My question is pertaining to B31.3 requirement for OCCASIONAL stress.

According to B31.3 requirement the "SUM OF THE longitudinal STRESSES due to
sustained loads such as pressure AND weight and OF THE STRESSES produced
by occasional loads" be added.

We can achive this by :

1) Stress in case W+P+U which for linear systems will be equal to :

a) Stress in a case { (W+P+U)-(W+P)}computed by vector difference of loads, i.e. ALGEBRAIC in CAESAR II terminology + stresses in case (W+P) combined by CAESAR II method of SCALAR.

b)Stress in case { (W+P+U)-(W+P)}computed by vector difference of loads, i.e. ALGEBRAIC in CAESAR II terminology + ALBEBRAIC combination with stresses in W+P if the line is in one direction only.

However linear systems and line in one direction only are hypothetical situations so CAESAR II meets the CODE requirement by option (a) above.

My questions are:

1)Are we deviating from the code requirement if option (b) is opted for ? If so is it because of the use of the word "AND" in the code requirement?

2) If (1) is correct, why the CODE requirement is like this? Why not by the option (b)? That is I would like to get the rationale behind the code requirement.

On this forum we have code committee members like John Breen , John C luf.I would request them to throw some light on this.

Best regards