Can we weld reinforcement bars instead of lapping

[Xaini]

Question:- If the steel bars are welded each other rather then reinforced so what will be the strength result? Either the steel bars with welded form gain required strength or northe ? Kindly Give the answer with proper reasoning...!!! Thanks

 

[amd007]

Please refer mentioned codes for your answer:

IS 2751: Code of Practice for Welding of Mild Steel Plain and Deformed Bars for Reinforced Concrete Construction
IS 9417: Recommendations for welding cold worked bars for reinforced concrete construction
IS 9595:1980: Recommendations for metal arc welding of carbon and carbon manganese steels.
IS : 1139-1966: Specification for hot rolled mild steel, medium tensile steel, and high yield strength steel deformed bars for concrete reinforcement ( revised )
IS : 1786-1979: Specification for cold-worked steel high strength deformed bars for concrete reinforcement r second revision

You can search for all the codes here: https://archive.org

Also, read the attached doc for an interesting journey of Indian reinforcing bars

 

[Dnyan Deshmukh]

Yes we can weld bars instead of lapping but it is not recommended in huge quantity.

The steel bars we used have 2 parts hard external core and soft / mild internal core.

For welding of bars cold welding rods should be used.

Normal arc welding rods can change properties of steel due to heat transmission.

When we can do welding

Lapping of bars goes in column Beam Junction
This is a most dangerous zone, you lapping of column reinforcement bars should never fall in column beam junction, if due to mistake your column lapping falls into column beam junction area, you need to weld those laps with cold welding rods with alternate fillets / stitches joint. Never weld bars from top to bottom from single face.

You should take care to ensure lapping of bars never fall in column beam junction.

Due to any reason you have lot of scrap steel at your Project
You can utilize this scrap steel and do a cost saving by ensuring steel which bought for higher rate is consumed in its desired place instead of selling it as a scrap for low price.

How you can do that
For using it for Structural purpose, you need to weld 2 scrap bars by lapping them at minimum 15D and welding those bars at 5D on alternate side by tacking or stitching (You can use normal welding rods for this type of work, ensure the weld is small tacks only do not over-weld which cause steel to loose its properties)

D is Diameter of steel, say you want to weld 20mm steel bars, so your lapping should be

15D = 15 x 20 = 300mm

So You will be welding this rods at ends of lap and at center of lap, to make it stagger you can do end welding on one face and center welding on other face.

To Use it as a Structural steel, you need to test sample bars from welded bars at third party laboratory for its tensile strength to ensure you welding system does correct work and you can finalize the process of how welding should be carried out so that welded steel rods have same strength like original steel rod without welding.

Once you get the desired result, you can start production of structural steel at you project.

What you required to do that
A Space, Small welding machine and Welder (semi skilled may do the Job)
After giving training to him, he can start welding of bars and form a bars of standard length (12 meter) by joining scrap steel)

Note - Before using those welded steel rods, you need to take approval from structural consultant by submitting test reports and method / process of welding followed.

If you do not wish to use it as a structural member, you can steel use those scrap steel in nonstructural work like staircase concrete rail, tie bands in brick / block wall and in areas where there is no risk of accidental human life loss.

To use scrap steel as a non structural member, you can use them by welding by lapping it for minimum 5D and tack welding.

Optionally if you want to check the strength of those steel bars, you can make third party testing.

Once you made steel bars of standard length, you should stack them as like how we stack new steel bars.
and consume it as you consume new bars, like cut the bars of required length from those welded bars.

What will be the strength of welded steel bars
It will be same as original provided, welding is done correctly.

 

[Bikash14641]

Yes we can weld bars instead of lapping but it is not recommended in huge quantity.

The steel bars we used have 2 parts hard external core and soft / mild internal core.

For welding of bars cold welding rods should be used.

Normal arc welding rods can change properties of steel due to heat transmission.

