Cf force coefficient ASCE7 2

[mekafime]

hello
I have a question about the force coefficient Cf for trussed towers with square cross section, to find the ratio in a square tower with round tubular tubes, how do I calculate the ratio exposed to the wind?

 

[HTURKAK]

For trussed towers the formula (29.4-1) is applicable.

_ F = qzGCf Af .

_ Regarding the force coefficient Cf, Cf = 4.0ε2 − 5.9ε + 4.0

_ ε = Ratio of solid area to gross area of one tower face for the segment under consideration

Calculate the gross area for unit tower face length Ag= W*H

Calculate the net solid area An= projection of vertical elements + horizontal struts + diagonals

ε = An/Ag

_ Calculate Cf and multiply with correction factor for round members ( 0.51ε2 + 0.57 )

_ The calculation of Af SHALL include Af= Solid ares for front panel + Solid ares for rear panel + projection of side panels diagonals..

Af= 2*An+ projection of side panels diagonals


Does this reply answer to your thread ? If not provide dimensions of tower , size of elements etc.. to get more detailed response.

 

[mekafime]

Thanks u!