Wind Loads on Roof
Wind Loads on Roof
(OP)
Hello all,
I am mounting an antenna on a roof of a building, and I am trying to figure out the wind loads it will experience. Once I have these loads I can calculate the stresses on the bolts it is mounted on. Here is my question:
How will the angle of the roof (14 degrees) affect the wind load? I had planned to use 130 mph for the wind load, but I'd like to know how much the wind speed coming over the top of the roof will change.
Any help is appreciated!
I am mounting an antenna on a roof of a building, and I am trying to figure out the wind loads it will experience. Once I have these loads I can calculate the stresses on the bolts it is mounted on. Here is my question:
How will the angle of the roof (14 degrees) affect the wind load? I had planned to use 130 mph for the wind load, but I'd like to know how much the wind speed coming over the top of the roof will change.
Any help is appreciated!





RE: Wind Loads on Roof
RE: Wind Loads on Roof
The roof slope should not affect your wind load negatively. At best it will block wind from one side, at worst, the wind will hit the antenna head on.
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Wind Loads on Roof
I wasn't given too much information about wind loads in the area, so I figured I'd assume a hurricane rolled in and they didn't take the antenna down.
Im using this equation to find the force on the antenna dish: Drag = 0.5*rho*wind speed^2*Area of object*Drag Coefficient. Since this force is greater than the weight, I will use the drag force when finding my stresses in the mounting bolts.
I hope I'm doing this correctly. This is my first assignment out of college, so I'd like to get it right.
Thanks for the help!
RE: Wind Loads on Roof
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Wind Loads on Roof
Joe Tank
RE: Wind Loads on Roof
RE: Wind Loads on Roof
ZCP
www.phoenix-engineer.com
RE: Wind Loads on Roof
RE: Wind Loads on Roof
I looked up 6.5.15 in ASCE 7 and used the equation: F=qz*G*Cf*Af. This is giving me a value of about 435 lb, as opposed to me using the force of drag equation: 0.5*rho*wind speed^2*Area of object*Drag Coefficient, which gave me about 630 lb.
Which should I use in my stress calculations?
RE: Wind Loads on Roof
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Wind Loads on Roof
RE: Wind Loads on Roof
RE: Wind Loads on Roof
RE: Wind Loads on Roof
If you "heard" it on the internet, it's guilty until proven innocent. - DCS
http://www.eng-tips.com/supportus.cfm
RE: Wind Loads on Roof