[TowerTalk] Need Foundation Opinion

[ROBKEL@aol.com]

Hi
I have a Heights tower installation which has been in place for over 30 yrs
with no problems. The tower is 56' aluminum, with a 'rating' of 14 ft^2. The
base is the 26" sections (24.5 inch c-t-c), mounted to (3) 4140 1" anchor
bolts. My concern is that I sized the base at the time (30 yrs ago) for the
minimum foundation size of abt 4 cu yds (4.5x4.5x5.5 ft). I now want to
increase the height and loading by replacing the tower itself with a higher
rated unit. All well and good, but I am not sure the foundation or the bolts
for that matter can handle it. The bolts are well aged (rust) and the amount
of concrete is on the light side. 
I calculate the OTM for the base to be about 30,000 ft-lbs before the ground
resistance is considered. (We have heavy clay soil here in Dallas). I want to
load it with about 60,000 or more. 
I seek opinions as to advisability of going with it as is, or "overbuilding'
it with a larger base and wider spaced anchors.

Thanks for any input.

Bob, W5LT

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