Nominal strength Of Concrete
Actual strength from the material properties is called the nominal strength.
Nominal x Ø = Design strength
As safe design is achieved when the structural strength obtained by multiplying the nominal strength by the reduction factor Ø, exceeds or equals the strength needed to withstand the factored loads.
where
Mu, Vu and Pu equals external factored moments, shear forces and axial forces.
Mn, Vn and Pn equals the nominal moment, shear and axial capacity of the member respectively.
The nominal strength is generally calculated using accepted, analytical procedures based on statistics and equilibrium. However, in order to account for the degree of accuracy within which the nominal strength can be calculated and for adverse variations in materials and dimensions, a strength reduction factor (Ø) should be used in the strength design method.