AISC LRFD 1.pdf

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App. F3.] WEB-TAPERED MEMBERS 105Fwg =5.9E( hL/ r )wTo2(A-F3-7)whereh s = factor equal to10 . + 0. 230g Ld / Aoh w = factor equal to10 . + 0. 00385g L/r Tor To = radius of gyration of a section at the smaller end, considering only thecompression flange plus one-third of the compression web area, taken aboutan axis in the plane of the web, in. (mm)A f = area of the compression flange, in. 2 (mm 2 )and where B is determined as follows:(a) When the maximum moment M 2 in three adjacent segments of approximatelyequal unbraced length is located within the central segment and M 1 is the largermoment at one end of the three-segment portion of a member:fæ M ö æ1M ö1B = 1.0 + 0.37ç 1.0 + + 0.50g1.0 + ³ 1.0è M ÷øçè M ÷ø2 2(A-F3-8)(b) When the largest computed bending stress f b2 occurs at the larger end of twoadjacent segments of approximately equal unbraced lengths and f b1 is the computedbending stress at the smaller end of the two-segment portion of a member:æ f ö æ f öB = +ç+ - + ³è f ÷øçè f ÷øb1 b11.0 0.58 1.0 0.70g1.0 1.0b2 b2(A-F3-9)(c) When the largest computed bending stress f b2 occurs at the smaller end of twoadjacent segments of approximately equal unbraced length and f b1 is the computedbending stress at the larger end of the two-segment portion of a member:æ f ö æ f öB = +ç+ + + ³è f ÷øçè f ÷øb1 b11.0 0.55 1.0 2.20g1.0 1.0b2 b2(A-F3-10)In the foregoing, =(d L -d o )/d o is calculated for the unbraced length that containsthe maximum computed bending stress. M 1 /M 2 is considered as negative whenproducing single curvature. In the rare case where M 1 /M 2 is positive, it is recommendedthat it be taken as zero. f b1 /f b2 is considered as negative when producingsingle curvature. If a point of contraflexure occurs in one of two adjacent unbracedsegments, f b1 /f b2 is considered as positive. The ratio f b1 /f b2 0.(d) When the computed bending stress at the smaller end of a tapered member orsegment thereof is equal to zero:<strong>LRFD</strong> Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION
106 WEB-TAPERED MEMBERS [App. F3.1.75B =1.0 + 0.25 g(A-F3-11)where =(d L -d o )/d o is calculated for the unbraced length adjacent to the point ofzero bending stress.5. Design Shear StrengthThe design shear strength of tapered flexural members shall be determined inaccordance with Section F2.6. Combined Flexure and Axial ForceFor tapered members with a single web taper subject to compression and bendingabout the major axis, Equation H1-1 applies, with the following modifications. P nand P ex shall be determined for the properties of the smaller end, using appropriateeffective length factors. M nx , M u , and M px shall be determined for the larger end; M nx= (5/3)S x F b , where S x is the elastic section modulus of the larger end, and F bg is thedesign flexural stress of tapered members. C mx is replaced by C m , determined as follows:(a) When the member is subjected to end moments which cause single curvaturebending and approximately equal computed moments at the ends:Cæ P ö æ P öuum¢ = 1.0 + 0.1ç+ 0.3èfbP÷exø çèfbP÷exø2(A-F3-12)(b) When the computed bending moment at the smaller end of the unbraced lengthis equal to zero:Cæ P ö æ P öuum¢ = 1.0 - 0.9ç+ 0.6èfbP÷exø çèfbP÷exø2(A-F3-13)When the effective slenderness parameter l eff 1.5 and combined stress is checkedincrementally along the length, the actual area and the actual section modulus at thesection under investigation is permitted to be used.<strong>LRFD</strong> Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION
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LOAD AND RESISTANCEFACTOR DESIGNSPE
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iiCopyright © 2000byAmerican Insti
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vTABLE OF CONTENTSSYMBOLS . . . . .
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TABLE OF CONTENTSviiSPECIFICATION (
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TABLE OF CONTENTSixSPECIFICATION (C
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TABLE OF CONTENTSxiCOMMENTARY (Cont
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SYMBOLSxviistrength (for those stee
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SYMBOLSxixS eff Effective section m
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SYMBOLSxxit s Web stiffener thickne
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xxiiiGLOSSARYAlignment chart for co
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GLOSSARYxxvEffective moment of iner
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GLOSSARYxxviiLateral bracing member
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GLOSSARYxxixPost-buckling strength.
