Seismic Provisions for Structural Steel Buildings

194 Pages·2015·1.21 MB·English

AISC 341-16

Seismic Provisions for
Structural Steel Buildings

PUBLIC REVIEW DRAFT dated March 16, 2015

AMERICAN INSTITUTE OF STEEL CONSTRUCTION
One East Wacker Drive, Suite 700
Chicago, Illinois 60601-1802
SYMBOLS-i

1
2 SYMBOLS
3
4 The symbols listed below are to be used in addition to or replacements for
5 those in the AISC Specification for Structural Steel Buildings. Where there
6 is a duplication of the use of a symbol between the Provisions and the AISC
7 Specification for Structural Steel Buildings, the symbol listed herein takes
8 precedence. The section or table number in the right-hand column refers to
9 where the symbol is first used.
10
11 Symbol Definition Reference
12
T
13 A Cross-sectional area of a horizontal
b F
14 boundary element, in.2 (mm2) .......................................... F5.5b
A
15 A Cross-sectional area of a vertical boundary
c R
16 element, in.2 (mm2) ........................................................... F5.5b
D
17 A Area of concrete between web plates, in.2 (mm2) ............ H7.5b
cw
18 A Gross area of flange, in.2 (mm2) .....................E................. E4.4b
f
19 A Gross area, in.2 (mm2) ...............................N.................... . E3.4a
g
20 A Web area of link (excluding flanges), inO.2 (mm2)
lw
21 .......................................................... ................................ F3.5b
W
22 A Cross-sectional area of the structural steel core,
s
23 in.2 (mm2) ................................E........................................ D1.4b
24 Asc Cross-sectional area of the VyIielding segment of steel core, in.2
25 (mm2) .............................E................................................... F4.5b
26 Ash Minimum area of tie rReinforcement, in.2 (mm2) .............. D1.4b
27 A Horizontal area of stiffened steel plate in composite plate shear
sp
28 wall, in.2 (mm2) .C.............................................................. H6.3b
I
29 Asr Area of transLverse reinforcement in coupling beam,
30 in.2 (mm2) B ........................................................................ H4.5b
31 A Area ofU longitudinal wall reinforcement provided over the
sr
32 embePdment length, L , in.2 (mm2) ................................... H5.5c
e
33 A Horizontal cross-sectional area of the link stiffener,
st
34 in.2 (mm2) ........................................................................ F3.5b
35 A Area of steel web plates, in.2 (mm2) ................................. H7.5b
sw
36 A Area of transfer reinforcement required in each of the first and
tb
37 second regions attached to each of the top and bottom flanges,
38 in.2 (mm2) ........................................................................ H5.5c
39 A Area of steel beam web, in.2 (mm2).................................. H4.5b
w
40 C Ratio of required strength to available strength ......Table D1.1
a
41 C Coefficient relating relative brace stiffness and curvature D1.2a
d
42 D Dead load due to the weight of the structural elements
43 and permanent features on the building, kips (N) ............ D1.4b
44 D Outside diameter of round HSS, in. (mm) ...............Table D1.1
45 D Diameter of the holes, in. (mm) .......................................F5.7a
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-ii

46 E Seismic load effect, kips (N) .............................................F1.4a
47 E Modulus of elasticity of steel = 29,000 ksi
48 (200 000 MPa) ........................................................Table D1.1
49 E Capacity-limited horizontal seismic load effect .................... B2
cl
50 E Horizontal seismic load effect, including the overstrength
mh
51 factor, kips (N) or kip-in. (N-mm) ....................................... B2
52 F Critical stress, ksi (MPa) ..................................................F1.6a
cr
53 F Critical stress calculated from Specification Chapter E using
cre
54 expected yield stress, ksi (MPa) ........................................F1.6a
55 F Specified minimum yield stress, ksi (MPa). As used in the
y
56 Specification, "yield stress" denotes either the minimum
57 specified yield point (for those steels that have a yield point) or
58 the specified yield strength (for those steels that do not have a
59 yield point). ....................................................................... A3T.2
60 F Specified minimum yield stress of a beam, ksi (MPa) .... EF3.4a
yb
61 F Specified minimum yield stress of a column, ksi (MPa) A E3.4a
yc
62 F Specified minimum yield stress of the steel core, or acRtual yield
ysc
63 stress of the steel core as determined from a couDpon test, ksi
64 (MPa) ................................................................ ............... F4.5b
E
65 F Specified minimum yield stress of the ties, ksi (MPa) ..... D1.4b
ysr N
66 F Specified minimum yield stress of transverse reinforcement, ksi
ysr
O
67 (MPa) ................................................................................ H4.5b

