I can recall a commercial tower design firm (1,000 and 2,000 foot broadcast
towers) telling me that you never run a ground cable through a concrete base
or guy anchor. That the rebar cage is intended for strength not grounding.
That if you run a lightning strike through the foundation or guy anchor, the
concrete will crack if the lightning tries to exit the concrete looking for
real ground ground or from the heat of the lightning. Is this theory
incorrect?
Jerry, K6JRY
____________________________________________
-----Original Message-----
From: towertalk-admin@contesting.com
[mailto:towertalk-admin@contesting.com]On Behalf Of Red
Sent: Thursday, September 19, 2002 3:56 PM
To: FireBrick
Cc: Andrew Pfeiffer; towertalk@contesting.com
Subject: Re: [Towertalk] Rebar Cage
In addition, welding all joints helps the rebar distribute lightning
discharges through the concrete, making your base a "Ufer" ground, named
after the investigator who established its value. The welded cage
assembly can then be set into the hole and braced with 2X4, with wires
or ropes to pull them out as the concrete is poured.
73 de Red
FireBrick wrote:
>As a retired mason contractor, I can see where you are going.
>You want the verticals stable so you can easily wire the horizontals on
>while in the hold.
>Ideally, rebar should not extend through the concrete, rebar should not be
>within 4" of the concrete.
>This is to minimize moisture reaching the rebar and eventually rusting.
>
>If your worried about the rebar cage maintaining it's shape during
>construction.
>Stick the verticals in the ground at the surface. It's easier to work on
>then in the hole.
>Then have someone help you lift it and place in the hole.
>
>I also strongly suggest a little gravel in the bottom of the hole which
>makes positioning the cage easier. You can wiggle it a bit to get it plumb.
>
>The trick with all rebar cages is to maintain their shape and position
while
>dumping and vibrating the concrete.
>If you gut a couple boards and drill holes to match the vertical rears, you
>can nail/clamp to braces on the surface.
>
>
>----- Original Message -----
>From: "Andrew Pfeiffer" <va3pl@cuic.ca>
>To: <towertalk@contesting.com>
>Sent: Thursday, September 19, 2002 11:36 AM
>Subject: [Towertalk] Rebar Cage
>
>
>>I become happy owner of TX455 crank up tower. I began planning the rebar
>>cage.
>>My questions is:
>>Can vertical rebar members be driven let say 2 feet deep to the ground at
>>the bottom of the hole or this is NO NO...
>>
>>Andy - VA3PL
>>
>>_______________________________________________
>>Self Supporting Towers, Wireless Weather Stations, see web site:
>>
>http://www.mscomputer.com
>
>>Call 888-333-9041 to place your order, mention you saw this ad and take an
>>
>additional 5 percent off
>
>>any weather station price.
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>>
>>
>
>
>_______________________________________________
>Self Supporting Towers, Wireless Weather Stations, see web site:
http://www.mscomputer.com
>Call 888-333-9041 to place your order, mention you saw this ad and take an
additional 5 percent off
>any weather station price.
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>
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_______________________________________________
Self Supporting Towers, Wireless Weather Stations, see web site:
http://www.mscomputer.com
Call 888-333-9041 to place your order, mention you saw this ad and take an
additional 5 percent off
any weather station price.
_______________________________________________
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