I have not analyzed FRP pipe before.I would like to know how FRP pipe stress analysis is different from the normal steel pipe stress analysis.I know there are some basic difference in the material properties of steel pipe & the FRP pipe.
1.FRP pipe is more flexible than the steel pipe so supporting span is less in FRP pipe as compared to steel pipe.
2.Expansion value of FRP pipe is 2-3 times that of steel pipe.
3.FRP pipe cannot withstand high temp./pressure.We don't use it beyound 100 degree C.

What are the codes & standards to be followed in case of FRP pipe?.From where do we get the allowable stress values for the FRP pipe.What is the arrangement to support/restrained the pipe?.
I feel we must be using clamp to hold the pipe.

Thanks
Saneh Gupta

Codes for GRP PIping:

BS 7159: Code of practice for design and construction of glass-reinforced plastics (GRP) piping systems
ISO 14692. Specifiacally, Glass-reinforced plastics (GRP) piping -- Part 3: System design is more relevant to stress analysis.

ISO 14692 is the newest and most comprehensive. It is extension of UKOOA standard, but not available in CAESAR II now. I am not sure if its now available in Verson 5. You can browse some earlier posting and particularly reply of Tom Van Laan in case you want to use ISO 14692 on CAESAR II. You can also read Tom's articles on GRP/FRP piping on COADE Newsletters.

Others:
- Allowable stress values can be derived from vendor catelogues/informations. However methodology differs in dfferent codes. e.g. in case of ISO 14692, allowable stress envelopes for SUS, OCC and OPE cases are developed and code calculation values are plotted on envelope.
-Similarly code stress calculations are different in different codes.
-SIF computation is different than steel piping. Check BS 7159.
-CAESAR II have inbuilt data base for some of FRP properties for many vendors.

There are many other intricacies involved in GRP piping system like type of joints, supporting,etc. Incase of underground systems many other criterias need to be considered apart from stress analysis. So if you are new in GRP, better get it done by specialised consultants. Mostly manufacturers/supplier can get it done for you.

None of the FRP codes specifically address the state of the art technology for FRP.Reasons: These are orthotropic materials and there are approximately 11 different failure theories each having its own merits /demerits.These failure theories can be classified into 3 types, interactive, partially interctive and non interactive.By and large the Tsai-Wu and Puck-Schurmann theories have been proven to be most "experimentally correct" with respect to theoretical predictions.You need to read an excellent text book on this subject authored by Issac M Daniel and Ori Ishai "Engineering Mechanics of composite materials" to get an overview of the applications of these different theories.

Practically, I can give you few tips:

1) Depend of vendor data.

2) Use proper support span, a conservative estimate is 3M span between supports.

3)Use pad under pipe .These pads are usually made up of the same pipe and hence adjust the CL of the pipe properly.

4)Support of valves directly and not "close by".

5) Follow vendor's recoemmendations for guide span and stops.

Regards

AWWA M 45 is also another recommended GRP reference.

The basic diff is the anisotropy of the GRP material,so you have modulus of elasticity differing in Hoop and axial directions. You can alos use the low axial elastic modulus to put the GRP pipe in compression i.e anchors in a straight pipe (which is very unusual in metallic pipes).

I would suggest to browse Ameron's website to have a good feel of the design guidelines.

Use elastomers at contact surfaces of pipe and supports.

There is now a DN 3000MM(yes 3m) GRP piping(underground as well as above ground) project underway in the middleeast. For information.

Imp:

Get your vendor finalised at an early stage of project.
Get the designers to plan for lower support spans from the beginning of project.

Cheers!!!!!!!!

One more point, none of the 11 failure theories I mentioned which includes Tsai Hill, Tsai Wu, Hashin -Rotem, Puck-Schurmann, LARC04 ( developed at NASA) address the issue of debonding, which is a subject by itself.

So FRP is still a gray area with lot of scope of research.

Regards

I noticed this inquiry a little late, but I know that another gentleman on another engineering e-mail list I watch had offered up the following reference to a similar request on that list (see his quote below -- I hope the original inquirer here is still around and might be helped by this):

"The paper referenced below provides good background on the design challenges associated with utilizing fiberglass pipe.

Hille, G. and Romer, A., "Fiberglass Pipe Design for Water Mains." ASCE, 2004 Pipelines Conference."

I took this gentleman's advice and upon reading found out this extensive/quite detailed in effect design, manufacturing, and installation case-study was written by a notable engineering consultant, after their experience with what was reportedly/apparently then the world's largest GRP pipe project.

Hi!
I'm having some problems in generating the stress analysis report.
I inserted the supplier information about the FRP material.
When I generate the report in the case: Stress: 2 (SUS) W + P1 and Stress: 3 (EXP) G # = L1.L2, the information in the report is CODE STRESS CHECK FAILED: LOADCASE 2 (SUS) W + P1 and NO CODE STRESS CHECK PROCESSED: LOADCASE 3 (EXP) L3 = L1-L2.
What could be wrong?

Open a Support Request on SmartSupport and send in your job file for review.