Specification for Structural Steel Buildings

278 Pages·2016·2.97 MB·English

_________________________
Specification
for Structural Steel Buildings
_________________________
Supersedes the
Specification for Structural Steel Buildings
datedJune 22, 2010
and all previous versions of this specification.

Approved by the AISC Committee on Specifications
One East Wacker Drive, Suite 700
Chicago, Illinois 60601-1802
1 Symbols
2
3 Some definitions in the list below have been simplified in the interest of
4 brevity. In all cases, the definitions given in the body of the Specification
5 govern. Symbols without text definitions, or used only in one location and
6 defined at that location, are omitted in some cases. The section or table
7 number in the righthand column refers to the Section where the symbol is
8 first used.
9
10 Symbol Definition Section
11
12 A Cross-sectional area of angle, in. 2 (mm2) ................................ F10.2
13 A Cross-sectional area of the base metal, in.2 (mm2) ...................... J2.4
BM
14 A Nominal unthreaded body area of bolt or threaded part, in.2 (mm2) ..
b
15 .................................................................................................... J3.6
16 A Cross-sectional area of the overlapping branch, in.2 (mm2) ..............
bi
17 ......................................................................................... Table K3.2
18 A Cross-sectional area of the overlapped branch, in.2 (mm2) ................
bj
19 ......................................................................................... Table K3.2
20 A Area of concrete, in.2 (mm2) ..................................................... I2.1b
c
21 A Area of concrete slab within effective width, in. 2 (mm2) ......... I3.2d
c
22 A Effective area, in. 2 (mm2) ........................................................ E7.2
e
23 A Effective net area, in. 2 (mm2) ........................................................ D2
e
24 A Summation of the effective areas of the cross section based on
e
25 the reduced effective widths, b , d or h in.2 (mm2) .................. E7.1
e e e
26 A Area of compression flange, in.2 (mm2) .................................... G2.2
fc
27 A Gross area of tension flange, in.2 (mm2) .................................. F13.1
fg
28 A Net area of tension flange, in. 2 (mm2) ..................................... F13.1
fn
29 A Area of tension flange, in.2 (mm2) ............................................. G2.2
ft
30 A Gross cross-sectional area of member, in. 2 (mm2) ..................... B3.3
g
31 A Gross area of composite member, in. 2 (mm2) ............................. I2.1
g
32 A Gross area subject to shear, in.2 (mm2) ....................................... J4.2
gv
33 A Net area of member, in. 2 (mm2) ................................................ B4.3
n
34 A Area of the directly connected elements, in.2 (mm2) ....... Table D3.1
n
35 A Net area subject to tension, in. 2 (mm2) ........................................ J4.3
nt
36 A Net area subject to shear, in. 2 (mm2) .......................................... J4.2
nv
37 A Projected area in bearing, in. 2 (mm2) ............................................. J7
pb
38 A Cross-sectional area of steel section, in. 2 (mm2) ....................... I2.1b
s
39 A Cross-sectional area of steel headed stud anchor, in.2 (mm2) ... I8.2a
sa
40 A Area on the shear failure path, in. 2 (mm2) ................................. D5.1
sf
41 A Area of continuous reinforcing bars, in. 2 (mm2) ......................... I2.1
sr
42 A Area of adequately developed longitudinal reinforcing steel within
sr
43 the effective width of the concrete slab, in.2 (mm2) .............. I3.2d(2)
44 A Net area in tension, in. 2 (mm2) ............................................. App. 3.4
t
45 A Nominal forces and deformations due to the design-basis fire
T
46 defined in Section 4.2.1 .................................................... App. 4.1.4
47 A Area of web, the overall depth times the web thickness, dt ,
w w
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-2

