Ldh greater than column width 1

[ebsico]

THE CONNECTION BETWEEN COLUMN AND BEAM, IF THE WIDTH OF THE COLUMN PARALLEL TO THE BEAM IS LESS THAN (Ldh) OF THE BEAM what can i do ? Column width could not be change
I have a second question developement length is for no.10 to no.36 what if i have no.40 what Ld be ?

 

[KootK]

1) Use smaller bars.

2) See if you can justify developing your bars for less than Fy.

3) Use alternate anchorage schemes such as headed bar ends.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[ebsico]

Thank you for you reply
but in my case
1)i cant use smaller bars
2)As provided = As required
3)for headed bars ldt is greater than my column width .

Here i have a question:
The 90 degree hook length should be min 12db.
Do you know if i can extend this bar ?if yes can you send me the reference please

 

[KootK]

By the sounds of it, what you have here is a poorly proportioned system.

Do you know if i can extend this bar ?

It depends, in part, on where you practice. In the UK, the concrete code has provisions for extending the hook to get your development. Attention must be paid to the radius in side the bend. In the US, you can use a curved bar node strut and tie model (Link).

Regardless of what you manage to accomplish regarding development of the rebar, you still need to design the joint to transfer the required moment (Link). And, by the sound of it, that's going to be tough given your proportions.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[ebsico]

I m working with the ACI code .
And i really appreciate your help even if i coulnt get the solution thank you a lot

 

[KootK]

Your very welcome ebsi. Let us know if there's anything else that we can do to help. If you post of sketch of your connection with some dimensions, we might be able to help come up with something that we haven't yet thought of.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[wannabeSE]

KootK,
Thanks for the link to the Curved-Bar Node article.

 

[KootK]

You're most welcome wannabe. To be honest, it's quite gratifying to know that someone else finds it relevant. I've been referencing it in threads for a few years now but it never really seems spark much interest.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Agent666]

Extend the beam slightly past the column to form a beam stub to accommodate the additional anchorage. This of course assumes you have a configuration where there is room for this.

 

[ebsico]

I have one more question how can i calculate Ld and Ldh for bar #40 (SI) since the code only give it for bars #10 to #36 (SI)
Thank you

 

[KootK]

Can you direct us to the ACI code clause that is giving you trouble? These are 40 mm diameter metric bars?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[ebsico]

Yes i m using metric bars
Its mentionned in Aci 318M-11 21.7.5.2
Thank you a lot kootk

 

[KootK]

I have one more question how can i calculate Ld and Ldh for bar #40 (SI) since the code only give it for bars #10 to #36 (SI)

I checked it out a bit and, to be honest, I don't know the answer to this one. If you look at the non-seismic Ldh requirements, they give you the impression that it's hard to derive any confinement benefit for hooked bars of such a large diameter. So it makes sense to me that ACI would discourage excessively large hooked bars for high seismic applications. I wouldn't think that same logic would apply to straight bars however. Perhaps that is just a vestigial carry over from the fact that Ld is expressed as a multiple of Ldh in chapter 21.

Sorry I'm not able to be more helpful on this one.


I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[ebsico]

Thank you kootk for your help i might increase my bars numbers and use smaller bars