Is the quality of welding in lapping acceptable in lap length.if not Pl provide the reasons for not acceptable along with correct procedures
Is the quality of welding in lapping acceptable in lap length
- Thread starter Srinivasan
- Start date
Dnyan Deshmukh
Staff member
It depends on
If the steel is lapped for doing non structural work - the above type of welding is OK.
But if it is lapped for doing structural work - It is not acceptable at all.
For lapping of bars done by welding we should ensure at least following.
For welding minimum overlap should be of;
For structural work - 15D
for Non structural works - 5D.
Welding should be tacked weld and should not be continuous and done with low heat rods only.
For structural purpose, few samples of welded rebars should be tested in third party laboratory for its tensile strength periodically.
If the steel is lapped for doing non structural work - the above type of welding is OK.
But if it is lapped for doing structural work - It is not acceptable at all.
For lapping of bars done by welding we should ensure at least following.
For welding minimum overlap should be of;
For structural work - 15D
for Non structural works - 5D.
Welding should be tacked weld and should not be continuous and done with low heat rods only.
For structural purpose, few samples of welded rebars should be tested in third party laboratory for its tensile strength periodically.
shafi12344
Apprentice
A lap is when two pieces of reinforcing bar (rebar) are overlapped to create a continuous line of rebar. The length of the lap varies depend on concrete strength, the rebar grade, size, and spacing.
D is the diameter of the bars to be lapped together. So if you want to lap 20 mm dia column bars , you need to provide a lap of minimum 45 x20 = 900 mm. Overlap length in columns, beams and slabs is the distance intersection between two joining reinforcement bars.
The factors that are seriously considered in the analysis of the lap welded joints are: The bar diameters (d= 8, 10, 12, 14, 16, 18, and 20 mm), the length of the weld (4d and 5d), the distance “a” between the ends of the welded parts and the free length of bars “l” for l=300, 400, 500, 600, 700, 800, 900, and 1000 mm.
D is the diameter of the bars to be lapped together. So if you want to lap 20 mm dia column bars , you need to provide a lap of minimum 45 x20 = 900 mm. Overlap length in columns, beams and slabs is the distance intersection between two joining reinforcement bars.
The factors that are seriously considered in the analysis of the lap welded joints are: The bar diameters (d= 8, 10, 12, 14, 16, 18, and 20 mm), the length of the weld (4d and 5d), the distance “a” between the ends of the welded parts and the free length of bars “l” for l=300, 400, 500, 600, 700, 800, 900, and 1000 mm.
Dnyan Deshmukh
Staff member
Yes it is possible, i am not a structural designer but no of rebars depends on load the section carries and maximum dia of bar you can place into it.
I had seen rectangular columns with 6 bars at some places, mostly seen with 8+ bars.
Here in this case the lap length is not as per standard.
Not acceptable.
Let us understand welding process first.
When we weld two members welding rod get melted simultaneously both metal part also get melted due to heat and they bind with each other.
As rightly mentioned by Mr. Danyan Deshmukh. " Welding should be tacked weld and should not be continuous and done with low heat rods only. "
When we melt MS losses its strength, ductility.
Thus welding must be carried out by very good welder and sufficient lap length must be provided.
Not acceptable.
Let us understand welding process first.
When we weld two members welding rod get melted simultaneously both metal part also get melted due to heat and they bind with each other.
As rightly mentioned by Mr. Danyan Deshmukh. " Welding should be tacked weld and should not be continuous and done with low heat rods only. "
When we melt MS losses its strength, ductility.
Thus welding must be carried out by very good welder and sufficient lap length must be provided.
The welding shown in the photo is not acceptable.... Further, the reinforcement which we are using here in India for Construction purpose is not conducive to welding, if we intend to use welding as a jointing media then the steel also needs to be composed in a manner which will permit welding. In short WELDABLE STEEL HAS TO BE USED FOR CONSTRUCTION.
Similar threads
