Re[2]: Guy Anchors on a flat concrete roof

sawyers sawyers@cacd.rockwell.com
Tue, 27 Aug 96 08:30:40 cst


I am a mechanical engineer and I second the idea of making a plate to set 
the angle.

Steve


______________________________ Reply Separator _________________________________
Subject: Re: Guy Anchors on a flat concrete roof
Author:  ken smith <kgsmith@onlink.net> at ccmgw1
Date:    8/26/96 10:13 PM


At 08:30 PM 8/26/96 -0700, you wrote:

>
>Heres my question.  Rohn specifies that the normal guy anchor should 
>be in line with the guy wires.  My problems is that I can only drill 
>straight down into the concrete.  
>
>        / <----- guy wire 
>       / 
>     O/ <------------ guy anchor (probably a forged eyebolt) 
>_____|_______ Roof
>     |
>     | <-------- Eyebolt surrounded by epoxy made for the job 
>
>
>As you can see, the guy wire is going to want to bend the guy anchor. 
>But I can't see anyway around it.  The dealer did not suggest drilling 
>the hole at a 45 degree angle.
>
>I am estimating that the eye bolt will only extend a few inches above 
>the roof so as to leave just enough room to install an equalizer plate. 
>
>Does anybody have any suggestions or do you think this will work fine? 
>
>73
>
>(p.s.  need to get this done before the October contest season, HI) 
>
>
First, I'm not a Mechanical engineer, so this is a personal opinion on the 
dynamics of what you are proposing. First, I don't think that sticking an eye 
bolt up in the air with a bending moment is a good idea. Most of the concrete 
anchors give a spec for holding a force strait out, with a sheer strength for 
the bolt. But your proposal is like a yagi ten feet up the mast as opposed to 
one foot up the mast.

How about looking at making a plate that has the required angle built in to 
it for the guy attachment, and having concrete anchors hold the plate tight 
to the roof. This would eliminate a bending moment on the bolts.

Ken Smith
VA3SK