Guying to metal structure

Discussion in 'Tower, Rooftop and Antenna Installation' started by David Olson, Jan 28, 2015.

  1. David Olson

    David Olson First Time Poster

    I've got a ROHN 25 tower, 55ft that sits next to my warehouse (32ft at eave; braced with ROHN building bracket at ~25ft) that I need to extend to 95ft (add 4 sections). At that height it will need to be guyed-and that's where my problems start....

    1. Since the tower sits next to the building, and once face is parallel to the wall, I will have to anchor 2 of the guys to the roof. I'm anticipating eyebolts thru the roof into a rafter or girder (it's a steel Morton building); however, buildings move (mine can move as much as 6" due to wind). With the third guy wire anchored to a concrete block buried in the yard, I now have the issue that if the building moves I'll end up with a slack guy OR a snapped guy...am I overthinking this? Any engineering info on how whether this is OK?

    2. So my parking lot is only 65ft from the building; a 95ft tower means I need guys at 80ft-ish, which I can't do because of the parking lot... so if my one anchor block is only 65ft from the tower the guy will be at a steeper angle, increasing the static load on the tower. (a) Do I need to adjust the tension on the guys (from 400#) to compensate? How do I calculate the right tension? (b) Should all three guys be at the same angle (i.e. put the roof anchors closer to the tower) or is a steeper angle on one guy but shallower on the others OK? I'm thinking they all need to be the same angle to ensure equal static load...

    Thoughts? Places to get solid info? And yes, we have a structural PE on the job...

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