How can I determine the N.A (neutral axis)of a rectanular column with bars in all 4 faces? It is different from beam, I cannot set C = T to evaluate the N.A, there is axial force, unlike beam? In addition, since there is axial force n bending, do I just refer to N.A or the plastic centroid still...
When there is steel (bottom layer) in a concrete beam,the steel is in compression while the concrete in tension when the section shrink. So, how does it form tension stiffening in the beam when cracks start?
How does tension stiffening help to reduce cracking moment?
Thank you for your help!
