INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Ldh greater than column width

Ldh greater than column width

(OP)

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 ?

RE: Ldh greater than column width

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.

RE: Ldh greater than column width

(OP)
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

RE: Ldh greater than column width

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

Quote (ebsi)

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.

RE: Ldh greater than column width

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

RE: Ldh greater than column width

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.

RE: Ldh greater than column width

KootK,
Thanks for the link to the Curved-Bar Node article.thumbsup2

RE: Ldh greater than column width

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.

RE: Ldh greater than column width

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.

RE: Ldh greater than column width

(OP)
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

RE: Ldh greater than column width

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.

RE: Ldh greater than column width

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

RE: Ldh greater than column width

Quote (ebsi)

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.

RE: Ldh greater than column width

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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close