[TowerTalk] base below ground level/drainage

[Gene Smar]

Art:

     Tell your wife it's not a good idea to allow galvanized steel of the tower to be buried below ground level - rust and falling over of the tower come to mind - if you were to sink your concrete base below ground level. What folks in the construction industry do to remove concrete foundations upon disassembly of the supported structure is jackhammer the concrete six inches below grade, fill it in with dirt, then resod or reseed the area.  

     I've engineered several removal projects like this when I worked for my local electric utlity company as a substation engineer.  When I had to decommission a substation, part of my drawings showed exactly what I described above:  Instructions to the crew to use the jackhammer and to backfill the area.  

     You can tell your wife that eliminating a concrete structural foundation after the structure itself has been removed is nothing new - it's done all the time.

73 de
Gene Smar  AD3F



     From: Arthur Trampler <atrampler at mchsi.com>
Date: 2007/07/14 Sat PM 08:43:49 CDT
To: towertalk at contesting.com
Subject: [TowerTalk] base below ground level/drainage

Hi All,

I was trying to sell my father's 50' Glen Martin (18" side) tower and Hazer when my wife (to my pleasure and surprise) decided she would be OK if there were guy wires in our backyard if that got me on the air (gotta love her).  My father, N0JT, has sadly reached the point at nearly 84 where declining health makes getting on the air a taxing event that yields less enjoyment than effort.  I don't have a tower and he is giving this to me.

However...her one request is that the top of the concrete be at least a few inches below ground so if/when we move, we can cover the spot and seed it...no harm, no foul.

I am concerned about water accumulation/corrosion/structural weakness to the concrete, and wonder if that is as much an issue as I think it is.  If so, my thought is to have the back how dig a trench away from the tower which I would partially fill with large gravel, like a lateral for a septic system.  I would then place a PVC pipe at the side of the concrete pour with a drain opening on it, and slightly contour the top of the concrete toward that drain opening. 

Hopefully water would flow toward the drain, down the pipe/through its L and drain out along the gravel.

Is this reasonable? Necessary? Not enough?  Or am I missing something?

Thanks for the input
Art, KC2G

P.S. Most tower mfrs. spec-out with 3000 PSI concrete; is it generally worth paying the extra for 5000 PSI?
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