Kent:
There are a couple of things folks do to keep the ends of rebar off the
dirt at the bottom of excavations. One is to purchase commercial blocks that
have tie wires built in. The name escapes me at the moment (gents?) You would
tie these to the bottoms of a couple/several bars on each side of the rebar
cage. The poured concrete envelopes these blocks and they become part of the
structure.
An alternative that I chose is simply to put regular bricks underneath a
couple/several of the bars and let the cage sit atop the bricks prior to the
pour. Here's a link to a photo of the bottom of my tower's hole:
http://tinyurl.com/logoxop . You might be able to see a couple of the
light-gray brick at the top of the photo. If you go this way, make sure that
the cage doesn't get pushed off the bricks when you pour the mix into the hole.
I managed to keep the cage motionless by tieing the top few bars to the wooden
form for the crown, which you can see in the photo. While the mix is being
poured you can cut these cage support wires off the rebar and pull them out
when the mix gets up to within a couple of inches of the wires. Don't wait
until all the concrete has been poured before you cut the wires. If you were
to do that, you'd end up with iron wires sticking out of the concrete. When
(not if) these wires corrode, you'll have a nice path into the top of the co
ncrete block for water to infiltrate and freeze/crack.
GL es 73 de
Gene Smar AD3F
On 12/16/14, Kent Olsen wrote:
I have never worked with rebar or concrete but it seem fairly strait
forward in building the cage and pouring the concrete. I have read the the
rebar cannot be with in 3" of the dirt or it will rust and fall apart. What
do you do in the bottom where the rebar sits on the dirt? Is this just a
sacrificial bit?
Thanks
73
Kent
K6DKO
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