where S = 0.2 (Strouhal number)
V2 = 6.25.
If the design wind velocity V>V1, perform the detailed vibration analysis from step 3 below with V1
If the design wind velocity V>V2, perform the detailed vibration analysis from step 3 below with V2
If V1 or V2 > 60 mph/27 m/s, ignore the calculation for that V value as there is cutoff for maximum critical wind speed for design consideration (page 120).
Determine δ and M.F. from the above selected combinations
Where, d = outside projected dia., ft., H= total column height, ft.
Note in the example only the moment at the junction of column and skirt is considered but APV has different approach of calculating at each individual level
stress intensification factor, β as follows
β = 1.2, shell plate with smooth finish,
β = 1.8, butt weld
β = 3.0 fillet weld
Reference: Henry H. Bednar, PE. (1991). Pressure Vessel Design Handbook Second Edition. Malabar, FL: Krieger Publishing Company.