what are the load conditions have to be considered for subsea piping analysis and which code has to be taken for analysis of subsea piping.


thanks in advance


regards

suresh kumar

Unless this is a point of interest question, you need serious help from an experienced subsea specialist.

Loads involve thermal, weight, internal and external pressure, environmental including waves, current, seismic (wind, wave slam if attached to a platform structure), bouyancy, imposed displacements, free spanning limitation, vortex shedding prevention, fatigue and quite a few others.

Codes used depend on where the pipeline is to be installed. It may be ASME, BS-8010 or DNV for example.

thanks mover z,

here in CAESAR how can we apply external pressure to piping, in the above question i am asking, in (subsea & marine)systems which code has to be considered for analysis and what are the load conditions to be taken. i think u r telling about topsides piping stress analysis.

Suresh

I assume you are looking at a submerged sub sea pipeline and analysing it.This is again a specialised area with companies like JP Kenny, AMEC and the likes are into. Moevrz has given an ovreview of the pecularities of the systems. Some may be approached with Caesar as a tool and some with typical Mathcad routines. Please approach a sub sea pipeline engineeiring specialist.

The offshore Codes in CAESAR II are: B31.4 Ch 9, B31.8 Ch 8, Dnv (1996), and (as of Version 5.10) PD-8010 Part 2.

For pressure effects these codes use (Pi-Pe) in place of "P". This is not to say that your are analyzing for external pressure - you're not. The "3D Beam Element" used by CAESAR II does not address buckling or local effects. Additionally, the piping codes are setup such that pressure is added to the overall longitudinal stress at the end of the analysis, using PD/4t or equivalent.

Some codes compute a hoop stress explicitly, which if applicable, CAESAR II will determine.

For the loading conditions, you need to refer to the applicable piping code you are employing.

thanks Rechard

in our project (hull system) we have fallowing piping systems
1 bilg and ballast piping
2 methonal piping
3 open drain piping
4 tank vents and sound piping
etc

one more thing our seniors telling me to do analysis of above piping using B 31.1 , is it correct.

so please reply

Suresh,

We might wonder how 'senior' this guy is. You might query what if anything these lines have to do with ASME B31.1 which concerns specifically Power Piping.

What material is the pipework ? The services you have listed are frequently non-metallic these days.

THNAKS MOVER Z

in the above piping what i have mentioned are CS and SS material pipes.
so for above mentioned piping,which code is taken for analysis.


pleas reply

Suresh,

Assuming it is acceptable to the local regulatory authorities,the vast majority of such piping would be designed in accordance with ASME B31.3, Process Piping.