Preface

(This Preface is not part of ANSI/AISC 360-22, Specification for Structural Steel Buildings, but is included for informational purposes only.)

This Specification is based upon past successful usage, advances in the state of knowledge, and changes in design practice. The 2022 American Institute of Steel Construction’s Specification for Structural Steel Buildings provides an integrated treatment of allowable strength design (ASD) and load and resistance factor design (LRFD), and replaces earlier Specifications. As indicated in Chapter B of the Specification, designs can be made according to either ASD or LRFD provisions.

This ANSI-approved Specification has been developed as a consensus document using ANSI-accredited procedures to provide a uniform practice in the design of steel-framed buildings and other structures. The intention is to provide design criteria for routine use and not to provide specific criteria for infrequently encountered problems that occur in the full range of structural design.

This Specification is the result of the consensus deliberations of a committee of structural engineers with wide experience and high professional standing, representing a wide geographical distribution throughout the United States. The committee includes approximately equal numbers of engineers in private practice and code agencies, engineers involved in research and teaching, and engineers employed by steel fabricating and producing companies. The contributions and assistance of more than 50 additional professional volunteers working in task committees are also hereby acknowledged.

The Symbols, Glossary, Abbreviations, and Appendices to this Specification are an integral part of the Specification. A nonmandatory Commentary has been prepared to provide background for the Specification provisions and the user is encouraged to consult it. Additionally, nonmandatory User Notes are interspersed throughout the Specification to provide concise and practical guidance in the application of the provisions.

A number of significant technical modifications have also been made since the 2016 edition of the Specification, including the following:

• A new table is incorporated into Section A3 that lists allowable grades and strengths and other specific limitations of referenced materials.
• Section J3 adopts ASTM F3148 bolts that provide a strength of 144 ksi. A new combined installation method is incorporated into Chapter J applicable to these bolts by reference to the RCSC Specification.
• Section A4 provides a detailed list related to what information must be provided on structural design documents. These criteria have been moved from the Code of Standard Practice for Structural Steel Buildings.
• A new Section A5, Approvals, is added to specifically address the review and approval of approval documents.
• A new Section B8, Dimensional Tolerances, is added to clarify that the provisions of the Specification are based on specific tolerances provided in the Code of Standard Practice and referenced ASTM standards.
• Provisions are added in Section E4 for doubly symmetric I-shaped compression members to address lateral bracing that is offset from the shear center.
• For flexural strength of members with holes in the tension flange, it is clarified that the Section F13.1 provisions apply only to bolt holes.
• Provisions are added to Chapter G to permit tension field action in end panels.
Provisions are added to Chapter H for HSS subjected to combined forces, to include biaxial bending and shear.
• Provisions are added to Chapter I for longitudinal and transverse reinforcing steel requirements for filled composite columns and for both encased composite and filled composite beams.
• Chapter I now includes additional stiffness and strength provisions for concrete filled composite plate shear walls consisting of two steel plates connected by tie bars.
Provisions for the design of rectangular filled composite members constructed from materials with strengths above the limits noted in Chapter I are added in a new Appendix 2.
• Section J2 provides revised requirements to qualify partial-joint-penetration groove welds with effective throats larger than those prescribed in AWS D1.1/D1.1M.
• Requirements regarding the use of low-hydrogen electrodes as they relate to minimum size fillet welds are revised in Table J2.4.
The directional strength increase for transversely loaded fillet welds is rewritten and prohibited for use in the ends of rectangular HSS.
• An alternative bolt tensile strength based on the net tensile area of bolts is added.
• Added limit states for rectangular HSS moment connections in Chapter K.
• Section N4 now addresses coating inspection personnel requirements.
• A new Section N8, Minimum Requirements for Shop or Field Applied Coatings, is added.
• Appendix 2, Design for Ponding, is removed and replaced with updated guidance on this topic in Section B3.10.
• Appendix 3 clarifies hole forming provisions for elements subjected to fatigue.
Appendix 4 incorporates temperature-dependent stress-strain equations from the Eurocode to provide material properties for steel at elevated temperatures.
Prescriptive steel fire-protection design equations and related information based on standard ASTM E119 fire tests are incorporated into Appendix 4.
• Appendix 4, Section 4.4d, Design by Simple Methods of Analysis, includes provisions for compressive strength in filled composite columns and for compression in filled composite plate shear walls.
Provisions for calculating rivet strength are added in Appendix 5.

This Specification was approved by the Committee on Specifications:

James O. Malley, Chair	Bruce R. Ellingwood, Emeritus
Scott F. Armbrust, Vice Chair	Michael D. Engelhardt
Allen Adams	Shu-Jin Fang, Emeritus
Taha D. Al-Shawaf	James M. Fisher, Emeritus
William F. Baker	John W. Fisher, Emeritus
John M. Barsom, Emeritus	Theodore V. Galambos, Emeritus
Roger L. Brockenbrough, Emeritus	Michael E. Gase
Susan B. Burmeister	Louis F. Geschwindner
Gregory G. Deierlein	Ramon E. Gilsanz
Bo Dowswell	Lawrence G. Griffis
Carol J. Drucker	Jerome F. Hajjar
W. Samuel Easterling	Ronald O. Hamburger

Patrick M. Hassett	R. Shankar Nair, Emeritus
Tony C. Hazel	Conrad Paulson
Todd A. Helwig	Douglas A. Rees-Evans
Richard A. Henige, Jr.	Rafael Sabelli
Mark V. Holland	Thomas A. Sabol
John D. Hooper	Fahim H. Sadek
Nestor R. Iwankiw	Benjamin W. Schafer
William P. Jacobs, V	Robert E. Shaw, Jr.
Ronald J. Janowiak	Donald R. Sherman, Emeritus
Lawrence A. Kloiber, Emeritus	W. Lee Shoemaker
Lawrence F. Kruth	William A. Thornton, Emeritus
Jay W. Larson	Chia-Ming Uang
Roberto T. Leon	Amit H. Varma
Judy Liu	Donald W. White
Duane K. Miller	Jamie Winans
Larry S. Muir	Ronald D. Ziemian
Thomas M. Murray, Emeritus	Cynthia J. Duncan, Secretary

The Committee honors former members, vice-chair, Patrick J. Fortney, and emeritus members, Reidar Bjorhovde, Duane S. Ellifritt, and Raymond H.R. Tide, who passed away during this cycle.

