Stress on Buried HDPE Pipe
Stress on Buried HDPE Pipe
(OP)
Hi all,
I've encountered a new problem, calculating the stresses on buried HDPE pipe. I have previously done similar calculations on steel pipe and was able to find some standards and guides that pertained directly to that material (e.g. API RP 1102, American Lifelines Alliance "Guidelines for the Design of Buried Steel Pipe", etc.), however my search for similar standards for HDPE pipe have come up empty.
Does anyone have experience with this particular situation? I'm wondering if there is a "procedure"-like calculation similar to the RP 1102 where you come up with a bunch of parameters and end up with an effective stress (see API RP 1102, Sec. 4.8.1.3) to compare against a minimum yield stress.
Thank you very much!
I've encountered a new problem, calculating the stresses on buried HDPE pipe. I have previously done similar calculations on steel pipe and was able to find some standards and guides that pertained directly to that material (e.g. API RP 1102, American Lifelines Alliance "Guidelines for the Design of Buried Steel Pipe", etc.), however my search for similar standards for HDPE pipe have come up empty.
Does anyone have experience with this particular situation? I'm wondering if there is a "procedure"-like calculation similar to the RP 1102 where you come up with a bunch of parameters and end up with an effective stress (see API RP 1102, Sec. 4.8.1.3) to compare against a minimum yield stress.
Thank you very much!





RE: Stress on Buried HDPE Pipe
http://www.plasticpipe.org/publications/pe_handboo...
RE: Stress on Buried HDPE Pipe
Thanks!
RE: Stress on Buried HDPE Pipe
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Stress on Buried HDPE Pipe
RE: Stress on Buried HDPE Pipe
It's been so long ago now that I cannot remember the exact standards I used. However, I do recall that we used Philips Driscopipe. I'm sure it's not called that anymore. In fact, I think it might be called "CP Chem" now. They did have a design guide I used extensively.
Anyway, B31.3 does have guidance as LittleInch stated, but for soil pressure loads you will have to go elsewhere. The handbook CVG posted is a good start to educate yourself on the pipe embedment zone and the types of backfill required. With HDPE, be careful that the backfill specified is graded per the manufacturer's recommendations to avoid large particles that may damage the pipe (i.e., NOT limestone or rocky soils - see ASTM D-2321 for soil classification).
Check this link out: HDPE Pipe Embedment
You must also specify the level of compaction ("Standard Proctor Density") to be used, both in the embedment zone and above it. In my case I remember specifically using AASHTO standards to calculate soil pressures due to 18-wheelers and railcars (of course) rolling over the buried piping. In some areas, these calcs proved that we needed to embed the HDPE in steel pipe conduit to protect it from crushing.
I learned a lot more civil engineering than I ever wanted to with that job. Good luck with yours. Hope I was of some help.
RE: Stress on Buried HDPE Pipe
RE: Stress on Buried HDPE Pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Stress on Buried HDPE Pipe
KLee777 - Thanks for the info, fortunately we have some pretty comprehensive specs on the type of soil, backfill, etc. And using AASHTO standards certainly helps things as well, I have referred to some of their standards on things such as truck loads. I've also used API 1102 in the past but it is for buried steel pipe specifically, they make no mention of HDPE in the code.
dicksewerrat - The pipe will be for fire water service, design pressure of 150 psig.
RE: Stress on Buried HDPE Pipe
If I was building HDPE in the States I'd look first to ASME B31.4 (or ASME B31.8 for gas) and I'd fill any gaps with the document CVG linked.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"
RE: Stress on Buried HDPE Pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Stress on Buried HDPE Pipe
Also texts Buried Pipelines by Moser or Structural Design of Pipelines by Watkins
“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King
http://waterhammer.hopout.com.au/
RE: Stress on Buried HDPE Pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Stress on Buried HDPE Pipe
This is not the way to go. The reason is a buried flexible pipe is a combined structure of soil, pipe and fluid. When a load is applied to the soil the pipe deflects and the soil carries the load. The pipe supplier knows little about your native soil, the trench width and depth, the embedment design, external live and dead loading, water table, pressure, temperature, soil movements in reactive clay etc etc.
The approach taken in AS 2566 considered the European and USA methods of such analysis. This included the work at Iowa State using soil box tests. It is comprehensive and a thoroughly good text on the subject.
It has been in use in Australia for 15 years or so. Although considered a relatively conservative approach is does consider the equations needed to determine deflection, stress, combined loading, strain, buckling criteria etc. The Standard and accompanying Commentary do contain many references that you may wish to draw upon.
You may also like to consider the relevant AWWA standard on the matter as that is quite comprehensive.
“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King
http://waterhammer.hopout.com.au/
RE: Stress on Buried HDPE Pipe
dicksewerrat and stanier are pointing in the right direction.
The most helpfull standard for the US is the M45 from AWWA. There is also a company which makes software for the structural calculation of burried pipes:
[link http://ingsoft.de/easypipe_en.ingsoft]
RE: Stress on Buried HDPE Pipe