Dears,

A GRP pipe (as purpose for sea water intake)is laid down between sea bed and sea surface, open at both ends. This means there is no inetrnal pressure in it.

There is external foces on pipe such as hydrodynamic loading etc.

Now the hoop stresses are due to these external laoding and given by CEASR II as positive direction. Code used is: BS 7159

What i think; due to external loading the hoop stresses are compressive and thus to be shown in negative direction instead of positive direction...

Am i correct? Is the problem with me, Code or CAESAR II.

Best Regards.

I suspect that your hoop stresses due to external loadings in BS 7159 are bending stresses in elbows, not due to external pressure. Bending stresses would create equally opposite, negative and positive bending stresses (depending on whether we are looking at the inside or outside of the wall thickness). Given the choice, we report stresses as positive.