The Committee gratefully acknowledges AISC Board Oversights, Matt Smith and Duff Zimmerman; advisory members, Carlos Aguirre and Tiziano Perea; and the following task committee and staff members for their involvement in the development of this document.

Farid Alfawakhiri	Rodney D. Gibble
Abbas Aminmansour	Nathaniel P. Gonner
Caroline R. Bennett	Arvind V. Goverdhan
Robert Berhinig	Perry S. Green
Eric Bolin	Christina Harber
Mark Braekevelt	John Harris
Michel Bruneau	Alfred A. Herget
Art Bustos	Stephen M. Herlache
Joel A. Chandler	Steven J. Herth
Robert Chmielowski	Devin Huber
Lisa Choe	Ronald B. Johnson
Douglas Crampton	Jeffrey Keileh
Rachel Chicchi Cross	Kerry Kreitman
Mark D. Denavit	David W. Landis
Matthew F. Fadden	Chad M. Larson
Larry A. Fahnestock	Dawn E. Lehman
Shelley C. Finnigan	Andres Lepage
Erica C. Fischer	Brent Leu
Timothy P. Fraser	Carlo Lini
Christine Freisinger	LeRoy A. Lutz
Michael Gannon	Andrew Lye
Rupa Garai	Bonnie E. Manley
Jeffrey Gasparott	Michael R. Marian

Jason P. McCormick	Kristi Sattler
Austin A. Meier	Brandt Saxey
Jared Moseley	Thomas J. Schlafly
J.R. Ubejd Mujagic	Jim Schoen
Kimberley T. Olson	William Scott
Jeffrey A. Packer	Richard Scruton
Garner Palenske	Bahram M. Shahrooz
Robert Pekelnicky	Thomas Sputo
Thomas D. Poulos	Ryan Staudt
Max Puchtel	Andrea E. Surovek
Christopher H. Raebel	James A. Swanson
Gian Andrea Rassati	Matthew Trammell
Charles W. Roeder	Sriramulu Vinnakota
John A. Rolfes	Michael A. West
Sougata Roy

SYMBOLS	xxxi
GLOSSARY	.1
ABBREVIATIONS	.lxv
A. GENERAL PROVISIONS	1
A1. Scope	1
1. Seismic Applications	2
2. Nuclear Applications	2
A2. Referenced Specifications, Codes, and Standards	2
A3. Material	6
1. Structural Steel Materials	6
1a. Listed Materials	8
1b. Other Materials	8
1c. Unidentified Steel	8
1d. Rolled Heavy Shapes	9
1e. Built-Up Heavy Shapes	9
2. Steel Castings and Forgings	10
3. Bolts, Washers, and Nuts	10
4. Anchor Rods and Threaded Rods	10
5. Consumables for Welding	11
6. Headed Stud Anchors	11
A4. Structural Design Documents and Specifications	11
1. Structural Design Documents and Specifications Issued for Construction	11
2. Structural Design Documents and Specifications Issued for Any Purpose	13
A5. Approvals	14
B. DESIGN REQUIREMENTS	15
B1. General Provisions	15
B2. Loads and Load Combinations	15
B3. Design Basis	15
1. Design for Strength Using Load and Resistance Factor Design (LRFD)	16
2. Design for Strength Using Allowable Strength Design (ASD)	16
3. Required Strength	16
4. Design of Connections and Supports	17
4a. Simple Connections	17
4b. Moment Connections	17
5. Design of Diaphragms and Collectors	17
6. Design of Anchorages to Concrete	18
7. Design for Stability	18

	8. Design for Serviceability	18
	9. Design for Structural Integrity	18
	10. Design for Ponding	18
	11. Design for Fatigue	19
	12. Design for Fire Conditions	19
	13. Design for Corrosion Effects	19
B4.	Member Properties	19
	1. Classification of Sections for Local Buckling	19
	1a. Unstiffened Elements	20
	1b. Stiffened Elements	20
	2. Design Wall Thickness for HSS	24
	3. Gross and Net Area Determination	24
	3a. Gross Area	24
	3b. Net Area	24
B5.	Fabrication and Erection	25
B6.	Quality Control and Quality Assurance	25
B7.	Evaluation of Existing Structures	25
B8.	Dimensional Tolerances	25
C. DESIGN FOR STABILITY		26
C1.	General Stability Requirements	26
	1. Direct Analysis Method of Design	26
	2. Alternative Methods of Design	27
C2.	Calculation of Required Strengths	27
	1. General Analysis Requirements	27
	2. Consideration of Initial System Imperfections	28
	2a. Direct Modeling of Imperfections	28
	2b. Use of Notional Loads to Represent Imperfections	29
	3. Adjustments to Stiffness	30
C3.	Calculation of Available Strengths	31
D. DESIGN OF MEMBERS FOR TENSION		32
D1.	Slenderness Limitations	32
D2.	Tensile Strength	32
D3.	Effective Net Area	33
D4.	Built-Up Members	33
D5.	Pin-Connected Members	35
	1. Tensile Strength	35
	2. Dimensional Requirements	36
D6.	Eyebars	36
	1. Tensile Strength	36
	2. Dimensional Requirements	37
E. DESIGN OF MEMBERS FOR COMPRESSION		38
E1.	General Provisions	38
E2.	Effective Length	40
E3.	Flexural Buckling of Members without Slender Elements	40

