Specification for Structural Steel Buildings

275 Pages·2015·2.89 MB·English

_________________________
Specification
for Structural Steel Buildings
_________________________

PUBLIC REVIEW DRAFT DATED March 2, 2015

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

Approved by the AISC Committee on Specifications

AMERICAN INSTITUTE OF STEEL CONSTRUCTION
One East Wacker Drive, Suite 700
Chicago, Illinois 60601-1802
Copyright © 20??

by

American Institute of Steel Construction

All rights reserved. This book or any part thereof
must not be reproduced in any form without the
written permission of the publisher.

The information presented in this publication has been prepared in accordance with recognized engineering
principles and is for general information only. While it is believed to be accurate, this information should not
be used or relied upon for any specific application without competent professional examination and
verification of its accuracy, suitability, and applicability by a licensed professional engineer, designer, or
architect. The publication of the material contained herein is not intended as a representation or warranty on
the part of the American Institute of Steel Construction or of any other person named herein, that this
information is suitable for any general or particular use or of freedom from infringement of any patent or
patents. Anyone making use of this information assumes all liability arising from such use.

Caution must be exercised when relying upon other specifications and codes developed by other bodies and
incorporated by reference herein since such material may be modified or amended from time to time
subsequent to the printing of this edition. The Institute bears no responsibility for such material other than
to refer to it and incorporate it by reference at the time of the initial publication of this edition.

Printed in the United States of America
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, 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 the base metal, in.2 (mm2) ...................... J2.4
BM
13 A Nominal unthreaded body area of bolt or threaded part, in.2 (mm2)J3.6
b
14 A Cross-sectional area of the overlapping branch, in.2 (mm2)Table K3.2
bi
15 A Cross-sectional area of the overlapped branch, in.2 (mm2)Table K3.2
bj
16 A Area of concrete, in.2 (mm2) ..................................................... I2.1b
c
17 A Area of concrete slab within effective width, in.2 (mm2) ......... I3.2d
c
18 A Effective net area, in.2 (mm2) ........................................................ D2
e
19 A Summation of the effective areas of the cross section based on the
e
20 reduced effective width, b , in.2 (mm2) ...................................... E7.2
e
21 A Area of compression flange, in.2 (mm2) .................................... G3.1
fc
22 A Gross area of tension flange, in.2 (mm2) .................................. F13.1
fg
23 A Net area of tension flange, in. 2 (mm2) ..................................... F13.1
fn
24 A Area of tension flange, in.2 (mm2) ............................................. G3.1
ft
25 A Gross cross-sectional area of member, in.2 (mm2) ..................... B3.3
g
26 A Gross area of composite member, in.2 (mm2) ............................. I2.1
g
27 A Gross area subject to shear, in.2 (mm2) ....................................... J4.2
gv
28 A Net area of member, in.2 (mm2) ................................................ B4.3
n
29 A Area of the directly connected elements, in.2 (mm2) ....... Table D3.1
n
30 A Net area subject to tension, in.2 (mm2) ........................................ J4.3
nt
31 A Net area subject to shear, in.2 (mm2) .......................................... J4.2
nv
32 A Projected area in bearing, in.2 (mm2) ............................................. J7
pb
33 A Cross-sectional area of steel section, in.2 (mm2) ....................... I2.1b
s
34 A Cross-sectional area of steel headed stud anchor, in.2 (mm2) ... I8.2a
sa
35 A Area on the shear failure path, in.2 (mm2) ................................. D5.1
sf
36 A Area of continuous reinforcing bars, in.2 (mm2) ......................... I2.1
sr
37 A Area of adequately developed longitudinal reinforcing steel within
sr
38 the effective width of the concrete slab, in.2 (mm2) .................. I3.2d
39 A Net area in tension, in.2 (mm2) ............................................. App. 3.4
t
40 A Area of web, the overall depth times the web thickness, dt ,
w w
41 in.2 (mm2) ................................................................................... G2.1
42 A Effective area of the weld, in.2 (mm2) ........................................ J2.4
we
43 A Loaded area of concrete, in.2 (mm2) .......................................... I6.3a
1
44 A Area of steel concentrically bearing on a concrete support,
1
45 in.2 (mm2) ....................................................................................... J8
46 A Maximum area of the portion of the supporting surface that is
2
47 geometrically similar to and concentric with the loaded area, in.2
48 (mm2) ............................................................................................. J8