48 in. 2 (mm2) ................................................................................... G2.1
49 A Effective area of the weld, in. 2 (mm2) ........................................ J2.4
we
50 A Loaded area of concrete, in.2 (mm2) .......................................... I6.3a
1
51 A Area of steel concentrically bearing on a concrete support,
1
52 in.2 (mm2) ....................................................................................... J8
53 A Maximum area of the portion of the supporting surface that is
2
54 geometrically similar to and concentric with the loaded area, in.2
55 (mm2) ............................................................................................. J8
56 B Overall width of rectangular HSS member, measured 90 to the
57 plane of the connection, in. (mm) ................................... Table D3.1
58 B Overall width of rectangular HSS branch member or plate,
b
59 measured 90 to the plane of the connection, in. (mm) ............. K1.1
60 B Effective width of rectangular HSS branch or plate in. (mm) ... K1.1
e
61 B Effective width of the overlapping branch, in. (mm) ..... Table K3.2
ei
62 B Effective width of the overlapping branch, in. (mm) ..... Table K3.2
ej
63 B Overall width of the overlapping branch, in. (mm) ................... K3.2
bi
64 B Overall width of the overlapped branch, in. (mm) .................... K3.2
bj
65 B Multiplier to account for P- effects ................................... App. 8.2
1
66 B Multiplier to account for P- effects ................................... App. 8.2
2
67 C HSS torsional constant ............................................................... H3.1
68 C Lateral-torsional buckling modification factor for nonuniform
b
69 moment diagrams ......................................................................... F1
70 C Coefficient accounting for increased required bracing stiffness at
d
71 inflection point ............................................................... App. 6.3.1a
72 C Constant from Table A-3.1 for the fatigue category ............ App. 3.3
f
73 C Equivalent uniform moment factor ................................. App. 8.2.1
m
74 C Ponding flexibility coefficient for primary member in a flat roof ....
p
75 ............................................................................................. App. 2.1
76 C Coefficient for web sidesway buckling ................................... J10.4
r
77 C Ponding flexibility coefficient for secondary member in a flat roof
s
78 ............................................................................................. App. 2.1
79 C Web shear strength strength coefficient .................................... G2.1
v1
80 C Web shear buckling coefficient ................................................ G2.2
v2
81 C Warping constant, in.6 (mm6) ...................................................... E4
w
82 C Coefficient for calculation of effective rigidity of encased
1
83 composite compression member ............................................... I2.1b
84 C Edge distance increment ................................................... Table J3.5
2
85 C Coefficient for calculation of effective rigidity of filled composite
3
86 compression member ................................................................ I2.2b
87 D Outside diameter of round HSS, in. (mm) ....................... Table B4.1
88 D Outside diameter of round HSS main member, in. (mm) .......... K1.1
89 D Nominal dead load, kips (N) ...................................................... B3.9
90 D Outside diameter of round HSS branch member, in. (mm) ....... K1.1
b
91 D In slip-critical connections, a multiplier that reflects the ratio of the
u
92 mean installed bolt pretension to the specified minimum bolt
93 pretension ................................................................................... J3.8
94 E Modulus of elasticity of steel= 29,000 ksi (200 000 MPa) ...............
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-3

