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[TowerTalk] Pad and Pier for ROHN SSV. Pad and Pier Foundations

To: "towertalk" <towertalk@contesting.com>
Subject: [TowerTalk] Pad and Pier for ROHN SSV. Pad and Pier Foundations
From: <isp@bnjcomp.com>
Date: Sat, 9 Jul 2005 09:42:44 -0500
List-post: <mailto:towertalk@contesting.com>
Of couse like everyone else here on this list that puts up thier own tower I am 
trying to save money.  But also trying to stay safe.   The property I am 
putting this on was originally part of a piece of land that was hopeful that 
the city would get a large business to be on.  So for that reason they did core 
samples of the property.  So I am going to try to acquire a copy of the results 
of those core samples to see what they say.   So my question is I don't see in 
Rohn's book a spot for "if XXX sandy conditions then modify piers by doing this 
or that"  or "if XXX compactness with clay then modify piers by doing this or 
that".     Once I get that where do I look for those modifications.  Also I 
tried when I bought this tower to get engineering drawings from ROHN but after 
MANY calls was unsuccessful.  Does anyone have any new experience with new 
radian / rohn and think my ability to get those drawings would be better?  
Better question is it seems all the information is in the 
 Rohn Catalog and I am wondering what I will get off of those drawings that is 
not in the catalog (since the drawings will probable be for the original owners 
Soil conditions).?

thanks terry

  ----- Original Message ----- 
  From: Bob Gates 
  To: isp@bnjcomp.com 
  Sent: Saturday, July 09, 2005 2:04 AM
  Subject: Re: [TowerTalk] Pad and Pier for ROHN SSV. Pad and Pier Foundations


  Terry,

  Well, you've forced me to go look at my Rohn catalog, and I see where the 
problem is.  The foundation dimensions for section 14 "assume" you have the 
other 13 sections on top of it.  That's why such a massive footing design.  
Since you're only using 8 sections (7-14 I think your original note said), the 
footing requirements are much less.  However, you can't use the dimensions for 
section 8 either because you have more weight and mass involved than if you 
were using sections 1-8.  

  Now I gather you don't need a permit for this, otherwise you wouldn't be 
asking.  But I would make a compromise between the section 8 dimensions and the 
section 14 dimensions.  Install a square footing using the "Drill and Bell" 
option basic numbers.  The dimensions would be about 12' deep and 5' square 
(the numbers for section 11).  Forget the bell portion, just a square hole.  
Having said that, it might be difficult to keep the hole only 5' square while 
digging down 12', so you may wind up with a slightly larger hole, which is also 
okay.  Just dig the hole, use the trackhole to drop in a modified  expanded 
rebar cage, and fill it with concrete.  Don't forget to keep the rebar cage off 
the bottom of the hole to prevent rusting over time.

  Hope this helps and GL,

  73, Bob W7BJ
    ----- Original Message ----- 
    From: isp@bnjcomp.com 
    To: towertalk 
    Sent: Friday, July 08, 2005 10:03 PM
    Subject: Re: [TowerTalk] Pad and Pier for ROHN SSV. Pad and Pier Foundations


    Bob,

    Please rember that I don;'t know or have access to a belling machine.  
Makes me kind of paranoid to think about getting 10-12' in a hole and hand 
belling out hole.  Are you suggesting a big square hole (have easy access to 
70' trackhole but would have to hire someone out (like a well boring person in 
our area) if I wanted a "round" hole) that is size of recomended rohn pad at 
bottom of pier?

    IN my rohn bible book on page SSV-3 is where I am getting my specs.  For a 
14N section:

    1.  pier pad combo is 12' down with a 2' X 2' X 2' pad at bottom.  18 yards 
of concrete
    2.  drill and bell is 14' down with a 6' bell   16.7 yards of concrete
    3.  drill is  25' down  27 yards of concrete.

    I am also thinking that all of these specs "assume" that you will have 
sections 6n - 1w which I don't so that should give me some relief.
    my concrete/tower  guy wants to go 10' and put a massive pad at bottom of 
piers to give it weight.
    I am going to ask my trackhole person how much of a "bell" he can put at 
bottom of 14' with his trackhole.  I mean the main hole is 3' right so that 
gives him room to go down and then scrap out 2' all way around right?  Guys am 
I way off here?

    I only get to do this once so am looking for good input from this list.

    thanks terry

      ----- Original Message ----- 
      From: Bob Gates 
      To: isp@bnjcomp.com 
      Sent: Friday, July 08, 2005 1:39 AM
      Subject: Re: [TowerTalk] Pad and Pier for ROHN SSV. Pad and Pier 
Foundations


      Terry,

      Pardon the expression, but that is a hell of a lot of digging and 
concrete.  Spent 30 years with a major oil company, most in Marketing 
Engineering.  I was a region manager when the company was going through a cost 
cutting exercise, and the next thing I knew the drawings for our large canopies 
were revised to show these spread footings.  I'm talking structures that were 
48'x105'++.  There were two columns every 25' lengthwise.  Upon asking why the 
change, I was advised that the bell footings used less concrete, ergo less 
cost.  When I pointed out that digging the bell, and forming out the rest of 
the hole so someone couldn't get buried if a wall fell in, actually increased 
the cost.  The design was quickly changed back to a rectangular footing.  BTW, 
the canopies had a wind rating of 110mph.  Would suggest the same in your case. 
 Either dig a rectangular hole the size of the bottom of the bell, or auger a 
hole the same diameter as the bottom.  Spend a few dollars more o
 n co
     ncrete and save significant man hours.  Net is a lower cost, and just as 
safe.  If you feel uneasy about this, ask a registered engineer in your area.  
GL.

      73, Bob W7BJ

    _______________________________________________

    See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any 
questions and ask for Sherman, W2FLA.

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_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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