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
2

49 B Overall width of rectangular HSS member, measured 90 to the
50 plane of the connection, in. (mm) ................................... Table D3.1
51 B Overall width of rectangular HSS branch member or plate,
b
52 measured 90 to the plane of the connection, in. (mm) ............. K1.1
53 B Effective width of rectangular HSS branch or plate, measured 90
e
54 to the plane of the connection, in. (mm)………………………K1.2
55 B Effective width of the overlapping branch, in. (mm)...…Table K3.2
ei
56 B Effective width of the overlapping branch, in. (mm)...…Table K3.2
ej
57 B Overall width of the overlapping branch, in. (mm) ................... K3.2
bi
58 B Overall width of the overlapped branch, in. (mm) .................... K3.2
bj
59 B Width of plate, measured 90 to the plane of the connection,
p
60 in. (mm) ........................................................................... Table K2.2
61 B Multiplier to account for P- effects .................................... App.8.2
1
62 B Multiplier to account for P- effects .................................... App.8.2
2
63 C HSS torsional constant ............................................................... H3.1
64 C Lateral-torsional buckling modification factor for nonuniform
b
65 moment diagrams ......................................................................... F1
66 C Coefficient accounting for increased required bracing stiffness at
d
67 inflection point ............................................................... App. 6.3.1a
68 C Constant from Table A-3.1 for the fatigue category ............ App. 3.3
f
69 C Coefficient accounting for non-uniform moment ............ App. 8.2.1
m
70 C Ponding flexibility coefficient for primary member in a
p
71 flat roof ............................................................................... App. 2.1
72 C Coefficient for web sidesway buckling ................................... J10.4
r
73
74 C Ponding flexibility coefficient for secondary member in a
s
75 flat roof ............................................................................... App. 2.1
76 C Web shear buckling coefficient ................................................ G2.1
vB
77 C Web shear post buckling strength coefficient………………. . ..G2.1
vPB
78 C Warping constant, in.6 (mm6) ...................................................... E4
w
79 C Coefficient for calculation of effective rigidity of encased
1
80 composite compression member ............................................... I2.1b
81 C Edge distance increment ................................................... Table J3.5
2
82 C Coefficient for calculation of effective rigidity of filled composite
3
83 compression member ................................................................ I2.2b
84 D Outside diameter of round HSS, in. (mm) ....................... Table B4.1
85 D Outside diameter of round HSS main member, in. (mm) .......... K1.1
86 D Nominal dead load, kips (N) ...................................................... B3.9
87 D Outside diameter of round HSS branch member, in. (mm) ....... K1.1
b
88 D In slip-critical connections, a multiplier that reflects the ratio of the
u
89 mean installed bolt pretension to the specified minimum bolt
90 pretension ................................................................................... J3.8
91 E Modulus of elasticity of steel = 29,000 ksi (200 000 MPa) ...............
92 ......................................................................................... Table B4.1
93 E Modulus of elasticity of concrete = w1.5 f, ksi (0.043w1.5 f,
c c c c c
94 MPa) ......................................................................................... I2.1b
95 E Modulus of elasticity of steel = 29,000 ksi (200 000 MPa) ..... I2.1b
s

