richard,
your setup is totally different from mine but im gonna add in my
info........1) 25g 90ft 1) 25g 130ft 1)55g 150ft (only 45ft in air for all 3 so
far)......i am using an elevated guy system at 9 anchor points ( on each tower)
so when im on the tractor i can avoid guy wires.......i used 8" seamless pipe
with 1/2" wall thickness that are 10ft in length.......i have 4ft of the pipe
set in a 36" bore hole with concrete filled to ground level. i took 1/2x6" flat
plate and cut 18" in length, on 1 end i drilled 3 holes for 3 sets of guys and
on the 25g and 4 holes for the 55g for 4 sets of guys. i slotted the top of the
pipe so the plate would sit at the average angle of the guys and welded 4 edges
with 5/8' fillet welds. on the back edge i drilled 1 hole just in case i later
want to back guy the post.....i made the elevated guy posts really heavy duty
because im not an engineer. i had planned on filling the pipe with concrete but
later decided not to and just welded a cap on. sorry i dont have a pic to send
to you but when i go home on vacation i can send you one if you
want.......................
9 years ago i did an elevated guy at my other house in town and i used 6"x1/4
wall welded pipe on a 60ft 25g tower.......welded pipe is not very structually
sound but seamless pipe is.
there are a lot of stresses put on guy wires that directly affect the anchors.
you can use trig to figure out the amount of force applied to 1 guy
wire,,,,,,,,,,, sine=o/h.......cosine=a/h........tangent=o/h opposite,
adjacent, hypotenuse............. just substitute in the expected force in your
pathegream therom........... a squared + b squared = c squared to find the
vertical, horizontal & diagonal force applied to the guy wire then just plug in
the numbers and will give you pretty close to the forces you need to plan for.
.......i over planned......
i dont have all my notes with me or i would give you more info on my
setup..........i do know there are several threads on here dealing with mast
sizes and materials and you can apply the same rules to elevated guy anchor
points.......most masts if they are 1020 DOM or 4120/4130/4140 crome molybdium
steel are only 1/4 inch wall thickness and just support an antenna or a few
have tremendous forces just from the boom & elements.......so in guy wires you
have to add in the surface areas of the tower sections and rotor.......so im
really lazy and just over engineered it
i have seen a commercial tower site that used I beam (some call it H beam) and
was a really nice setup as well but i got a good deal on the high pressure pipe
remember rohn 25g guy wires are 3/16 with a preload of #400 pounds which is
1/10 (10%) of their anticipated breaking strength........myltiply 400 pounds
times 4foot of pipe sticking out of the ground and it is 1600 pounds of stress
at the base where the pipe is in the ground.........just something to think
about.
i know there are many more hams that are engineers and know 1000x more about
the forces and equations than i do but just giving you my thoughts on your
plans.
sgtokie@aol.com
Who’s yer Baghdaddy !
Karrada district
Baghdad, Iraq
David Howard دايفيد
-----Original Message-----
From: towertalk-request <towertalk-request@contesting.com>
To: towertalk <towertalk@contesting.com>
Sent: Sat, Oct 29, 2011 11:48 am
Subject: TowerTalk Digest, Vol 106, Issue 67
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Message: 7
ate: Sat, 29 Oct 2011 11:09:33 -0500
rom: Richard <yvadir@gmail.com>
ubject: [TowerTalk] pipe anchors
o: towertalk@contesting.com
essage-ID: <4EAC253D.9030905@gmail.com>
ontent-Type: text/plain; charset=ISO-8859-1; format=flowed
I live on a small city lot and am in the process of installing a 40 ft
ohn 25G tower in my back yard with a pier pin base. I'd really like to
void using screw in anchors in such close quarters and would prefer to
se an elevated guy anchor like pipe set in cement. I originally thought
hat 11 ft would be great to clear my roof line but have been told that
ould require a pipe larger than what I can obtain around here. Revising
y plans a 4 ft high pipe in the corners of the back yard would still be
etter than going to ground level. Can anyone give me an approximate
dea as to what size pipe and what size base might be needed?
My tower is 40 ft, I would have at most 12 lbs of wind load on it, my
oil is a pretty heavy clay with no sand and no rock at least down to 4
t., our wind zone is said to be 70 MPH. Any input would be greatly
ppreciated.
73
Richard / N5YPJ
-----------------------------
Message: 8
ate: Sat, 29 Oct 2011 12:48:00 -0400 (EDT)
rom: Cqtestk4xs@aol.com
ubject: Re: [TowerTalk] pipe anchors
o: TOWERTALK@contesting.com
essage-ID: <1632c.8a0ccf9.3bdd8840@aol.com>
ontent-Type: text/plain; charset="US-ASCII"
My GUESS would be that 4" galvanized pipe would work. I would sink it
bout four feet in a base about 3 x 3 x 1.5 feet of concrete. That would be
n a hole 3 x 3 x 4 so you would only fill the hole up 18 inches with
oncrete and back fill the rest with the dirt from the hole. if it was in my
ackyard, I would sleep well at night with the set up. You might be able to
et by with less, but do you really want to try. Towers make a big boom
hen they come down.
he three anchor bases would need a total of 1.5 yards and your base for
he Rohn 25 will need another yard or so. If your concrete company has a 5
ard minimum (many do) simply pour the rest into the three anchor holes.
hey will never go anywhere...for sure.
s an extra you might want to dump concrete down the pipe...stops the pipe
rom filling with water and adds some strength. If you do I would order
he mud with small agregate for easier pouring.
ill KH7XS/K4XS
n a message dated 10/29/2011 4:09:54 P.M. Greenwich Standard Time,
vadir@gmail.com writes:
I live on a small city lot and am in the process of installing a 40 ft
ohn 25G tower in my back yard with a pier pin base. I'd really like to
void using screw in anchors in such close quarters and would prefer to
se an elevated guy anchor like pipe set in cement. I originally thought
hat 11 ft would be great to clear my roof line but have been told that
ould require a pipe larger than what I can obtain around here. Revising
y plans a 4 ft high pipe in the corners of the back yard would still be
etter than going to ground level. Can anyone give me an approximate
dea as to what size pipe and what size base might be needed?
My tower is 40 ft, I would have at most 12 lbs of wind load on it, my
oil is a pretty heavy clay with no sand and no rock at least down to 4
t., our wind zone is said to be 70 MPH. Any input would be greatly
ppreciated.
73
Richard / N5YPJ
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