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Re: Unreinforced foundation walls - Fix?

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Not in any particular order:

1) Knock a hole in the top two cores (outside) and fish in a bar, then grout the cell column solid (open the bottom core inside to verify bar position and grout fill). Do it every (choose your spacing) inches.

2) Use a small wide flange section (usu W4 to W8) and secure it to the slab or footing at the bottom, and to the floor system above. Repeat at specified intervals.  Attaching to the floor system can be tricky. I always hold the steel back a bit from the wall and NS grout the space.

3) Anchor plate in the yard attached to threaded rod through the wall and a wall plate. Turn the nut to pull the wall back into line and leave the whole thing in place as a permanent support. I've never used this, but there was an article in JLC a couple of months ago about a contractor doing this in the northeast.

4) Glue an FRP strip to the wall on the inside face. (No, I'm not kidding. Nor have I tried this) "The Reinforcer" by Walder Foundation Products is one such beast.


At 08:47 AM 2/2/2005 -0800, you wrote:

Several have recommended fixing the larger size cracks.  I am curious as to what type of system and material you recommend for the fix (i.e. a solid type grout or a flexible mastic?).  Since the cores are hollow it would seem that only a surface/cosmetic type "fix" is possible.

Thomas Hunt, S.E.
ABS Consulting



"Jordan Truesdell, PE" <seaint(--nospam--at)truesdellengineering.com>

02/02/2005 08:36 AM
Please respond to
<seaint(--nospam--at)seaint.org>


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Subject
Re: Unreinforced foundation walls




At 09:42 AM 2/2/2005 -0600, you wrote:
>I've seen plenty of non-reinforced HCMU basement walls in Iowa and
>Illinois and virtually all of them have a chest-high crack, some opened more
>than others.  Realtors used to call me for a report on "sale-pending"
>basement wall cracks, but they finally figured out I always say repair is
>necessary; and they quit calling.
>      Another troubling thing about non-reinforced HCMU basement walls is
>that the first course was/is often not a full mortar bed.  The result is
>that if water appears on the basement floor in the northeast corner it may
>be entering the wall at the southwest corner, no way to know.
>      My rule is (and this may have come from a code or something else I
>read) all below-grade HCMU should be fully grouted, all cells.  I can live
>with that.
>John P. Riley


Show me an unreinforced HCMU basement wall, and I'll show you a crack.  I
won't design them, but I see them in real estate transactions regularly.
Instead of failing every one of them (most are 30 to 50 years old), I
usually let anything less than 3/16" go with a warning to verify grading
and drainage, and to monitor the crack on a regular basis. Bigger, and
we're looking at a fix.

What I've found more interesting is that the crack usually occurs one to
three courses _above_ the mid-height.  It's worth noting, as it means that
the wall is not in a pinned-pinned condition, as usually assumed in design
texts, but is fixed-pinned. Fixed-pinned has the maximum moment  occur at
(no surprise) about 0.55H above the fixed end.  If i were fixed-fixed (the
sill & floor) or pinned-pinned, you should be seeing the tension crack
about 1/3 or 2/5 from the bottom of he wall.  But now I'm just rambling....

Jordan



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