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
3

96
97
98 EI Effective stiffness of composite section, kip-in.2 (N-mm2) ...... I2.1b
eff
99 F Available stress, ksi (MPa) ........................................................ K1.1
c
100 F Available axial stress at the point of consideration, ksi (MPa)..... H2
ca
101 F ,F Available flexural stress at the point of consideration, ksi (MPa) H2
cbw cbz
102 F Critical stress, ksi (MPa) .............................................................. E3
cr
103 F Elastic buckling stress, ksi (MPa) ................................................. E3
e
104 F Flexural elastic buckling stress about the major principal axis, ksi
ex
105 (MPa) ........................................................................................... E4
106 F Filler metal classification strength, ksi (MPa) ............................ J2.4
EXX
107 F Flexural elastic buckling stress about the major principal axis, ksiE4
ey
108 F Torsional elastic buckling stress, ksi (MPa) ................................. E4
ez
109 F Magnitude of flexural stress in compression flange at which flange
L
110 local buckling or lateral-torsional buckling is influenced by
111 yielding, ksi (MPa) .......................................................... Table B4.1
112 F Nominal stress, ksi (MPa).......................................................... H3.3
n
113 F Nominal tensile stress F , or shear stress, F , from Table J3.2, ksi
n nt nv
114 (MPa) .......................................................................................... J3.6
115 F Nominal stress of the base metal, ksi (MPa) .............................. J2.4
nBM
116 F Nominal tensile stress from Table J3.2, ksi (MPa) ..................... J3.7
nt
117 F Nominal tensile stress modified to include the effects of shear
nt
118 stress, ksi (MPa) ......................................................................... J3.7
119 F Nominal shear stress from Table J3.2, ksi (MPa) ....................... J3.7
nv
120 F Nominal stress of the weld metal, ksi (MPa) .............................. J2.4
nw
121 F Nominal stress of the weld metal (Chapter J) with no increase in
nw
122 strength due to directionality of load, ksi (MPa) ......................... K5
123 F Allowable stress range, ksi (MPa) ....................................... App. 3.3
SR
124 F Threshold allowable stress range, maximum stress range for
TH
125 indefinite design life from Table A-3.1, ksi (MPa) ............. App. 3.3
126 F Specified minimum tensile strength, ksi (MPa) ............................ D2
u
127 F Specified minimum yield stress, ksi (MPa). As used in this
y
128 Specification, “yield stress” denotes either the specified minimum
129 yield point (for those steels that have a yield point) or specified
130 yield strength (for those steels that do not have a yield point) .. B3.3
131 F Specified minimum yield stress of HSS branch member or plate
yb
132 material, ksi (MPa) .................................................................... K1.1
133 F Specified minimum yield stress of the overlapping branch material,
ybi
134 ksi (MPa) ......................................................................... Table K3.2
135 F Specified minimum yield stress of the overlapped branch material,
ybj
136 ksi (MPa) ......................................................................... Table K3.2
137 F Specified minimum yield stress of the flange, ksi (MPa) ......... J10.1
yf
138 F Specified minimum yield stress of plate, ksi (MPa) ....... Table K2.2
yp
139 F Specified minimum yield stress of reinforcing bars, ksi (MPa) I2.1b
ysr
140 F Specified minimum yield stress of the stiffener material, ksi
yst
141 (MPa) ......................................................................................... G3.2
142 F Specified minimum yield stress of the web material, ksi (MPa)G3.2
yw
143 G Shear modulus of elasticity of steel = 11,200 ksi (77 200 MPa) .. E4

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
4

144 H Flexural constant ........................................................................... E4
145 H Story shear, in the direction of translation being considered,
146 produced by the lateral forces used to compute  , kips (N)
H
147 .......................................................................................... App. 8.2.2
148 H Overall height of rectangular HSS member, measured in the plane
149 of the connection, in. (mm) .............................................. Table D3.1
150 H Overall height of rectangular HSS branch member, measured in the
b
151 plane of the connection, in. (mm) .............................................. K1.1
152 H Overall depth of the overlapping branch, in. (mm) ......... Table K3.2
bi
153 I Moment of inertia, in.4 (mm4) ........................................... App. 8.2.1
154 I Moment of inertia of the concrete section about the elastic neutral
c
155 axis of the composite section, in.4 (mm4) ................................. I2.1b
156 I Moment of inertia of the steel deck supported on secondary
d
157 members, in.4 (mm4) ............................................................ App. 2.1
158 I Moment of inertia of primary members, in.4 (mm4) ............ App. 2.1
p
159 I Moment of inertia of secondary members, in.4 (mm4) ......... App. 2.1
s
160 I Moment of inertia of steel shape about the elastic neutral axis of
s
161 the composite section, in.4 (mm4) ............................................. I2.1b
162 I Moment of inertia of reinforcing bars about the elastic neutral axis
sr
163 of the composite section, in.4 (mm4) ......................................... I2.1b
164 I Moment of inertia of transverse stiffeners about an axis in the web
st
165 center for stiffener pairs, or about the face in contact with the web
166 plate for single stiffeners, in.4 (mm4) ......................................... G2.2
167 I Minimum moment of inertia of transverse stiffeners required for
st1
168 development of the full web shear resistance without tension field
169 action in Section G2.2, in.4 (mm4) ............................................. G3.2
170 I Minimum moment of inertia of transverse stiffeners required for
st2
171 development of the full tension field resistance of the stiffened web
172 panels, V = V , in.4 (mm4) ........................................................ G3.2
r c2
173 I , I Moment of inertia about the principal axes, in.4 (mm4) ................ E4
x y
174
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 Effective length in the plane of bending, calculated based on the
c1
187 assumption of no lateral translation at the member ends, set equal
188 to the member’s unbraced length unless analysis justifies a smaller
189 value, in. (mm) .................................................................. App. 8.2.1
190 L Height of story, in. (mm) .................................................. App. 7.3.2
191 L Length of member, in. (mm)...................................................... H3.1

