huangyhg

wind loads on a flagpole??
i do not see any reference to this in either aashto lts-4, 2001 or asce-7, 98. given f=0.00256*kz*kh*i*cd*(v)^2*a, what would you use for the cd? all other coefficients are easy to calculate. is this the correct methodology?
check out our whitepaper library.
see ansi/naamm fp1001-97 guide specifications for metal flagpoles.
australian standard as 1170.2:2002 structural design actions: wind actions, appendix f, has a treatment for calculating the aerodynamic shape factor for free flags, which includes the dynamic effects from flutter.
c = 0.05 + [0.7 * m/(p*c) * (a/c^2)^-1.25]
where:
- m is the unit mass of the flag (kg/m^2)
- q is the density of air (nominally 1.2 kg/m^3)
- c is the height of the flag (m) {note this is not height above ground of flag but actual height of flag}
- a is the area of flag perpendicular to wind direction (m^2)
dbuzz,
is a just the flag area? with the wind blow, the flag will be in the wind direction and vibrate.
civilgee,
cd is the drag coefficient for a cylinder; roughly 1.0 max for high wind speeds (> 100 mph), assuming a 6" diameter; and it won't change much at higher speeds or at diameters within .5x to 2x of that. most good fluid dynamics textbooks will give a plot of the cd of a cylinder for various reynold's numbers.
i appreciate the help. i will order the naamm fp 1001-97 standard and see if that helps. as far as the wind load on the pole i have that under control....it is just how to determine the loads from a flag that is flapping. thanks again.
this may be an oversimplification, but why not call a flag manufacturer, give them the size of the flag and pole and where it is to be located and have them provide the foundation loads?
if you are accustomed to the asce 7 code, chances are this would be classified as a flexible structure with a frequency less than 1hz. it is also a round pole. if you follow the code closely, there are specific methods for calculating the wind pressure for these types of structures. reference asce 7-95 for some background information first.

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