Parallel Axis Theorem

[Catjacob]

Classic bending stress for a beam is My/I and the stress at both extremities are not zero. However, for some reasons, I want to make the (equivalent) stress/strain at the soffit is zero so it makes me more easy input them into a bridge analysis program. Can I use parallel axis theorem to transfer the “normal bending stress” into my equivalent stress block (push the original NA down to the soffit so stress/strain = 0 at bottom)

(PS: The whole story is the the program allows the user to input the temp diff across the deck ""lineraly"". Hence, I would like to work out the restrained BM from the non-linear temp distribution and convert it back to a linear temp difference with 0 degree at the bottom and “T” at the top_

 

[Dinosaur]

I don't quite follow your question, but I can tell you this. Proper use of the parallel axis theorum will not change the stress distribution across the section. Good Luck.