[TowerTalk] Tower base advise

[Jim Jarvis]

Greg wrote:

Not sure if I over did this or not.  <snip>
The specs only call for a 4x4x8 hole.  <snip>(summarize, we did 6.5x6.5x7.5)

I hope to schedule the concrete pour for this week.  4000 psi and gonna have
it poured pretty wet.  Do I need to get one of those vibrating things or is
pouring it wet sufficient?

Thanks
Greg


Greg:

I am not a mechanical engineer.  They measure the strength of the pour by
the "slump" of the concrete.  The drier it is, the stronger it sets up.
(and the longer it takes to come to strength)

Concrete companies may not see this as important, and will cut corners for
easy delivery.  You should be very specific with your vendor...place the
order for 4000psi concrete...and ask how you verify that's what you get.
If you get a half-baked answer back, you'll probably get whatever happens
to be on the truck.  Ask what they do when they pour concrete basement
walls for houses.  I think that's 4000psi stuff.

Was the base design overkill to begin with...and you've upgraded it further?
Was the concrete spec overkill to begin with...and doesn't merit worry?
I would contact the tower manufacturer and be guided by their advice.

My guess is you'll be fine with what you've done, and with whatever
they're pouring that day.  I WOULD vibrate it to settle out the air.
If it were my tower, though, I wouldn't be satisfied with my guesses.
I'd get professional advice.

Sparing you the stories, I WILL observe that on two different directional AM
station systems I worked on, the mechanical engineer REJECTED half the
delivered
concrete as having too low a slump, and inherently too weak.