β	The bond coefficient of steel fiber.
θ	The angle of inclination of the concrete strut, taken as 45°.
ρf	The volume ratio of fibers.
ρl	Longitudinal steel reinforcement ratio.
ρt	Transversal steel reinforcement ratio.
Acp	Total concrete cross-sectional area.
Al	Total cross-sectional area of longitudinal steel reinforcement.
A 0	The area enclosed inside centerline of shear flow path.
As	Cross-sectional area of steel stirrup.
At	The cross-section area of one branch of the steel stirrups.
c 1	Constant with value equal to 0.5, 0.55 and 0.86 for beams with rectangular, flanged and circular cross-section, respectively.
c 2	Constant with value equal to 0.04, 0.08 and 0.92 for beams with rectangular, flanged and circular cross-section, respectively.
D	The diameter of cross-section.
df	Diameter of fiber.
F	The fiber factor, which is taken as β (lf/df) ρf.
$f_c^{\prime }$	The cylinder compressive strength of the concrete.
$f_{cu}$	The cubic compressive strength of the concrete.
$f_{ly}$	The yield stress of longitudinal steel reinforcing bars.
$f_t$	The concrete tensile strength, taken as $\left(0.45\sqrt{f_{cu}}\right)$.
$f_{ty}$	The yield stress of transversal steel reinforcement (stirrups).
k 2	The longitudinal reinforcement factor.
lf	Length of fiber.
m	The ratio between the longitudinal and transversal reinforcement, which is taken as ρl fly/ρt fty.
Pcp	The perimeter of concrete section.
Ph	The perimeter of outermost closed stirrup.
s	The spacing between steel stirrups along the longitudinal direction of the beam.
T	Torsion capacity of the cross-section.
x	the smaller dimension of the cross-section.
x 0	The smaller center to center dimension of the thin wall tube analogy, which is taken approximately as (5/6) x.
x 1	The smaller dimension of the steel stirrup, which is taken approximately as 0.9 x.
y	The larger dimension of the cross-section.
y 0	The larger center to center dimension of the thin wall tube analogy, which is taken approximately as (5/6) y.
y 1	The larger dimension of the steel stirrup, which is taken approximately as 0.9 y.