Hi Pipers,
I have a bridge connection between a jacket and a platform. Due to wave crest and trough the maximum deflection in the jacket and platform is 500mm on either side.I have 6 inch line on the bridge.
1.How can one analyse the impact of the structural deflection on the piping?
2.How to absorb this deflection and how to input in Caeser?
Regards
Piper78

How have you found yourself in this position ?

The problem you have posed requires a thorough understanding of piping engineering, stress analysis, wave induced dynamics and fatigue resistant design. Get it wrong, and rapid and very expensive failure will result.
Have you heard of Miner's rule ? Probablistic fatigue analysis ?

Give the problem to someone who knows what he / she is doing, and admit that you are out of your depth.

Search using bridge. One example found of many is http://www.coade.com/ubbthreads/ubbthrea...=true#Post13152

Basically you impose the movement into your calc from the OTHER platform and design the piping accordingly. This is fairly standard stuff for the offshore guys.

The structural deflection shall be imposed on all the piping supports on the platform.This movement shall be imposed through CNODE in Caesar-II.Sometime you have to provide a loop in order to absorb this relative deflection between the two platform.
There could be some other movements as well like Jacket settlement.Fatique analysis is very common in the offshore analysis.Your piping flexibility specification will tell you about that & code to be followed for the fatique analysis to calculate the allowable stress values.Also very typical in the offshore piping is the blast analysis.That you have to impose on your system as wind force.

Hope it will help you.

Cheers
Saneh

For pipes that cross from one platform to other through bridges, bridge displacement in the most critical cominations will be considered in the calculation.

Analysis shall be carried out considering one end of the bridge piping as fixed and imposing the relative displacements of the platforms along the axial direction at the other end of the piping, acting towards the fixed end.

The worst case shall be when both the platforms move towards each other.

The bridge displacement values shall be taken from the structural design basis or calculation reports.