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Re: [TowerTalk] Looking for some foundation advice

To: Jeff Blaine <KeepWalking188@ac0c.com>
Subject: Re: [TowerTalk] Looking for some foundation advice
From: Mickey Baker <fishflorida@gmail.com>
Date: Thu, 28 May 2020 09:49:23 -0400
List-post: <mailto:towertalk@contesting.com>
>> Inspection was required at my site and the inspectors wanted to see no
more than 1/2 inch of standing water.

A "wet hole" design by a PE will likely specify a compliance procedure that
will dictate the inspection that will satisfy the building inspector.

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 Thu, May 28, 2020 at 1:50 AM Jeff Blaine <KeepWalking188@ac0c.com> wrote:

> I don't think the water is an issue for the foundation, but I can say
> from personal experience it sure can be a headache with respect to
> INSPECTION if that's needed prior to the pour.
>
> Inspection was required at my site and the inspectors wanted to see no
> more than 1/2 inch of standing water.   And the rebar had to be in
> position when the guy came to inspect which was another headache.  I
> could not drop the cages into the holes because repeated rains would
> cause slight sidewall erosion and the nice initially square holes would
> round-out taking on a bowl shape. Hired two high school guys to square
> out the holes when it looked like things were drying up a bit, of course
> each time the hole got a bit bigger.
>
> There were 12 holes we wanted to pour and it took 3 months of waiting to
> find a time window where most of the holes were dry.  I think there were
> 3 of them that had to be pumped and one was at a point in the yard where
> it would fill up in a couple of hours. For that one I sunk a 5-gallon
> bucket into the bottom of the hole so the top was flush with the hole
> floor.  That would let the sump pump fit down through the rebar and into
> the bucket where it would keep the hole drained.  I ran the generator
> and pump until the inspector showed up.  Pulled the pump.  He looked at
> the hole and signed it off.
>
> Poured the 12 holes all in one day.  Each guy anchor ended up taking
> about a yard more concrete than Rohn spec - that increase from all the
> sidewall cleanup by the boys over the summer.  For sure those things are
> never going to fly out of the ground, no matter how big the tornado is
> that comes calling...
>
> If the county would have let me poor the holes with water in them, I
> could have had the project done months earlier!
>
> So my guess is that the water is not a issue with respect to the tower
> base, but it is going to provide some challenges in other areas.  Good
> luck!
>
> 73/jeff/ac0c
>
> alpha-charlie-zero-charlie
> www.ac0c.com
>
>
> On 5/28/20 12:36 AM, Mickey Baker wrote:
> > 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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