# AnsweredHow to find out Ld?

#### Sathish Kumar

##### Junior Member
How can find development length in below fig?

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#### Sivaji jayavarapu

##### Newbie
How can find development length in below fig?
Take 10 times of daineter,(10d)

#### Aisha

##### Newbie
Ld is given by the formula

Where phi is the diameter of the bar
Sigma-S is the strength of the bar
Tbd as follows -
For M20- 1.2
For M25-1.4
For M30-1.5
For M35-1.7
For M40 and above-1.9
These Tbd values are for mild steel bars, i.e, Fe250
For HYSD bars, like Fe415 and Fe500 multiply the value given above by 1.6 (or in short we're increasing it by 60% as per codal recommendations)

Sigma S is 415
Tbd is (1.6*1.2)
Plugging in these values into the formula we get the Development length as
Ld=54d
Or Ld=54*25=1350 mm or 1.35m

Hope it's clear.
P. S this formula is available in IS 456:2000,pages 42-43.
Regards.

#### Pankaj rai

##### Newbie
? You had mark should be minimum 300mm and Ld should be calculated from the edge of change of thicknesses of elements. In above case Ld will be measured from ground till bend end and it should be as per above formula advised by aisha.

#### johnswa

##### Newbie
Ld is given by the formula
View attachment 2711
Where phi is the diameter of the bar
Sigma-S is the strength of the bar
Tbd as follows -
For M20- 1.2
For M25-1.4
For M30-1.5
For M35-1.7
For M40 and above-1.9
These Tbd values are for mild steel bars, i.e, Fe250
For HYSD bars, like Fe415 and Fe500 multiply the value given above by 1.6 (or in short we're increasing it by 60% as per codal recommendations)

Sigma S is 415
Tbd is (1.6*1.2)
Plugging in these values into the formula we get the Development length as
Ld=54d
Or Ld=54*25=1350 mm or 1.35m

Hope it's clear.
P. S this formula is available in IS 456:2000,pages 42-43.
Regards.
1.35m is for one side or including 2 sides (0.675m per side)? Also does it only include only the horizontal length or does in include horizontal and vertical length?

#### Raja4107

##### Newbie
How can find development length in below fig?
It should be 24 D or 300 mm which ever is higher is acceptable as per standard specification

#### Aisha

##### Newbie
1.35m is for one side or including 2 sides (0.675m per side)? Also does it only include only the horizontal length or does in include horizontal and vertical length?
The development length is calculated per bar (of a given diameter).
Development length is the excess amount of reinforcement provided either into a column(in case of a cantilever) or into a beam(as in this case).
In the cantilever case the Development length includes some portion the horizontal length and the vertical length,
While in this case, the Development length is only in the horizontal potion.

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