[TowerTalk] Need help locating Rohn BXB 7-8

[Bill Coleman]

On 6/29/01 10:45 AM, alsopb at alsopb@gloryroad.net wrote:

>This practice recommended by Rohn has me a bit puzzled.  Rebar in the
>concrete has to stop 3" from the end of the concrete on all sides. 
>The reason given is that they will rust, disintegrate and form a
>cavity which weakens the base.  

Rebar is not galvanized. Rebar is a really low-quality steel.

But it forms an important part of the foundation, so rebar is important. 
Without it, concrete isn't that strong, and will prone to crack and 
disintegrate. 

>I guess Rohn believes their towers legs never rust-- inside or
>outside.

If you leave the tower legs full of water -- you are guaranteed to get 
rust.

>Is that true?  I agree with wanting to keep water out of the legs.
>
>Also, if the water table rises above the base of the bed of rocks,
>doesn't it guarantee water being in the tower legs?

If the ends of the tower are sealed in concrete, water will build up 
(through condensation), until it fills the tower section to the first 
joint. This is likely to be above the base. Not good.

However, if some of the bottom few inches of tower sticking out of the 
concrete bottom rusts -- does it really matter?

It ain't gonna last forever. But, if installed according to Rohn's 
guidelines, it ought to last decades.


Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901


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