SIF shall be used in Jackup operation of platform

Posted by: prashpan1

SIF shall be used in Jackup operation of platform - 06/09/06 09:37 AM

I am working on a drilling rig project, the upperdeck will be jacked up for the Installation with all piping & supports in place. During jackup the centre of rig will be deflected by 150mm. I have made a load combination as WNC+D1 (SUS). Do i have to consider the SIF on welded tee's for this condition?
Posted by: John Breen

Re: SIF shall be used in Jackup operation of platform - 06/09/06 10:35 AM

Hi PRASHU,

Welcome to the forum. Next time you post, use the "new topic" box to open the discussion - the "post a poll" box is just for opinion polls.

I would use the SIF's because they are also applied for Code sustained stress calculations. The same areas of stress concentration will be affected during your "jack-up" load application. It is intuitive to picture the deflection as only in the down direction (as the deck goes up) but the jack-up, being a dynamic loading, will likely cause some alternating deflections. It would be prudent to provide as much temporary bracing as is practical to limit the range of this alternating deflection

Regards, John.
Posted by: prashpan1

Re: SIF shall be used in Jackup operation of platform - 06/09/06 10:39 AM

Hi John,

Thanks for your reply. Already i have used the SIF in my claculation but needed to confirm this. I will keep some supports & equipment nozzles loose during the jack-up operation.
Regards
Prashant