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RE: Wind Loads on Monopoles

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I work for Valmont/Microflect designing communication structures
(Self-supporting towers and poles).

Since this is a communication pole, you may want to use the TIA/EIA-222-F
specification.  The UBC suggests that this code be used for communication
towers and poles.  It is very straight forward to use.  This would resolve
the issue surrounding the terminology (flagpole, lightpole).

When a client does specify the UBC (specifically) in California, we do not
use the 25 PSF minimum.  Actually most checkers don't even question if we've
used CA UBC versus the standard UBC.

My 2 cents....

-Shawn


Shawn Wicks Freilinger
Valmont/Microflect
Shawn(--nospam--at)valmont.com <mailto:Shawn(--nospam--at)valmont.com> 
(503) 315-4515


	-----Original Message-----
	From:	Bill Allen, S.E. [SMTP:bill(--nospam--at)allendesigns.com]
	Sent:	Monday, August 31, 1998 4:18 PM
	To:	seaint(--nospam--at)seaint.org
	Subject:	Wind Loads on Monopoles

	I have received some plan check comments on a foundation design I
have
	prepared. This foundation supports a monopole, 30 inches in diameter
and 100
	ft. tall. The foundation is 5 ft. diameter and 15 feet deep. I used
the UBC
	flagpole formula for the design (non-constrained).

	For the design, I used a Cq of 0.8 for the pole (based on "Chimneys,
tanks
	and solid towers" in UBC table 16-H). The plan checker wants me to
consider
	the monopole as "Signs, flagpoles, lightpoles and minor structures"
and a Cq
	of 1.4 with a 2/3 reduction for cylindrical elements. The kicker is
(this is
	a DSA project) that, in the CA UBC, there is an additional footnote
to the
	table which reads "Minimum wind design pressure for flagpoles and
lightpoles
	shall be 25 pounds per square foot." This equates to a wind pressure
for a
	structure 350 feet tall w/o reductions (Ce=2.12, Cq=2/3*1.4,
qs=12.6). This
	footnote does not appear in the regular version of the UBC.

	I am interested if anyone has a reference for this code requirement
and what
	kind of structure the authors of this provision was this provision
intended.

	Regards,
	Bill Allen