95 ......................................................................................... Table B4.1
96 E Modulus of elasticity of concrete = w1.5 f , ksi
c c c
97 (0.043w1.5 f , MPa) ............................................................... I2.1b
c c
98 E Modulus of elasticity of steel= 29,000 ksi (200 000 MPa) ..... I2.1b
s
99 EI Effective stiffness of composite section, kip-in.2 (N-mm2) ...... I2.1b
eff
100 F Available stress in main member, ksi (MPa) ............................. K1.1
c
101 F Available axial stress at the point of consideration, ksi (MPa)..... H2
ca
102 F ,F Available flexural stress at the point of consideration, ksi (MPa) H2
cbw cbz
103 F Critical stress, ksi (MPa) .............................................................. E3
cr
104 F Elastic buckling stress, ksi (MPa) ................................................. E3
e
105 F Elastic local buckling stress, ksi (MPa) .................................... E7.1
el
106 F Flexural elastic buckling stress about the major principal axis, ksi
ex
107 (MPa) ........................................................................................... E4
108 F Filler metal classification strength, ksi (MPa) ............................ J2.4
EXX
109 F Flexural elastic buckling stress about the major minor principal
ey
110 axis, ksi (MPa) .............................................................................. E4
111 F Torsional elastic buckling stress, ksi (MPa) ................................. E4
ez
112 F Nominal bond stress ksi (Mpa) ................................................ I6.3c
in
113 F Magnitude of flexural stress in compression flange at which flange
L
114 local buckling or lateral-torsional buckling is influenced by
115 yielding, ksi (MPa) .......................................................... Table B4.1
116 F Nominal stress, ksi (MPa).......................................................... H3.3
n
117 F Nominal stress of the base metal, ksi (MPa) .............................. J2.4
nBM
118 F Nominal tensile stress from Table J3.2, ksi (MPa) ..................... J3.6
nt
119 F Nominal tensile stress modified to include the effects of shear
nt
120 stress, ksi (MPa) ......................................................................... J3.7
121 F Nominal shear stress from Table J3.2, ksi (MPa) ....................... J3.6
nv
122 F Nominal stress of the weld metal, ksi (MPa) .............................. J2.4
nw
123 F Nominal stress of the weld metal (Chapter J) with no increase in
nw
124 strength due to directionality of load, ksi (MPa) ......................... K5
125 F Allowable stress range, ksi (MPa) ....................................... App. 3.3
SR
126 F Threshold allowable stress range, maximum stress range for
TH
127 indefinite design life from Table A-3.1, ksi (MPa) ............. App. 3.3
128 F Specified minimum tensile strength, ksi (MPa) ............................ D2
u
129 F Specified minimum yield stress, ksi (MPa). As used in this
y
130 Specification, “yield stress” denotes either the specified minimum
131 yield point (for those steels that have a yield point) or specified
132 yield strength (for those steels that do not have a yield point) .. B3.3
133 F Specified minimum yield stress of HSS branch member or plate
yb
134 material, ksi (MPa) .................................................................... K1.1
135 F Specified minimum yield stress of the overlapping branch material,
ybi
136 ksi (MPa) ......................................................................... Table K3.2
137 F Specified minimum yield stress of the overlapped branch material,
ybj
138 ksi (MPa) ......................................................................... Table K3.2
139 F Specified minimum yield stress of the flange, ksi (MPa) ......... J10.1
yf
140 F Specified minimum yield stress of reinforcing bars, ksi (MPa) I2.1b
ysr
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-4

141 F Specified minimum yield stress of the stiffener material, ksi
yst
142 (MPa) ......................................................................................... G2.3
143 F Specified minimum yield stress of the web material, ksi (MPa)G2.3
yw
144 G Shear modulus of elasticity of steel= 11,200 ksi (77 200 MPa) .. E4
145 H Flexural constant ........................................................................... E4
146 H Story shear, in the direction of translation being considered,
147 produced by the lateral forces used to compute , kips (N)
H
148 .......................................................................................... App. 8.2.2
149 H Overall height of rectangular HSS member, measured in the plane
150 of the connection, in. (mm) ..............................................T able D3.1
151 H Overall height of rectangular HSS branch member, measured in the
b
152 plane of the connection, in. (mm) .............................................. K1.1
153 H Overall depth of the overlapping branch, in. (mm) ......... Table K3.2
bi
154 I Moment of inertia, in.4 (mm4) ........................................... App. 8.2.1
155 I Moment of inertia of the concrete section about the elastic neutral
c
156 axis of the composite section, in.4 (mm4) ................................. I2.1b
157 I Moment of inertia of the steel deck supported on secondary
d
158 members, in.4 (mm4) ............................................................ App. 2.1
159 I Moment of inertia of primary members, in.4 (mm4) ............ App. 2.1
p
160 I Moment of inertia of secondary members, in.4 (mm4) ......... App. 2.1
s
161 I Moment of inertia of steel shape about the elastic neutral axis of
s
162 the composite section, in.4 (mm4) ............................................. I2.1b
163 I Moment of inertia of reinforcing bars about the elastic neutral axis
sr
164 of the composite section, in.4 (mm4) ......................................... I2.1b
165 I Moment of inertia of transverse stiffeners about an axis in the web
st
166 center for stiffener pairs, or about the face in contact with the web
167 plate for single stiffeners, in.4 (mm4) ......................................... G2.3
168 I Minimum moment of inertia of transverse stiffeners required for
st1
169 development of the full shear post buckling resistance of the
170 stiffened web panels, V = V ,in.4 (mm4) ................................. G2.3
r c1
171 I Minimum moment of inertia of transverse stiffeners required for
st2
172 development of web shear buckling resistance, V = V , in.4
r c2
173 (mm4) ......................................................................................... G2.3
174 I , I Moment of inertia about the principal axes, in.4 (mm4) ................ E4
x y
175 I Effective out-of-plane moment of inertia, in.4 (mm4)… App. 6.3.2a
yeff
176 I Moment of inertia of the compression flange about the y-axis, in.4
yc
177 (mm4) ......................................................................................... F4.2
178 I Moment of inertia of the tension flange about the y-axis, in. 4 (mm4)
yt
179 ....................................................................................... App. 6.3.2a
180 I Minor principal axis moment of inertia, in.4 (mm4) ................. F10.2
z
181 J Torsional constant, in.4 (mm4) ...................................................... E4
182 K Effective length factor .................................................................. E2
183 K Effective length factor for flexural buckling about x-axis ............ E4
x
184 K Effective length factor for flexural buckling about y-axis ............ E4
y
185 K Effective length factor for torsional buckling ............................... E4
z
186 L Height of story, in. (mm) .................................................. App. 7.3.2
187 L Length of member, in. (mm)...................................................... H3.1
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-5

