Your way would work also. In fact, the top "mat" could be worked in after to
pour or at a pause in the pour. That way, you have no obstructions in the way
to work the concrete into corners, etc.
73 de Perry - K4PWO
Sent on the Sprint® Now Network from my BlackBerry®
-----Original Message-----
From: "Gary \"Joe\" Mayfield" <gary_mayfield@hotmail.com>
Sender: towertalk-bounces@contesting.com
Date: Fri, 17 Sep 2010 00:17:27
To: 'Tower and HF antenna construction topics.'<towertalk@contesting.com>
Subject: Re: [TowerTalk] Newbee concrete rebar questions
Would you want to do this (vertical rebar) if it is not in the prime
directive? My simple mind would say if some rebar is good, more rebar is
better...... Is that really true, or should I do what the manufacturer
says?
Rohn, HDBX tower drawings do not show any vertical rebar, nor do the specs
call for it. In fact they claim you can use wire mesh instead of rebar if
the surface area is the same. I just figured the tower bolts were the
vertical component.
Correct me if I am wrong, but I thought when you put the concrete in, the
top 'mat' of rebar could be suspended with wires, and then the wires could
be removed as the concrete level reaches the appropriate height. I do not
think the rebar will work its way down through the concrete.
73,
Joe kk0sd
P.S. We'll see what everyone else says as I am wrong a lot!
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Scott Reed
Sent: Thursday, September 16, 2010 3:30 PM
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Newbee concrete rebar questions
I don't do towers on a regular basis, nor concrete, but from what I
have done, I have never seen a foundation specified with no vertical
rebar members. Stand the vertical members on the ground and as Perry
says tie them to the horizontal memebers. The place you get the rebar
should have "tie wire" as well. For the most part you wrap it
diagonally around the joint and twist it so it holds the horizontal
members where you want them.
On 9/16/2010 3:53 PM, Perry - K4PWO wrote:
> Even though not "specified", you can add vertical rebar to form a true
> "cage". Then you just support the rebar off the bottom of the hole. You
> would probably want at least one diagonal on each side to prevent
"racking"
> of the cage if you "tie" it together. A "X" would work even better.
> I had a basic welded "skeleton" of a "cube" built out of rebar and then
tied
> in the additional horizontal rebars at the bottom and top.
>
> 73 de Perry - K4PWO
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Dick Dievendorff
> Sent: Thursday, September 16, 2010 2:28 PM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Newbee concrete rebar questions
>
> I have never personally installed rebar.
>
>
>
> My tower and guy anchor foundation drawings specify a "mat" of #5 (5/8")
> rebar , 5 rods each way, top& bottom, just below the top surface and just
> above the bottom surface of the concrete block.
>
>
>
> I know to suspend the bottom mat at least 3" above the bottom of the hole
> with little concrete blocks so that the bottom rebar mat ends up 3" above
> the bottom of the concrete so that it is adequately covered.
>
>
>
> I also need to suspend a top 5 x 5 mat about 1-1/2" to 2" below the top
> surface of the concrete block. If it were going to be later protected
from
> the elements, I'd be able to suspend it with wires from the wooden form
and
> cut the wires flush with the foundation after the concrete sets. But since
> this tower foundation is going to be exposed to the elements, I'm worried
> that even if I cut the wire off flush, the wires themselves will become a
> conduit for corrosion to get to the embedded rebar.
>
>
>
> What techniques are used to support the top "mat" so that it ends up about
> 1-1/2" below the top finish surface?
>
>
>
> I found "high support chairs" in some literature, but the top mat is about
> 28 inches from the bottom of the hole, and the "chairs" don't seem to be
> that high.
>
>
>
> Maybe I can find some vertical plastic rods to tie the top mat to the
bottom
> mat and the plastic rods could stick out the bottom.
>
>
>
> I'm sure this is a well-understood fairly basic technique by those who do
> this. But I need to be educated.
>
>
>
> 73 de Dick, K6KR
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
--
Scott Reed
Owner
NewWays Networking, LLC
Wireless Networking
Network Design, Installation and Administration
Mikrotik Advanced Certified
www.nwwnet.net
(765) 855-1060
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|