Thank you Pete. I thought of that, unfortunately the rock is brittle shale,
and will break very readily.
What I was looking at doing, was using large anchor bolts in the existing
slab (at least 19 cubic feet of concrete!), and attach to tower in place,
attaching the tower to the house.
My tower loading will be substantially less. It will be a M2 9WL 432 beam
(20' boom); Modified Cushcraft 505S with 18' boom; a modified 15' Cushcraft
215WB, and possibly a Cushcraft A3S. This would be on a 10-12 AISI 4340
mast (probably heat treated to 150 ksi). Based on my calculations, it looks
like it will work. But I wanted a reality check.
My background is PhD Metallurgical Engineering, with strong structural
analysis. I was planning to have it looked at by a PE to double check me
(nice having relatives with PEs - they always kid me about not being a REAL
Scott AKA KBOFHP
From: HFDXJUNKIE@aol.com [mailto:HFDXJUNKIE@aol.com]
Sent: Saturday, January 28, 2006 7:38 PM
Subject: Re: [TowerTalk] MA-55 Tower and Foundation
I would think the j-bolts or straight ones need to be anchored in at least
the 27 inch size they sell the tower with. I am not sure what you have
planned, but if its solid bedrock type of rock, I would drill into the rock
and epoxy the bolt studs right in, maybe making a 3x3 x whatever base. That
would surely work. I have a few towers and one is a MA-55 with rotating
base. I have stacked 6 element, 6 meter antennas with...... a 2 meter 20
ft boom in the middle of the stack. Even with the tower cranked all the way
down, I am still not used to seeing that baby rock back and forth ! When its
up and it gets a little windy, I don't even look at it anymore, kinda makes
me want to lower it in 5 mph winds !.
73 Pete NA2P
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