[TowerTalk] Wind loading

[Stan Stockton]

Thanks to Gerald for correcting me.  Calculation was done with Yagi Stress and I forgot to halve the numbers.  The 41 MPH number should be correct.

Stan

> On Aug 30, 2016, at 9:26 PM, emailve1dt at gmail.com wrote:
> 
> Stan,
>  
> Something went wrong with your area calculations. Even if this was 24 feet of 1 inch tubing, the area would only be 24 * 1 / 12 = 2 s.f. Here’s my spreadsheet calculation for exposed area. Typically, this will be further reduced by 2/3 for calculating the windload since this is round tubing.
>  
> Diameter"
> Length"
> Sq Feet
> 0.75
> 72
> 0.375
> 0.625
> 66
> 0.286
> 0.5
> 66
> 0.229
> 0.375
> 66
> 0.172
> Total sq feet
> 1.063
>  
> >> Gerald, VE1DT
>  
>  
>  
>  
> The wind load of the element starting with 6 feet of 3/4 inch and then 66
> inches each of 5/8, 1/2 and 3/8 is 2.55 SF.  The weight is 4.9 pounds not
> counting hardware.  It is rated for 41 mph.
>  
> This doesn't answer the question about what it will take to turn it over but
> first you probably want the elements to be rated for higher than 41 mph.  If
> you want me to tell you what you can do to make them stronger, specify the wind
> rating for the element and I'll tell you.
>  
> I did something similar to what you described for a very heavy duty full sized
> 40 meter vertical on the beach - starting with 2 inch X 1/8 inch wall at
> bottom.  I used a section of PVC electrical conduit (2 inch schedule 40) and
> drilled 3/4 inch holes at right angles and about an inch or two apart.  I then
> used aluminum tubing to create a "+" at the bottom that extended out about six
> feet in all four directions.  A big rock on each end made it very stable.
>  
> I would think a sack of pre mixed concrete either formed up or not at each
> vertical location would also be easy to accomplish and do the job. 
>  
> 73... Stan, K5GO
>