I am refering to B31.3 ASME committe page-B31 Case 178 "Providing an equation for Longitudinal stress for Sustained Loads In ASME B31.3 Construction" where committe has specified the equation for Sl.

http://cstools.asme.org/csconnect/pdf/CommitteeFiles/15243.PDF

However I read on Becht's site A Code Case(Sustain) is presently under discussion that would provide a specific equation that can be used for the longitudinal stress(Sl) evaluation.

As per my understanding, now we are calculating Sl by summing up Slp, Sb and F/A. This equation seems to be different to me. Can B 31.3 experts throw more light on this ? Does it affect our present sustained stress calculations ?

Best Regards,