[Segui] Steel Design 6th PDF

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w w w .ja m ar an a. co m SYMBOLS a moment arm for plastic moment internal couple, c1, c2 constants used in determining the elastic local longitudinal spacing of connectors in a built-up buckling stress compression member, distance from support to C compressive force in an internal resisting couple ...

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SYMBOLS c1, c2 constants used in determining the elastic local buckling stress C compressive force in an internal resisting couple C1 coefficient in equation for effective flexural rigidity of an encased composite column C2 coefficient in equation for compressive yield load, Pp, for a compact filled composite column C3 coefficient in equation for effective flexural rigidity of a filled composite column Cb moment gradient factor for lateral-torsional ­buckling strength Cm bending factor for braced beam-columns Cv1 coefficient for computing shear strength when no tension field is present Cv2 coefficient for computing shear strength when a tension field is present Cw warping constant d total depth of a rolled or built-up steel beam, distance between axes (for use in the parallel axis theorem), bolt diameter, bolt hole diameter d9 reduced diameter of a staggered bolt hole db beam depth, bolt diameter dc column depth D service dead load effect to be used in computation of factored load combinations, outer diameter of a hollow circular steel shape, fillet weld size in sixteenths of an inch Du ratio of mean actual bolt pretension to specified minimum pretension e eccentricity of load in a connection E modulus of elasticity (29,000 ksi for structural steel), service earthquake load EI* flexural rigidity of a frame member Ecol modulus of elasticity of a column for determining effective length factor Es modulus of elasticity of structural steel 5 29,000 ksi Et tangent modulus of elasticity f stress f1 direct shear stress in an eccentric welded shear ­connection f 2 torsional shear stress in an eccentric welded shear connection fa axial compressive stress fb flexural stress fc flexural stress in concrete fc9 28-day compressive strength of concrete fp bearing stress frv required shear strength (stress) in a bolt subject to shear and tension fsb flexural stress at bottom of steel shape fst flexural stress at top of steel shape

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moment arm for plastic moment internal couple, longitudinal spacing of connectors in a built-up compression member, distance from support to load, depth of equivalent compressive stress distribution in concrete at ultimate load, clear spacing of intermediate web stiffeners in a plate girder aw constant used in computing plate girder strengthreduction factor A area A1 bearing area of a bearing plate or base plate A2 full area of support for a bearing plate or base plate Ab cross-sectional area of the unthreaded part of a bolt Ac area of concrete flange in a composite beam, area of concrete in a composite column Ae effective area Af flange area Afc area of compression flange Afg gross area of flange Afn net area of flange Aft area of tension flange Ag gross area Agv gross area in shear for block shear computation An net area Ant net area in tension for block shear computation Anv net area in shear for block shear computation Apb bearing area of a plate girder stiffener Ar area of reinforcing steel within the effective width of a composite beam slab As area of steel cross section Asa cross-sectional area of a steel headed stud anchor Ast cross-sectional area of a stiffener Aw web area b width of a plate, width of cross-sectional element to be used in width-to-thickness ratio, effective flange width of a composite beam bb width of a beam flange or flange plate be effective edge distance for a pin-connected member, ­ ­ effective width of a slender stiffened ­compression ­element bf flange width bfc width of compression flange bft width of tension flange B width of an HSS, width of bearing plate or base plate, factor used in computing bending strength of double-angle and tee shapes B1, B2  amplification factors for beam-columns Bc bolt tensile force (including effects of prying) c distance from elastic neutral axis to extreme fiber in bending, constant in equation for critical lateraltorsional buckling stress a

