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Comm. J2.] WELDS 239(b) Plane 2-2, in which the resistance is governed by the shear strength of the weldmetal.(c) Plane 3-3, in which the resistance is governed by the shear strength of the materialB.The resistance of the welded joint is the lowest of the resistance calculated in eachplane of shear transfer. Note that planes 1-1 and 3-3 are positioned away from thefusion areas between the weld and the base material. Tests have demonstrated thatthe stress on this fusion area is not critical in determining the shear strength of filletwelds (Preece, 1968).The shear planes for plug and partial-joint-penetration groove welds are shown inFigure C-J2.11 for the weld and base metal. Generally the base metal will governthe shear strength.5. Combination of WeldsThis method of adding weld strengths does not apply to a welded joint using a partial-joint-penetrationsingle bevel groove weld with a superimposed fillet weld. Inthis case, the effective throat of the combined joint must be determined and thedesign strength based upon this throat area.6. Weld Metal RequirementsApplied and residual stresses and geometrical discontinuities from back-up barswith associated notch effects contribute to sensitivity to fracture. Some weld metalsin combination with certain procedures result in welds with low notch toughness.The Specification requires a minimum specified toughness for weld metals in thosejoints that are subject to more significant applied stresses and toughness demands.The level of toughness required was selected as one level more conservative thanFig. C-J2.11. Shear planes for plug and partial-joint-penetration groove welds.<strong>LRFD</strong> Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION
240 WELDS [Comm. J2.the base metal requirement for Group 4 and 5 shapes. Research continues on thissubject.7. Mixed Weld MetalProblems can occur when incompatible weld metals are used in combination andnotch-tough composite weld metal is required. For instance, tack welds depositedusing a self-shielded process with aluminum deoxidizers in the electrodes and subsequentlycovered by SAW weld passes can result in composite weld metal withlow notch-toughness, despite the fact that each process by itself could providenotch-tough weld metal.J3. BOLTS AND THREADED PARTS1. High-Strength BoltsIn general, the use of high-strength bolts is required to conform to the provisions ofthe Load and Resistance Factor Design Specification for Structural Joints UsingASTM A325 or A490 Bolts (RCSC, 1994) as approved by the Research Council onStructural Connections.Occasionally the need arises for the use of high-strength bolts of diameters andlengths in excess of those available for A325 or A325M and A490 or A490M bolts,as for example, anchor rods for fastening machine bases. For this situation SectionA3.3 permits the use of A449 bolts and A354 threaded rods.With this edition of the Specification snug-tightened installation is permitted forstatic applications involving ASTM A325 or A325M bolts (only) in tension orcombined shear and tension. Figures C-J3.1 and C-J3.2 illustrate the results of testingby Johnson (1996) on tee stubs bolted flange-to-flange with two ASTM A325bolts. This testing involved two lengths (2 3 4 in. and 3 1 4 in.) (70 mm and 83 mm) andseveral combinations of installed pretension (finger-tight, snug-tight, andpretensioned). The 2 3 4-in. (70 mm) bolt length corresponds to the least number ofthreads remaining in the grip. The 3 1 4-in. (83 mm) bolt length corresponds to themaximum number of threads remaining in the grip. As evidenced by the data, theinstallation condition does not affect the ultimate strength.Fracture Load (kips)1009080706050403020100FT/FT FT/FT FT/ST FT/PT ST/ST ST/ST ST/PT PT/PT PT/PTFig. C-J3.1. Johnson (1996) tests, 2 3 4-in.-long, 3 4-in.-diameter ASTM A325 bolts.<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
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Sect. J2.] WELDS 55For end-loaded f
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Sect. J2.] WELDS 57Types of Weld an
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Sect. J3.] BOLTS AND THREADED PARTS
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Sect. J4.] DESIGN RUPTURE STRENGTH
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Sect. J8.] BEARING STRENGTH 69J6. F
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71Chap. KCHAPTER KCONCENTRATED FORC
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Sect. K1.] FLANGES AND WEBS WITH CO
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For P u 0.4P yR v = 0.60F y d c t
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Sect. K3.] DESIGN FOR CYCLIC LOADIN
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79Chap. LCHAPTER LSERVICEABILITY DE
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81Chap. MCHAPTER MFABRICATION, EREC
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Sect. M4.] ERECTION 83(2) Bottom su