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
5

192 L Nominal occupancy live load .................................................... B3.9
193 L Laterally unbraced length of member, in. (mm) ........................... E2
194 L Length of span, in. (mm) ................................................ App. 6.3.2a
195 L Length of member between work points at truss chord centerlines,
196 in. (mm) ........................................................................................ E5
197 L Length between points that are either braced against lateral
b
198 displacement of compression flange or braced against twist of the
199 cross section, in. (mm) ............................................................... F2.2
200 L Distance between braces, in. (mm) ...................................... App. 6.1
b
201 L Largest laterally unbraced length along either flange at the point of
b
202 load, in. (mm) ........................................................................... J10.4
203 L Flange unbraced length, in. (mm)……………..………….App. 6.1
br
204 L Limiting laterally unbraced length for eligibility for moment
m
205 redistribution in beams ................................................................... F13.5
206 L Limiting laterally unbraced length for the limit state of yielding, in.
p
207 (mm) .......................................................................................... F2.2
208 L Length of primary members, ft (m) ..................................... App. 2.1
p
209 L Limiting laterally unbraced length for plastic analysis, in.
pd
210 (mm) ............................................................................... App. 1.2.2c
211 L Limiting laterally unbraced length for the limit state of inelastic
r
212 lateral-torsional buckling, in. (mm) ........................................... F2.2
213 L Length of secondary members, ft (m) .................................. App. 2.1
s
214 L Distance from maximum to zero shear force, in. (mm) ................ G6
v
215 M Absolute value of moment at quarter point of the unbraced
A
216 segment, kip-in. (N-mm) .............................................................. F1
217 M Required flexural strength using ASD load combinations, kip-in.
a
218 (N-mm) ..................................................................................... J10.4
219 M Absolute value of moment at centerline of the unbraced segment,
B
220 kip-in. (N-mm) .............................................................................. F1
221 M Absolute value of moment at three-quarter point of the unbraced
C
222 segment, kip-in. (N-mm) .............................................................. F1
223 M ,M Available flexural strength determined in accordance with Chapter
cx cy
224 F, kip-in. (N-mm) ...................................................................... H1.1
225 M Available lateral-torsional strength for strong axis flexure
cx
226 determined in accordance with Chapter F using C = 1.0, kip-in.
b
227 (N-mm) ...................................................................................... H1.1
228 M Available flexural strength about the x-axis for the limit state of
cx
229 tensile rupture of the flange, kip-in. (N-mm) ................................ H4
230 M First-order moment using LRFD or ASD load combinations, due to
lt
231 lateral translation of the structure only, kip-in. (N-mm) App. 8.2
232 M Absolute value of maximum moment in the unbraced segment,
max
233 kip-in. (N-mm) .............................................................................. F1
234 M Moment at the middle of the unbraced length, kip-in. (N-mm)
mid
235 ........................................................................................ App. 1.2.2c
236 M Nominal flexural strength, kip-in. (N-mm) .................................. F1
n

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
6

237 M Nominal flexural strength for in-plane bending Table K4.1
n-ip
238 M Nominal flexural strength for out-of-plane bending Table K4.1
n-op
239 M First-order moment using LRFD or ASD load combinations, with
nt
240 the structure restrained against lateral translation, kip-in. (N-mm) ...
241 ............................................................................................. App. 8.2
242 M Plastic flexural strength, kip-in. (N-mm) ......................... Table B4.1
p
243 M Moment corresponding to plastic stress distribution over the
p
244 composite cross-section, kip-in. (N-mm) ................................. I3.4b
245 M Required second-order flexural strength under LRFD or ASD load
r
246 combinations, kip-in. (N-mm) ............................................. App. 8.2
247 M Required flexural strength using LRFD or ASD load combinations,
r
248 kip-in. (N-mm) ........................................................................... H1.1
249 M Required flexural strength of the beam within the panel under
r
250 consideration using LRFD or ASD load combinations, kip-in. (N-
251 mm) ................................................................................. App. 6.3.1a