When we can do welding

Lapping of bars goes in column Beam Junction
This is a most dangerous zone, you lapping of column reinforcement bars should never fall in column beam junction, if due to mistake your column lapping falls into column beam junction area, you need to weld those laps with cold welding rods with alternate fillets / stitches joint. Never weld bars from top to bottom from single face.

You should take care to ensure lapping of bars never fall in column beam junction.

Due to any reason you have lot of scrap steel at your Project
You can utilize this scrap steel and do a cost saving by ensuring steel which bought for higher rate is consumed in its desired place instead of selling it as a scrap for low price.

How you can do that
For using it for Structural purpose, you need to weld 2 scrap bars by lapping them at minimum 15D and welding those bars at 5D on alternate side by tacking or stitching (You can use normal welding rods for this type of work, ensure the weld is small tacks only do not over-weld which cause steel to loose its properties)

D is Diameter of steel, say you want to weld 20mm steel bars, so your lapping should be

15D = 15 x 20 = 300mm

So You will be welding this rods at ends of lap and at center of lap, to make it stagger you can do end welding on one face and center welding on other face.

To Use it as a Structural steel, you need to test sample bars from welded bars at third party laboratory for its tensile strength to ensure you welding system does correct work and you can finalize the process of how welding should be carried out so that welded steel rods have same strength like original steel rod without welding.

Once you get the desired result, you can start production of structural steel at you project.

What you required to do that
A Space, Small welding machine and Welder (semi skilled may do the Job)
After giving training to him, he can start welding of bars and form a bars of standard length (12 meter) by joining scrap steel)

Note - Before using those welded steel rods, you need to take approval from structural consultant by submitting test reports and method / process of welding followed.

If you do not wish to use it as a structural member, you can steel use those scrap steel in nonstructural work like staircase concrete rail, tie bands in brick / block wall and in areas where there is no risk of accidental human life loss.

To use scrap steel as a non structural member, you can use them by welding by lapping it for minimum 5D and tack welding.

Optionally if you want to check the strength of those steel bars, you can make third party testing.

Once you made steel bars of standard length, you should stack them as like how we stack new steel bars.
and consume it as you consume new bars, like cut the bars of required length from those welded bars.

What will be the strength of welded steel bars
It will be same as original provided, welding is done correctly.

is this welding length mentioned in any Indian code

 

[Dnyan Deshmukh]

is this welding length mentioned in any Indian code

Please refer mentioned codes for your answer:

IS 2751: Code of Practice for Welding of Mild Steel Plain and Deformed Bars for Reinforced Concrete Construction
IS 9417: Recommendations for welding cold worked bars for reinforced concrete construction

 

[K Kiran]

what is the Minimum diameter reinforcement bar allowed for welding ?

 

[Dhaval Thanki]

Yes we can weld bars instead of lapping but it is not recommended in huge quantity.

The steel bars we used have 2 parts hard external core and soft / mild internal core.

For welding of bars cold welding rods should be used.

Normal arc welding rods can change properties of steel due to heat transmission.

When we can do welding

Lapping of bars goes in column Beam Junction
This is a most dangerous zone, you lapping of column reinforcement bars should never fall in column beam junction, if due to mistake your column lapping falls into column beam junction area, you need to weld those laps with cold welding rods with alternate fillets / stitches joint. Never weld bars from top to bottom from single face.

You should take care to ensure lapping of bars never fall in column beam junction.

Due to any reason you have lot of scrap steel at your Project
You can utilize this scrap steel and do a cost saving by ensuring steel which bought for higher rate is consumed in its desired place instead of selling it as a scrap for low price.

How you can do that
For using it for Structural purpose, you need to weld 2 scrap bars by lapping them at minimum 15D and welding those bars at 5D on alternate side by tacking or stitching (You can use normal welding rods for this type of work, ensure the weld is small tacks only do not over-weld which cause steel to loose its properties)

D is Diameter of steel, say you want to weld 20mm steel bars, so your lapping should be

15D = 15 x 20 = 300mm

So You will be welding this rods at ends of lap and at center of lap, to make it stagger you can do end welding on one face and center welding on other face.