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GLOSSARYxxxiStrain-hardening strain
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1CHAPTER AGENERAL PROVISIONSA1. SCO
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Sect. A3.] MATERIAL 3Cold-Formed We
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Sect. A3.] MATERIAL 5ASTM A449 bolt
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Sect. A6.] REFERENCED CODES AND STA
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Sect. A7.] DESIGN DOCUMENTS 9tion A
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Sect. B4.] STABILITY 11(a) When the
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Sect. B10.] PROPORTIONS OF BEAMS AN
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Sect. B10.] PROPORTIONS OF BEAMS AN
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17Chap. CCHAPTER CFRAMES AND OTHER
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Sect. C3.] STABILITY BRACING 19all
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Sect. C3.] STABILITY BRACING 214. B
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Sect. C3.] STABILITY BRACING 231.0;
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Sect. D3.] PIN-CONNECTED MEMBERS AN
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27Chap. ECHAPTER ECOLUMNS AND OTHER
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Sect. E4.] BUILT-UP MEMBERS 29(a) F
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31Chap. FCHAPTER FBEAMS AND OTHER F
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Sect. F1.] DESIGN FOR FLEXURE 33Lp=
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Sect. F2.] DESIGN FOR SHEAR 35Lpd
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37Chap. GCHAPTER GPLATE GIRDERSI-sh
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Sect. H3.] ALTERNATIVE INTERACTION
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Sect. I2.] COMPRESSION MEMBERS 41ti
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Sect. I3.] FLEXURAL MEMBERS 434. Lo
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Sect. I3.] FLEXURAL MEMBERS 45welde
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Sect. I5.] SHEAR CONNECTORS 47A c =
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49Chap. JCHAPTER JCONNECTIONS, JOIN
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Sect. J1.] GENERAL PROVISIONS 518.
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Sect. J2.] WELDS 53Welding ProcessT
Page 88 and 89: Sect. J2.] WELDS 55For end-loaded f
Page 90 and 91: Sect. J2.] WELDS 57Types of Weld an
Page 92 and 93: Sect. J3.] BOLTS AND THREADED PARTS
Page 100 and 101: Sect. J4.] DESIGN RUPTURE STRENGTH
Page 102 and 103: Sect. J8.] BEARING STRENGTH 69J6. F
Page 104 and 105: 71Chap. KCHAPTER KCONCENTRATED FORC
Page 106 and 107: Sect. K1.] FLANGES AND WEBS WITH CO
Page 108 and 109: For P u 0.4P yR v = 0.60F y d c t
Page 110 and 111: Sect. K3.] DESIGN FOR CYCLIC LOADIN
Page 112 and 113: 79Chap. LCHAPTER LSERVICEABILITY DE
Page 114 and 115: 81Chap. MCHAPTER MFABRICATION, EREC
Page 116 and 117: Sect. M4.] ERECTION 83(2) Bottom su
Page 118 and 119: Sect. M5.] QUALITY CONTROL 85The fa
Page 120 and 121: Sect. N3.] EVALUATION BY STRUCTURAL
Page 122 and 123: 89App. BAPPENDIX BDESIGN REQUIREMEN
Page 124 and 125: App. B5.] LOCAL BUCKLING 914kc=h/tw
Page 126 and 127: App. B5.] LOCAL BUCKLING 93é0.877
Page 128 and 129: App. E3.] DESIGN COMPRESSIVE STRENG
Page 130 and 131: App. F1.] DESIGN FOR FLEXURE 97For
Page 132 and 133: App. F1.] DESIGN FOR FLEXURE 99TABL
Page 134 and 135: App. F1.] DESIGN FOR FLEXURE 101Cri
Page 136 and 137: App. F3.] WEB-TAPERED MEMBERS 103j
Page 140 and 141: 107App. GAPPENDIX GPLATE GIRDERSThi
Page 142 and 143: App. G3.] DESIGN SHEAR STRENGTH 109
Page 144 and 145: App. G5.] FLEXURE-SHEAR INTERACTION
Page 146 and 147: App. H3.] ALTERNATIVE INTERACTION E
Page 148 and 149: 115App. JAPPENDIX JCONNECTIONS, JOI
Page 150 and 151: App. J3.] BOLTS AND THREADED PARTS
Page 152 and 153: App. K2.] PONDING 119æçMetric:lC
Page 154 and 155: App. K3.] DESIGN FOR CYCLIC LOADING
Page 174 and 175: NUMERICAL VALUES 141TABLE 2ItemShap
Page 176 and 177: NUMERICAL VALUES 143Klr123456789101
Page 178 and 179: NUMERICAL VALUES 145TABLE 3-50Desig
Page 180 and 181: NUMERICAL VALUES 147TABLE 4Values o
Page 182 and 183: NUMERICAL VALUES 149TABLE 5 (cont
Page 184 and 185: NUMERICAL VALUES 151TABLE 7Values o
Page 186 and 187: NUMERICAL VALUES 153f vVAwnTABLE 8-
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NUMERICAL VALUES 155f vVAwnTABLE 8-
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NUMERICAL VALUES 157hf vVAwnTABLE 9
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NUMERICAL VALUES 159f vVAwnTABLE 9-
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NUMERICAL VALUES 161ht wf vVAwnTABL
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163COMMENTARYon the Load and Resist
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Comm. A2.] TYPES OF CONSTRUCTION 16
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Comm. A3.] MATERIAL 167and Chen, 19
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Comm. A3.] MATERIAL 169than the ant
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Comm. A4.] LOADS AND LOAD COMBINATI
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Comm. A5.] DESIGN BASIS 173where =
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Comm. A5.] DESIGN BASIS 175( )bsln(
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177Comm. BCHAPTER BDESIGN REQUIREME
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Comm. B5.] LOCAL BUCKLING 179(c) Al
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Comm. B5.] LOCAL BUCKLING 181load.
