Hi Julius,

You could only have an expansion stress during

ex.

L1=W+P1+T1(OPE)
L2=W+P1(SUS)
L3=T1(EXP)

L1-L2(exp)non-linear
L3(exp)linear

That's why perhaps in sticky topic you will find people asking "why there is no allowable stress evaluation for operating case". As I understand in the code, the whole operating system is to be evaluated in two type of stress/failure, that is sustain and expansion. Those algebraic forms explain why and when you will have an expansion and sustain stress.

Regards!