68 Fysr Specified minimum yield stress of Wtransfer reinforcement, ksi
69 (MPa) ................................................................................ H5.5c
E
70 F Specified minimum yield stress of web skin plates,
yw I
71 ksi (MPa) ..........................V............................................... H7.5b
72 F Specified minimum tensEile strength, ksi (MPa) ................ A3.2
u
73 H Height of story, in. (mRm) ................................................. D2.5c
74 H Clear height of the column between beam connections,
c C
75 including a structural slab, if present, in. (mm) ............... F2.6d
I
76 I Moment of inLertia, in.4 (mm4) ......................................... E4.5b
B
77 I Moment of inertia of a horizontal boundary element taken
b
78 perpendUicular to the direction of the web plate line, in.4 (mm4)
P
79 ........................................................................................... F5.4a
80 I Moment of inertia of a vertical boundary element taken
c
81 perpendicular to the direction of the web plate line, in.4 (mm4)
82 ...........................................................................................F5.4a
83 I Moment of inertia about an axis in the plane of the EBF in.4
y
84 (mm4) ................................................................................ F3.5b
85 I Moment of inertia of the plate, in.4 (mm4) ...................... F5.7b
y
86 K Effective length factor ...................................................... F1.5b
87 L Live load due to occupancy and moveable equipment, kips (N)
88 ....................................................................................... D1.4b
89 L Length of column, in. (mm) ............................................ E3.4c
90 L Length of truss span, in. (mm) ........................................ E4.5b
91 L Length of brace, in. (mm) ................................................ F1.5b
92 L Distance between vertical boundary element centerlines, in.
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-iii

93 (mm) ..................................................................................F5.4a
94 L Length between points which are either braced against lateral
b
95 displacement of compression flange or braced against twist of
96 the cross section, in. (mm)................................................ D1.2a
97 L Clear length of beam, in. (mm) ........................................ E1.6b
cf
98 L Clear distance between column flanges, in. (mm) ........... F5.5b
cf
99 L Embedment length of coupling beam, in. (mm) ............... H4.5b
e
100 L Distance between plastic hinge locations, as defined within the
h
101 test report or ANSI/AISC 358, in. (mm) .......................... E2.6d
102 L Length of the special segment, in. (mm) ......................... E4.5b
s
103 M Required flexural strength, using ASD load combinations, kip-
a
104 in. (N-mm) ....................................................................... D1.2c
105 M Nominal flexural strength of the chord member of the special
nc
106 segment, kip-in. (N-mm) ................................................. E4.5Tb
107 M Nominal flexural strength of PR connection at a rotation of F0.02
n,PR
108 rad, kip-in. (N-mm) ........................................................A. E1.6c
109 M Plastic flexural strength, kip-in. (N-mm) ...................R..... E1.6b
p
110 M Plastic flexural strength of a link, kip-in. (N-mm) .D...........F3.4a
p
111 Mp Plastic flexural strength of the steel, conEcr ete-encased or
112 composite beam, kip-in. (N-mm) .................................... G2.6b
N
113 M Moment corresponding to plastic stress distribution over the
p
O
114 composite cross section, kip-in. (N-mm) ......................... G4.6c