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Comm. B7.] LIMITING SLENDERNESS RAT
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Comm. C1.] SECOND ORDER EFFECTS 185
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Comm. C1.] SECOND ORDER EFFECTS 187
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Comm. C2.] FRAME STABILITY 189Buckl
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Comm. C2.] FRAME STABILITY 191Notes
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Comm. C2.] FRAME STABILITY 193Where
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Comm. C3.] STABILITY BRACING 195age
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Comm. C3.] STABILITY BRACING 197pla
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Comm. C3.] STABILITY BRACING 199The
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Comm. C3.] STABILITY BRACING 201Par
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203Comm. ECHAPTER ECOLUMNS AND OTHE
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Comm. E4.] BUILT-UP MEMBERS 205TABL
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Comm. F1.] DESIGN FOR FLEXURE 207ha
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Comm. F1.] DESIGN FOR FLEXURE 2092b
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Comm. F4.] BEAMS AND GIRDERS WITH W
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Comm. H2.] UNSYMMETRIC MEMBERS AND
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Comm. I2.] COMPRESSION MEMBERS 215d
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Comm. I3.] FLEXURAL MEMBERS 217may
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Comm. I3.] FLEXURAL MEMBERS 219The
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Comm. I3.] FLEXURAL MEMBERS 221wher
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Comm. I3.] FLEXURAL MEMBERS 223proc
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Comm. I4.] COMBINED COMPRESSION AND
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Comm. I5.] SHEAR CONNECTORS 227tal
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229Comm. JCHAPTER JCONNECTIONS, JOI
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Comm. J1.] GENERAL PROVISIONS 231 P
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Comm. J2.] WELDS 2332b. Limitations
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Comm. J2.] WELDS 235When longitudin
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Comm. J2.] WELDS 237due to cyclic f
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Comm. J2.] WELDS 239(b) Plane 2-2,
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Comm. J3.] BOLTS AND THREADED PARTS
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Comm. J4.] DESIGN RUPTURE STRENGTH
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249Comm. KCHAPTER KCONCENTRATED FOR
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Comm. K1.] FLANGES AND WEBS WITH CO
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Comm. K1.] FLANGES AND WEBS WITH CO
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Comm. K2.] PONDING 255Even on the b
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257Comm. LCHAPTER LSERVICEABILITY D
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Comm. L5.] CORROSION 259orthotropic
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Comm. M4.] ERECTION 261It is sugges
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Comm. N4.] EVALUATION BY LOAD TESTS
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Comm. N5.] EVALUATION REPORT 265N5.
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267Comm. A-EAPPENDIX ECOLUMNS AND O
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Comm. App. F3.] WEB-TAPERED MEMBERS
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271Comm. A-GAPPENDIX GPLATE GIRDERS
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273Comm. A-KAPPENDIX JCONNECTIONS,
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Comm. J2.] WELDS 275found to be con
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Comm. K3.] DESIGN FOR CYCLIC LOADIN
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279ReferencesAckroyd, M. H., and Ge
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REFERENCES 281Bjorhovde, R. (1972),
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REFERENCES 283Fielding, D. J., and
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REFERENCES 285Johnson, D. L. (1985)
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REFERENCES 287Ollgaard, J. G., Slut
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REFERENCES 289Zhou, S. P., and Chen
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SUPPLEMENTARY BIBLIOGRAPHY 291Kotec
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Metric Conversion Factors for Commo
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