[Antennas] RE:Re-bar "Cage" To Use For Your Tower

Tue, 10 Sep 2002 22:35:31 -0400

I had witnessed a lot of tall-buiding construction in China where the re-bar
was welded (oxy-acet) into a cage and then encased...  The same was done for
pilings.  The 40' x 3' tube cage was welded on the ground and then dfropped
into a pounded hole.  The hole wasd then poused with a rising 'vibrator'
coming up a foot or two under the concrete..  Although I'm not in the
building trades, I asked the construction firm why they did this.

Turns out Northern China is a very active earthquake zone.  While the
tensile pull on a slab is low, the pull on both the vertical structure and
the floor slabs is tremendous while the ground shakes...   Only time will
tell if the welded joints survive TIME as well as quakes.

 ._._.
----- Original Message -----
From: "Wendell Wyly W5FL" <[email protected]>
To: "Karl Kanalz" <[email protected]>; "'Jacqui'" <[email protected]>; "Lyn
Williams" <[email protected]>
Cc: <[email protected]>
Sent: Tuesday, September 10, 2002 10:12 PM
Subject: RE: [Antennas] RE:Re-bar "Cage" To Use For Your Tower

> Rebar would hardly be called high tensile steel.  With a brazed joint
using
> gas or a low penetration rod for arc welding the effect on the strength of
> the rebar would be minimal for normal amateur tower bases and ground
> anchors. The steel does absolutely nothing except on the face that you are
> putting in tension and using a minimum 5/8 rebar, it doesn't take much
steel
> to keep the concrete from breaking under tension. Tying a joint is only to
> hold it together until you get the concrete poured and is not an
acceptable
> joint if you are depending on it for a Ufer ground.
>
> I sure wish that I had welded the rebar in my concrete slab house
foundation
> together and used it for a huge (5500 sq ft) ground mat.  Almost none of
the
> 3/8 steel under a house is structural or heavily loaded EXCEPT the steel
in
> the beams which is normally 5/8 or better.
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Karl Kanalz
> Sent: Monday, September 09, 2002 5:19 PM
> To: 'Jacqui'; Lyn Williams
> Cc: [email protected]
> Subject: [Antennas] RE:Re-bar "Cage" To Use For Your Tower
>
>
> >From my observation, Jacqui, and talking to varius concrete/re-bar
experts
> in the area, it is not a good idea to "weld" re-bar when constructing a
> cage for a foundation or tower base (also a foundation).
>
>
>
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