DESIGN OF MEMBERS FOR FLEXURE 50
E4. Torsional and Flexural-Torsional Buckling of Single Angles and Members without Slender Elements	41
E5. Single-Angle Compression Members	43
E6. Built-Up Members	45
1. Compressive Strength	45
2. General Requirements	46
E7. Members with Slender Elements	48
1. Slender Element Members Excluding Round HSS	48
2. Round HSS	49
F1. General Provisions	52
F2. Doubly Symmetric Compact I-Shaped Members and Channels Bent About Their Major Axis	53
1. Yielding	53
2. Lateral-Torsional Buckling	53
F3. Doubly Symmetric I-Shaped Members with Compact Webs and Noncompact or Slender Flanges Bent About Their Major Axis	55
1. Lateral-Torsional Buckling	55
2. Compression Flange Local Buckling	55
F4. Other I-Shaped Members with Compact or Noncompact Webs Bent About Their Major Axis	56
1. Compression Flange Yielding	56
2. Lateral-Torsional Buckling	56
3. Compression Flange Local Buckling	59
4. Tension Flange Yielding	59
F5. Doubly Symmetric and Singly Symmetric I-Shaped Members with Slender Webs Bent About Their Major Axis	60
1. Compression Flange Yielding	60
2. Lateral-Torsional Buckling	60
3. Compression Flange Local Buckling	61
4. Tension Flange Yielding	61
F6. I-Shaped Members and Channels Bent About Their Minor Axis	61
1. Yielding	62
2. Flange Local Buckling	62
F7. Square and Rectangular HSS and Box Sections	62
1. Yielding	63
2. Flange Local Buckling	63
3. Web Local Buckling	63
4. Lateral-Torsional Buckling	64
F8. Round HSS	65
1. Yielding	65
2. Local Buckling	65
F9. Tees and Double Angles Loaded in the Plane of Symmetry	65
1. Yielding	65
2. Lateral-Torsional Buckling	66

3.	Flange Local Buckling of Tees and Double-Angle Legs	67
4.	Local Buckling of Tee Stems and Double-Angle Web Legs in Flexural Compression	67
F10.	Single Angles	68
1.	Yielding	69
2.	Lateral-Torsional Buckling	69
3.	Leg Local Buckling	70
F11.	Rectangular Bars and Rounds	71
1.	Yielding	71
2.	Lateral-Torsional Buckling	71
F12.	Unsymmetrical Shapes	71
1.	Yielding	72
2.	Lateral-Torsional Buckling	72
3.	Local Buckling	72
F13.	Proportions of Beams and Girders	72
1.	Strength Reductions for Members with Bolt Holes in the Tension Flange	72
2.	Proportioning Limits for I-Shaped Members	73
3.	Cover Plates	73
4.	Built-Up Beams	74
G.	DESIGN OF MEMBERS FOR SHEAR	75
G1.	General Provisions	75
G2.	I-Shaped Members and Channels	75
1.	Shear Strength of Webs	75
2.	Shear Strength of Interior Web Panels with a/h ≤ 3 Considering Tension Field Action	77
3.	Shear Strength of End Web Panels with a/h ≤ 3 Considering Tension Field Action	78
4.	Transverse Stiffeners	78
G3.	Single Angles and Tees	80
G4.	Rectangular HSS, Box Sections, and Other Singly and Doubly Symmetric Members	80
G5.	Round HSS	80
G6.	Doubly Symmetric and Singly Symmetric Members Subjected to Minor-Axis Shear	81
G7.	Beams and Girders with Web Openings	81
H.	DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION	82
H1.	Doubly and Singly Symmetric Members Subjected to Flexure and Axial Force	82
1.	Doubly and Singly Symmetric Members Subjected to Flexure and Compression	82
2.	Doubly and Singly Symmetric Members Subjected to Flexure and Tension	83
3.	Doubly Symmetric Rolled Compact Members Subjected to Single-Axis Flexure and Compression	83

H2.	Unsymmetric and Other Members Subjected to Flexure and Axial Force	84
H3.	Members Subjected to Torsion and Combined Torsion, Flexure, Shear, and/or Axial Force.	85
1.	Round and Rectangular HSS Subjected to Torsion	85
2.	HSS Subjected to Combined Torsion, Shear, Flexure, and Axial Force	86
3.	Non-HSS Members Subjected to Torsion and Combined Stress	87
H4.	Rupture of Flanges with Bolt Holes and Subjected to Tension	87
DESIGN OF COMPOSITE MEMBERS 89
I1.	General Provisions	89
1.	Concrete and Steel Reinforcement	89
2.	Nominal Strength of Composite Sections	90
2a.	Plastic Stress Distribution Method	90
2b.	Strain Compatibility Method	90
2c.	Elastic Stress Distribution Method	90
2d.	Effective Stress-Strain Method	91
3.	Material Limitations	91
4.	Classification of Filled Composite Sections for Local Buckling	91
5.	Stiffness for Calculation of Required Strengths	93
6.	Requirements for Composite Plate Shear Walls	94
6a.	Slenderness Requirement	95
6b.	Tie Bar Requirement	95
I2.	Axial Force	95
1.	Encased Composite Members	95
1a.	Limitations.	95
1b.	Compressive Strength	96
1c.	Tensile Strength.	97
1d.	Load Transfer	97
1e.	Detailing Requirements	97
2.	Filled Composite Members	98
2a.	Limitations.	98
2b.	Compressive Strength	98
2c.	Tensile Strength.	99
2d.	Load Transfer	99
2e.	Detailing Requirements	100
3.	Composite Plate Shear Walls	100
3a.	Compressive Strength	100
3b.	Tensile Strength.	100
I3.	Flexure	100
1.	General	100
1a.	Effective Width	100
1b.	Strength During Construction	100
2.	Composite Beams with Steel Headed Stud or Steel Channel Anchors	101
2a.	Positive Flexural Strength.	101

	2b.	Negative Flexural Strength	101
	2c.	Composite Beams with Formed Steel Deck	101
		1. General	101
		2. Deck Ribs Oriented Perpendicular to Steel Beam	102
		3. Deck Ribs Oriented Parallel to Steel Beam	102
	2d.	Load Transfer Between Steel Beam and Concrete Slab	102
		1. Load Transfer for Positive Flexural Strength	102
		2. Load Transfer for Negative Flexural Strength	103
	3.	Encased Composite Members	103
		3a. Limitations	103
		3b. Detailing Requirements	104
	4.	Filled Composite Members	104
		4a. Limitations	104
		4b. Flexural Strength	105
		4c. Detailing Requirements	106
	5.	Composite Plate Shear Walls	106
14.		Shear	106
		1. Encased Composite Members	106
		2. Filled Composite Members	106
		3. Composite Beams with Formed Steel Deck	107
		4. Composite Plate Shear Walls	107
15.		Combined Flexure and Axial Force	108
16.		Load Transfer	109
		1. General Requirements	109
		2. Force Allocation	109
		2a. External Force Applied to Steel Section	110
		2b. External Force Applied to Concrete	110
		2c. External Force Applied Concurrently to Steel and Concrete	111
		3. Force Transfer Mechanisms	111
		3a. Direct Bearing	111
		3b. Shear Connection	111
		3c. Direct Bond Interaction	112
		4. Detailing Requirements	112
		4a. Encased Composite Members	112
		4b. Filled Composite Members	112
17.		Composite Diaphragms and Collector Beams	112
18.		Steel Anchors	113
		1. General	113
		2. Steel Anchors in Composite Beams	113
		2a. Strength of Steel Headed Stud Anchors	113
		2b. Strength of Steel Channel Anchors	114
		2c. Required Number of Steel Anchors	115
		2d. Detailing Requirements	115
		3. Steel Anchors in Composite Components	115
		3a. Shear Strength of Steel Headed Stud Anchors in Composite Components	116

