In a message dated 97-11-19 11:08:29 EST, firstname.lastname@example.org writes:
> I did precisely this for my self supporting tower base. The problem is,
> the act of pouring the concrete twisted and turned my anchor bolts in
> ways that I could not perfectly correct. Now that the concrete has
> cured, the bolts are slightly off. Big pain.
> If I had it to do over again, I would pour first and then set the entire
> template/anchor bolt assembly down into the wet concrete. (How
> exactly I would avoid the rebar cage I am not sure. Perhaps by making
> precise markings of where it was?).
I've used a flat wood template before with some success. For small
footings, it's acceptable. But if you're dealing with a big footprint, I
would not use it. The problem is that you may not be able to get the concrete
to flow completely under it and with a big piece of plywood you won't be able
to see if you have any voids.
A better way to do it is to tack weld the J-bolts into position with
rebar or some peices of steel. Then you have minimized or eliminated any
potential problems with the anchor bolts shifting and concrete voids.
I don't think you'll be able to push the base fixture into the concrete
after it's been poured. The concrete is pretty dense and even doing it right
away when the concrete is as wet as it'll get is pretty difficult. Don't
forget you'll have to stand IN the concrete to do it while horsing the
fixture around as well. It doesn't sound very feasible.
You really need to have everything installed and plumbed before the
concrete arrives. It's a lot of work even then but it will give you a much
better chance of success. This is one job that you don't want to have to
re-do. (Now THAT'S a pain!)
73, Steve K7LXC
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com