Determine the cutting length of bend up or crank bar in Slab

In this construction video tutorial, you will learn the detailed method to work out the cutting length of bend up or crank bar in slab.

Given below, the detail dimensions of bend up bar :-

Diameter (D) of the bar is taken as 12 mm.
Clear cover is given as 25 mm.
Clear span (distance between inner bar to inner bar) is given as 7000 mm.
Density of the slab is taken as 200 mm.
Development length (Ld) is taken as 40d (d denotes dia of bar).

The bend up bar is bend on both side. So, inner length in which the both side is bend is known as development length. The length of the bar is required to transmit the stresses to the other bar.

To find out the cutting length of the bar, the following formula is used :-

Cutting Length = Clear span of slab + (2 x Development Length) + (2 x inclined length) – (450 bend x 4) – (900 bend x 2).
Here value of inclined length and values of all the bends are unknown.
The value of inclined length is assumed as 0.42 D.
The value of 450 bend is taken as 1d
The value of 900 bend is taken as 2d

To learn how the value of inclined length is derived, watch the following video tutorial youtu.be

By putting all the values, the following out is obtained.
Cutting Length = 7000 + (2 x 40d) + (2 x 0.42D) – (1d x 4) – (2d x 2)

Watch the following video tutorial to get the complete details.

Video Source: All Tech