Hi Don, and all,
I live in Florida and once had a bridge and connecting seawall adjacent to
my property replaced.The new seawall connected to mine, so I watched the
pour right next to my dock with interest.
They brought in an excavator, dropped sheet steep forms on the water side
of the new seawall and used the excavator and removed the old seawall and
several yards of muck. Water never drained - they built a plywood form into
the water on the land side of the seawall and steel sheets on the water
side, all the way up to a piling on the bridge. A long steel rebar cage
with a coating (zinc chromate? Yellow) was placed into the trough.
The pour was supervised directly by the project engineer. He examined
everly load with a slurry test and the chute from 3 trucks full of
readymix was poured into a placement box, a 12" plywood square tube about
6' long reinforced with steel straps every foot or so. It fit perfectly
between the rebar. A worker stood on the form and filled the tube so that
it placed the concrete into the bottom of the pour without mixing with sea
water and picked it up and moved down the rebar squares, got to the end and
started back. There were four courses, so it appears they placed 2 feet per
vertical course. The final course was above water and was poured directly
and finished.
So concrete is placed directly into water - into sea water even - and lasts
for decades.
As everyone has said, find yourself a good engineer who knows how to design
and pour footings in your local geology. It will be good money spent!
Mickey Baker, N4MB
Palm Beach Gardens, FL
*“The servant-leader is servant first… It begins with the natural feeling
that one wants to serve, to serve first. Then conscious choice brings one
to aspire to lead." Robert K. Greenleaf*
On Wed, May 27, 2020 at 6:44 PM Don Solberg <dsolberg8132@gmail.com> wrote:
> I was planning on purchasing a used US Tower HDX-572, 72 ft crank up
> tower. It looks like I may have run into a problem with the foundation. I
> had some trenching done today for a new well and discovered that the ground
> water level is just slightly lower than 6ft. US Tower specifications call
> from a 7.5 foot deep hole. My soil is mostly sand, so in addition to not
> being able to go down 7.5 ft, I probably also want to make the foundation
> wider.
>
> Is it practical to put up the 72ft tower with a wider pad, or should I look
> at getting a smaller 55ft tower? Another alternative is find another
> location for the tower. I have about a 10 ft hill on another property that
> I own across a gravel road. This would most likely eliminate the ground
> water problem but I would have about a 300 ft cable run and I would have to
> trench across the town's gravel road.
>
> I am looking for recommendations.
>
> 73,
>
> Don K9AQ
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