Reinforced beam analysis is carried out to check the nominal moment of the beam. When beam is analyzed than one already know about the beam cross section, steel area and effective depth of beam. In analysis, answers are unique. There is only one possible answer if more than one engineer is doing calculations.
Reinforced Beam Analysis Example:
A single reinforced rectangular beam cross section has a total width of eleven inches and depth of eighteen inches. Calculate the nominal moment capacity of the beam if;
f’c = 3000psi
Fy = 40000Psi
Area of steel = As= 5 inch square.
Taking moment about the tension side of neutral axis
Mn = T*jd
Mn = (As*Fy)*jd Since T = As*Fy
Assume jd= 0.88*d
d=Effective depth= 18’’
Therefore; jd = 0.88*18 = 15.84’’
Nominal Moment = Mn = 5*40000*15.84 = 3168000lb-in. = 3168kips-in.