[TowerTalk] Tower base concrete work
spelunk.sueno at prodigy.net
Tue May 6 12:30:15 EDT 2003
I, too, was a novice at installing self-supporting towers when I built
my Trylon in 2001. I had helped a couple of friends construct guyed Rohns
years ago, though. Plus I had worked as a brick mason's helper in college.
So I learned a little from those experiences. Even still, I was
apprehensive when I decided to go for the Trylon at my QTH.
I suppose there are two important things about your project: make sure
everything is straight, true, level, plumb, etc. and then make sure nothing
moves while the concrete is being poured. My back yard has a bit of a slope
to it, like yours, and so I had to build up the framing for the concrete cap
about ten inches on the downhill side. I constructed the cap's double-wall
frame out of 2X6 and 2X10 lumber and held it in place with several short
pieces of rebar pounded into the ground like tent stakes. Then I packed
dirt around the outside of the form to add more bracing to the cap and to
act as a dam against concrete leakage. (Anal, I know. But I expected to
have about a ton of concrete - half a yard - in the above-ground cap.) I
also added three 2X6's as additional props held in place by three more
rebar pieces on the downhill side of the cap. This entire frame served as a
very stable platform for my T500-64 tower's bottom section.
When the concrete truck arrived, the driver was able to pull right
along side of the excavation and dump. I had a neighbor's kid help vibrate
the concrete as it was being poured. (I'd rented an electric concrete
vibrator for the day.) The top of the pour is not very pretty! I never did
get a chance to finish off any masonry work I did back in college, so the
tower base's cap is a bumpy mess. But I did manage to form three small
hills around the three legs to help keep water away from the legs. Because
you'll be using leveling screws for your tower, you won't have this drainage
worry. However, I believe it is suggested (by others on TowerTalk) that you
should pack the area underneath the base plate with grout of some kind.
Another inquiry to the reflector will give you the answer here. Also, make
sure you use a template of some kind (plywood is ok) to keep the anchor
bolts in position during the pour and curing.
To help with all this my advice is, if you don't have the proper tools,
BUY 'EM! I bought a four-foot mason's level, a finishing trowel, a 10 inch
by 10 inch tamper (to help level the bottom of the tower excavation), a
digging bar, short pieces of rebar, good lumber for the cap frame (over $100
as I recall - don't tell my YF!), large box-end, open-end and spanner
wrenches (for the large tower bolts), etc., etc., etc. I doubt I'll need any
of this stuff for quite a while. But it made the job easier for me.
Lastly, use this reflector as a resource during the entire project. I
learned quite a bit from the denizons here and am quite happy with the way
my Trylon project turned out as a result.
GL es 73 de
Gene Smar AD3F
From: David Greer <davidgreer73 at yahoo.com>
To: towertalk at contesting.com <towertalk at contesting.com>
Date: Tuesday, May 06, 2003 10:53 AM
Subject: [TowerTalk] Tower base concrete work
>I am ready to install a new U.S. Tower TX-455 55-foot
>free-standing tower. I previously had one of their
>towers, the TX-438, but had help with the concrete
>work from the dad of my daughter's boyfriend. The dad
>builds convenience stores for a living and has had
>much experience in concrete work in installing large
>signs, canopies over gas pumps, etc. Compared to
>those, he said, the concrete base for the tower was
>Well, I have moved a bunch of miles from there, the
>daughter doesn't have the same boyfriend anymore, etc.
>So, Sam, the concrete man, isn't available. Can an
>almost concrete-work novice (me) expect success in
>pouring the base and doing the finishing work of
>getting it all level, etc. for the T-base? Anything to
>watch for in particular?
>I will buy a dense grade mixture of concrete, as per
>Sam's advice the first time, and have it delivered.
>The installation site is on a slight incline so I have
>to build the concrete form to compensate.
>I have studied several web sites showing tower
>installations. K4ZZR's site is particularly good. But,
>as he says on his site, any mistake is one you have to
>live with forever when it involves 4 cubic yards of
>concrete. Obviously, the leveling nuts under the
>T-base can make up for some imperfection in how level
>one gets the top of the base once poured. How much
>compensation can those nuts provide?
>Any observations, words of wisdom, advice, etc. will
>73, Dave, N4KZ
>Do you Yahoo!?
>The New Yahoo! Search - Faster. Easier. Bingo.
>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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