Ring Stiffner Need

[mohammed43]

Can someone tell me when we have to use ring stiffeners??. Iam checking the previous projects, where they had used internal ring stiffeners in Cylindrical legs of tubular members for jackups.
Does API says anything related to need for ring stiffener?? Is it related to Geometry? Also, if we are using the stiffener do we need to check the strength ?? If so, what kind of loads?? (hydrostatic...??)

Thanks for the help..

 

[Ussuri]

You use ring stiffeners when your calculations say you need them. That may be due to hydrostatic loading or it may be due to member forces at joints.

API RP 2A and ISO 19902 are useful references for you. They give you guidance for sizing and spacing rings stiffeners to prevent hydrostatic collapse and methods for assessing ring stiffened tubular joints.