Design the rectangular beams shown along Grid $4$ below. The floor is made of $150$mm thick concrete slab which will be covered with terrazo tiles $(25$mm thick$)$ on stone$-$concrete fill. The ceiling below is made of suspended metal lath and gypsum plaster supported by a suspended steel channel system. Additionally, the beam will be supporting a $3$m high concrete masonry units with thickness of $152$mm$,$ high$-$density, fully grouted with plastering on each side. Thefloor will serve as an office space.

PART A$.$ Determine the Critical Ultimate Moment Mu

PART B$.$ Design the beams along Grid B as Singly, Doubly and T$-$Beam Sections.