement bar
- The clear cover to the reinforcement bar
The clear cover is the distance between the surface of the concrete and the outside of the reinforcement bar. It is typically specified in building codes and standards.
For example, if a column reinforcement bar has a diameter of 20 mm and a clear cover of 40 mm, then the crank length of the bar would be 60 mm.
Here is the formula for calculating the crank length of a column reinforcement bar:
Crank length = Diameter of reinforcement bar + Clear cover
It is important to note that the crank length of a column reinforcement bar should not be less than 300 mm. This is to ensure that the bar has sufficient anchorage in the concrete.
Here are some additional considerations for calculating the crank length of column reinforcement bars:
- The crank length should be perpendicular to the main reinforcement.
- The crank length should be bent smoothly and gradually.
- The crank length should be free of cracks and defects.
Cranked reinforcement bars are an important part of concrete column design. By providing additional reinforcement at the critical sections of the column, crank reinforcement helps to improve the structural performance and durability of the column.
what is cutting length?
- clear span = 4000mm.
- development length. We have to development length in two sides of column which will be provided in beam. Development length=2Ld.
- inclined length =0.42H. We have to inclind length of bent Up Bar in both sides so total incline length is equal to.
- bend elongation.
How do you measure crank length?

Crank length is measured from the centre of the bottom bracket axle to the centre of the pedal axle. If you’re not sure what length the cranks on your bike are, the quickest way of finding out is typically to just look at the backside of your cranks, just below the pedal axle.
What is crank length of reinforcement?
Crank is a slight bending in bars at the lap so that maintains the clear cover even at the lap position. The rule that is generally practiced is that the slope of crank 1:10 & minimum length of crank 300 mm.
How do you calculate bend length in reinforcement?
How To Calculate Bend Deduction Length Of Bar
How To Calculate Bend Deduction Length Of Bar:
For 45° bend = 1 x d.
For 90° bend = 2 x d.
For 135° Bend = 3 x d.
For 180° bend = 4 x d.
Where d = diameter of the bar.
How is bar bend length calculated?
KNOW HOW TO CALCULATE THE CUTTING LENGTH OF BENT UP BARS
Inclined Length = D/(sin 45°) – dD/ (tan 45°)
= (D/0.7071) – (D/1)
= (1D – 0.7071D)/0.7071.
= 0.42 D.
What is standard crank length?
The crank length represents the distance between the centre of the bottom bracket and the centre of the pedal axis. The most common lengths are 170, 172.5 and 175 mm, but it is possible to find cranks between 165 and 180 mm in the market.
What is the formula for bending pipe?
Use the correct formula to calculate the circumference of the bend. For example, the formula used when making a 90˚ bend is: Circumference = (pi2r) / (360/90). When bending, take into account the ability of the material to bend and sustain the bend.
How to calculate the crank length of reinforcement?
Crank is a slight bending in bars at the lap so that maintains the clear cover even at the lap position. The rule that is generally practiced is that the slope of crank 1:10 & minimum length of crank 300 mm. Crank length of reinforcement Formula of Crank length = (d1+d2+5)*10mm
How to calculate the crank bar length in slabs?
But as a site engineer, you need to calculate the cutting length of bars according to the slab dimensions and give instructions to the bar benders. Now considering angle of bend to be 45 degrees (not necessary to do so always) and development length of 40 times diameter of bar..
How to find crank length in steel bars for RCC?
Crank bars are provided as reinforcement in slabs. Formulae for calculating Crank length is given as D/sin45° – D/tan45° =1.42D – D = 0.42D Where D = Clear height of the bar = Thickness of slab – (Top cover + Bottom cover) –Diameter of the bar.
How is the lap length of tension reinforcement calculated?
The lap splice length in tension reinforcement is calculated as per ACI 12.15. In a tension lap, the force is transferred from the reinforcement bars to the concrete by the bond which in turn force back to the reinforcement. This hence results in a continuous line of reinforcement.