188 L Nominal occupancy live load .................................................... B3.9
189 L Laterally unbraced length of member, in. (mm) ........................... E2
190 L Length of span, in. (mm) ................................................ App. 6.3.2a
191 L Length of member between work points at truss chord centerlines,
192 in. (mm) ........................................................................................ E5
193 L Length between points that are either braced against lateral
b
194 displacement of compression flange or braced against twist of the
195 cross section, in. (mm) ............................................................... F2.2
196 L Largest laterally unbraced length along either flange at the point of
b
197 load, in. (mm) ........................................................................... J10.4
198 L Distance between braces, in. (mm) ...................................... App. 6.1
b
199 L Unbraced length adjacent to the point brace,
br
200 in.(mm)……………..…………. ...................................... App. 6.1.2
201 L Unbraced length within the panel under consideration, in. (mm)
br
202 ……………..…………. ................................................... App. 6.2.1
203 L Effective length = KL, in. (mm)……………..…………. ............. E2
c
204 L Effective length of member for buckling about the x-axis = KL,
cx x x
205 in (mm) ......................................................................................... E4
206 L Effective length of member for buckling about the y-axis = KL,
cy y y
207 in (mm) ..................................................................................... …E4
208 L Effective length of member for buckling about the longitudinal
cz
209 axis = KL, in (mm) .....................................................… ………E4
z z
210 L Effective length in the plane of bending, calculated based on the
c1
211 assumption of no lateral translation at the member ends, set equal
212 to the member’s unbraced length unless analysis justifies a smaller
213 value, in. (mm) .................................................................. App. 8.2.1
214 L Load induction introduction length, in. (mm) .......................... I6.3c
in
215 L Limiting laterally unbraced length for eligibility for moment
m
216 redistribution in beams ................................................................... F13.5
217 L Limiting laterally unbraced length for the limit state of yielding, in.
p
218 (mm) .......................................................................................... F2.2
219 L Length of primary members, ft (m) ..................................... App. 2.1
p
220 L Limiting laterally unbraced length for plastic analysis, in.
pd
221 (mm) ............................................................................... App. 1.2.2c
222 L Limiting laterally unbraced length for the limit state of inelastic
r
223 lateral-torsional buckling, in. (mm) ........................................... F2.2
224 L Length of secondary members, ft (m) .................................. App. 2.1
s
225 L Distance from maximum to zero shear force, in. (mm) ................ G5
v
226 M Absolute value of moment at quarter point of the unbraced
A
227 segment, kip-in. (N-mm) .............................................................. F1
228 M Required flexural strength using ASD load combinations, kip-in.
a
229 (N-mm) ..................................................................................... J10.4
230 M Absolute value of moment at centerline of the unbraced segment,
B
231 kip-in. (N-mm) .............................................................................. F1
232 M Absolute value of moment at three-quarter point of the unbraced
C
233 segment, kip-in. (N-mm) .............................................................. F1
234 M Elastic lateral-torsional buckling moment…………………....F10.2
cr
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-6

