A 6m x 6m slab panel serves as a floor for a light storage room, The slab has no ceiling on it but with a 25mm thick concrete fill finish for the flooring. The slab is an interior slab with adjacent slabs on all of its sides. Determine the required rebar spacing for the top column strip using a diameter 12 rebar. f'c= 28 MPa
fy = 414 MPa