Reinf crack for prestressed concrete

Hi all.

I have a question about Reinf crack for prestressed concrete as follows:

If you calculator stress bot of section beam in MinMz_Service exceeding allowable stress tension limit is 0,5 x sqrt(f'c), you can calculator reinf area to control crack concrete as follows:

stress in Reinf for control crack concrete = (stress crack in Service - 0,5 x sqrt(f'c)) x S / (0.7h x As) < 0,6 x fy, with S = I / ybot, I is moment of inertia of section, As is Reinf area for control crack concrete, h is height of section beam, fy is Yield strength of Reinf.

Thank you for reading and hope get your reply.

Best regards.