To Use it as a Structural steel, you need to test sample bars from welded bars at third party laboratory for its tensile strength to ensure you welding system does correct work and you can finalize the process of how welding should be carried out so that welded steel rods have same strength like original steel rod without welding.

Once you get the desired result, you can start production of structural steel at you project.

What you required to do that
A Space, Small welding machine and Welder (semi skilled may do the Job)
After giving training to him, he can start welding of bars and form a bars of standard length (12 meter) by joining scrap steel)

Note - Before using those welded steel rods, you need to take approval from structural consultant by submitting test reports and method / process of welding followed.

If you do not wish to use it as a structural member, you can steel use those scrap steel in nonstructural work like staircase concrete rail, tie bands in brick / block wall and in areas where there is no risk of accidental human life loss.

To use scrap steel as a non structural member, you can use them by welding by lapping it for minimum 5D and tack welding.

Optionally if you want to check the strength of those steel bars, you can make third party testing.

Once you made steel bars of standard length, you should stack them as like how we stack new steel bars.
and consume it as you consume new bars, like cut the bars of required length from those welded bars.

What will be the strength of welded steel bars
It will be same as original provided, welding is done correctly.

Sir,

Can you please tell me name of electrode to use for welding ??

 

[Baskar Renganathan]

Sir,

Can you please tell me name of electrode to use for welding ??

See the IS 9417

 

[Baskar Renganathan]

Yes we can weld bars instead of lapping but it is not recommended in huge quantity.

The steel bars we used have 2 parts hard external core and soft / mild internal core.

For welding of bars cold welding rods should be used.

Normal arc welding rods can change properties of steel due to heat transmission.

When we can do welding

Lapping of bars goes in column Beam Junction
This is a most dangerous zone, you lapping of column reinforcement bars should never fall in column beam junction, if due to mistake your column lapping falls into column beam junction area, you need to weld those laps with cold welding rods with alternate fillets / stitches joint. Never weld bars from top to bottom from single face.

You should take care to ensure lapping of bars never fall in column beam junction.

Due to any reason you have lot of scrap steel at your Project
You can utilize this scrap steel and do a cost saving by ensuring steel which bought for higher rate is consumed in its desired place instead of selling it as a scrap for low price.

How you can do that
For using it for Structural purpose, you need to weld 2 scrap bars by lapping them at minimum 15D and welding those bars at 5D on alternate side by tacking or stitching (You can use normal welding rods for this type of work, ensure the weld is small tacks only do not over-weld which cause steel to loose its properties)

D is Diameter of steel, say you want to weld 20mm steel bars, so your lapping should be

15D = 15 x 20 = 300mm

So You will be welding this rods at ends of lap and at center of lap, to make it stagger you can do end welding on one face and center welding on other face.

To Use it as a Structural steel, you need to test sample bars from welded bars at third party laboratory for its tensile strength to ensure you welding system does correct work and you can finalize the process of how welding should be carried out so that welded steel rods have same strength like original steel rod without welding.

Once you get the desired result, you can start production of structural steel at you project.

What you required to do that
A Space, Small welding machine and Welder (semi skilled may do the Job)
After giving training to him, he can start welding of bars and form a bars of standard length (12 meter) by joining scrap steel)

Note - Before using those welded steel rods, you need to take approval from structural consultant by submitting test reports and method / process of welding followed.

If you do not wish to use it as a structural member, you can steel use those scrap steel in nonstructural work like staircase concrete rail, tie bands in brick / block wall and in areas where there is no risk of accidental human life loss.

To use scrap steel as a non structural member, you can use them by welding by lapping it for minimum 5D and tack welding.

Optionally if you want to check the strength of those steel bars, you can make third party testing.

Once you made steel bars of standard length, you should stack them as like how we stack new steel bars.
and consume it as you consume new bars, like cut the bars of required length from those welded bars.

What will be the strength of welded steel bars
It will be same as original provided, welding is done correctly.

thank you sir very useful information