Section	Title	Page
3b.	Tensile Strength of Steel Headed Stud Anchors in Composite Components	117
3c.	Strength of Steel Headed Stud Anchors for Interaction of Shear and Tension in Composite Components	118
3d.	Shear Strength of Steel Channel Anchors in Composite Components	119
3e.	Detailing Requirements in Composite Components	119
4.	Performance-Based Alternative for the Design of Shear Connection	119
4a.	Test Standard	119
4b.	Nominal and Available Strength	120
4c.	Shear Connection Slip Capacity	120
4d.	Acceptance Criteria	120

J. DESIGN OF CONNECTIONS

J1.	General Provisions	121
	1. Design Basis	121
	2. Simple Connections	121
	3. Moment Connections	122
	4. Compression Members with Bearing Joints	122
	5. Splices in Heavy Sections	122
	6. Weld Access Holes	123
	7. Placement of Welds and Bolts	123
	8. Bolts in Combination with Welds	123
	9. Welded Alterations to Structures with Existing Rivets or Bolts	124
	10. High-Strength Bolts in Combination with Existing Rivets	124
J2.	Welds and Welded Joints	124
	1. Groove Welds	125
	1a. Effective Area	125
	1b. Limitations	126
	2. Fillet Welds	126
	2a. Effective Area	126
	2b. Limitations	127
	3. Plug and Slot Welds	129
	3a. Effective Area	129
	3b. Limitations	129
	4. Strength	130
	5. Combination of Welds	133
	6. Filler Metal Requirements	133
	7. Mixed Weld Metal	133
J3.	Bolts, Threaded Parts, and Bolted Connections	134
	1. Common Bolts	134
	2. High-Strength Bolts	134
	3. Size and Use of Holes	135
	4. Minimum Spacing	138
	5. Minimum Edge Distance	139
	6. Maximum Spacing and Edge Distance	140

	7.		Tensile and Shear Strength of Bolts and Threaded Parts	141
	8.		Combined Tension and Shear in Bearing-Type Connections.	141
	9.		High-Strength Bolts in Slip-Critical Connections	142
	10.		Combined Tension and Shear in Slip-Critical Connections.	143
	11.		Bearing and Tearout Strength at Bolt Holes..	143
		11a.	Snug-Tightened or Pretensioned High-Strength Bolted Connections	143
		11b.	Connections Made Using Bolts or Rods That Pass Completely Through an Unstiffened Box Member or HSS ……….	144
	12.		Special Fasteners	145
	13.		Wall Strength at Tension Fasteners	145
J4.			Affected Elements of Members and Connecting Elements ..	145
	1.		Strength of Elements in Tension	145
	2.		Strength of Elements in Shear	145
	3.		Block Shear Strength	146
	4.		Strength of Elements in Compression..	146
	5.		Strength of Elements in Flexure..	146
J5.			Fillers	147
	1.		Fillers in Welded Connections	147
		1a.	Thin Fillers	147
		1b.	Thick Fillers	147
	2.		Fillers in Bolted Bearing-Type Connections.	147
J6.			Splices	147
J7.			Bearing Strength..	148
J8.			Column Bases and Bearing on Concrete.	148
J9.			Anchor Rods and Embedments	149
J10.			Flanges and Webs with Concentrated Forces	150
	1.		Flange Local Bending	150
	2.		Web Local Yielding	151
	3.		Web Local Crippling.	151
	4.		Web Sidesway Buckling	152
	5.		Web Compression Buckling	153
	6.		Web Panel-Zone Shear	153
	7.		Unframed Ends of Beams and Girders.	154
	8.		Additional Stiffener Requirements for Concentrated Forces	155
	9.		Additional Doubler Plate Requirements for Concentrated Forces	155
	10.		Transverse Forces on Plate Elements	156

K. ADDITIONAL REQUIREMENTS FOR HSS AND BOX-SECTION

CONNECTIONS: 157 K1. General Provisions and Parameters for HSS Connections: 157

Definitions of Parameters: 158
Rectangular HSS: 159 2a. Effective Width for Connections to Rectangular HSS: 159
Chord-Stress Interaction Parameter: 159
End Distance: 160 K2. Concentrated Forces on HSS: 160

	1. Definitions of Parameters	160
	2. Round HSS	160
	3. Rectangular HSS	160
K3.	HSS-to-HSS Truss Connections	160
	1. Definitions of Parameters	162
	2. Round HSS	162
	3. Rectangular HSS	162
K4.	HSS-to-HSS Moment Connections	164
	1. Definitions of Parameters	164
	2. Round HSS	164
	3. Rectangular HSS	168
K5.	Welds of Plates and Branches to HSS	168
L.	DESIGN FOR SERVICEABILITY	174
L1.	General Provisions	174
L2.	Deflections	174
L3.	Drift	174
L4.	Vibration.	175
L5.	Wind-Induced Motion	175
L6.	Thermal Expansion and Contraction	175
L7.	Connection Slip	175
M.	FABRICATION AND ERECTION	176
M1.	Fabrication and Erection Documents	176
	1. Fabrication Documents for Steel Construction	176
	2. Erection Documents for Steel Construction	176
M2.	Fabrication	176
	1. Cambering, Curving, and Straightening	176
	2. Thermal Cutting	177
	3. Planing of Edges	178
	4. Welded Construction	178
	5. Bolted Construction	178
	6. Compression Joints	178
	7. Dimensional Tolerances	178
	8. Finish of Column Bases	179
	9. Holes for Anchor Rods	179
	10. Drain Holes	179
	11. Requirements for Galvanized Members	179
M3.	Shop Painting	179
	1. General Requirements	179
	2. Inaccessible Surfaces	180
	3. Contact Surfaces	180
	4. Finished Surfaces	180
	5. Surfaces Adjacent to Field Welds	180
M4.	Erection	180
	1. Column Base Setting	180
	2. Stability and Connections	180
	3. Alignment	180

