ASCE 7-02 Gust Effect Factor

[sme75]

What is the highest value you have calculated and used for the gust effect factor, Gf? I am working on some tall vessels, which require me to use section 6.5.8.2 to calculate the factor. They are fixed at the base and have a guide to brace the vessel laterally at approximately half way up the vessel. I can see that the damping ratio can affect the calculation significantly and I have been tyring to be conservative, but I don't want to go overboard. Is a value of Gf = 1.4 unreasonable or have others used similar values for design.

 

[letsengineer]

A gust effect factor of 1.4 is quite high but it all depends on how flexible your structure is. There is a procedure in ASCE 7 to calculate Gf and it uses as a main input the fundamental frequency (f) of the structure.... Thus, your best bet is to estimate f and use the procedure.