235 M ,M Available flexural strength determined in accordance with
cx cy
236 Chapter F, kip-in. (N-mm) ......................................................... H1.1
237 M Available lateral-torsional strength for major axis flexure
cx
238 determined in accordance with Chapter F using C = 1.0, kip-in.
b
239 (N-mm) ...................................................................................... H1.3
240 M Available flexural strength about the x-axis for the limit state of
cx
241 tensile rupture of the flange, kip-in. (N-mm) ................................ H4
242 M First-order moment using LRFD or ASD load combinations, due to
lt
243 lateral translation of the structure only, kip-in. (N-mm) App. 8.2
244 M Absolute value of maximum moment in the unbraced segment,
max
245 kip-in. (N-mm) .............................................................................. F1
246 M Moment at the middle of the unbraced length, kip-in. (N-mm)
mid
247 ........................................................................................ App. 1.2.2c
248 M Nominal flexural strength, kip-in. (N-mm) .................................. F1
n
249 M Nominal flexural strength for in-plane bending Table K4.1
n-ip
250 M Nominal flexural strength for out-of-plane bending Table K4.1
n-op
251 M First-order moment using LRFD or ASD load combinations, with
nt
252 the structure restrained against lateral translation, kip-in. (N-mm) ...
253 ............................................................................................. App. 8.2
254 M Plastic flexural strength, kip-in. (N-mm) ......................... Table B4.1
p
255 M Moment corresponding to plastic stress distribution over the
p
256 composite cross-section, kip-in. (N-mm) ................................. I3.4b
257 M Required second-order flexural strength under LRFD or ASD load
r
258 combinations, kip-in. (N-mm) ............................................. App. 8.2
259 M Required flexural strength using LRFD or ASD load combinations,
r
260 kip-in. (N-mm) ........................................................................... H1.1
261 M Required flexural strength of the beam within the panel under
r
262 consideration using LRFD or ASD load combinations, kip-in. (N-
263 mm) ................................................................................. App. 6.3.1a

264 M Largest of the required flexural strengths of the beam within the
r
265 unbraced lengths adjacent to the point brace using LRFD or ASD
266 load combinations, kip-in. (N-mm)…………………….App. 6.3.1b
267 M Required flexural strength of the brace, kip-in. (N-mm) App. 6.3.2a
br
268 M Required flexural strength in chord at a joint, on the side of joint
ro
269 with lower compression stress, kips (N) .......................... Table K2.1
270 M Required in-plane flexural strength in branch using LRFD or ASD
r-ip
271 load combinations, kip-in. (N-mm) ................................. Table K4.1
272 M Required out-of-plane flexural strength in branch using LRFD or
r-op
273 ASD load combinations, kip-in. (N-mm) ........................ Table K4.1
274 M ,M Required flexural strength, kip-in. (N-mm) ............................... H1.1
rx ry
275 M Required flexural strength at the location of the bolt holes; positive
rx
276 for tension in the flange under consideration, negative for
277 compression, kip-in. (N-mm) ....................................................... H4
278 M Required flexural strength using LRFD load combinations, kip-in.
u
279 (N-mm) ..................................................................................... J10.4
280 M Moment at yielding of the extreme fiber, kip-in. (N-mm)Table B4.1
y
281 M Yield moment corresponding to yielding of the tension flange
y
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-7

