API 650-intermediate wind girder-clause 5.9.6-pwd calculation

[EngineerEPC]

Hello All,

I have 2 queries regarding the definition of Pwv. (for the 1st value)

a) Pwv is wind pressure at 10 m above ground per applicable building code considering all applicable factors, such as gust factor, exposure factor, height factor, importance factor
== why is it considered only at 10 m? does the tank height have no influence on this?

b) Does the value of Pwv as computed from above definition should or should not consider force coefficient for cylindrical body?

Thanks and regards
Ariba

 

[HTURKAK]

The answers to your queries ;

a) The wind speed maps present basic wind speeds correspond to 3-s gust speeds at 33 ft (10 m). This height (10 m ) typically applicable to AST s which the height in general less than 20 m. ( Pls look ASCE 7 wind section and API 650 5.2.1 )

b) The expression for the maximum height of the unstiffened shell (Pwd ; design wind pressure including inward drag ) does not include shape factor.

...

He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[EngineerEPC]

Thank you Hturkak.