willshak wrote:

On 12/29/2004 11:07 AM US(ET), took fingers to
keys, and typed the following:

I have an 8 foot gate which opens in the middle. Each gate has a bent
bar toward the bottom that is put in a hole in the ground to help keep
the gate closed. Recently I had concrete poured in the area and they
covered the holes. I want to drill holes into the slab so I can use
the bars again. I am concerned that water will get into the holes,
freeze, and crack the slab. Is this a valid concern? If yes, what can
I do to reduce this risk?
TIA
Jody

Drill the holes deep enough so that they penetrate the full depth of the
concrete (4"?) and drain into the stone or ground beneath.
Another suggestion is to drill the holes wide enough to be able to
insert a short piece of steel pipe into the hole. Any ice will have to
expand the pipe before cracking the concrete. Another advantage is that
the steel bar won't be banging against the concrete sides of the hole
when the wind is blowing.

--
Bill

Suggestion (a) is possible, but more likely to lead to a formation of
cavity under the slab near the holes if there is a slope and used much
sand...I don't think I personally like that idea too much...

If one were to put the pipe in the hole, I'd recommend using a sealant
around the outer edge and have it shorter than the hole depth by a
little bit in order to minimize the freeze-thaw around the outer edge
and the concrete...

We've got a couple of these in shed driveway areas that have been just a
hole that have been there since the barn was built in 1918 and they've
not expanded greatly in that time w/ KS winters and being in a corral
for the first 50 years of that time before we moved the corrals away
from the barn. Since the hole is open on the top the water column
simply rises rather than being trapped in narrow cracks such as a wall.
On occasion one has to shake the shed door a couple of times to pull the
pin, but normally there's not sufficient thickness to make pulling it
hard...