On 4/17/2011 1:17 PM, Arthur Bernstein wrote:
> Hello to all,
> I have a Hy Gain HG-52 SS 52 foot crankup. It's been up for a number of
> years. The concrete base is as per specs. 42" on a side and about 5'6" deep
> with about 6 more inches of concrete above the ground.
There are still a few unknowns so please pardon the many weasel words.
Also, I can only deal in generalities.
"I think" one of the important things would be to determine *why* the
base has shifted and not just assume it has settled and if it did
settle, why. If the "Why" isn't fixed it's unlikely any fix will be
This is a *relatively* small base, although when trying to reposition
it, the thing may seem huge.
There are a number of ways it can be re leveled, or even replaced and
most have been mentioned.
It may depend on your zoning. Here it wouldn't.
You can hire a contractor and let them worry about it...(It's only
You can get a soil analysis which most of us wouldn't. For a small tower
and base most can usually get a good idea as to what is needed, BUT the
simplest things are often overlooked. Larger towers and particularly
self supporting ones require much more care.
You can in typical ham fashion tackle it your self, which is what I'm
assuming you plan and most of us would do.
Typically a chunk of concrete that size with that small a load would not
settle unevenly *unless* it was poured at the junction of undisturbed
soil and back fill. IE most homes have about a 3 to 4' wide sand back
fill around the foundation/basement. With a 5' deep base a normal
foundation without a basement should not cause settling. OTOH That area
should be avoided although very small bases will usually survive nicely
in the sand.
Two other problems are soil shifting when on an uneven slope (which you
have not mentioned) and the freeze thaw cycle.
As you say your back yard is not large, I'm going to make an assumption
that the tower base is located relatively close to the foundation (you
said "near"). I made the remark above that settling unevenly is unlikely
(or rare), BUT for foundations like this that are poured close to a home
foundation or basement, "heaving" due to frost and uneven freezing is
quite common even when the concrete extends well below the frost line if
the inside of the foundation/basement wall stays well above freezing.
Fortunately in this case the process has been slow. However IF the
problem is due to the freeze thaw cycle, it is unlikely you will be able
to do more than re-level with the inevitable shift continuing on unless
you move the entire base farther from the foundation.
If I didn't slip up, I come up with just shy of 2.5 yards of concrtete.
At an average of 3300# per cubic yard for commercial concrete this would
weight approximately 8200#. (concrete runs from 2000# to about 3500#
per cubic yard. 2000# would be a pretty poor mix) 8200# is not beyond
the realm of moving if need be although it would take some skill and a
fair amount of digging and a wrecker or some good rigging.
I have a 8' X 8' generator shed behind my garage. The shed is
constructed on 6' 4X4 pilings set in concrete that extend about 5'
deep. Each concrete section is about a foot larger in diameter on the
bottom than at the top. The garage is unheated, BUT the contractor
poured the large concrete apron with very small expansion joints which
are non existent is some areas. In the spring the NE "man door" will not
open as that corner of the garage is forced up and to the west. This
puts pressure on the entire garage floor and even the West foundation.
The shed is about 6 feet from that foundation and directly behind the
section of floor that moves the most. Whether that actually has any
effect on the shed I don't know, but about 3 years after we built the
shed, the West side of it appeared to start raising...or the East side
was sinking. In two years the West side was a good 10 inches higher than
the East. That's a pretty steep slope. I finally ended up cutting about
14" off the piling on the NW corner and lesser amounts to the South on
the West side. It has apparently reached equilibrium with no more
movement in the last two years.
This shed is no where near a temperature gradient that I would expect to
have any effect, yet the major movement had to be related to the freeze
thaw cycle even though the pilings were properly shaped and extended
well below the frost line.
> The problem is the tower is leaning due to the apparent settling of the
> concrete base on one side. The base is near the rear of my house and is
> leaning away from the house.
This is the wrong direction from what I'd expect from settling near a
house, but it is in line with what I'd expect from a freeze thaw cycle.
OTOH the base could sink with the bottom moving toward the house
foundation if it has a sand back fill around a basement. This would
likely be obvious when looking at the edge of the concrete away from the
In either of these cases I would think the prognosis is not good for
just re leveling.
One other question comes to mind. Is the tower tilting toward or away
from the water?
> For those not familiar with this tower and its
> base, it uses 3 "dog ear" type mounts that are attached to a rebar cage
> imbedded in the concrete. Each of the "ears" has two holes that are mated to
> the similar dog ears on the bottom of the tower. The base is very similar to
> the Tri Ex bases, such as for the W-51.
> A few years ago, a friend re plumbed the tower by redrilling some of the
> holes in the dog ears and welding new nuts onto it, thus making the tower
> vertical. It seems that the ground behind my home is not as stable as I had
> thought, over 20 years ago (unfortunately.) We have run out of room on the
> dog ears to redrill to plumb the tower.
> Any suggestions? My rear yard is not that large, so abandoning the base and
> putting in a new one is really not an option.
> Any help would be appreciated. Thanks.
> Art., N2KA
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