[TowerTalk] Erections (Tower)

[K7LXC at aol.com]

In a message dated 4/20/04 12:41:21 PM Pacific Daylight Time, K8fu at 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