Dang I'm Tired...This working for a living is harder than I thought.
Add to the new day job the tasks of finally finishing removing my life and possessions from boxes and having to spend the evenings and weekend trying to explain my stack calculations to
I just spent three hours writing an Excel spreadsheet to do something called a Wind Gust Response Factor calculation to prove that some numbers I routinely use are correct. I lost all of my stack design software in the house fire a few years ago and I've been slowly re-writing each section as each job requires the data.
Any way, having run a few thousand gust factor calculations over the past 25 years, I've basically settled on numbers between 1.0 and 1.5 for most of my designs, and I let
On the current new design on the Mississippi coast I used a 150 mile wind velocity with a 1.5 gust factor.
Massive bitching and complaining ensued, because our customer failed to tell me that their customer--a petroleum company--had their own standards and required a 183 MPH design wind loading with a .85 gust factor.
Problem is, the 0.85 number is for short fat stiff structures like buildings, and I have a tall flexible structure with a frequency of around 1 Hertz, but I could see an inquisition coming featuring highly educated people whose experience with stacks consisting of designing two or three and having stood by a smokestack once in a paper mill.
I, on the other hand, have designed and built (and in some cases installed) over 400 stacks in my career and by default have a pretty good idea what is going on with tall thin tubes standing around with smoke coming out of their tops.
So any way, I just finished the spreadsheet and ran some test numbers to check the accuracy, then I plugged in my stack design and guess what???
The actual gust factor is 1.472!!
For those of you that went to Georgia or LSU, 1.472 easily rounds up to my original number of 1.5.
It's time for a celebratory cocktail, I think...
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