At 12:54 PM 7/17/01 -0700, Hank Lonberg wrote:
>Actually the number of guy points required is a function of both the
>axial load, wind moment in tower section and distance between guy
>points.
>
>There is no need to beef up the lower guys because you are using a
>larger guy higher up. In practical terms the added vertical load does
>not increase and load required to keep the lower guy points in plumb.
But Mike raises an interesting question. I'd always understood that the
purpose of pretensioning is to take enough of the sag out of a guy so that
it is operating primarily in elongation when wind forces are applied. The
10% rule of thumb is usually cited for EHS steel, and I know it is also the
manufacturer's recommendation for Phillystran. but even the biggest
Phillystran is much lighter, per foot, than even small EHS. Doesn't it
follow that it really requires far less pre-tensioning to take a given
amount of sag out of a run of Phillystran guy? Or is there something else
at work here that I don't understand?
73, Pete N4ZR
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