252 M Largest of the required flexural strengths of the beam within the
r
253 unbraced lengths adjacent to the point brace using LRFD or ASD
254 load combinations, kip-in. (N-mm)…………………….App. 6.3.1b
255 M Required flexural strength of the brace, kip-in. (N-mm) App. 6.3.2a
br
256 M Required flexural strength in chord at a joint, on the side of joint
ro
257 with lower compression stress, kips (N) .......................... Table K2.1
258 M Required in-plane flexural strength in branch using LRFD or ASD
r-ip
259 load combinations, kip-in. (N-mm) ................................. Table K4.1
260 M Required out-of-plane flexural strength in branch using LRFD or
r-op
261 ASD load combinations, kip-in. (N-mm) ........................ Table K4.1
262 M ,M Required flexural strength, kip-in. (N-mm) ............................... H1.1
rx ry
263 M Required flexural strength at the location of the bolt holes; positive
rx
264 for tension in the flange under consideration, negative for
265 compression, kip-in. (N-mm) ....................................................... H4
266 M Required flexural strength using LRFD load combinations, kip-in.
u
267 (N-mm) ..................................................................................... J10.4
268 M Moment at yielding of the extreme fiber, kip-in. (N-mm)Table B4.1
y
269 M Yield moment about the axis of bending, kip-in. (N-mm) ........ F9.1
y
270 M Moment at yielding of the extreme fiber in the compression flange,
yc
271 kip-in. (N-mm) ........................................................................... F4.2
272 M Moment at yielding of the extreme fiber in the tension flange, kip-
yt
273 in. (N-mm) ................................................................................. F4.4
274 M  Effective moment at the end of the unbraced length opposite from
1
275 M2, kip-in. (N-mm) ......................................................... App. 1.2.2b
276 M Smaller moment at end of unbraced length, kip-in.
1
277 (N-mm) .................................................................................... F13.5
278 M Larger moment at end of unbraced length, kip-in.
2
279 (N-mm) .................................................................................... F13.5
280 N Notional load applied at level i, kips (N) ................................. C2.2b
i
281 N Additional lateral load, kips (N) ....................................... App. 7.3.2
i
282 O Overlap connection coefficient .................................................. K3.1
v
283 P Required axial strength in chord using ASD load combinations,
a

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
7

284 kips (N) ...................................................................................... Table K2.1
285 P Available axial strength, kips (N) .............................................. H1.1
c
286 P Available axial compressive strength out of the plane of bending,
cy
287 kips (N) ...................................................................................... H1.1
288 P Elastic critical buckling load determined in accordance with
e
289 Chapter C or Appendix 7, kips (N) ........................................... I2.1b
290 P Nominal cross-section compressive strength, kips (N)…. ........ C2.3
ns
291 P Elastic critical buckling strength for the story in the direction of
e story
292 translation being considered, kips (N) ............................... App 8.2.2
293 P Elastic critical buckling load for buckling about the weak axis, kips
ey
294 (kN) ............................................................................................ H1.2
295 P Elastic critical buckling strength of the member in the plane of
e1
296 bending, kips (N) .............................................................. App. 8.2.1
297 P First-order axial force using LRFD or ASD load combinations, due
lt
298 to lateral translation of the structure only, kips (N) ............. App. 8.2
299 P Total vertical load in columns in the story that are part of moment
mf
300 frames, if any, in the direction of translation being considered, kips
301 (N) ..................................................................................... App. 8.2.2
302 P Nominal axial strength, kips (N) .................................................. D2
n
303 P Nominal axial compressive strength, kips (N).............................. E1
n
304 P Nominal axial compressive strength of zero length, doubly
no
305 symmetric, axially loaded composite member, kips (N) .......... I2.1b
306 P First-order axial force using LRFD and ASD load combinations,
nt
307 with the structure restrained against lateral translation,
308 kips (N) ................................................................................ App. 8.2
309 P Nominal bearing strength, kips (N) ............................................... J8
p
310 P Required second-order axial strength using LRFD or ASD load
r
311 combinations, kips (N) ........................................................ App. 8.2
312 P Required axial compressive strength using LRFD or ASD load
r
313 combinations, kips (N) .............................................................. C2.3
314 P Required axial strength using LRFD or ASD load combinations,
r
315 kips (N) ...................................................................................... H1.1
316 P Required axial strength of the member at the location of the bolt
r
317 holes; positive in tension, negative in compression, kips (N) ...... H4
318 P required external force applied to the composite member, kips
r
319 (N) ............................................................................................. I6.2a
320 P Required end and intermediate point brace strength using LRFD or
br
321 ASD load combinations, kips (N) ..................................... App. 6.2.2
322 P Required axial strength in chord at a joint, on the side of joint with
ro
323 lower compression stress, kips (N) .................................. Table K2.1
324 P Total vertical load supported by the story using LRFD or ASD
story
325 load combinations, as applicable, including loads in columns that
326 are not part of the lateral force resisting system, kips (N) App. 8.2.2
327 P Required axial strength in chord using LRFD load combinations,
u
328 kips (N) ............................................................................. Table K2.1
329 P Required axial strength using LRFD load combinations,
u
330 kips (N) .......................................................................... App. 1.2.2b
331 Q Available tensile strength, kips (N) .......................................... I8.3c
ct