4. Fit of Column Compression Joints and Base Plates	180
5. Field Welding	181
6. Field Painting.	181
N. QUALITY CONTROL AND QUALITY ASSURANCE	182
N1. General Provisions	182
N2. Fabricator and Erector Quality Control Program	183
1. Material Identification	183
2. Fabricator Quality Control Procedures	183
3. Erector Quality Control Procedures	183
N3. Fabricator and Erector Documents	184
1. Submittals for Steel Construction	184
2. Available Documents for Steel Construction	184
N4. Inspection and Nondestructive Testing Personnel	185
1. Quality Control Inspector Qualifications	185
2. Quality Assurance Inspector Qualifications	185
3. NDT Personnel Qualifications	186
N5. Minimum Requirements for Inspection of Structural Steel Buildings	186
1. Quality Control	186
2. Quality Assurance	186
3. Coordinated Inspection	187
4. Inspection of Welding.	187
5. Nondestructive Testing of Welded Joints.	188
5a. Procedures	188
5b. CJP Groove Weld NDT	189
5c. Welded Joints Subjected to Fatigue	189
5d. Ultrasonic Testing Rejection Rate	190
5e. Reduction of Ultrasonic Testing Rate	190
5f. Increase in Ultrasonic Testing Rate	190
5g. Documentation	190
6. Inspection of High-Strength Bolting	190
7. Inspection of Galvanized Structural Steel Main Members	192
8. Other Inspection Tasks	192
N6. Approved Fabricators and Erectors	193
N7. Nonconforming Material and Workmanship	193
N8. Minimum Requirements for Shop- or Field-Applied Coatings	194
APPENDIX 1. DESIGN BY ADVANCED ANALYSIS	195
1.1. General Requirements	195
1.2. Design by Elastic Analysis	195
1. General Stability Requirements	195
2. Calculation of Required Strengths	195
2a. General Analysis Requirements	196
2b. Adjustments to Stiffness	196
3. Calculation of Available Strengths	197
1.3. Design by Inelastic Analysis	197
1. General Requirements	197
2. Ductility Requirements	198

	2a. Material	198
	2b. Cross Section	198
	2c. Unbraced Length	199
	2d. Axial Force	200
	3. Analysis Requirements	200
	3a. Material Properties and Yield Criteria	200
	3b. Geometric Imperfections	201
	3c. Residual Stress and Partial Yielding Effects	201
APPENDIX 2. DESIGN OF FILLED COMPOSITE MEMBERS (HIGH STRENGTH)		202
2.1.	Rectangular Filled Composite Members	202
	1. Limitations	202
	2. Compressive Strength	202
	3. Flexural Strength	203
	4. Combined Flexure and Axial Force	203
APPENDIX 3. FATIGUE		204
3.1.	General Provisions	204
3.2.	Calculation of Maximum Stresses and Stress Ranges	205
3.3.	Plain Material and Welded Joints	205
3.4.	Bolts and Threaded Parts	207
3.5.	Fabrication and Erection Requirements for Fatigue	208
3.6.	Nondestructive Examination Requirements for Fatigue	209
APPENDIX 4. STRUCTURAL DESIGN FOR FIRE CONDITIONS		230
4.1.	General Provisions	230
	1. Performance Objective	230
	2. Design by Engineering Analysis	231
	3. Design by Qualification Testing	231
	4. Load Combinations and Required Strength	231
4.2.	Structural Design for Fire Conditions by Analysis	231
	1. Design-Basis Fire	231
	1a. Localized Fire	232
	1b. Post-Flashover Compartment Fires	232
	1c. Exterior Fires	232
	1d. Active Fire-Protection Systems	232
	2. Temperatures in Structural Systems Under Fire Conditions	233
	3. Material Properties at Elevated Temperatures	233
	3a. Thermal Elongation	233
	3b. Mechanical Properties of Structural Steel, Hot-Rolled Reinforcing Steel, and Concrete at Elevated Temperatures.	233
	4. Structural Design Requirements	237
	4a. General Requirements	237
	4b. Strength Requirements and Deformation Limits	238
	4c. Design by Advanced Methods of Analysis	238
	4d. Design by Simple Methods of Analysis	239
	4e. Design by Critical Temperature Method	244

4.3. Design by Qualification Testing	246
1. Qualification Standards	246
2. Structural Steel Assemblies	246
2a. Steel Columns	246
2b. Composite Steel-Concrete Columns	260
2c. Composite or Noncomposite Steel I-Shaped Beams and Girders	262
2d. Concrete-Encased Steel Beams and Girders	264
2e. Trusses	264
2f. Concrete Floor Slabs on Steel Deck	264
2g. Composite Plate Shear Walls	265
3. Restrained Construction	266
4. Unrestrained Construction	266
APPENDIX 5. EVALUATION OF EXISTING STRUCTURES	267
5.1. General Provisions	267
5.2. Material Properties	267
1. Determination of Required Tests	267
2. Tensile Properties	267
3. Chemical Composition	268
4. Base Metal Notch Toughness	268
5. Weld Metal	268
6. Bolts and Rivets	268
5.3. Evaluation by Structural Analysis	268
1. Dimensional Data	268
2. Strength Evaluation	268
2a. Rivets	269
3. Serviceability Evaluation	269
5.4. Evaluation by Load Tests	269
1. General Requirements	269
2. Determination of Load Rating by Testing	269
3. Serviceability Evaluation	270
5.5. Evaluation Report	270
APPENDIX 6. MEMBER STABILITY BRACING	271
6.1. General Provisions	271
6.2. Column Bracing	272
1. Panel Bracing	272
2. Point Bracing	273
6.3. Beam Bracing	273
1. Lateral Bracing	274
1a. Panel Bracing	274
1b. Point Bracing	275
2. Torsional Bracing	275
2a. Point Bracing	275
2b. Continuous Bracing	277
6.4. Beam-Column Bracing	277

APPENDIX 7. ALTERNATIVE METHODS OF DESIGN FOR
	STABILITY	279
7.1.	General Stability Requirements	279
7.2.	Effective Length Method	279
	1. Limitations	279
	2. Required Strengths	279
	3. Available Strengths	280
7.3.	First-Order Analysis Method	280
	1. Limitations	280
	2. Required Strengths	281
	3. Available Strengths	282
APPENDIX 8. APPROXIMATE ANALYSIS		283
8.1.	Approximate Second-Order Elastic Analysis	283
	1. Calculation Procedure	283
	2. Multiplier B₁ for P-8 Effects	284
	3. Multiplier B2 for P-A Effects	285
8.2.	Approximate Inelastic Moment Redistribution	286
COMMENTARY ON THE SPECIFICATION FOR STRUCTURAL STEEL BUILDINGS
	INTRODUCTION	287
	COMMENTARY SYMBOLS	288
	COMMENTARY GLOSSARY	292
A.	GENERAL PROVISIONS	295
A1.	Scope	295
	Referenced Specifications, Codes, and Standards	297
A3.	Material	297
	1. Structural Steel Materials	297
	1a. Listed Materials	297
	1d. Rolled Heavy Shapes	302
	1e. Built-Up Heavy Shapes	303
	2. Steel Castings and Forgings	303
	3. Bolts, Washers, and Nuts	304
	4. Anchor Rods and Threaded Rods	304
	5. Consumables for Welding	305
	Structural Design Documents and Specifications	305
	1. Structural Design Documents and Specifications Issued for Construction	305
	2. Structural Design Documents and Specifications Issued for Any Purpose	308
A5.	Approvals	309
B. DESIGN REQUIREMENTS		310
B1.	General Provisions	310
B2.	Loads and Load Combinations	311

B3.	Design Basis..	..	313
	1. Design for Strength Using Load and Resistance Factor
	Design (LRFD).		313
	2. Design for Strength Using Allowable Strength Design (ASD)		316

E2.	Effective Length..		354
E3.	Flexural Buckling of Members without Slender Elements		356
	Torsional and Flexural-Torsional Buckling of Single Angles and Members without Slender Elements		358
E5.	Single-Angle Compression Members	.	362
E6.	Built-Up Members		363
	1. Compressive Strength		364
	2. General Requirements.	.	365
E7.	Members with Slender Elements		366
	1. Slender Element Members Excluding Round HSS		366
	2. Round HSS	.	369
DESIGN OF MEMBERS FOR FLEXURE ..			370
F1.	General Provisions		372
	Doubly Symmetric Compact I-Shaped Members and Channels Bent About Their Major Axis		377
F3.	Doubly Symmetric I-Shaped Members with Compact Webs and Noncompact or Slender Flanges Bent About Their Major Axis		378
F4.	Other I-Shaped Members with Compact or Noncompact Webs Bent About Their Major Axis		379
F5.	Doubly Symmetric and Singly Symmetric I-Shaped Members with Slender Webs Bent About Their Major Axis		381
F6.	I-Shaped Members and Channels Bent About Their Minor Axis..		381
F7.	Square and Rectangular HSS and Box Sections	.	381
F8.	Round HSS	.	383
F9.	Tees and Double Angles Loaded in the Plane of Symmetry.	.	383
F10.	Single Angles	.	388
	1. Yielding.	.	388
	2. Lateral-Torsional Buckling		389
	3. Leg Local Buckling		392
F11.	Rectangular Bars and Rounds		392
F12.	Unsymmetrical Shapes		393
F13.	Proportions of Beams and Girders		393
	1. Strength Reductions for Members with Bolt Holes in the
	Tension Flange		393
	2. Proportioning Limits for I-Shaped Members		394
	3. Cover Plates		394
G. DESIGN OF MEMBERS FOR SHEAR 396
G1.	General Provisions		396
G2.	I-Shaped Members and Channels		396
	1. Shear Strength of Webs		396
	2. Shear Strength of Interior Web Panels with a/h ≤3 Considering Tension Field Action		398
	3. Shear Strength of End Web Panels with a/h ≤3 Considering Tension Field Action		399
	4. Transverse Stiffeners..		401
G3.	Single Angles and Tees ..		401

G4. Rectangular HSS, Box Sections, and Other Singly and Doubly Symmetric Members	402
G5. Round HSS	402
G6. Doubly Symmetric and Singly Symmetric Members Subjected to Minor-Axis Shear	402
G7. Beams and Girders with Web Openings	403
H. DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION 404
H1. Doubly and Singly Symmetric Members Subjected to Flexure and Axial Force	404
1. Doubly and Singly Symmetric Members Subjected to Flexure and Compression	404
2. Doubly and Singly Symmetric Members Subjected to Flexure and Tension	408
3. Doubly Symmetric Rolled Compact Members Subjected to Single-Axis Flexure and Compression	408
H2. Unsymmetric and Other Members Subjected to Flexure and Axial Force	410
H3. Members Subjected to Torsion and Combined Torsion, Flexure, Shear, and/or Axial Force	413
1. Round and Rectangular HSS Subjected to Torsion	414
2. HSS Subjected to Combined Torsion, Shear, Flexure, and Axial Force	415
3. Non-HSS Members Subjected to Torsion and Combined Stress	416
H4. Rupture of Flanges with Bolt Holes and Subjected to Tension	417
I. DESIGN OF COMPOSITE MEMBERS 418
I1. General Provisions	418
1. Concrete and Steel Reinforcement	419
2. Nominal Strength of Composite Sections	419
2a. Plastic Stress Distribution Method	420
2b. Strain-Compatibility Method	421
2c. Elastic Stress Distribution Method	421
2d. Effective Stress-Strain Method	421
3. Material Limitations	422
4. Classification of Filled Composite Sections for Local Buckling	422
5. Stiffness for Calculation of Required Strengths	424
6. Requirements for Composite Plate Shear Walls	426
6a. Slenderness Requirement	427
6b. Tie Bar Requirement	428
I2. Axial Force	429
1. Encased Composite Members	429
1a. Limitations	429
1b. Compressive Strength	430
1c. Tensile Strength	430
2. Filled Composite Members	430
2a. Limitations	430
2b. Compressive Strength	431

	2c.	Tensile Strength	432
	3.	Composite Plate Shear Walls	432
	3a.	Compressive Strength	432
I3.		Flexure	432
	1.	General	432
	1a.	Effective Width	432
	1b.	Strength During Construction	432
	2.	Composite Beams with Steel Headed Stud or Steel Channel Anchors	433
	2a.	Positive Flexural Strength	436
	2b.	Negative Flexural Strength	438
	2c.	Composite Beams with Formed Steel Deck	440
	2d.	Load Transfer Between Steel Beam and Concrete Slab	442
	1.	Load Transfer for Positive Flexural Strength	442
	2.	Load Transfer for Negative Flexural Strength	444
	3.	Encased Composite Members	445
	4.	Filled Composite Members	445
	5.	Composite Plate Shear Walls	448
I4.		Shear	448
	1.	Encased Composite Members	448
	2.	Filled Composite Members	448
	3.	Composite Beams with Formed Steel Deck	449
	4.	Composite Plate Shear Walls	449
I5.		Combined Flexure and Axial Force	450
I6.		Load Transfer	455
	1.	General Requirements	455
	2.	Force Allocation	456
	3.	Force Transfer Mechanisms	457
	3a.	Direct Bearing	458
	3b.	Shear Connection	458
	3c.	Direct Bond Interaction	458
	4.	Detailing Requirements	458
I7.		Composite Diaphragms and Collector Beams	459
I8.		Steel Anchors	462
	1.	General	462
	2.	Steel Anchors in Composite Beams	463
	2a.	Strength of Steel Headed Stud Anchors	463
	2b.	Strength of Steel Channel Anchors	465
	2d.	Detailing Requirements	466
	3.	Steel Anchors in Composite Components	467
	4.	Performance-Based Alternative for the Design of Shear Connection	469
	4a.	Test Standard	470
	4b.	Nominal and Available Strength	470
	4c.	Shear Connection Slip Capacity	471
	4d.	Acceptance Criteria	471

J.	DESIGN OF CONNECTIONS		473
J1.		General Provisions	473
	1.	Design Basis	473
	2.	Simple Connections	474
	3.	Moment Connections	474
	4.	Compression Members with Bearing Joints	474
	5.	Splices in Heavy Sections	475
	6.	Weld Access Holes	476
	7.	Placement of Welds and Bolts	478
	8.	Bolts in Combination with Welds	478
	10.	High-Strength Bolts in Combination with Existing Rivets	479
J2.		Welds and Welded Joints	479
	1.	Groove Welds	480
	1a.	Effective Area	480
	1b.	Limitations	480
	2.	Fillet Welds	481
	2a.	Effective Area	481
	2b.	Limitations	481
	3.	Plug and Slot Welds	486
	3a.	Effective Area	487
	3b.	Limitations	487
	4.	Strength	487
	5.	Combination of Welds	491
	6.	Filler Metal Requirements	491
	7.	Mixed Weld Metal	492
J3.		Bolts, Threaded Parts, and Bolted Connections	492
	2.	High-Strength Bolts	492
	3.	Size and Use of Holes	495
	4.	Minimum Spacing	495
	5.	Minimum Edge Distance	496
	6.	Maximum Spacing and Edge Distance	496
	7.	Tension and Shear Strength of Bolts and Threaded Parts	496
	8.	Combined Tension and Shear in Bearing-Type Connections	499
	9.	High-Strength Bolts in Slip-Critical Connections	500
	11.	Bearing and Tearout Strength at Bolt Holes	504
	13.	Wall Strength at Tension Fasteners	505
J4.		Affected Elements of Members and Connecting Elements	506
	1.	Strength of Elements in Tension	506
	2.	Strength of Elements in Shear	506
	3.	Block Shear Strength	506
	4.	Strength of Elements in Compression	508
	5.	Strength of Elements in Flexure	508
J5.		Fillers	509
J7.		Bearing Strength	509
J8.		Column Bases and Bearing on Concrete	509
J9.		Anchor Rods and Embedments	509
J10.		Flanges and Webs with Concentrated Forces	511

1.	Flange Local Bending	512
2.	Web Local Yielding	513
3.	Web Local Crippling	514
4.	Web Sidesway Buckling	514
5.	Web Compression Buckling	516
6.	Web Panel-Zone Shear	516
7.	Unframed Ends of Beams and Girders	519
8.	Additional Stiffener Requirements for Concentrated Forces	519
9.	Additional Doubler Plate Requirements for Concentrated Forces	521
10.	Transverse Forces on Plate Elements	522

K. ADDITIONAL REQUIREMENTS FOR HSS AND BOX-SECTION

CONNECTIONS		524
K1.	General Provisions and Parameters for HSS Connections	526
	2. Rectangular HSS	526
	3. Chord-Stress Interaction Parameter	530
	4. End Distance	531
K2.	Concentrated Forces on HSS	531
	1. Definitions of Parameters	531
	2. Round HSS	531
	3. Rectangular HSS	531
K3.	HSS-to-HSS Truss Connections	533
	1. Definitions of Parameters	534
	2. Round HSS	535
	3. Rectangular HSS	536
K4.	HSS-to-HSS Moment Connections	539
K5.	Welds of Plates and Branches to HSS	539
L. DESIGN FOR SERVICEABILITY		542
L1.	General Provisions	542
L2.	Deflections	543
L3.	Drift	544
L4.	Vibration	545
L5.	Wind-Induced Motion	546
L6.	Thermal Expansion and Contraction	547
L7.	Connection Slip	547
M. FABRICATION AND ERECTION		548
M1.	Fabrication and Erection Documents	548
M2.	Fabrication	548
	1. Cambering, Curving, and Straightening	548
	2. Thermal Cutting	549
	4. Welded Construction	549
	5. Bolted Construction	549
	10. Drain Holes	550
	11. Requirements for Galvanized Members	550
M3.	Shop Painting	552
	1. General Requirements	552

General Requirements

552

	3. Contact Surfaces	552
	5. Surfaces Adjacent to Field Welds	552
M4.	Erection	552
	2. Stability and Connections	552
	4. Fit of Column Compression Joints and Base Plates	552
	5. Field Welding	552
N. QUALITY CONTROL AND QUALITY ASSURANCE		554
N1.	General Provisions	554
N2.	Fabricator and Erector Quality Control Program	555
N3.	Fabricator and Erector Documents	556
	1. Submittals for Steel Construction	556
	2. Available Documents for Steel Construction	556
N4.	Inspection and Nondestructive Testing Personnel	557
	1. Quality Control Inspector Qualifications	557
	2. Quality Assurance Inspector Qualifications	557
	3. NDT Personnel Qualifications	558
N5.	Minimum Requirements for Inspection of Structural Steel Buildings	558
	1. Quality Control	558
	2. Quality Assurance	559
	3. Coordinated Inspection	560
	4. Inspection of Welding	560
	5. Nondestructive Testing of Welded Joints	564
	5a. Procedures	564
	5b. CJP Groove Weld NDT	565
	5c. Welded Joints Subjected to Fatigue	565
	5e. Reduction of Ultrasonic Testing Rate	565
	5f. Increase in Ultrasonic Testing Rate	566
	6. Inspection of High-Strength Bolting	566
	7. Inspection of Galvanized Structural Steel Main Members	568
	8. Other Inspection Tasks	570
N6.	Approved Fabricators and Erectors	570
N8.	Minimum Requirements for Shop- or Field-Applied Coatings	571
APPENDIX 1. DESIGN BY ADVANCED ANALYSIS		572
1.1.	General Requirements	572
1.2.	Design by Elastic Analysis	572
	1. General Stability Requirements	573
	2. Calculation of Required Strengths	574
	3. Calculation of Available Strengths	579
1.3.	Design by Inelastic Analysis	579
	1. General Requirements	579
	2. Ductility Requirements	582
	2a. Material	582
	2b. Cross Section	582
	2c. Unbraced Length	583
	2d. Axial Force	585
	3. Analysis Requirements	585

3a.	Material Properties and Yield Criteria	.	585
3b.	Geometric Imperfections	.	586
3c.	Residual Stresses and Partial Yielding Effects	.	586

APPENDIX 2. DESIGN OF FILLED COMPOSITE MEMBERS

(HIGH STRENGTH)

588


2.1	Rectangular Filled Composite Members	588
	1. Limitations	588
	2. Compressive Strength	588
	4. Combined Flexure and Axial Force	588
APPENDIX 3. FATIGUE		589
3.1.	General Provisions	589
3.2.	Calculation of Maximum Stresses and Stress Ranges	590
3.3.	Plain Material and Welded Joints	590
3.4.	Bolts and Threaded Parts	592
3.5.	Fabrication and Erection Requirements for Fatigue	595
APPENDIX 4. STRUCTURAL DESIGN FOR FIRE CONDITIONS		597
4.1.	General Provisions	597
	1. Performance Objective	598
	2. Design by Engineering Analysis	598
	3. Design by Engineering Analysis	598
	4. Load Combinations and Required Strength	599
4.2.	Structural Design for Fire Conditions by Analysis	600
	1. Design-Basis Fire	600
	1a. Localized Fire	600
	1b. Post-Flashover Compartment Fires	600
	1c. Exterior Fires	601
	1d. Active Fire-Protection Systems	601
	2. Temperatures in Structural Systems Under Fire Conditions	601
	3. Material Properties at Elevated Temperatures	605
	4. Structural Design Requirements	608
	4a. General Requirements	608
	4b. Strength Requirements and Deformation Limits	609
	4c. Design by Advanced Methods of Analysis	610
	4d. Design by Simple Methods of Analysis	612
	4e. Design by Critical Temperature Method	617
4.3.	Design by Qualification Testing	617
	1. Qualification Standards	617
	2. Structural Steel Assemblies	621
	2a. Steel Columns	623
	2b. Composite Steel-Concrete Columns	623
	2c. Composite or Noncomposite Steel I-Shaped Beams and Girders	624
	2e. Trusses	625
	2f. Concrete Floor Slabs on Steel Deck	625
	2g. Composite Plate Shear Walls	626
	3. Restrained Construction	626
	4. Unrestrained Construction	627

APPENDIX 5. EVALUATION OF EXISTING STRUCTURES		628
5.1.	General Provisions	628
5.2.	Material Properties	628
	1. Determination of Required Tests	628
	2. Tensile Properties	628
	3. Chemical Composition	629
	4. Base Metal Notch Toughness	629
	5. Weld Metal	629
	6. Bolts and Rivets	630
5.3.	Evaluation by Structural Analysis	630
	2. Strength Evaluation	630
	2a. Rivets	630
5.4.	Evaluation by Load Tests	630
	1. General Requirements	630
	2. Determination of Load Rating by Testing	631
	3. Serviceability Evaluation	631
5.5.	Evaluation Report	631
APPENDIX 6. MEMBER STABILITY BRACING		632
6.1.	General Provisions	632
6.2.	Column Bracing	639
6.3.	Beam Bracing	640
	1. Lateral Bracing	640
	2. Torsional Bracing	642
6.4.	Beam-Column Bracing	645
APPENDIX 7. ALTERNATIVE METHODS OF DESIGN FOR STABILITY		648
7.2.	Effective Length Method	648
7.3.	First-Order Analysis Method	657
APPENDIX 8. APPROXIMATE ANALYSIS		659
8.1.	Approximate Second-Order Elastic Analysis	659
8.2.	Approximate Inelastic Moment Redistribution	665
REFERENCES		667
METRIC CONVERSION FACTORS FOR COMMON STEEL DESIGN UNITS USED IN THE AISC SPECIFICATION		709

TABLE OF CONTENTS

J. DESIGN OF CONNECTIONS

K. ADDITIONAL REQUIREMENTS FOR HSS AND BOX-SECTION

K. ADDITIONAL REQUIREMENTS FOR HSS AND BOX-SECTION

APPENDIX 2. DESIGN OF FILLED COMPOSITE MEMBERS

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