Dear All,

I am doing Under ground piping stress analysis for FRP piping. Iam getting failure on Elbows. I tried with increasing the thickness on elbows (2.2 times the pipe thk). Then also getting the same failure on Elbows. This is for under ground piping of 400ND.
Please suggest. I kept the pipe under 1.9M depth. Friction-0.5, Soil density-0.00185. here Laminated joints are used. Is there any other factor to conttrol?

1. How would we represent the thrust block while modelling. Is the same anchoring the elbow on both side. ? What are all the changes we need to do? please explain.
2. I heard that, for Laminates pipes in Underground piping, we should not give thrust block..Why? Then How to do analysis?
3. How would we decide the max restaints loads for larger pipe dia (ex. 1800ND,1400ND etc). From what size we need to consider Saddle support.
Kindly reply me for the above queries. Thankx in advance.