282 and first yield of the compression flange, kip-in. (N-mm) ....... I3.4b
283 M Yield moment about the axis of bending, kip-in. (N-mm) ........ F9.1
y
284 M Moment at yielding of the extreme fiber in the compression flange,
yc
285 kip-in. (N-mm) ........................................................................... F4.2
286 M Moment at yielding of the extreme fiber in the tension flange,
yt
287 kip-in. (N-mm) ........................................................................... F4.4
288 M Effective moment at the end of the unbraced length opposite from
1
289 M2, kip-in. (N-mm) ......................................................... App. 1.2.2b
290 M Smaller moment at end of unbraced length, kip-in. (N-mm) ... F13.5
1
291 M Larger moment at end of unbraced length, kip-in.(N-mm) ..... F13.5
2
292 N Notional load applied at level i, kips (N) ................................. C2.2b
i
293 N Additional lateral load, kips (N) ....................................... App. 7.3.2
i
294 O Overlap connection coefficient .................................................. K3.1
v
295 P Required axial strength in chord using ASD load combinations,
a
296 kips (N) ...................................................................................... Table K2.1
297 P Required end and intermediate point brace strength using LRFD or
br
298 ASD load combinations, kips (N) ..................................... App. 6.2.2
299 P Available axial strength, kips (N) .............................................. H1.1
c
300 P Available axial strength for the limit state of tensile rupture of the
c
301 net section at the location of bolt holes, kips (N)……………….H4
302 P Available axial compressive strength out of the plane of bending,
cy
303 kips (N) ...................................................................................... H1.3
304 P Elastic critical buckling load determined in accordance with
e
305 Chapter C or Appendix 7, kips (N) ........................................... I2.1b
306 P Nominal cross-section compressive strength, kips (N)…. ........ C2.3
ns
307 P Elastic critical buckling strength for the story in the direction of
e story
308 translation being considered, kips (N) ............................... App 8.2.2
309 P Elastic critical buckling load for buckling about the weak axis, kips
ey
310 (kN) ............................................................................................ H1.2
311 P Elastic critical buckling strength of the member in the plane of
e1
312 bending, kips (N) .............................................................. App. 8.2.1
313 P First-order axial force using LRFD or ASD load combinations, due
lt
314 to lateral translation of the structure only, kips (N) ............. App. 8.2
315 P Total vertical load in columns in the story that are part of moment
mf
316 frames, if any, in the direction of translation being considered, kips
317 (N) ..................................................................................... App. 8.2.2
318 P Nominal axial strength, kips (N) .................................................. D2
n
319 P Nominal axial compressive strength, kips (N).............................. E1
n
320 P Nominal axial compressive strength of zero length, doubly
no
321 symmetric, axially loaded composite member, kips (N) .......... I2.1b
322 P Cross-section compressive strength, kips (N) ........................... C2.3
ns
323 P First-order axial force using LRFD and ASD load combinations,
nt
324 with the structure restrained against lateral translation,
325 kips (N) ................................................................................ App. 8.2
326 P Nominal bearing strength, kips (N) ............................................... J8
p
327 P Required second-order axial strength using LRFD or ASD load
r
328 combinations, kips (N) ........................................................ App. 8.2
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-8

329 P Required axial compressive strength using LRFD or ASD load
r
330 combinations, kips (N) .............................................................. C2.3
331 P Required axial strength using LRFD or ASD load combinations,
r
332 kips (N) ...................................................................................... H1.1
333 P Required axial strength of the member at the location of the bolt
r
334 holes; positive in tension, negative in compression, kips (N) ...... H4
335 P Required external force applied to the composite member, kips
r
336 (N) ............................................................................................. I6.2a
337 P Required end and intermediate point brace strength using LRFD or
br
338 ASD load combinations, kips (N) ..................................... App. 6.2.2
339 P Cross-section compressive strength, kips (N)................... App. 7.3.1
ns
340 P Required axial strength in chord at a joint, on the side of joint with
ro
341 lower compression stress, kips (N) .................................. Table K2.1
342 P Total vertical load supported by the story using LRFD or ASD
story
343 load combinations, as applicable, including loads in columns that
344 are not part of the lateral force resisting system, kips (N) App. 8.2.2
345 P Required axial strength in chord using LRFD load combinations,
u
346 kips (N) ............................................................................. Table K2.1
347 P Required axial strength using LRFD load combinations,
u
348 kips (N) .......................................................................... App. 1.3.2b
349 P Axial yield strength of the column, kips (N) ........................... J10.6
y
350 Q Available tensile strength, kips (N) .......................................... I8.3c
ct
351 Q Available shear strength, kips (N) ............................................ I8.3c
cv
352 Q Chord-stress interaction parameter .......................................... J10.3
f
353 Q Gapped truss joint parameter accounting for geometric effects
g
354 ......................................................................................... Table K3.1
355 Q Nominal strength of one steel headed stud or steel channel
n
356 connector, kips (N) ................................................................... I3.2d
357 Q Nominal tensile strength of steel headed stud anchor, kips (N) I8.3b
nt
358 Q Nominal shear strength of steel headed stud anchor, kips (N) . I8.3a
nv
359 Q Required tensile strength, kips (N) ........................................... I8.3c
rt
360 Q Required shear strength, kips (N) ............................................. I8.3c
rv
361 R Radius of joint surface, in. (mm) ......................................T able J2.2
362 R Seismic response modification coefficient ................................A 1.1
363 R Required strength using ASD load combinations ..................... B3.2
a
364 R Reduction factor for joints using a pair of transverse fillet welds
FIL
365 only ...................................................................................... App. 3.3
366 R Coefficient to account for group effect .................................... I8.2a
g
367 R Coefficient to account for influence of P- on P- ..........A pp. 8.2.2
M
368 R Nominal strength, specified in Chapters B through K .............. B3.2
n
369 R Nominal slip resistance, kips (N) ................................................ J1.8
n
370 R Nominal strength of the applicable force transfer mechanism,
n
371 kips (N) ...................................................................................... I6.3
372 R Total nominal strength of longitudinally loaded fillet welds, as
nwl
373 determined in accordance with Table J2.5, kips (N) ................. J2.4
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
Symbols-9