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
8

332 Q Available shear strength, kips (N) ............................................ I8.3c
cv
333 Q Chord-stress interaction parameter ................................. Table K2.1
f
334 Q Gapped truss joint parameter accounting for geometric effects
g
335 ......................................................................................... Table K3.1
336 Q Nominal strength of one steel headed stud or steel channel
n
337 connector, kips (N) ................................................................... I3.2d
338 Q Nominal tensile strength of steel headed stud anchor, kips (N) I8.3b
nt
339 Q Nominal shear strength of steel headed stud anchor, kips (N) . I8.3a
nv
340 Q Required tensile strength, kips (N) ........................................... I8.3c
rt
341 Q Required shear strength, kips (N) ............................................. I8.3c
rv
342 R Radius of joint surface, in. (mm) ...................................... Table J2.2
343 R Seismic response modification coefficient ................................ A1.1
344 R Required strength using ASD load combinations ..................... B3.2
a
345 R Reduction factor for joints using a pair of transverse fillet welds
FIL
346 only ...................................................................................... App. 3.3
347 R Coefficient to account for group effect .................................... I8.2a
g
348 R Coefficient to account for influence of P- on P- .......... App. 8.2.2
M
349 R Nominal strength, specified in Chapters B through K .............. B3.2
n
350 R Nominal slip resistance, kips (N) ................................................ J3.8
n
351 R Nominal strength of the applicable force transfer mechanism, kips
n
352 (N) .............................................................................................. I6.3
353 R Total nominal strength of longitudinally loaded fillet welds, as
nwl
354 determined in accordance with Table J2.5, kips (N) ................. J2.4
355 R Total nominal strength of transversely loaded fillet welds, as
nwt
356 determined in accordance with Table J2.5 without the alternate in
357 Section J2.4(a), kips (N) ............................................................ J2.4
358 R Position effect factor for shear studs ....................................... I8.2a
p
359 R Web plastification factor............................................................ F4.1
pc
360 R Bending strength reduction factor ............................................. F5.2
pg
361 R Reduction factor for reinforced or nonreinforced transverse partial-
PJP
362 joint-penetration (PJP) groove welds .................................. App. 3.3
363 R Web plastification factor corresponding to the tension flange
pt
364 yielding limit state ..................................................................... F4.4
365 R Required strength using LRFD load combinations ................... B3.2
u
366 S Elastic section modulus, in.3 (mm3) ........................................... F8.2
367 S Spacing of secondary members, ft (m) ................................ App. 2.1
368 S Elastic section modulus to the toe in compression relative to the
c
369 axis of bending, in.3 (mm3). ..................................................... F10.3
370 S Effective section modulus about major axis, in.3 (mm3) ............ F7.2
e
371 S Effective elastic section modulus of welds for in-plane bending
ip
372 (Table K5.1), in.3 (mm3) ............................................................... K5
373 S Lowest elastic section modulus relative to the axis of bending, in.3
min
374 (mm3) .......................................................................................... F12
375 S Effective elastic section modulus of welds for out-of-plane bending
op
376 (Table K5.1), in.3 (mm3) ............................................................... K5
377 S , S Elastic section modulus referred to compression and tension
xc xt
378 flanges, respectively, in.3 (mm3) ...................................... Table B4.1
379 S Elastic section modulus taken about the x-axis, in.3 (mm3) ....... F2.2
x

Specification for Structural Steel Buildings,
public review draft dated March 2, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION