API 650 Storage tank - Do I need intermediate wind girder ? 1

[Abdelrahman_Yousef]

As subjected,
I have a 28m diameter 5.7m high water tank. shell thickness is 8mm
I want to figure out if I need intermediate wind girder .. can anyone suggest how ?

I have top wind girder that is L120X120X10mm angle

 

[Geoff13]

Use the rules in API 650 (12th Edition) clause 5.9.7.

 

[JStephen]

You calculate the allowable height of unstiffened shell, if that is not exceeded, no intermediate wind girder is required. If it is exceeded, you can use an intermediate wind girder or increase shell thickness until it is no longer required- which is often the most economical choice.

 

[ali.pk]

Simply follow the instructions given in 5.9.7 of API 650

Step 1) Calculate the unstiffened height of the tank

Step 2) Calculate the Tansposed width of each shell course.

Step 3) Transformed shell height = Sum all transposed width of all shell courses.

Step 4) If the sum transformed shell height is greater than the maximum unstiffened shell height, Intermediate wind girder is required.

Regards,

Asad