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members, lateral building loads, flange force in a moment ­connection I _ moment of inertia (second moment of area) I moment of inertia of component area about its ­centroidal axis Ic Moment of inertia of the concrete section about the elastic neutral axis of the composite section Ig moment of inertia of a girder cross section ILB lower-bound moment of inertia of a composite beam Is moment of inertia of steel section Ist moment of inertia of a stiffener cross section Itr moment of inertia of transformed section Ix, Iy moments of inertia about x- and y-axes J torsional constant, polar moment of inertia k distance from outer face of flange to toe of fillet in the web of a rolled shape kc factor used in computing the flexural strength of a plate girder ksc multiplier for bolt slip-critical strength when tension is present kv factor used in computing shear strength K effective length factor for compression members Ki effective length factor for a component in a builtup compression member­­ Kx, Ky, Kz  effective length factors for x-, y-, and z-axes KxL, KyL, KzL effective lengths for buckling about x-, y-, and z-axes length of a connection, length of end welds, factor / for computing column base plate thickness /b length of bearing of a beam bearing plate /c distance from edge of bolt hole to edge of connected part or to edge of adjacent hole /e bolt edge distance L service live load effect to be used in computation of factored load combinations, member length, story height, length of a weld segment Lb unbraced beam length, unbraced length of a column in the equation for required bracing stiffness Lc effective length of a compression member Lcol length of a column for determining effective length factor Lcx, Lcy, Lcz  effective lengths with respect to the x-, y-, and z-axes Lg length of girder Lp largest unbraced beam length for which lateral-­ torsional buckling will not occur Lpd largest unbraced beam length for which plastic analysis can be used. Lr service roof live load effect to be used in computation of factored load combinations, unbraced beam length at which elastic lateral-torsional buckling will occur m length of unit width of plate in bending (for beam ­bearing plate and column base plate design) M bending moment

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ft tensile stress shearing stress fv F 9nt nominal bolt tensile strength (stress) in the ­presence of shear Fa allowable axial compressive stress Fcr critical compressive or bending stress used to determine nominal strength Fcry flexural buckling strength corresponding to the axis of symmetry in a structural tee or double-angle compression member Fcrz stress used in computing torsional or flexuraltorsional buckling strength of a structural tee or double-angle compression member Fe Euler buckling stress, critical elastic buckling stress in an unsymmetrical compression member (torsional or flexural-torsional buckling stress) Fel elastic local buckling stress Fex, Fey, Fez  stresses used in computing torsional or ­flexural-torsional buckling strength Fn nominal strength (stress) Fnt nominal bolt tensile strength (stress) Fnv nominal bolt shear strength (stress) Fnw ultimate shearing stress of weld electrode Fpl stress at proportional limit Ft allowable member tensile stress, ultimate tensile stress of a bolt, allowable bolt tensile stress Fu ultimate tensile stress Fv allowable member shear stress Fy yield stress Fyf , Fyw  yield stresses of flange and web Fysr yield stress of reinforcing steel Fyst yield stress of a stiffener Fyt yield strength of tension flange g gage distance for bolts (transverse spacing) G shear modulus of elasticity 5 11,200 ksi for ­structural steel factors for use in nomographs for effective GA, GB  length factor K h width of web from toe of flange fillet to toe of flange fillet for a rolled shape, width of web from inside of flange to inside of flange for a welded shape, bolt hole diameter hc twice the distance from the elastic neutral axis to the inside face of the compression flange of a built-up flexural member (same as h for girders with equal flanges) hf filler factor for slip-critical connections ho distance between W-shape flange centroids hp twice the distance from the plastic neutral axis to the inside face of the compression flange of a built-up flexural member (same as h for girders with equal flanges) H depth of an HSS, factor used in computation of flexural-torsional buckling strength of ­compression

Steel Design m ar an

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6th Edition

William T. Segui

The University of Memphis

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© 2018, 2013 Cengage Learning®

Steel Design, Sixth Edition William T. Segui

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About the Author

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William T. Segui is a Professor Emeritus of Civil Engineering at The University of Memphis, where he has been a member of the faculty since 1968. He holds a B.S.C.E, M.S., and Ph.D. from the University of South Carolina. After obtaining his B.S.C.E., he served as a commissioned officer in the U.S. Air Force from 1960-1963. In 1963, he joined Wilbur Smith Associates, where he was a highway bridge designer. In 1964, he enrolled in graduate school and was the recipient of an NSF Graduate Traineeship. Since joining the Department of Civil Engineering at The University of Memphis, he has received two NASA/ASEE Summer Faculty Fellowships at the Marshall Space Flight Center in Huntsville, Alabama. He has worked several summers for various consulting firms and for the U.S. Army Corps of Engineers. He was a recipient of the University of Memphis Distinguished Teaching Award in 2000. Professor Segui is a member of the American Institute of Steel Construction and is an emeritus member of the Committee on Manuals. He received the 2011 AISC Special Achievement Award for his contributions to steel design education. He is a Life Member of the American Society of Civil Engineers and a member of the Tennessee Structural Engineers Association. He is a licensed professional engineer in Tennessee.

