A | Cross sectional area |

Ae | Effective cross sectional area |

AISI | American Iron and Steel Institute |

Area | Cross sectional area |

ASCE | American Society of Civil Engineers |

ASD | Allowable Strength Design |

B | Required bimoment strength |

Ba | Allowable bimoment strength |

ϕBn | Design bimoment strength |

b/t | Ratio of flange width to thickness |

Cbx | Bending coefficient dependent on moment gradient for bending about the X axis |

Cby | Bending coefficient dependent on moment gradient for bending about the Y axis |

Cmx | Moment coefficient in interaction formula for bending about the X axis |

Cmy | Moment coefficient in interaction formula for bending about the Y axis |

Cw | Torsional warping constant |

D/t | Ratio of outside diameter to thickness |

D/w | Ratio of lip overall depth to flange flat width |

d/t | Ratio of lip flat width to thickness |

d₀/b₀ | Ratio of lip outside width to flange outside width |

E | Modulus of elasticity (initial modulus for stainless steel) |

ex | Axial load eccentricity in the X direction, measured from the origin with positive to the right |

ey | Axial load eccentricity in the Y direction, measured from the origin with positive up |

Fu | Longitudinal ultimate tensile strength |

Fy | Yield strength |

h | Height of the flat portion of a web |

h/t | Ratio of web flat width to thickness |

I₁ | Moment of inertia about the major axis |

I₂ | Moment of inertia about the minor axis |

Ic | Polar moment of inertia about the centroid |

I₀ | Polar moment of inertia about the shear center |

Ix | Moment of inertia about the X axis |

Ixe | Effective moment of inertia about the X axis |

Ixy | Product of inertia about the X and Y axes |

Iy | Moment of inertia about the Y axis |

Iye | Effective moment of inertia about the Y axis |

J | St. Venant torsion constant |

jx | Asymmetry property for lateral-torsional buckling: (∫x³dA + ∫xy²dA)/2Iy - x₀ |

jy | Asymmetry property for lateral-torsional buckling: (∫y³dA + ∫yx²dA)/2Ix - y₀ |

KL/r | Slenderness ratio of a compressive member |

Kx | Effective length factor for buckling about the X axis ( in the Y direction) |

Ky | Effective length factor for buckling about the Y axis ( in the X direction) |

Kt | Effective length factor for torsional buckling |

k | Plate buckling coefficient |

kϕ | Rotational stiffness provided to a flange by attachment to deck or sheathing |

LRFD | Load and Resistance Factor Design |

LSD | Limit States Design |

Lm | Distance between discrete distortional buckling restraints |

Lx | Unbraced length for buckling about the X axis (in the Y direction) |

Ly | Unbraced length for buckling about the Y axis (in the X direction) |

Lt | Unbraced length for torsional buckling |

Max | Allowable moment strength about the X axis |

Maxo | Allowable moment strength about the X axis, based on yielding and local buckling (fully braced) |

May | Allowable moment strength about the Y axis |

Mayo | Allowable moment strength about the Y axis, based on yielding and local buckling (fully braced) |

ϕMnx | Design moment strength about the X axis |

ϕMnxo | Design moment strength about the X axis, based on yielding and local buckling (fully braced) |

ϕMny | Design moment strength about the Y axis |

ϕMnyo | Design moment strength about the Y axis, based on yielding and local buckling (fully braced) |

Mx | Applied moment about the X axis, positive moment has compression above the X axis |

My | Applied moment about the Y axis, positive moment has compression to the right of the Y axis |

N | Bearing length for web crippling check |

n | Modified Ramberg-Osgood Equation coefficient, indicating the linearity of the stress-strain curve. |

P | Applied compressive force |

Pa | Allowable compressive strength |

Pa | Allowable web crippling strength for an element, perpendicular to the bearing flange |

Pao | Allowable compressive strength, based on initiation of yielding (fully braced) |

Pax | Allowable web crippling strength for an element, in the X direction |

Pay | Allowable web crippling strength for an element, in the Y direction |

ϕPn | Design axial compressive strength |

ϕPn | Design web crippling strength for an element, perpendicular to the bearing flange |

ϕPno | Design axial compressive strength, based on initiation of yielding (fully braced) |

ϕPnx | Design web crippling strength for an element, in the X direction |

ϕPny | Design web crippling strength for an element, in the Y direction |

R | Moment reduction factor for beam with braced tension flange |

R/t | Ratio of inside bend radius to thickness |

r₁ | Radius of gyration about the major axis |

r₂ | Radius of gyration about the minor axis |

rc | Polar radius of gyration about the centroid |

r₀ | Polar radius of gyration about the shear center |

rx | Radius of gyration about the X axis |

ry | Radius of gyration about the Y axis |

Sx(b) | Section modulus about the X axis for the extreme bottom fiber |

Sxe(b) | Effective section modulus about the X axis for the extreme bottom fiber |

Sx(t) | Section modulus about the X axis for the extreme top fiber |

Sxe(t) | Effective section modulus about the X axis for the extreme top fiber |

Sy(l) | Section modulus about the Y axis for the extreme left fiber |

Sye(l) | Effective section modulus about the Y axis for the extreme left fiber |

Sy(r) | Section modulus about the Y axis for the extreme right fiber |

Sye(r) | Effective section modulus about the Y axis for the extreme right fiber |

t | Design thickness of the material |

Ta | Allowable tensile strength |

ϕTn | Design axial tensile strength |

Tsv | Internal St. Venant (pure) torque |

Tw | Internal warping torque |

Vax | Allowable shear strength in the horizontal direction |

Vay | Allowable shear strength in the vertical direction |

ϕVnx | Design shear strength in the horizontal direction |

ϕVny | Design shear strength in the vertical direction |

Vx | Applied shear force in the horizontal direction |

Vy | Applied shear force in the vertical direction |

Wt. | Weight per unit length for a section |

w | Width of the flat portion of an element |

w/t | Width to thickness ratio for an element |

X | Horizontal axis or dimension in the plane of the cross section, positive is to the right |

x₀ | Horizontal coordinate of the shear center relative to the centroid |

x(l) | Horizontal distance from the centroid of the section to the extreme left fiber |

x(r) | Horizontal distance from the centroid of the section to the extreme right fiber |

Y | Vertical axis or dimension in the plane of the cross section, positive is up |

y₀ | Vertical coordinate of the shear center relative to the centroid |

y(b) | Vertical distance from the centroid of the section to the extreme bottom fiber |

y(t) | Vertical distance from the centroid of the section to the extreme top fiber |

Zx | Plastic section modulus about the X axis |

Zy | Plastic section modulus about the Y axis |

α | Angle of the major axis with respect to the X axis, counter-clockwise is positive. |