Dick Green WC1M wrote:
> I've only done one tower base, but I agree with Bob and Steve.
>
> I hired a contractor to do the base for my UST MA-770MDP 72' tubular tower.
> As I recall, the spec called for a 3'x3'x6' hole. Despite using his smallest
> scoop, the guy on the excavator, who was quite experienced and a real artist
> with the machine (he had done a lot of work on our house remodeling and
> driveway overhaul) was not able to dig a perfectly square hole. It ended up
> sort of pyramid shape. The guy dug the hole too deep -- I think it was 9' --
> and had to refill the bottom with a couple of feet of gravel. I don't recall
> the exact measurements, but I think the top is something like 4'x4' or
> 4'x5'and the bottom is even wider -- perhaps as much as 5'x6'. And the hole
> is at least 7' deep. It should have taken 2-3 of yards of concrete to do the
> job, but they told me it took most of a truckload -- 9 yards, I think. I
> don't know if they were trying to churn the fee or if that was what it took,
> but as I'd made a fixed-price deal with the contractor on the base he had to
> eat the difference. He complained, but I held him to it -- after all, they
> missed the spec by a mile. Besides, his company made plenty on the house and
> driveway!
>
> Anyhow, there's no way that giant pyramid of concrete is going anywhere. The
> cable on the MA-770MDP will fail long before the pier moves.
>
> I also agree with whoever said these pad-pier base designs are rediculous. I
> looked at getting an AN-Wireless tower, which is otherwise a nice
> cost-effective solution for medium loads, and couldn't get past the base
> design. They seem to sell a lot of towers to amateurs, so they really should
> rethink the base. BTW, both the fixed Bertha and Big Bertha sold by Array
> Solutions use a square block type base. Those monsters have *huge* windload
> capacity. I don't have specs on the base, but judging from some pictures
> I've seen the fixed Bertha base is on the order of 6'x'6'x6'. Although I've
> stood on the base for NT1Y's Big Bertha (140' rotating pole that's something
> like 3 feet in diameter at the base) and *that's* a real chunk of concrete.
>
> 73, Dick WC1M
The specs for the "Big Bertha" poles are 85-150 sq ft. of load and the
base is 8'x8'x12' adjusted for soil conditions. About 28.5 yards of
concrete.
--
R. Kevin Stover ACØH
K2/100 #4684
Reclaim Your Inbox!
http://www.mozilla.org/products/thunderbird
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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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