In a message dated 4/20/04 12:41:21 PM Pacific Daylight Time, K8fu@aol.com
writes:
> I'm hoping to erect a Hy-Gain 52SS 52' self supporting twr this Spring. The
> twr utilizes a base mounting plate with 12 holes pre-drilled for bolts to
be
> set in concrete.
> My questions are to the length of the bolts to be set in the concrete to
> provide adequate support, the necessary grade of steel for the bolts, any
> special
> hints to ensure the maximum cohesion between the bolts and concrete. and
the
> grade of concrete needed. I am also curious as to whether fiber mesh
> concrete adds significant strength to the mix.
Umm, sufficient strength is determined by the factory specs or PE calcs.
I've never seen fiber mesh in a tower base spec.
The bolts are nothing special. The bolt material spec is for a common
grade of steel; it's basically the same material as allthread stock in your
local
hardware store. Just get something big enough to fit the holes in your base
fixture and you'll be okay.
As far as the length goes, I think that 24 inches is way plenty. After
that any additional length doesn't do anything. There's an engineering term for
this but not being an engineer I don't remember what it is.
Here's a simple way to get the anchor bolts in the concrete. Install the
anchor bolts securely to the base fixture. Take the fixture with the bolts
sticking out to your local welder and have him tack weld some rebar or other
material he might have laying around to the bolts at the bottom of the bolts
and
somewhere farther up but a place where the welded bracing would be buried in
the concrete. After welding, unbolt the rods and you've got a nifty little
fixture that'll be easy to handle, put in the hole and guaranteed to line up
with
the holes on the base fixture when you're done!
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for commercial and amateur
888-833-3104
_______________________________________________
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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