115 Mpc Plastic flexural strength of the columW n, kip-in. (N-mm) . D2.5c
116 M Plastic flexural strength of a composite column, kip-in. (N-mm)
pcc E
117 ....................................................................................... G2.6f
I
118 M Expected flexural strength, Vkip-in. (N-mm) .................... D1.2c
p,exp
119 M Probable maximum momEent at the location of the plastic hinge,
pr
120 as determined in acRcordance with ANSI/AISC 358, or as
121 otherwise determi ned in a connection prequalification in
C
122 accordance with Section K1, or in a program of qualification
I
123 testing in accLordance with Section K2, kip-in. (N-mm) .. E3.4a
B
124 M Required flexural strength, kip-in. (N-mm) ..................... D1.2a
r
U
125 M Required flexural strength, using LRFD load combinations, kip-
u
P
126 in. (N-mm) ....................................................................... D1.2c
127 M Additional moment due to shear amplification from the location
v
128 of the plastic hinge to the column centerline, kip-in. (N-mm) ..
129 ....................................................................................... E3.4a
130 M Moment due to shear amplification from the location of the
uv
131 plastic hinge to the column centerline, kip-in. (N-mm) .. G3.4a
132 M* Moment at the intersection of the beam and column centerlines
pb
133 determined by projecting the beam maximum developed
134 moments from the column face, kip-in. (N-mm) ............. E3.4a
135 M* The flexural strengths of the columns above and below the joint,
pc
136 reduced for axial loads, projected to the beam centerline, kip-in.
137 (N-mm) ............................................................................ E3.4a
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-iv

138 M* Moment in the column above or below the joint at the
pcc
139 intersection of the beam and column centerlines, kip-in. (N-mm)
140 ..................................................................................... ….G3.4a
141 M* Moment in the steel beam or concrete-encased composite beam
p,exp
142 at the intersection of the beam and column centerlines, kip-in.
143 (N-mm) ............................................................................ G3.4a
144 N Notional load factor for design of multi-tiered buckling-
MV
145 restrained braced frames to account for material variability ......
146 .............................................................................F4.4c
147 N Number of horizontal rows of perforations .......................F5.7a
r
148 P Required axial strength using ASD load combinations, kips (N)
a
149 Table D1.1
150 P Required compressive strength using ASD load combinations,
ac
151 kips (N) ............................................................................ E3.4Ta
152 P Axial design strength of wall at balanced condition, kips (NF)
b
153 ......................................................................................A... H5.4
154 P Available axial strength, kips (N) ...............................R..... E3.4a
c
155 P Nominal axial compressive strength, kips (N) ......D.......... E4.5a
n
156 Pnc Nominal axial compressive strength of the choEr d member at the
157 ends, kips (N) .................................................................. E4.4c
N
158 P Nominal axial tensile strength of diagonal members of the
nt
O
159 special segment, kips (N) ................................................ E4.5b

160 Pr Required axial compressive strengtWh, kips (N) ............... E4.4d
161 P Required axial strength using LRFD load combinations, kips (N)
u E
162 .................................................................................Table D1.1
I
163 P Required compressive strenVgth using LRFD load combinations,
uc
164 kips (N) .........................E................................................... E3.4a
165 P Axial yield strength, ,R kips (N) ................................Table D1.1
y
166 P Axial yield strengt h of steel core, kips (N) ......................F4.2a
ysc C
167 P Maximum specified axial yield strength of steel core, ksi
ysc-max I
168 (MPa) ..........L......................................................................F4.4c
B
169 P Minimum specified axial yield strength of steel core, ksi
ysc-min
U
170 (MPa) ................................................................................F4.4c
P
171 R Seismic response modification coefficient ........................... A1
172 R Radius of the cut-out, in. (mm) ....................................... F5.7b
173 R Factor to account for expected strength of concrete = 1.5.. H5.5d
c
174 R Nominal strength, kips (N) ................................................ A3.2
n
175 R Ratio of the expected tensile strength to the specified minimum
t
176 tensile strength F ............................................................... A3.2
u
177 R Ratio of the expected yield stress to the specified minimum yield
y
178 stress, F ........................................................................... A3.2
y
179 R Ratio of the expected yield stress of the beam material to the
yb
180 specified minimum yield stress ........................................ E3.6f
181 R Ratio of the expected yield stress of the column material to the
yc
182 specified minimum yield stress ........................................ E3.6f
183 R Ratio of the expected yield stress of the transverse
yr
184 reinforcement material to the specified minimum yield
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-v

185 stress ................................................................................. H5.5d
186 S Shortest center-to-center distance between holes, in. (mm) ......
diag
187 ........................................................................................F5.7a
188 V Required shear strength using ASD load combinations, kips (N)
a
189 ....................................................................................... E1.6b
190 V Limiting expected shear strength of an encased composite
comp
191 coupling beam, kips (N) .................................................. H4.5b
192 V Nominal shear strength of link, kips (N) ........................... F3.3
n
193 V Expected shear strength of a steel coupling beam, kips (N) ......
n
194 .......................................................................................... H4.5b
195 V Expected shear strength of an encased composite coupling beam,
n,comp
196 kips (N) ............................................................................. H4.5b
197 V Expected vertical shear strength of the special segment, kips (N)
ne
198 ....................................................................................... E4.5Tb
199 V Plastic shear strength of a link, kips (N) ..........................FF3.4a
p
200 V Required shear strength using LRFD or ASD load combinAations,
r
201 kips (N) .......................................................................R..... F3.5b
202 V Required shear strength using LRFD load combinatiDons, kips (N)
u
203 ........................................................................ ............... E1.6b
E
204 V Nominal shear yield strength, kips (N) ........................... F3.5b
y N
205 Y Distance from the top of the steel beam to the top of concrete
con
O
206 slab or encasement, in. (mm) ........................................... G3.5a

207 YPNA Maximum distance from the maximW um concrete compression
208 fiber to the plastic neutral axis, in. (mm) ......................... G3.5a
E
209 Z Plastic section modulus about the axis of bending, in.3 (mm3)
I
210 D1.2a V
211 Z Plastic section modulus oEf the column about the axis of bending,
c
212 in.3 (mm3) ................R........................................................ E3.4a
213 Z Plastic section mod ulus about x-axis, in.3 (mm3) ............. E2.6g
x C
214 Z Minimum plastic section modulus at the reduced beam section,
RBS I
215 in.3 (mm3) ...L..................................................................... E3.4a
B
216 a Distance between connectors, in. (mm) ........................... F2.5b
U
217 b Width of compression element as defined in Specification
P
218 Section B4.1, in. (mm) ............................................Table D1.1
219 b Inside width of a box section, in. (mm) ............................ F3.5b
220 b Width of beam flange, in. (mm) ....................................... E3.6f
bf
221 b Width of column flange, in. (mm) .................................... E3.6f
cf
222 b Width of flange, in. (mm) ................................................ D2.5b
f
223 b Thickness of wall pier, in. (mm) ..................................... H4.5b
w
224 b Width of wall, in. (mm) .................................................... H5.5c
w
225 b Width of concrete encasement, in. (mm) ........................ H4.5b
wc
226 d Overall depth of beam, in. (mm) .............................Table D1.1
227 d Nominal bolt diameter, in. (mm) ....................................... D2.2
228 d Overall depth of link, in. (mm) ........................................ F3.5b
229 d Effective depth of concrete encasement, in. (mm) ........... H4.5b
c
230 d d2t of the deeper beam at the connection, in. (mm) ..... E3.6e
z f
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-vi

231 e Length of EBF link, in. (mm) .......................................... F3.5b
232 f Specified compressive strength of concrete, ksi (MPa) .. D1.4b
c
233 g Clear span of coupling beam, in. (mm) ........................... H4.5b
234 h Clear distance between flanges less the fillet or corner radius for
235 rolled shapes; and for built-up sections, the distance between
236 adjacent lines of fasteners or the clear distance between flanges
237 when welds are used; for tees, the overall depth; and for
238 rectangular HSS, the clear distance between the flanges less the
239 inside corner radius on each side, in. (mm) ..............Table D1.1
240 h Distance between horizontal boundary element centerlines, in.
241 (mm) ............................................................................F5.4a
242 h Overall depth of the boundary member in the plane of the wall,
243 in. (mm) ........................................................................... H5.5b
244 hcc Cross-sectional dimension of the confined core region iTn
245 composite columns measured center-to-center of the transvFerse
246 reinforcement, in. (mm) ..................................................A. D1.4b
247 h Distance between flange centroids, in. (mm) .............R..... D1.2c
o
248 r Governing radius of gyration, in. (mm) ................D.......... E3.4c
249 r Minimum radius of gyration of individual comp onent, in. (mm)
i E
250 …. ..................................................................................... F2.5b
N
251 r Radius of gyration about y-axis, in. (mm) ........................ D1.2a
y O
252 r Radius of gyration of individual components about their weak
y

253 axis, in. (mm)..................................W.................................. E4.5d
254 s Spacing of transverse reinforcement, in. (mm) ............... D1.4b
E
255 t Thickness of element, in. (mm) ...............................Table D1.1
I
256 t Thickness of column web oVr doubler plate, in. (mm) ..... E3.6e
257 t Thickness of beam flangEe, in. (mm) ................................ E3.4c
bf
258 t Minimum required Rthickness of column flange when no
cf
259 continuity plates ar e provided, in. (mm) .......................... E3.6f
C
260 t Effective web-plate thickness, in. (mm) ...........................F5.7a
eff I
261 t Thickness of Lflange, in. (mm) ......................................... D2.5b
f
B
262 t Thickness of steel web plate, in. (mm) ............................. H7.4e
s
U
263 t Thickness of web, in. (mm) ............................................. F3.5b
w
P
264 t Web-plate thickness, in. (mm) .........................................F5.7a
w
265 t Thickness of wall, in. (mm).............................................. H7.4e
w
266 w Minimum of w and w , in. (mm) ..................................... H7.4e
min 1 2
267 w Maximum spacing of tie bars in vertical and horizontal
1
268 directions, in. (mm) .......................................................... H7.4a
269 w Maximum spacing of tie bars or shear studs in vertical and
1
270 horizontal directions, in. (mm) ......................................... H7.4b
271 w , w Vertical and horizontal spacing of tie bars, respectively,
1 2
272 in. (mm) .......................................................................... H7.4e
273 w Width of panel zone between column flanges, in. (mm)….E3.6e
z
274  Design story drift, in. (mm) ..............................................F3.4a
275  Deformation quantity used to control loading of test specimen
b
276 (total brace end rotation for the subassemblage test specimen;
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
SYMBOLS-vii

277 total brace axial deformation for the brace test specimen), in.
278 (mm) ................................................................................ K3.4c
279  Value of deformation quantity,  ,corresponding to the design
bm b
280 story drift, in. (mm) ......................................................... K3.4c
281  Value of deformation quantity,  , at first yield of test specimen,
by b
282 in. (mm) ........................................................................... K3.4c
283  Safety factor ...................................................................... B3.2
284  Safety factor for compression ...................................Table D1.1
c
285  System overstrength factor ................................................... B2
o
286  Safety factor for shear strength of panel zone of beam-to-column
v
287 connections ...................................................................... E3.6e
288  LRFD-ASD force level adjustment factor = 1.0 for LRFD and
s
289 1.5 for ASD ..................................................................... D1.2a
T
290  Angle of diagonal members with the horizontal, degrees..E4.5b
F
291  Angle of web yielding, as measured relative to the vertical,
A
292 degrees ............................................................................. F5.5b
R
293  Angle of the shortest center-to-center lines in the opening array
D
294 to vertical, degrees .............................................................F5.7a

295  Compression strength adjustment factor ........E..................F4.2a
N
296  Factor relating depth of equivalent rectangular compressive
1
297 stress block to neutral axis depth, as defOined in ACI 318 H4.5b
298  Total link rotation angle .................. ................................ K2.4c
total W
299  Story drift angle, rad ......................................................... K2.4b
E
300  ,λ Limiting slenderness parameter for highly and moderately
hd md
I
301 ductile compression elemenVts, respectively .................... D1.1b
302  Resistance factor ...........E..................................................... B3.2
303  Resistance factor for cRompression ...........................Table D1.1
c
304  Resistance factor f or shear .............................................. E3.6e
v C
305  Strength adjusted reinforcement ratio .............................. H7.5b
I
L

306  Strain hardening adjustment factor ...................................F4.2a
B
U
P
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
GLOSS-1

350

351
Glossary
352

353
354 The terms listed below are to be used in addition to those in the AISC
355 Specification for Structural Steel Buildings. Some commonly used terms are
356 repeated here for convenience.
357
358 Notes:
359 (1) Terms designated with † are common AISI-AISC terms that are coordinated
360 between the two standards developers.
361 (2) Terms designated with * are usually qualified by the type of load effect, for
362 example, nominal tensile strength, available compressive strength, design flexural
T
363 strength.
F
364
A
365 Adjusted brace strength. Strength of a brace in a buckling-restrained braced
R
366 frame at deformations corresponding to 2.0 times the design story drift.
D
367 Adjusted link shear strength. Link shear strength includin g the material
E
368 overstrength and strain hardening.
N
369 Allowable strength*†. Nominal strength divided by theO safety factor, Rn / .
370
W
371 Applicable building code†. Building code under which the structure is designed.
E
372 ASD (allowable strength design)†. Method of proportioning structural
I
V
373 components such that the allowable strength equals or exceeds the
E
374 required strength of the component under the action of the ASD load
R
375 combinations.

376 ASD load combination†. Load cCombination in the applicable building code
377 intended for allowable sItrength design (allowable stress design).
L
378 Authority having jurisdictioBn (AHJ). Organization, political subdivision, office
379 or individual chUarged with the responsibility of administering and
380 enforcing the pProvisions of this Standard.
381 Available strength*†. Design strength or allowable strength, as applicable.
382 Boundary member. Portion along wall or diaphragm edge strengthened with
383 structural steel sections and/or longitudinal steel reinforcement and
384 transverse reinforcement.
385 Brace test specimen. A single buckling-restrained brace element used for
386 laboratory testing intended to model the brace in the prototype.
387 Braced frame†. An essentially vertical truss system that provides resistance to
388 lateral forces and provides stability for the structural system.
389 Buckling-restrained brace. A pre-fabricated, or manufactured, brace element
390 consisting of a steel core and a buckling-restraining system as described in
391 Section F4 and qualified by testing as required in Section K3.
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION
GLOSS-2

392 Buckling-restrained braced frame (BRBF). A diagonally braced frame
393 employing buckling-restrained braces and meeting the requirements of
394 Section F4.
395 Buckling-restraining system. System of restraints that limits buckling of the steel
396 core in BRBF. This system includes the casing surrounding the steel core
397 and structural elements adjoining its connections. The buckling-restraining
398 system is intended to permit the transverse expansion and longitudinal
399 contraction of the steel core for deformations corresponding to 2.0 times
400 the design story drift.
401 Casing. Element that resists forces transverse to the axis of the diagonal brace
402 thereby restraining buckling of the core. The casing requires a means of
403 delivering this force to the remainder of the buckling-restraining system.
404 The casing resists little or no force along the axis of the diagonal brace.
T
405 Capacity-limited seismic load. The capacity-limited horizontal seismic load
F
406 effect, Ecl, determined in accordance with these Provisions, substituAted for
407 Emh, and applied as prescribed by the load combinations in the aRpplicable
408 building code. D
409 Collector. Also known as drag strut; member that serves to transfer loads
E
410 between diaphragms and the members of the vertical force-resisting
N
411 elements of the seismic force-resisting system.
O
412 Column base. Assemblage of structural shapes, plates, connectors, bolts and

W
413 rods at the base of a column used to transmit forces between the steel
414 superstructure and the foundation. E
415 Columnar system. A series of columns or VcIolumn truss elements designed to
416 support in-plane loading induced fErom multi-tiered braced frames.
417 Complete loading cycle. A cycle of roRtation taken from zero force to zero force,
418 including one positive and o ne negative peak.
C
419 Composite beam. Structural stIeel beam in contact with and acting compositely
L
420 with a reinforced concrete slab designed to act compositely for seismic
B
421 forces.
U
422 Composite brace. CoPncrete-encased structural steel section (rolled or built-up) or
423 concrete-filled steel section used as a diagonal brace.
424 Composite column. Concrete-encased structural steel section (rolled or built-up)
425 or concrete-filled steel section used as a column.
426 Composite eccentrically braced frame (C-EBF). Composite braced frame
427 meeting the requirements of Section H3.
428 Composite intermediate moment frame (C-IMF). Composite moment frame
429 meeting the requirements of Section G2.
430 Composite ordinary braced frame (C-OBF). Composite braced frame meeting
431 the requirements of Section H1.
432 Composite ordinary moment frame (C-OMF). Composite moment frame meeting
433 the requirements of Section G1.
2016 Seismic Provisions for Structural Steel Buildings
PUBLIC REVIEW Draft Dated March 16, 2015
AMERICAN INSTITUTE OF STEEL CONSTRUCTION