Answered Is it column lapping is correct?if not tell me what happened.

Reddy

Senior Member
Sep 8, 2017
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In this first column bar lapping was at some distance from main bar so it is fine or any problem with this lapping?
 
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amd007

Active Member
Premium Member
Apr 17, 2018
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mumbai
View attachment 2958
In this first column bar lapping was at some distance from main bar so it is fine or any problem with this lapping?
View attachment 2958
In this first column bar lapping was at some distance from main bar so it is fine or any problem with this lapping?
I will say that it is incorrect.

have always quoted on this forum and elsewhere, that all such details cant be generalized in fact lots depends on the structural drawings and structural engineer design.

once again would reiterate that for all structural matters always refer to structural drawings and take advice from the structual engineer.

am attaching a general drawing at one of my sites for reference purpose only, pls ensure that you consult your designer before implementing anything.

most of the details are covered for knowledge of all but again its a general drawing, always be specific and refer to your structural engineer ask him for general drawing for your site, all designers issue the same at the start of the project.
 

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HockeyPuck

Senior Member
Feb 3, 2019
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Chicago, Illinois (USA)
I will say that it is incorrect.

have always quoted on this forum and elsewhere, that all such details cant be generalized in fact lots depends on the structural drawings and structural engineer design.

once again would reiterate that for all structural matters always refer to structural drawings and take advice from the structual engineer.

am attaching a general drawing at one of my sites for reference purpose only, pls ensure that you consult your designer before implementing anything.

most of the details are covered for knowledge of all but again its a general drawing, always be specific and refer to your structural engineer ask him for general drawing for your site, all designers issue the same at the start of the project.
amd007 You raise a great point - Even though this installation doesn't necessarily look like we think it should look like, it doesn't make it wrong if the designer prescribed it.....

It is very rare, using US concrete codes & agency specifications, that some of the laps (or in this picture's case, the non-contact laps...) are appropriate, particularly with the size of the bars installed. I, like you, would definitely want to consult the design engineer on this one....
 
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Harshal.khode

Newbie
May 25, 2019
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5
Pune
View attachment 2958
In this first column bar lapping was at some distance from main bar so it is fine or any problem with this lapping?
This is incorrect, because most of lapping bars length are variable and as per SP 34, All the lapped joints length shall be lapping till bend of the alternate rod, which is not shown in attached pictures. Technically this is totally wrongs.
 

Dnyan Deshmukh

Eternal Member
Staff member
Sep 7, 2017
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4,049
Pune
It look like lapping of column is short.
from the pic it indicate the lapping of column not done before casting of columns.
After casting of the column bars are simply lapped which got short lap length which made crank to go up.

The lapping of column reinforcement bars should never fall in column beam junction area.

remedy for current situation -
break the column concrete so that bar with sufficient lap length can be lapped with bars coming from column.

in most of the cases remedy suggested by structural consultant for laps where it falls in column beam junction area is to stitch weld the bars at 3 places 2 on one face at ends and 1 stitch on opposite face of lapped bars at center.

you should show the lapping of column bar gone in column beam junction to your structural consultant and take approval from them for the same.
 
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Reddy

Senior Member
Sep 8, 2017
71
31
I will say that it is incorrect.

have always quoted on this forum and elsewhere, that all such details cant be generalized in fact lots depends on the structural drawings and structural engineer design.

once again would reiterate that for all structural matters always refer to structural drawings and take advice from the structual engineer.

am attaching a general drawing at one of my sites for reference purpose only, pls ensure that you consult your designer before implementing anything.

most of the details are covered for knowledge of all but again its a general drawing, always be specific and refer to your structural engineer ask him for general drawing for your site, all designers issue the same at the start of the project.
Thank you sir
 

civil kumar

Newbie
Aug 24, 2019
5
3
MUMBAI
Lapping should always be " Ld+300 "
and must be staggered from adj. bar,

in pic. lap is in tension zone which is wrong it's should be in compression zone i.e. in centre,

remedy: use HILTI and increase lap-length for the short-rebars
 

sonukhode

Apprentice
Jun 8, 2018
10
9
Pune
View attachment 2958
In this first column bar lapping was at some distance from main bar so it is fine or any problem with this lapping?
Dear Reddy,

This was one of the first issues we've discussed. From the posts it appeared that there was a general consensus that trying to implement the following three requirements of Column Bar splicing was sometimes impracticable:

a) max 50% bars to be spliced at a section,
b) splicing at in the middle half of the column height, as well as
c) trying to keep a clear distance between laps of 0.3 development length

Reference to international codes brought home the point that while all codes frown on more than 50% of bars being lapped at one location, they allow it after a punitive increase in the required development length. This is significant in situations where you are tying the column reinforcement cage at the ground level, complete with column rings and lifting this cage by means of mechanized methods such as a Crane. (This is not an uncommon practice for towers). In such cases, bars of unequal length become very difficult to maneuver and it may become imperative to have a system by which you may splice bars at one location without compromising on the structural integrity. Presently we do not have such an option available to us in IS 13920.

This could be reviewed in the next proposed revision of this code. We would welcome more discussion regarding this and would like to hear apprehensions of changing this clause 7.2.1 in IS 13920. There were issues raised about what does one do or those buildings where there is a future floor provision. Would the lapping of bars be all at the same location? It appears in such a case you would need to provide taller pedestals for the future columns, up to say about half the proposed floor height.

Attached lapping of bars is incorrect location and incorrect method as per national and International Standards and construction industry practices.

Regards
Harshal