374 R Total nominal strength of transversely loaded fillet welds, as
nwt
375 determined in accordance with Table J2.5 without the alternate in
376 Section J2.4(a), kips (N) ............................................................ J2.4
377 R Position effect factor for shear studs ....................................... I8.2a
p
378 R Web plastification factor............................................................ F4.1
pc
379 R Bending strength reduction factor ............................................. F5.2
pg
380 R Reduction factor for reinforced or nonreinforced transverse
PJP
381 partial-joint-penetration (PJP) groove welds ...................... App. 3.3
382 R Web plastification factor corresponding to the tension flange
pt
383 yielding limit state ..................................................................... F4.4
384 R Required strength using LRFD load combinations ................... B3.2
u
385 S Elastic section modulus about the axis of bending, in.3 (mm3) . F7.2
386 S Spacing of secondary members, ft (m) ................................ App. 2.1
387 S Elastic section modulus to the toe in compression relative to the
c
388 axis of bending, in.3 (mm3). ..................................................... F10.3
389 S Effective section modulus determined with the effective width of
e
390 the compression flange, in.3 (mm3) ............................................ F7.2
391 S Effective elastic section modulus of welds for in-plane bending
ip
392 (Table K5.1), in.3(mm3) ............................................................... K5
393 S Lowest elastic section modulus relative to the axis of bending, in.3
min
394 (mm3) .......................................................................................... F12
395 S Effective elastic section modulus of welds for out-of-plane bending
op
396 (Table K5.1), in.3(mm3) ............................................................... K5
397 S , S Elastic section modulus referred to compression and tension
xc xt
398 flanges, respectively, in.3 (mm3) ...................................... Table B4.1
399 S Elastic section modulus taken about the x-axis, in.3 (mm3) ....... F2.2
x
400 S Elastic section modulus taken about the y-axis, in.3 (mm3) ....... F6.1
y
401 T Elevated temperature of steel due to unintended fire exposure,

402 F ( C) ........................................................................... App. 4.2.4d
403 T Required tension force using ASD load combinations,
a
404 kips (kN) ..................................................................................... J3.9
405 T Minimum fastener tension given in Table J3.1 or J3.1M,
b
406 kips (kN) ..................................................................................... J3.8
407 T Available torsional strength, kip-in. (N-mm) ............................H 3.2
c
408 T Nominal torsional strength, kip-in. (N-mm) ..............................H 3.1
n
409 T Required torsional strength using LRFD or ASD load
r
410 combinations, kip-in. (N-mm) ...................................................H 3.2
411 T Required tension force using LRFD load combinations,
u
412 kips (kN) ..................................................................................... J3.9
413 U Shear lag factor ............................................................................. D3
414 U Utilization ratio ................................................................ Table K2.1
415 U Reduction coefficient, used in calculating block shear rupture
bs
416 strength ....................................................................................... J4.3
417 U Stress index for primary members ....................................... App. 2.2
p
418 U Stress index for secondary members ................................... App. 2.2
s
419 V Nominal shear force between the steel beam and the concrete slab
420 transferred by steel anchors, kips (N) ....................................... I3.2d
Specification for Structural Steel Buildings, draft dated December 18, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION