Load and resistance factor design: manual of steel construction

147 Pages·2001·2.14 MB·English

Revisions, January 2003
Manual of Steel Construction
Load and Resistance Factor Design
3rd Edition
The following technical revisions and corrections have been made
in the second printing of the Third Edition (January, 2003). To facil-
itate the incorporation of revisions and corrections, this booklet
has been constructed using excerpts from revised pages, with cor-
rections noted. The user may find it convenient in some cases to
hand-write corrections; in others, a cut-and-paste approach may
be more efficient.
vi
Copyright © 2001
by
American Institute of Steel Construction, Inc.
ISBN 1-56424-051-7
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
First Printing:November2001
SeconSde Pcorinndti nPgr:i nJtainngu:a Jrayn 2u0a0ry3 2w0it0h3 revisions
AMERICANINSTITUTE OF STEELCONSTRUCTION
vii
PREFACE
This 3rd Edition LRFD Manual of Steel Construction is the twelfth major update of the
AISC Manual of Steel Construction, which was first published in 1927. With this revision,
member and connection design information has been condensed back into a single
volume. It has been reorganized and reformatted to provide practical and efficient access
to the information it contains, with a roadmap format to guide the user quickly to the
applicable specifications, codes and standards, as well as the applicable provisions in
those standards.
The following specifications, codes and standards are included in or with this Manual:
• 1999 LRFD Specification for Structural Steel Buildings
• 2000 LRFD Specification for Steel Hollow Structural Sections
• 2000 LRFD Specification for Single-Angle Members
• 2000 RCSC Specification for Structural Joints Using ASTM A325 or A490 Bolts
• 2000 Code of Standard Practice for Steel Buildings and Bridges
• AISC Shapes Database V3 CD
The following major improvements have been made in this revision:
• Workable gages for flange fasteners have been reintroduced.
• The revised T,k and k values for W-shapes and the 0.93 wall-thickness reduction
1
factor for HSS have been considered.
• Guidance is provided on the new OSHA safety regulations, stability bracing
requirements and proper material specification.
• New information is provided on design drawing information requirements, criteria
needed for connection design, mill, fabrication and erection tolerances, façade
issues, temperature effects and fire protection requirements with summaries of
common UL assemblies.
• Shape information has been updated to the current series.
• Coverage of round HSS has been added.
• Dimensions and properties have been added for double channels back-to-back.
• Tables of surface and box perimeter, weight/area-to-perimeter ratios and surface
areas have been expanded to cover all common structural shapes.
• A new section on properly specifying materials, including shapes, plates, fasteners
and other products, has been added.
• New information on corrosion protection and seismic design has been added.
• A new section has been added with design aids for tension members, including
explicit consideration of net section requirements to ensure connectable member
selection.
• Beam selection tables are included for selection based upon I,Z,I , and Z .
x x y y
• Beam charts (φM vs. L ) are plotted for both W-shapes and channels.
n b
• New floor plate deflection and bending design aids have been added.
• Additional beam diagrams and formulas have been added.
• A new section has been added with design aids for W-shape beam-columns.
• New bolt length selection tables have been added.
• Bolt entering and tightening clearances have been updated.
• Bolting information has been updated for consistency with the 2000 RCSC
Specification.
AMERICANINSTITUTE OF STEELCONSTRUCTION
viii
• Welding information, including the prequalified welded joint tables, has been
updated to for consistency with AWS D1.1-2000.
• Information on prying action, Whitmore section and strength of coped beams has
been updated.
• Selection tables for shear end-plate connections and single-plate connections have
been improved and expanded, including single-plate connections with up to 12
rows of bolts and up to 11/ -in. diameter.
8
• New information and examples for flexible moment connections has been added as
an update of Disque’s historic “type 2 with wind” moment connection design
approach.
• Previous limitations on the use of moment end-plate connections have been
relaxed.
• Information on the design of anchor rods has been updated, including a new table
of minimum dimensions for washers used with anchor rods.
• Composite member tables have been updated to include coverage of both 4 ksi
and 5 ksi concrete.
• A cross-reference between U.S. customary and Metric shapes series has been
included.
In addition, many other improvements have been made throughout this Manual.
By the AISC Committee on Manuals and Textbooks,
William A. Thornton, Chairman Barry L. Barger, Vice Chairman
Charles J. Carter Charles R. Page
Robert O. Disque Davis G. Parsons II
Marshall T. Ferrell David T. Ricker
Lanny J. Flynn Marc L. Sorenson
Mark V. Holland Scott T. Undershute
Bill R. Lindley II Gary C. Violette
Leonard R. Middleton Michael A. West
William C. Minchin Heath E. Mitchell, Secretary
Thomas M. Murray
The Committee gratefully acknowledges the following people for their contributions to this
Manual: Abbas Aminmansour, Roger L. Brockenbrough, Jennifer R. Ceccotti, Harry A.
Cole, Richard A. DeVries, Guy J. Engebretson, Areti Gertos, Louis F. Geschwindner, Jr.,
John L. Harris III, Richard C. Kaehler, Suzanne W. Kaehler, Gerald F. Loberger, Jr.,
William T. Segui, Janet S. Tuegel, and Ramulu S. Vinnakota.
AMERICANINSTITUTE OF STEELCONSTRUCTION
1–30 DIMENSIONSANDPROPERTIES
Table1-5.
C-Shapes
(AmericanStandardChannels)
Dimensions
Web Flange Distance
Shape ArAea, Dedpth, Thickness, tw Width, Thickness, k T Waobrlek-
tw 2 bf tf Gage†
in.2 in. in. in. in. in. in. in. in.
C15×50 14.7 15.0 15 0.716 11/16 3/8 3.72 33/4 0.650 5/8 17/16 121/8 21/4
×40 11.8 0.520 1/2 1/4 3.52 31/2 2
×33.9 9.95 0.400 3/8 3/16 3.40 33/8 2
C12×30 8.81 12.0 12 0.510 1/2 1/4 3.17 31/8 0.501 1/2 11/8 93/4 13/4
×25 7.34 0.387 3/8 3/16 3.05 3
×20.7 6.08 0.282 5/16 3/16 2.94 3
C10×30 8.81 10.0 10 0.673 11/16 3/8 3.03 3 0.436 7/16 1 8 13/4
×25 7.34 0.526 1/2 1/4 2.89 27/8 13/4
×20 5.87 0.379 3/8 3/16 2.74 23/4 11/2
×15.3 4.48 0.240 1/4 1/8 2.60 25/8 11/2
C9×20 5.87 9.00 9 0.448 7/16 1/4 2.65 25/8 0.413 7/16 1 7 11/2
×15 4.41 0.285 5/16 3/16 2.49 21/2 13/8
×13.4 3.94 0.233 1/4 1/8 2.43 23/8 13/8
C8×18.75 5.51 8.00 8 0.487 1/2 1/4 2.53 21/2 0.390 3/8 15/16 61/8 11/2
×13.75 4.04 0.303 5/16 3/16 2.34 23/8 13/8
×11.5 3.37 0.220 1/4 1/8 2.26 21/4 13/8
C7×14.75 4.33 7.00 7 0.419 7/16 1/4 2.30 21/4 0.366 3/8 7/8 51/4 11/4
×12.25 3.60 0.314 5/16 3/16 2.19 21/4
×9.8 2.87 0.210 3/16 1/8 2.09 21/8
C6×13 3.81 6.00 6 0.437 7/16 1/4 2.16 21/8 0.343 5/16 13/16 43/8 13/8
×10.5 3.08 0.314 5/16 3/16 2.03 2 11/8
×8.2 2.39 0.200 3/16 1/8 1.92 17/8 11/8
C5×9 2.64 5.00 5 0.325 5/16 3/16 1.89 17/8 0.320 5/16 3/4 31/2 11/8
×6.7 1.97 5.00 5 0.190 3/16 1/8 1.75 13/4 0.320 5/16 3/4 31/2 –
C4×7.25 2.13 4.00 4 0.321 5/16 3/16 1.72 13/4 0.296 5/16 3/4 21/2 1
R11e/1v/0.2 ××54..45 11..5382 00..118245 13//816 11//816 11..5588 1155//88 ––
C3×6 1.76 3.00 3 0.356 3/8 3/16 1.60 15/8 0.273 1/4 11/16 15/8 –
×5 1.47 0.258 1/4 1/8 1.50 11/2 –
Rev. ×4.1 1.20 0.170 3/16 1/8 1.41 13/8 –
11/1/02 ×3.5 1.03 0.132 1/8 1/16 1.37 13/8 –
†Seedefinitionof“WorkableGage”inNomenclaturesectionatthebackofthisManual.
–inWorkableGagecolumnindicatesthatflangeistoonarrowtoallowtabulationofaworkablegage.
AMERICANINSTITUTEOFSTEELCONSTRUCTION
1–36 DIMENSIONSANDPROPERTIES
Table1-7(cont.).
Angles
(L-Shapes)
Properties
Area, AxisX-X
k Wt.
Shape A
I S r y Z yp
in. lb/ft in.2 in.4 in.3 in. in. in.3 in.
L5×31/2×3/4 13/16 19.8 5.82 13.9 4.26 1.55 1.74 7.60 1.12
×5/8 16.8 4.93 12.0 3.63 1.56 1.69 6.50 1.06
×1/2 15/16 13.6 4.00 9.96 2.97 1.58 1.65 5.33 0.997
×3/8 13/16 10.4 3.05 7.75 2.28 1.59 1.60 4.09 0.933
×5/16 3/4 8.72 2.56 6.58 1.92 1.60 1.57 3.45 0.901
×1/4 11/16 7.03 2.07 5.36 1.55 1.61 1.55 2.78 0.868
L5×3×1/2 15/16 12.8 3.75 9.43 2.89 1.58 1.74 5.12 1.25
×7/16 7/8 11.3 3.31 8.41 2.56 1.59 1.72 4.53 1.21
×3/8 13/16 9.74 2.86 7.35 2.22 1.60 1.69 3.93 1.18
×5/16 3/4 8.19 2.41 6.24 1.87 1.61 1.67 3.32 1.15
×1/4 11/16 6.60 1.94 5.09 1.51 1.62 1.64 2.68 1.12
L4×4×3/4 11/8 18.5 5.43 7.62 2.79 1.18 1.27 5.02 0.679
×5/8 1 15.7 4.61 6.62 2.38 1.20 1.22 4.28 0.576
×1/2 7/8 12.7 3.75 5.52 1.96 1.21 1.18 3.50 0.468
×7/16 13/16 11.2 3.30 4.93 1.73 1.22 1.15 3.10 0.413
×3/8 3/4 9.72 2.86 4.32 1.5 1.23 1.13 2.69 0.357
×5/16 11/16 8.16 2.40 3.67 1.27 1.24 1.11 2.26 0.300
×1/4 5/8 6.58 1.93 3.00 1.03 1.25 1.08 1.82 0.242
L4×31/2×1/2 15/16 11.9 3.50 5.30 1.92 1.23 1.24 3.46 0.497
×3/8 13/16 9.10 2.68 4.15 1.48 1.25 1.20 2.66 0.433
×5/16 3/4 7.65 2.25 3.53 1.25 1.25 1.17 2.24 0.401
×1/4 11/16 6.18 1.82 2.89 1.01 1.26 1.14 1.81 0.368
1R1e/1v./02 L4×3××51//82 1115//1166 1131..61 33..9295 65..0012 21..2887 11..2234 11..3372 43..0386 00..871407
×3/8 13/16 8.47 2.49 3.94 1.44 1.26 1.27 2.60 0.683
××51//146 113//146 75..1725 21..0699 32..3765 10..29288 11..2277 11..2252 21..1797 00..665118
L31/2×31/2×1/2 7/8 11.1 3.27 3.63 1.48 1.05 1.05 2.66 0.466
×7/16 13/16 9.82 2.89 3.25 1.32 1.06 1.03 2.36 0.412
×3/8 3/4 8.51 2.50 2.86 1.15 1.07 1.00 2.06 0.357
×5/16 11/16 7.16 2.10 2.44 0.969 1.08 0.979 1.74 0.301
×1/4 5/8 5.79 1.70 2.00 0.787 1.09 0.954 1.41 0.243
L31/2×3×1/2 7/8 10.3 3.02 3.45 1.45 1.07 1.12 2.61 0.480
×7/16 13/16 9.09 2.67 3.10 1.29 1.08 1.09 2.32 0.446
×3/8 3/4 7.88 2.32 2.73 1.12 1.09 1.07 2.03 0.411
×5/16 11/16 6.65 1.95 2.33 0.951 1.09 1.05 1.72 0.375
×1/4 5/8 5.38 1.58 1.92 0.773 1.10 1.02 1.39 0.336
L31/2×21/2×1/2 7/8 9.41 2.76 3.24 1.41 1.08 1.20 2.52 0.736
×3/8 3/4 7.23 2.12 2.56 1.09 1.10 1.15 1.96 0.668
×5/16 11/16 6.10 1.79 2.20 0.925 1.11 1.13 1.67 0.633
×1/4 5/8 4.94 1.45 1.81 0.753 1.12 1.10 1.36 0.596
AMERICANINSTITUTEOFSTEELCONSTRUCTION
DIMENSIONSANDPROPERTIES 1–151
Table1-55.
S-Shapes,M-Shapes,andChannels
∗Backofsquareandcenterlineofwebtobeparallelwhenmeasuring“out-of-square”
PermissibleCross-SectionalVariations
Aa B FTla+ngTe(cid:1)bs E
Nominal, Depth,in. Flangewidth,in. outof Weboff
Shape Depth,in. square, Center,
Over Under Over Under perin.of in.
B,in.
3to7,incl. 3/32 1/16 1/8 1/8
S-sahnadpes Overin7ctl.o14, 1/8 3/32 5/32 5/32 1/32 3/16
M-shapes Overi1n4cl.to24, 3/16 1/8 3/16 3/16
3to7,incl. 3/32 1/16 1/8 1/8
Channels Overin7ctl.o14, 1/8 3/32 1/8 5/32 1/32 –
Over14 3/16 1/8 1/8 3/16
PermissibleVariationsinLength
VariationsOverSpecifiedLengthforLengthsGivenc,in.
Shape 5to10ft, 10to20ft, 20to30ft, Over30to Over40to
Over65ft
excl. excl. incl. 40ft,incl. 65ft,incl.
All 1 11/2 13/4 21/4 23/4 –
MillStraightnessTolerancesd
1R1e/v1./02 Camber 1/8in.×(totalle5ngth,ft)
Duetotheextremevariationsinflexibilityoftheseshapes,permittedvariationsforsweepare
Sweep
subjecttonegotiationbetweenthemanufacturerandpurchaserfortheindividualsectionsinvolved.
OtherPermissibleRollingVariations
AreaandWeight ±2.5percenttheoreticalorspecifiedamount.
EndsOutofSquare S-shapes,M-shapesandchannels1/64in.perin.ofdepth.
–indicatesthatthereisnorequirement.
aAismeasuredatcenterlineofwebforbeamsandatbackofwebforchannels.
bT+T(cid:2)applieswhenflangesofchannelsaretoedinorout.
cThepermittedvariationunderthespecifiedlengthis0in.foralllengths.Therearenorequirementsforlengthsover65ft.
dThetoleranceshereinaretakenfromASTMA6andapplytothestraightnessofmembersreceivedfromtherollingmill,mea-
suredasillustratedinFigure1-1.Fortoleranceoninducedcamberandsweep,seeCodeofStandardPracticeSection6.4.4.
AMERICANINSTITUTEOFSTEELCONSTRUCTION
2–28 GENERALDESIGNCONSIDERATIONS
WhilestillformallypermittedintheLRFDSpecification,theuseofothermaterialspeci-
ficationsinsteel-to-steelstructuralboltingapplicationshasbecomequiteuncommon.ASTM
A307 bolts are almost as infrequently specified today as are ASTM A501 and A502
rivets.
Twist-Off-TypeTension-ControlBoltAssemblies
AsshowninTable2-3,thepreferredmaterialspecificationfortwist-off-typetension-control
bolt assemblies is ASTM F1852, which offers a strength level that is equivalent to that of
ASTM A325 bolts. When a higher strength is desired, twist-off-type tension-control bolt
assembliescanbeobtainedinastrengthlevelthatisequivalenttothatofASTMA490bolts
usingtheprovisionsforalternative-designfastenersinRCSCSpecificationSection2.8.In
eithercase,Type1(medium-carbonsteel)ismostcommonlyspecified.Whenatmospheric
corrosionresistanceisdesired,Type3canbespecified.
Nuts
As shown in Table 2-3, the preferred material specification for heavy-hex nuts is ASTM
A563.TheappropriategradeandfinishisspecifiedperASTMA563TableX1.1accordingto
theboltorthreadedpartwithwhichthenutwillbeused.Forsteel-to-steelstructuralbolting
applications,theappropriategradeandfinishissummarizedinRCSCSpecificationSection
2.4.Ifitsavailabilitycanbeconfirmedpriortospecification,ASTMA194grade2Hnutsare
permittedasanalternativeasindicatedinRCSCSpecificationTable2.1.
Washers
As shown in Table 2-3, the preferred material specification for hardened steel washers is
ASTMF436.Thisspecificationprovidesforbothflatandbeveledwashers.Whilestandard
ASTMF436washersaresufficientinmostapplications,thereareseveralspecificapplications
whenspecialwashersarerequired.ThespecialwasherrequirementsinRCSCSpecification
Section6applywhenoversizedorslottedholesareusedintheouterplyofasteel-to-steel
structural joint. In anchor rod and other embedment applications, hole sizes are generally
largerthanthoseforsteel-to-steelstructuralboltingapplications(seeTable14-2formaxi-
mumanchor-rodholesizes).Accordingly,washersusedinsuchapplicationsaregenerally
largerandmayrequiredesignconsiderationforproperforcetransfer,particularlywhenthe
anchorageissubjecttotension.SeeTable14-2foranchor-rodwashersizes. Rev.
11/1/02
Compressible-Washer-TypeDirect-TensionIndicators
When bolted joints are specified as pretensioned or slip-critical and the direct-tension-
indicatorpretensioningmethodisused,ASTMF959compressible-washer-typedirect-tension
indicators are specified, as shown in Table 2-3. Type 325 is used with ASTM A325 high-
strengthboltsandtype490isusedwithASTMA490high-strengthbolts.
AnchorRods
AsshowninTable2-3,thepreferredmaterialspecificationforanchorrodsisASTMF1554,
whichcovershooked,headedandthreadedandnuttedanchorrodsinthreestrengthgrades:
36,55and105.ASTMF1554grade36ismostcommonlyspecified,althoughgrades55and
105arenormallyavailable,albeitwithpotentiallylongerleadtimes,whenhigherstrength
isrequired.ASTMF1554grade36orASTMF1554grade55withweldabilitysupplement
S1andthecarbonequivalentformulainASTMF1554SectionS1.5.2.1canbespecifiedto
allowweldedfieldcorrectionshouldtheanchorrodsbeplacedincorrectlyinthefield.ASTM
F1554grades36,55and105areessentiallytheanchor-rodequivalentsofthegenericrod
specificationsASTMA36,ASTMA572grade55andA193gradeB7,respectively.
AMERICANINSTITUTEOFSTEELCONSTRUCTION
FIREPROTECTIONANDENGINEERING 2–47
Table 2-10.
Construction Classification,
Restrained and Unrestrained
Single-span
and simply Open-web steel joists or steel beams, supporting concrete slab, unrestrained
precast units, or metal decking
supported
end spans
of multiple Concrete slabs, precast units, or metal decking unrestrained
g baysa
n
all Beari Ocopnetnin-uwoeubs sctoenecl rjoeitset ss,l asbteel beams or metal decking, supporting restrained
W Interior spans Open-web steel joists or steel beams, supporting precast units or
unrestrained
of multiple metal decking
bays Cast-in-place concrete slab systems restrained
Precast concrete where the potential thermal expansion is resisted
restrained
by adjacent constructionb
Steel beams welded, riveted, or bolted to the framing members restrained
All types of cast-in-place floor and roof systems (such as
beam-and-slabs, flat slabs, pan joists, and waffle slabs) where the restrained
floor or roof system is secured to the framing members
Steel
Framing All types of prefabricated floor or roof systems where the structural
members are secured to the framing members and the
potential thermal expansion of the floor or roof system is resisted restrained
by the framing system or the adjoining floor or roof
constructionb
Beams securely fastened to the framing members restrained
All types of cast-in-place floor and roof systems (such as
beam-and-slabs, flat slabs, pan joists, and waffle slabs) where the restrained
floor system is cast with the framing members
Interior and exterior spans of precast systems with cast-in-place
Concrete joints resulting in restraint equivalent to that which would restrained
Framing exist in [concrete framing] b(i)
All types of prefabricated floor or roof systems where the structural
members are secured to such systems and the potential thermal Rev.
expansion of the floor or roof systems is restrained 11/1/02
resisted by the framing system or the adjoining floor or roof
constructionb
Wood
All types unrestrained
Construction
aFloor and roof system scan be considered restrained when they are tied into walls or without tie beams,
the walls being designed and detailed to resist thermal thrust from the floor or roof system.
bFor example, resistance to potential thermal expansion is considered to be achieved when:
(i) Continuous structural concrete topping is used,
(ii) The space between the ends of precast units or between the ends of units and the vertical face of
supports is filled with concrete or mortar, or
(iii) The space between the ends of precast units and the vertical faces of supports, or between the
ends of solid or hollow core slab units does not exceed 0.25% of the length for normal weight
concrete members of 0.1% of the length for structural light weight concrete members.
From ASTM E119-2000 Table X 3.1. Copyright ASTM. Reprinted with permission.
AMERICANINSTITUTEOFSTEELCONSTRUCTION
DESIGNEXAMPLES 3–7
designstrengthwith A =0.75A =5.31in.2istabulatedas259kips.
e g
(cid:1) (cid:2)
A
φP =259kips e
t n 0.75A
g
(cid:1) (cid:2)
5.11in.2
=259kips
5.31in.2
=249kips
Similarly,forsolutionb,
A 5.68in.2
e =
A 7.08in.2
g
=0.802<0.923
Therefore,tensionrupturecontrols.Fortensionrupture,theW8×24de-
signstrengthwith A =0.75A =5.31in.2istabulatedas259kips.
e g
(cid:1) (cid:2)
A
φP =259kips e
t n 0.75A
g
(cid:1) (cid:2)
5.68in.2
=259kips
5.31in.2
=277kips
Notethatend-connectionlimit-states,suchasblockshearruptureandbolt
bearingstrengthmustalsobechecked.
EXAMPLE3.2.Single-angletensionmemberdesign.
Given: DeterminethedesignstrengthofanASTMA36L4×4×1/ withoneline
2
of3/ -in.-diameterboltsinstandardholes,twoperflange,asillustrated
4
inFigure3–2.Assumetheconnectionlengthis18in.Also,calculateat
whatlengththistensionmemberwouldceasetosatisfytheslenderness
limitationinSingle-AngleSpecificationSection2.
Fy =36ksi Ag =3.75in.2 rz=0.776 in. 1R1e/1v/.02
F =58ksi y =1.18
u
Solution: Fortensionyielding,perSingle-AngleSpecificationSection2,
φP =φF A
t n t y g
=0.9(36ksi)(3.75in.2)
=122kips
Fig.3–2. IllustrationforExample3.2.
AMERICANINSTITUTEOFSTEELCONSTRUCTION