Can any one from COADE kindly let me know the stress allowables to be considered for GRE pipes.
I would like to see a sample calculation and the way the result to be compared.
This is for a underground GRE piping.

Regards
Sunder Singh

Take the values from the vendor. Not only the allowable stress but also the other properties like elastic moduli, poisson ratios ,f2,etc.

For u/g GRE piping,the effect of the soil load including wt. of vehicle movement , if any, has to be considered .Vendors catalogue provide guidelines on the same.

If uncoupled mechanical joints are used, thrust blocks will be required.If key-lock type mechanical joints are used, thrust blocks will not be required.

Regards

Have you read the Chapter on FRP Analysis in the Technical Reference Manual? You are planning to use either UKOOA or BS-7159 as the piping code right?

Check if your project requires a Minimum stiffness of pipes. If so your wall thickness calcs should consider the minimum stiffness requirements.I would suggest you to have a look at AWWA M 45.

Cheers

GRE/GRP : Just do the analysis ,but final analysis/approval by vendor is required.

GRE - Epoxy : upto 110 deg C & GRP - Phenolic (150 deg C)
In offshore platform...for firewater Deluge system - we use Phenolic.
properties are slightly different.
(Read BS7159- Fig 2.1 and UKOOA std)

Guide(read caesar manual/consult vendor):

1. select material number 20 (frp)

2.Key in EMOD/Axial , Ea/Eh*Vh/a , pipe wt,alpha SM/Emodaxi,SIF(if reqd).
(all this values...for preliminary analysis, u can download from vendor website itself)

3.UKOOA code refers BS7159 to calculate SIF .
( read specification and recommended practices for the use of GRP offshore-part3 -system design)..page 20.

4.f2(0.67=sus/ope=0.83/occ=.87)..eff field.

5.f1*LTHS = SH1,SH2,SH3 etc.,

6.Fac (sec 7.2.1 BS7159) 0.85 for liquids and 0.8gases

7.provide anc/fixed point at all GRP/Metallic intersections/UG-AG entry.

8.Usual mistake- don't forget to change code 31.3 where metallic portion starts and check allowable stresses.

9.some time if you see stress failure...do the modelling exactly,i mean
give exact thickness of bend/tees. Normally this thickness values are higher than what is given in spec. see catalogue...best way talk to vendor.

Last but not the least...do it and give it to vendor for approval.

We have to be very careful in design/Analysis of BELLOWS and GRP pipes...otherwise immediate failure/ie Joint leakage .
Not like steel pipe.

All the best
Krishnabharathi