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Sect. M5.] QUALITY CONTROL 85The fa
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Sect. N3.] EVALUATION BY STRUCTURAL
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89App. BAPPENDIX BDESIGN REQUIREMEN
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App. B5.] LOCAL BUCKLING 914kc=h/tw
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App. B5.] LOCAL BUCKLING 93é0.877
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App. E3.] DESIGN COMPRESSIVE STRENG
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App. F1.] DESIGN FOR FLEXURE 97For
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App. F1.] DESIGN FOR FLEXURE 99TABL
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App. F1.] DESIGN FOR FLEXURE 101Cri
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App. F3.] WEB-TAPERED MEMBERS 103j
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App. F3.] WEB-TAPERED MEMBERS 105Fw
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107App. GAPPENDIX GPLATE GIRDERSThi
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App. G3.] DESIGN SHEAR STRENGTH 109
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App. G5.] FLEXURE-SHEAR INTERACTION
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App. H3.] ALTERNATIVE INTERACTION E
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115App. JAPPENDIX JCONNECTIONS, JOI
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App. J3.] BOLTS AND THREADED PARTS
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App. K2.] PONDING 119æçMetric:lC
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App. K3.] DESIGN FOR CYCLIC LOADING
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NUMERICAL VALUES 141TABLE 2ItemShap
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NUMERICAL VALUES 143Klr123456789101
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NUMERICAL VALUES 145TABLE 3-50Desig
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NUMERICAL VALUES 147TABLE 4Values o
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NUMERICAL VALUES 149TABLE 5 (cont
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NUMERICAL VALUES 151TABLE 7Values o
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NUMERICAL VALUES 153f vVAwnTABLE 8-
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NUMERICAL VALUES 157hf 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
Page 222 and 223: Comm. C2.] FRAME STABILITY 189Buckl
Page 224 and 225: Comm. C2.] FRAME STABILITY 191Notes
Page 226 and 227: Comm. C2.] FRAME STABILITY 193Where
Page 228 and 229: Comm. C3.] STABILITY BRACING 195age
Page 230 and 231: Comm. C3.] STABILITY BRACING 197pla
Page 232 and 233: Comm. C3.] STABILITY BRACING 199The
Page 234 and 235: Comm. C3.] STABILITY BRACING 201Par
Page 236 and 237: 203Comm. ECHAPTER ECOLUMNS AND OTHE
Page 238 and 239: Comm. E4.] BUILT-UP MEMBERS 205TABL
Page 240 and 241: Comm. F1.] DESIGN FOR FLEXURE 207ha
Page 242 and 243: Comm. F1.] DESIGN FOR FLEXURE 2092b
Page 244 and 245: Comm. F4.] BEAMS AND GIRDERS WITH W
Page 246 and 247: Comm. H2.] UNSYMMETRIC MEMBERS AND
Page 248 and 249: Comm. I2.] COMPRESSION MEMBERS 215d
Page 250 and 251: Comm. I3.] FLEXURAL MEMBERS 217may
Page 252 and 253: Comm. I3.] FLEXURAL MEMBERS 219The
Page 254 and 255: Comm. I3.] FLEXURAL MEMBERS 221wher
Page 256 and 257: Comm. I3.] FLEXURAL MEMBERS 223proc
Page 258 and 259: Comm. I4.] COMBINED COMPRESSION AND
Page 260 and 261: Comm. I5.] SHEAR CONNECTORS 227tal
Page 262 and 263: 229Comm. JCHAPTER JCONNECTIONS, JOI
Page 264 and 265: Comm. J1.] GENERAL PROVISIONS 231 P
Page 266 and 267: Comm. J2.] WELDS 2332b. Limitations
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Page 270 and 271: Comm. J2.] WELDS 237due to cyclic f
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Page 280 and 281: Comm. J4.] DESIGN RUPTURE STRENGTH
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Page 284 and 285: Comm. K1.] FLANGES AND WEBS WITH CO
Page 286 and 287: Comm. K1.] FLANGES AND WEBS WITH CO
Page 288 and 289: Comm. K2.] PONDING 255Even on the b
Page 290 and 291: 257Comm. LCHAPTER LSERVICEABILITY D
Page 292 and 293: Comm. L5.] CORROSION 259orthotropic
Page 294 and 295: Comm. M4.] ERECTION 261It is sugges
Page 296 and 297: Comm. N4.] EVALUATION BY LOAD TESTS
Page 298 and 299: Comm. N5.] EVALUATION REPORT 265N5.
Page 300 and 301: 267Comm. A-EAPPENDIX ECOLUMNS AND O
Page 302 and 303: Comm. App. F3.] WEB-TAPERED MEMBERS
Page 304 and 305: 271Comm. A-GAPPENDIX GPLATE GIRDERS
Page 306 and 307: 273Comm. A-KAPPENDIX JCONNECTIONS,
Page 308 and 309: Comm. J2.] WELDS 275found to be con
Page 310 and 311: Comm. K3.] DESIGN FOR CYCLIC LOADIN
Page 312 and 313: 279ReferencesAckroyd, M. H., and Ge
Page 314 and 315: REFERENCES 281Bjorhovde, R. (1972),
Page 316 and 317: REFERENCES 283Fielding, D. J., and
Page 318 and 319: REFERENCES 285Johnson, D. L. (1985)
Page 320 and 321: 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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