Bob,
Not a Civil Engineer by any stretch of the imagination but one of the
reasons for not having the rebar breach the concrete is rust. That exposed
end will make a super-highway for rust and assuming there is a path,
eventually there will be no more rebar in your concrete. Instead there will
be nice 1/2 inch paths with nothing but air - or worse - moisture in them.
No idea where or when I read it but seem to recall the proper method is to
put something like paving stones of the appropriate size under the rebar
such that, when the concrete is poured, the paving stones keep the rebar
waway from the surrounding earth and themselves become sealed in the
concrete.
Mike / W8DN
----- Original Message -----
From: "Bob Gates" <regates@kingwoodcable.com>
To: "Tower Talk" <towertalk@contesting.com>
Sent: Sunday, August 10, 2003 4:11 PM
Subject: [TowerTalk] Rebar cage for tower footing
> I've noted the UST footing design for most/all their towers, and they
specify a
> rebar cage with the vertical pieces set approximately 3" above the bottom
of the
> footing. This is obviously a clumsy undertaking in the real world,
because it
> would entail pouring 3" of concrete in the hole, let it set up, insert the
cage
> and continue the pour. After 30 years in the construction business, I've
seen a
> few footings poured, and many were designed by engineers who never had to
> actually install their designs, such as spread footings which are
extremely
> labor intensive, and for no reason. To make a long question short, any
civil
> engineers out there who see a problem with the rebar cage sitting on the
dirt
> floor of the hole and pouring around it?
>
> Regards,
> Bob KG7KW
> _______________________________________________
>
> 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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