Design pipeline for earth load

[mofathi]

Good afternoon Gents
I am designing a new pipeline which will cross above an existing pipelines corridor. At the crossing we will run the new pipeline covered with berm only without a right of way. my client is asking to check the effect of the new pipeline on the existing buried lines. As there is no right of way I will not consider any cyclic loads due to vehicles movement and the check will be only for earth load and hoop stress and longitudinal stress
The question is the API 1102 still valid for these calculations setting the vehicle loads (Ps and PT) to zero
If not what do you suggest
Thanks

 

[LittleInch]

Yes I believe it is. I've recently done something very similar where we had a very low design pressure.

What is the existing pipeline made of - paper??

Appreciate your client may not be technically minded, but this really should not be required.

The stresses involved by driving over the existing pipelines while you build the new one will be far more....



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mofathi]

thanks LittleInch for your help
the problem is that the hoop and thermal stress are taking a large part of the allowable stress leaving only small part for the cyclic and earth load stress, so any small stress due to earth or vehicles can make it fail (keep in mind that the existing pipelines are not designed to have a crossing at these locations). and we don't use any additional wall thickness( we don't add corrosion allowance and we don't use the higher commercial standard wall thickness)we use only what comes from e the wall thickness equation

i proceeded using the API 1102 and some existing lines will fail under the earth load(combined with hoop and longitudinal) due to the new cover depth and as you said "The stresses involved by driving over the existing pipelines while we build the new one is not yet considered ". seems that thrust boring is justified after all