×
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

Anchor Bolts

Anchor Bolts

Anchor Bolts

(OP)
What is this 2.5 increase requirement for anchor bolt design. In most cases steel strength supercedes concrete strength. Meaning that if the concrete is not strong enough then their wont be ductile failure of bolts. Since this is always the case does this mean that I will need to reinforce the the concrete and or embed the anchor bolt a lot in order to make it work? Recently we have been getting comments from the building department that we need to apply this factor to the concrete strength. It just seems so rediculous the amount of reinforcement needed on an elevated 16ft tall Nitrogen tank on unbraced legs to make the concrete work.

RE: Anchor Bolts

The 2.5 factor is required for SDC D and above (only for the seismic loads, obviously) when the controlling failure mode is not the (ductile) steel.  You can usually use the steel that's already in the pier to make it work.  It is a pain sometimes, but you've got to do it.

RE: Anchor Bolts

The 2.5 factor also applies in SDC C.  It can be a challenge, especially where edge distances are small.

RE: Anchor Bolts

My apologies......... it is SDC C or worse.  It shouldn't be that difficult to get to work if you use steel across the plane, then the edge distances don't even matter (unless you're governed by blowout).  There's usually steel there anyway, so why not take advantage of it?

RE: Anchor Bolts

The 2.5 is a global seismic CYA for the code officials. An alternative to a ductile failure of the bolts would be a ductile failure of the attaching member (I forget the code reference). Make sure your bolts are "ductile". Other then that, go deeper or use more smaller bolts. Try Hilti's Profis program. It's easy to modify your bolt layouts.
Good Luck!

Clarke Engineering Services, PC
Construction Consulting & Anchor Testing
www.anchorengineer.com

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