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v

Contents About the Author  v Preface x MindTap Online Course  xiii

Structural Design  3

1.2

Loads 6

1.3

Building Codes  7

1.4

Design Specifications  7

1.5

Structural Steel  8

1.6

Standard Cross-Sectional Shapes  12



Problems 17

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chapter 1: Introduction  3

chapter 2: Concepts in Structural Steel Design  21 Design Philosophies  21

2.2

American Institute of Steel Construction Specification  23

2.3

Load Factors, Resistance Factors, and Load Combinations for LRFD  24

2.4

Safety Factors and Load Combinations for ASD  26

2.5

Probabilistic Basis of Load and Resistance Factors  29

2.6

Steel Construction Manual  33

2.7

Design Computations and Precision  35



Problems 38

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2.1

chapter 3: Tension Members  41 Introduction 41

3.2

Tensile Strength  42

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3.3 Effective Area  50

vi

3.4

Staggered Fasteners  57

3.5

Block Shear  64

3.6

Design of Tension Members  67

3.7

Threaded Rods and Cables 75

3.8

Tension Members in Roof Trusses 78

3.9

Pin-Connected Members  88



Problems 90

Contents  vii

chapter 4: Compression Members  107 4.1

Introduction 107

4.2

Column Theory  108

4.3

AISC Requirements  115

4.4

Local Stability  119

4.5

Tables for Compression Members  125

4.6 Design 127 More on Effective Length  134

4.8

Torsional and Flexural-Torsional Buckling  151

4.9

Built-Up Members  158



Problems 167

chapter 5: Beams  185

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4.7

5.1

Introduction 185

5.2

Bending Stress and the Plastic Moment  186

5.3 Stability 192 Classification of Shapes  194

5.5

Bending Strength of Compact Shapes  195

5.6

Bending Strength of Noncompact Shapes  207

5.7

Summary of Moment Strength  210

5.8

Shear Strength  212

5.9

Deflection 220

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5.4

5.10 Design 222

Floor and Roof Framing Systems  238

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5.12 Holes in Beams  243 5.13

Open-Web Steel Joists  246 Beam Bearing Plates and Column Base Plates  250

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Biaxial Bending  264

5.16

Bending Strength of Various Shapes  274



Problems 280

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chapter 6: Beam–Columns  297 6.1

Definition 297

6.2

Interaction Formulas  298

6.3

Methods of Analysis for Required Strength  303

6.4

The Moment Amplification Method  305

6.5

Braced versus Unbraced Frames  308

6.6

Members in Braced Frames  309

6.7

Members in Unbraced Frames  323

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viii  Contents 6.8

Design of Beam–Columns  335

6.9

Trusses with Top-Chord Loads Between Joints  355



Problems 361

chapter 7: Simple Connections  375 Introduction 375

7.2

Bolted Shear Connections: Failure Modes  378

7.3

Bearing Strength, Spacing, and Edge-Distance Requirements  380

7.4

Shear Strength  386

7.5

Installation of High-Strength Bolts  392

7.6

Slip-Critical and Bearing-Type Connections  394

7.7

Design Examples  400

7.8 High-Strength Bolts in Tension  414

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7.1

Combined Shear and Tension in Fasteners  426

7.10

Welded Connections  439

7.11

Fillet Welds  441



Problems 460

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chapter 8: Eccentric Connections  475 8.1 Examples of Eccentric Connections  475

8.2 Eccentric Bolted Connections: Shear Only  476

8.3 Eccentric Bolted Connections: Shear Plus Tension  489 8.4 Eccentric Welded Connections: Shear Only  494

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8.5 Eccentric Welded Connections: Shear Plus Tension  509 Moment-Resisting Connections  517

8.7

Column Stiffeners and Other Reinforcement  534

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8.8 End Plate Connections  557 Concluding Remarks  571



Problems 572

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chapter 9: Composite Construction  591 9.1

Introduction 591

9.2

Shored versus Unshored Construction  602

9.3 Effective Flange Width  604 9.4

Steel Headed Stud Anchors  608

9.5

Design 611

9.6

Deflections 618

9.7

Composite Beams with Formed Steel Deck  622

9.8

Tables for Composite Beam Analysis and Design  635

Composite Columns

645

 



654

 



Problems

 

ha ter 10: Plate Girders 665 p

Introduction 665

10.2

General Considerations 667

10.6

Bearing Stiffeners

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680

696

 







Design

 



Problems 714

 

 

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eferences

733

nswers to Selected Problems

 

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ISC equirements

 



Introduction 721

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ppendix: Plastic Analys...