×
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

Post-installed anchors in stemwall

Post-installed anchors in stemwall

Post-installed anchors in stemwall

(OP)
I have found myself trying to get some post-installed anchors to resist uplift in existing foundation stem walls many times over the years and it is always hard to do. The numbers from ACI 318 App. D just don't work out to where you can resist more than 2500 or 3000 lbs in tension or shear without blowing out the side. Forget about it if you have to resist 3000 lbs in tension and shear. What solutions have you guys come up with where you have to resist more than this?

RE: Post-installed anchors in stemwall

I've bolted steel straps to the sides of concrete stem walls. Desperation is the mother of invention. It can be intrusive to the building envelope system.

With longer wood shear walls, I've argued that the boundary tension and compression loads are shared by two stud packs at the ends of each wall rather than one. If those packs can be separated such that the anchor breakout cones don't intersect, you can cut the demand down a fair bit.

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: Post-installed anchors in stemwall

(OP)
I had considered straps to the sides of the stem wall but was worried about corrosion. Do precautions other than galvanized strap or something need to be taken? The top of the stemwall in this case goes down 4' or so but the top is only 6" above grade and it would be hard to regrade the area to not have the straps partially buried. In the past I have had the contractors drill 24" or so into the stemwalls to try to develop the strength of the rebar but I am not sure how effective that really is and the contractors have not liked doing it.

RE: Post-installed anchors in stemwall

Yeah, I've used galvanized steel at least 1/4" thick and reconstituted the building envelope around it where it was there to begin with.

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: Post-installed anchors in stemwall

In our area, most stemwalls are 4" brick/4" CMU for residential. Try working with that! I usually have them take off a face and epoxy the rod into the footing and then notch the CMU back over the rod.

RE: Post-installed anchors in stemwall

(OP)
Wow, XR250, that sounds less fun.

RE: Post-installed anchors in stemwall

I've used laser-cut decorative steel plates thru-bolted which worked well and looked classy. Use thick steel and it will last (but leave rust stains).

RE: Post-installed anchors in stemwall

There's new documents and testing from HILTI that allows the use of ACI Ch 12 development length equations for reinforcement bars. This document has a lot of information on the theory and testing, including design examples.
http://submittals.us.hilti.com/PIR_Guide/files/ass...

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