×
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

Rock foundation wall supporting concrete foundation wall repair

Rock foundation wall supporting concrete foundation wall repair

Rock foundation wall supporting concrete foundation wall repair

(OP)
A friend of mine wanted to know my opinion on a foundation failure he has on a property he recently bought. The structure is a 1880's era barn (was listed as the poor house on old tax maps) but is in amazing condition. Beautiful post and timber construction, no major sag in the roof, great example of the longevity of these kinds of buildings when maintained.

Unfortunately, we had a bad winter in New England last year and one of the foundation walls is blowing in. The foundation consists of a rock wall foundation with a more modern poured concrete wall on top. There's soil on the exterior of the wall plus a removed tree. The location is difficult to get to from the outside and right next to the property line. Excavating likely would require hand tools and a lot of labor, not the best option if it can be avoided.

Here's some pictures of the foundation showing the failure:
http://files.engineering.com/download.aspx?folder=63d344ca-5160-445f-8988-fd3a28fae51c&file=Rock_Wall_Foundation_Failure.pdf

What are your guys and gals thoughts on restraining this motion? So far the structure hasn't settled but obviously this wall is about to loose all of it's bearing capacity (if it hasn't already).

There is a poured concrete slab in the building and one of our thoughts was to erect a thrust block of sorts and put some steel channels and wood on the rock wall and use a hydraulic jack to push the foundation back to plumb. Once we get the wall back to plumb we could pour concrete into the existing rock wall to help resist any future motion. Another option would be to find any gaps in the wall and use a torpedo-style, wire rope soil anchor back to steel channels with some threaded rod and nuts. By slowly tightening the nuts we could pull the wall back to plumb and also provide additional restraint. Another idea would be to pour a concrete counterfort wall against the existing wall as deflected just to restraint further motion but neither of us like this for both structural and aesthetic reasons.

Thoughts?

Maine Professional and Structural Engineer
American Concrete Industries
www.americanconcrete.com

RE: Rock foundation wall supporting concrete foundation wall repair

Are you saying the wall pushed in from ice lenses forming in the soil? My understanding of ice lenses is that they push vertically, not horizontally. Are we sure the wall wasn't pushed in from removing the nearby tree?

RE: Rock foundation wall supporting concrete foundation wall repair

(OP)
I assumed more moisture pressure and frost heaves causing the soil to shift. The tree was cut and the stump remains but perhaps that contributed.

Maine Professional and Structural Engineer
American Concrete Industries
www.americanconcrete.com

RE: Rock foundation wall supporting concrete foundation wall repair

I'd contact a pressure grouting firm. Chances are with a temporary wall on the inside that it would be possible to inject grout into the stone system to secure it in place. There are other possible ways to work from the inside that these grouting experts can offer.

As to frost heave, yes it goes in the direction of least resistance, many times pushing walls in.

RE: Rock foundation wall supporting concrete foundation wall repair

Ice lenses, by definition, cause vertical uplift. To me, it seems that the ground was overly saturated and froze, which is different. Maybe a warm spell that caused all the snow to melt followed by a cold spell. What I'm getting at is there may be a drainage issue at this wall.

RE: Rock foundation wall supporting concrete foundation wall repair

(OP)
That wouldn't surprise me Jerehmy given the age of the structure and the presence of the tree. I believe my friend is going to look into soil drainage improvements but for now we're mostly concerned with the structure.

Maine Professional and Structural Engineer
American Concrete Industries
www.americanconcrete.com

RE: Rock foundation wall supporting concrete foundation wall repair

Jerehmy:

To provide you with some info on horizontal frost heave I did a Google search for "horizontal frost heave"

Some of the results are:

http://www.sciencedirect.com/science/article/pii/0...

One of the referenced that came up has a lot of info. In this second one look into the text that shows up with key words highlighted.

Ground Freezing 1980: Selected Papers from the Second ...
https://books.google.com/books?isbn=0444600590

Once you see evidence of horizontal frost heaving, you will be convinced, as I have been.

It just happens that most experiences people have are not where there is a vertical feature that shows the effect.

RE: Rock foundation wall supporting concrete foundation wall repair

I would not try pushing it back, just stabilize it where it is. Given it is near a corner and you have that concrete cap I think you can get away with leaving the stone as-is and stabilizing it. Vertical strongbacks or a concrete sister wall would do the trick. Fix the drainage and get rid of the old stump as well.

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