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Appendix 4
Symbols

Table A8.1 Symbols

Symbol	Definition	Imperial	Metric
#_b	bending (flexure) property or action	vary
#_c	compression property or action	vary
#_D	dead load-related action	vary
#_L	live load-related action	vary
#_n	nominal capacity	vary
#_S	snow load-related action	vary
#_t	tension property or action	vary
#_u	factored load, any type	vary
#_v	shear property or action	vary
#_W	wind load-related action	vary
a	fillet weld leg size	in	mm
A	area	in²	mm²
A_b	nominal unthreaded bolt cross-section	area	in²
mm²	A_e	effective area	in²
mm²	A_g	gross cross	section area
in²	mm²	A_gv	gross shear
area	in²	mm²	A_n
net cross	section area	in²	mm²
A_nt	net tension area	in²	mm²
A_nv	net shear area	in²	mm²
A_req	required area	in²	mm²
A_w	web area	in²	mm²
A_we	effective weld area	in²	mm²
B	width of HSS	in	mm
b	width of unstiffened compression element	in	mm
b’	material cantilever in prying	in	mm
b_f	flange width	in	mm
C	compression	lb or k	N, kN, MN
C	HSS torsion parameter	in³	mm³
C_b	lateral torsional buckling factor	unitless
CE	carbon equivalent	%
C_v	web shear buckling coefficient	unitless
C_w	torsion warping factor	unitless
d	nominal bolt diameter	in	mm
d	depth	in	mm
D	dead load	k, k/ft, k/ft² lb, lb/ft, lb/ft²	kN, kN/m, kN/m² N, N/m, N/m²
E	modulus of elasticity	lb/in²	GN/m², GPa
E	seismic load	lb or k	N, kN, MN
e	eccentricity	in	mm
F	stress	lb/in²	MN/m², MPa
F_cr	critical stress	lb/in²	MN/m², MPa
F^e	elastic buckling stress	lb/in²	MN/m², MPa
F_EXX	weld filler metal strength classification	lb/in²	MN/m², MPa
F_n	nominal fastener stress	lb/in²	MN/m², MPa
F_nt	nominal fastener tensile stress	lb/in²	MN/m², MPa
F_nv	nominal fastener shear stress	lb/in²	MN/m², MPa
F_nw	nominal weld metal stress	lb/in²	MN/m², MPa
F_u	nominal tensile stress	lb/in²	MN/m², MPa
F_y	nominal yield stress	lb/in²	MN/m², MPa
g	gage	in	mm
G	shear modulus of elasticity	lb/in²	MN/m², MPa
h	story height	ft	m
h	clear distance between flanges minus fillets	in	mm
H	HSS depth	in	mm
h_o	distance between flange centroids	in	mm
I, I_x, I_y	moment of inertia	in⁴	mm⁴
ID	inside diameter	in	mm
J	torsion factor	in⁴	mm⁴
K	effective length factor	unitless
k_v	shear buckling coefficient	unitless
L	live load	k, k/ft, k/ft² lb, lb/ft, lb/ft²	kN, kN/m, kN/m^2, N, N/m N/m²
L	span length	ft	m
l	connection length	in	mm
L_b	length between points of lateral beam bracing	ft	m
L_c	effective length factor	in	mm
l_c	clear distance between edge of material and hole	in	mm
L_o	base live load	k, k/ft, k/ft², lb lb/ft, lb/ft²	kN, kN/m, kN/m²,^, N N/m, N/m²
L_p	limiting laterally unbraced length for plastic flexural yielding	ft	m
L_r	limiting laterally unbraced length for elastic flexural yielding	ft	m
L_t	tributary width	ft	m
l_w	weld length	in	mm
M_p	plastic flexural capacity	k-ft	kN-m
M_r	flextural capacity at elastic transition	k-ft	kN-m
M_u	flexural moment demand	k-ft	kN-m
M_y	moment at yield	k-ft	kN-m
n	number, quantity	unitless
OD	outside diameter	in	mm
P	point load, axial compression	k	kN, MN
p	tributary length to fastener	in	mm
P_n	nominal compression capacity	k	kN, MN
P_u	factored compression demand	k	kN, MN
q, q_x	area unit load, pressure	lb/ft², k/ft²	N/m², kN/m²
r	radius of a circle or cylinder	in, ft	mm, m
R	response modification factor for seismic	force	unitless
R, R_#	reaction	lb or k	N, kN, MN
R_n	nominal connection strength	k	kN, MN
R_t	ratio of expected to specified ultimate	strength	unitless
r_ts	effective radius of gyration	in	mm
r_x, r_y, r_z	radius of gyration	in	mm
R_y	ratio of expected to specified yield strength	unitless
S	snow load	k, k/ft, k/ft², lb, lb/ft, lb/ft²	kN, kN/m, kN/m², N, N/m, N/m²
s	spacing	in	mm
S, S_x, S_y	elastic section modulus	in³	mm³
T	tension	lb or k	N, kN, MN
t	thickness	in	mm
t_des	design thickness	in	mm
t_e	fillet weld throat	in	mm
t_f	flange thickness	in	mm
t_min	minimum thickness to ignore prying	in	mm
T_n	nominal tension capacity	k	kN
T_u	factored tension demand	k	kN
T_u	factored torsion demand	k-ft	kN-m
t_w	web thickness	in	mm
U	shear lag factor	unitless
U_bs	shear lag factor for block shear	unitless
V	shear	lb or k	N, kN, MN
V_n	nominal shear capacity	k	kN
V_u	factored shear demand	k	kN
v^u	unit shear	lb/ft	kN/m
w	width	in	mm
w	line load, or uniform load	lb/ft	kN/m
W	wind load	k, k/ft, k/ft², lb, lb/ft, lb/ft²	kN, kN/m, kN/m², N, N/m, N/m²
W	weight	lb or k	N, kN, MN
W	diaphragm width	ft	m
w_D	line dead load	lb/ft	kN/m
w_L	line live load	lb/ft	kN/m
w_S	line snow load	lb/ft	kN/m
w_u	factored line load	lb/ft	kN/m
x	geometric axis, distance along axis	unitless
$\bar{x}$	connection eccentricity	in	mm
y	geometric axis, distance along axis	unitless
z	geometric axis, distance along axis	unitless
Z, Z_x, Z_y	plastic section modulus	in³	m³
Δ	drift	in	mm
δ	deflection	in	mm
δ _a	allowable deflection	in	mm
ε	strain	unitless
φ	strength reduction factor	unitless
γ	unit weight	lb/ft³	kN/m³
λ _r	plastic slenderness parameter	unitless
λ _ρ	compact slenderness parameter	unitless

1) # indicates a general case of symbol and subscript, or subscript and symbol. It can be replaced with a letter or number, depending on how you want to use it. For example R_# may become R_V for a vertical reaction. Similarly, #_c may become P_c, indicating a compressive point load.

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Appendix 4 Symbols

Steel Design

Appendix 4
Symbols