Recent content by robb4

Which are the main parameter to decide the straight length of a pipeline at the starting point, before any bend? How to determine the minimum feasible length? As far as I know this length is connected to the friction of soil and should be at least one catenary length. Any help will be appreciated...

Finally, I found a reference paper for the minimum gap ratio below that no VIV occurs. It is " 1997 OMAE, Volume V, Pipeline Technology, ASME 1997 (Mark, Vitali, Velley) – The multispan project: design guideline for free spanning pipelines". In this paper it is stated "In general it can be...

Hi Big", maybe there is a misunderstanding because with free span clearance/External Pipeline Diameter I meant a different thing (see attached). Anyway I agree with you that a very important thing is the other ratio (free span length/external diameter). Thank you...

Hi guys, Regarding free span analysis according DNV RP F105 I've the following question: Is there a minimum gap ratio (free span clearance/External Pipeline Diameter) that lead to VIV onset (i.e. below that limit no VIV occurs)? I found in a document that with gaps ratio below 0.3 no VIV...

Hi, I'm involved in on bottom stability study of a offshore pipeline. Due to extreme enviromental loads we are thinking about use of mattresses to ensure the stability during design life. Since the DNV codes (RP 305 and RP F109) don't consider this situation, do you have any reference or...

Hi, My Company has bougth an Offpipe (http://www.offpipe.com/) license and I found that it use a DOS interface. Anyone knows a software that can interface with Offpipe to avoid to use the Dos interface? Thanks

Thanks for your reply. Of course the wave is another aspects to be considered in liquefaction study but considering my water depth (60m) maybe it wouldn't be an issue. Regarding the return period the only one reference I find is on DNV OS F101 that states the following (Sec 4 C500): C 500...

SFLM, Thanks for your reply. when you need to reach high value of thermal insulation (below 4W/m2K), the concrete cannot be used as insulation so you would need to add a proper layer. After the post of SJones I got in contact with that Company and they states that is possible to do that...

Hi, I'm collecting input data for a Detail offshore pipeline project. Regarding the soil liquefaction analysis due to seismic hazard I'm collecting data regarding Peak Ground Acceleration assosiaceted with return period of 200, 500 and 1000 years. My question is which is return period to be...

At least the minimum lateral displacement (and pipeline heading) should be enough to allow the barge to deploy dead man anchor (so the dimension of barge plus some meters could be enough). Consider that anchor pattern can be adapted to pass over that zone. It's not a good idea to have a lot of...

Yes, it's correct. In this case you've three different options: - don't consider the trench (very conservative approach) - use another standard like Danish Submarine Pipelines Guidelines (very old standard) - use a software to simulate hydrodinamic flow inside tranch (like AGA).

Hi, my question is about pipeline coatings. In particular I would know if it is possible to put concrete coatings above thermal insulation coatings. The main pipeline data are: Pipeline 8" Insulation Thickness 40 mm Concrete coating thickness 40 mm Thank you.

For atedionyahoo. Do you mean the standard buckle detector (like a gauge plate)? I know that for deep water application it's not a standard to use it because the risk of rupture of buckle detector itself.

Hi Guys, I'm involved in a deep water project (1400 m WD), and I'm writing a functional specification for installation of rigid pipeline. My question is what are the most suitable methods for buckle detection in such deep water (either in j-lay and reeled pipeline)? Of course the gauging plate...

Dearl all, I'm writing a specification for the purchase of unbounded flexible riser (about OD 16", ID 8" in a water depth of 1400m). I'm thinking about the protection from dropped object, how can I fix the requirements in terms of Impact Energy and Object Diameter? The only reference I found...