As per IS-456: 2000 clause 26.2.1, the development length Ld is given by
Design bond stress (τbd ) |
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For Limit state method |
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Concrete grade |
M20 |
M25 |
M30 |
M35 |
M40 & above |
For plain bars in tension |
1.2 |
1.4 |
1.5 |
1.7 |
1.9 |
For deformed bars in tension |
1.92 |
2.24 |
2.40 |
2.72 |
3.04 |
Design bond stress (τbd ) |
|||||||
For Working stress method |
|||||||
Concrete grade |
M20 |
M25 |
M30 |
M35 |
M40
|
M45 |
M50 |
For plain bars in tension |
0.8 |
0.9 |
1.0 |
1.1 |
1.2 |
1.3 |
1.4 |
For deformed bars in tension |
1.28 |
1.44 |
1.6 |
1.76 |
1.92 |
2.08 |
2.24 |
Design bond stress (τbd )N/mm2 |
|||||||
For Working stress method |
|||||||
Concrete grade |
M20 |
M25 |
M30 |
M35 |
M40
|
M45 |
M50 |
For plain bars in compression. |
1.0 |
1.125 |
1.25 |
1.375 |
1.5 |
1.625 |
1.75 |
For deformed bars in compression. |
1.60 |
1.80 |
2.0 |
2.20 |
2.40 |
2.60 |
2.80 |
Design bond stress (τbd )N/mm2 |
|||||
For Limit state method |
|||||
Concrete grade |
M20 |
M25 |
M30 |
M35 |
M40 & above |
For plain bars in compression. |
1.5 |
1.75 |
1.875 |
2.125 |
2.375 |
For deformed bars in compression. |
2.4 |
2.8 |
3.0 |
3.4 |
3.8 |
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1. Example - 1
Given data
Calculate the development length for rebar in tension, by the limit state method for the below-given data.
Grade of concrete = M30
Reinforcement bar = Fe500 (σs = 500 )
Diameter of the bar = 16mm. (∅ )
2. Example - 2 :
Given data
Calculate the development length for rebar in compression, by working stress method for the below-given data.
Grade of concrete = M25
Reinforcement bar = Fe415 (σs = 415 )
Diameter of the bar = 12mm. (∅ )
For you 👇
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