×
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!
  • Students Click Here

*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.

Students Click Here

Jobs

Using links as column ties?

Using links as column ties?

Using links as column ties?

(OP)
Have y'all ever seen links used in columns as shown in the attachment? I understand at some spots in the column, like where vertical bars splice and so they have to slope,it might not be preferable to use square ties since their size will be changing along the slope. However even then I've only seen U-bars to accommodate the sloped bars, never ties. What are y'alls opinion on these?

RE: Using links as column ties?

By "link" you mean the diamond tie, right? If so, it's very common in my jurisdiction. I believe that the intent is to leave the center of the column open and easier to pour concrete into.

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: Using links as column ties?

(OP)
In this case they're making the diamond tie out of 4 separate links (like 1-legged stirrups; do these have another name?) though, is that still okay?

Actually though I didn't know that was a reason for using diamond ties, that's neat; thanks.

RE: Using links as column ties?

Ah... now I get it. I didn't pick up on the separate tie business from the picture. I've never, ever seen this done or proposed. I don't have any problem with it however. Conceptually, it doesn't seem materially different from regular cross ties.

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: Using links as column ties?

The outer stirrups appear to be 2 u bars, in this part of the world it's a big no no to do that as there is no lapping of bars in the cover concrete unless you have a full lap length and turn in hooks into the concrete core.

RE: Using links as column ties?

(OP)
Well for those U bars, I considered them okay because the required lap length is 16" which they're providing (column is 24x24.) However with those links, I was wondering if they needed to be lapped similarly and so maybe U bars had to be used. But KootK I think you're correct, they do just seem like cross ties. Thank you.

RE: Using links as column ties?

I still wouldn't do it and I'm surprised your code allows it, if the column is subject to any cyclic loading the bond can breakdown, especially if there is an spalling of the cover concrete.

In this part of the world we generally use plain round bars for the stirrups which can't be lapped with a straight lap.

If you are trying to improve the buildability why not have one u shaped stirrup with 2 135 degree hooks with a closing link

RE: Using links as column ties?

Just to clarify, I was talking just about the u bars in previous post. Internal links are fine as far as I can tell.

RE: Using links as column ties?

(OP)
Oh! These U bars are only where the vertical bars slope, which happens about 4" below a beam intersection to within the intersection; so for the most part within the beam cage. At all other locations we require closed ties. Would you still think there's an issue with this?

RE: Using links as column ties?

Ok got it. I've never seen a smaller stirrup being used in the region where the bars crank in at a column lap. Usually the main stirrups just carry through with a bit of a gap to them.

Never given it much thought to be honest, so not sure what others do?



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