×
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

Concrete Pryout Strength of anchors in Shear
2

Concrete Pryout Strength of anchors in Shear

Concrete Pryout Strength of anchors in Shear

(OP)
Hello,

I'm designing the anchors from a pre-manufactured metal building that is going to be supported on 27x27 columns. I'm having problems with the concrete pryout strength in shear. According to what I understand from the code, Anchor reinforcement would only help concrete breakout, but not pryout. Is there anything (more reinforcement) that we can do to avoid this failure without changing my column dimensions?
Thanks

RE: Concrete Pryout Strength of anchors in Shear

I have only seen some people reference that as long as the anchor is a certain length, pryout should not control. No specific code reference that I know of.

RE: Concrete Pryout Strength of anchors in Shear

Ah yes, the famous Metal Building Anchorage issue. A while back I had a similar problem. I lengthened the bolts such that they were embedded deep into the footing (they ended up about 4'-0" long) and used the edge distances to the footing rather than the column (I did the calculations for pryout just for the portion embedded in the footing) to get them to work. This only works if the columns sit on spread footings.
I always felt that I was gaming the system, but I had to do something to make the numbers come out.

RE: Concrete Pryout Strength of anchors in Shear

According to the ACI- appendix D the pray-out equation is a factor multiplied by the tensile breakout strength. tension breakout strength depends mainly on the embedded length and the edge distance. So, think about playing these two variables or using a shear key which might be more effective in transferring shear

RE: Concrete Pryout Strength of anchors in Shear

(OP)
Just so that you guys now, I e-mailed the ACI technical guys and they said Pryout will not control if embedment depth is greater than 5d, but that the code hasn't been changed!

RE: Concrete Pryout Strength of anchors in Shear

5d sounds light to me. I would stick with twelve.

RE: Concrete Pryout Strength of anchors in Shear

27x27 concrete columns with steel building base plates mounted on top?

If so, I would use all-thread rods and lap them with vertical column reinforcement in the column to get full development, and avoid APP D all together.

RE: Concrete Pryout Strength of anchors in Shear

Hi,

You need to use supplement reinceforcement... When you use it you dont need to worry about pryout or breakout in shear, because the anchor bolt and rebar lap each other (need longer anchor) and work as one, so pryout or breakout dont happen.

Review PIP STE05121 Anchor Bolt Design Guide, you will find there how design this supplement reinceforcement.

Regards

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