(livro) ansi - north american specification for the design of cold-formed steel
(Parte 2 de 6)
| Stiffened Elements with Intermediate Stiffeners | 56 |
| Intermediate Stiffeners | 56 |
| B5.1.1 Specific Case: ‘n’ Identical Stiffeners, Equally Spaced | 57 |
| B5.1.2 General Case: Arbitrary Stiffener Size, Location and Number | 57 |
| B5.2 Edge Stiffened Elements with Intermediate Stiffeners | 59 |
| C. MEMBERS | 60 |
| C1 Properties of Sections | 60 |
| C2 Tension Members | 60 |
| C3 Flexural Members | 60 |
| C3.1 Bending | 60 |
| C3.1.1 Nominal Section Strength [Resistance] | 60 |
| C3.1.2 Lateral-Torsional Buckling Strength [Resistance] | 62 |
B5 Effective Widths of Stiffened Elements with Multiple Intermediate Stiffeners or Edge B5.1 Effective Widths of Uniformly Compressed Stiffened Elements with Multiple
| Section Members | 62 |
C3.1.2.1 Lateral-Torsional Buckling Strength [Resistance] of Open Cross
| Members | 65 |
| C3.1.3 Beams Having One Flange Through-Fastened to Deck or Sheathing | 65 |
| C3.1.4 Beams Having One Flange Fastened to a Standing Seam Roof System | 67 |
| C3.1.5 Strength [Resistance] of Standing Seam Roof Panel Systems | 67 |
| C3.2 Shear | 68 |
| C3.2.1 Shear Strength [Resistance] of Webs without Holes | 68 |
| C3.2.2 Shear Strength [Resistance] of C-Section Webs with Holes | 69 |
| C3.3 Combined Bending and Shear | 69 |
| C3.3.1 ASD Method | 69 |
| C3.3.2 LRFD and LSD Methods | 70 |
| C3.4 Web Crippling | 7 1 |
| C3.4.1 Web Crippling Strength [Resistance] of Webs without Holes | 71 |
| C3.4.2 Web Crippling Strength [Resistance] of C-Section Webs with Holes | 74 |
| C3.5 Combined Bending and Web Crippling | 75 |
| C3.5.1 ASD Method | 75 |
| C3.5.2 LRFD and LSD Methods | 7 |
| C3.6 Stiffeners | 79 |
| C3.6.1 Transverse Stiffeners | 79 |
| C3.6.2 Shear Stiffeners | 80 |
| C3.6.3 Non-Conforming Stiffeners | 80 |
| C4 Concentrically Loaded Compression Members | 81 |
| C4.1 Sections Not Subject to Torsional or Torsional-Flexural Buckling | 81 |
C3.1.2.2 Lateral-Torsional Buckling Strength [Resistance] of Closed Box C4.2 Doubly- or Singly-Symmetric Sections Subject to Torsional or Torsional-Flexural Buckling .............................................................................................................................. 82
North American Cold-Formed Steel Specification
| C4.3 Point-Symmetric Sections | 82 |
| C4.4 Nonsymmetric Sections | 83 |
| C4.5 Built-Up Members | 83 |
| Sheathing | 83 |
| C5 Combined Axial Load and Bending | 85 |
| C5.1 Combined Tensile Axial Load and Bending | 85 |
| C5.1.1 ASD Method | 85 |
| C5.1.2 LRFD and LSD Methods | 86 |
| C5.2 Combined Compressive Axial Load and Bending | 86 |
| C5.2.1 ASD Method | 86 |
| C5.2.2 LRFD and LSD Methods | 8 |
| C6 Closed Cylindrical Tubular Members | 91 |
| C6.1 Bending | 91 |
| C6.2 Compression | 91 |
| C6.3 Combined Bending and Compression | 92 |
| D. STRUCTURAL ASSEMBLIES | 93 |
| D1 Built-Up Sections | 93 |
| D1.1 I-Sections Composed of Two C-Sections | 93 |
| D1.2 Spacing of Connections in Compression Elements | 94 |
| D2 Mixed Systems | 94 |
| D3 Lateral Bracing | 94 |
| D3.1 Symmetrical Beams and Columns | 94 |
| D3.2 C-Section and Z-Section Beams | 94 |
December 2001 1 C4.6 Compression Members Having One Flange Through-Fastened to Deck or
| Flange Connected to Sheathing | 95 |
| D3.2.2 Neither Flange Connected to Sheathing | 97 |
| D4 Wall Studs and Wall Stud Assemblies | 98 |
| D4.1 Compression | 9 |
| D4.2 Bending | 102 |
| D4.3 Combined Axial Load and Bending | 102 |
| D5 Floor, Roof or Wall Steel Diaphragm Construction | 102 |
| E. CONNECTIONS AND JOINTS | 104 |
| E1 General Provisions | 104 |
| E2 Welded Connections | 104 |
| E2.1 Groove Welds in Butt Joints | 104 |
| E2.2 Arc Spot Welds | 105 |
| E2.2.1 Shear | 105 |
| E2.2.2 Tension | 108 |
| E2.3 Arc Seam Welds | 109 |
| E2.4 Fillet Welds | 110 |
| E2.5 Flare Groove Welds | 112 |
| E2.6 Resistance Welds | 114 |
| E2.7 Fracture in Net Section of Members other than Flat Sheets (Shear Lag) | 115 |
D3.2.1 Anchorage of Bracing for Roof Systems Under Gravity Load With Top E3 Bolted Connections..................................................................................................................... 116
Table of Contents
| E3.1 Shear, Spacing and Edge Distance | 116 |
| E3.2 Fracture in Net Section (Shear Lag) | 117 |
| E3.3 Bearing | 117 |
12 December 2001
| E3.3.2 Strength [Resistance] with Consideration of Bolt Hole Deformation | 118 |
| E3.4 Shear and Tension in Bolts | 118 |
| E4 Screw Connections | 118 |
| E4.1 Minimum Spacing | 119 |
| E4.2 Minimum Edge and End Distances | 119 |
| E4.3 Shear | 119 |
| E4.3.1 Connection Shear Limited by Tilting and Bearing | 119 |
| E4.3.2 Connection Shear Limited by End Distance | 120 |
| E4.3.3 Shear in Screws | 120 |
| E4.4 Tension | 120 |
| E4.4.1 Pull-Out | 120 |
| E4.4.2 Pull-Over | 120 |
| E4.4.3 Tension in Screws | 120 |
| E5 Rupture | 120 |
| E6 Connections to Other Materials | 121 |
| E6.1 Bearing | 121 |
| E6.2 Tension | 121 |
| E6.3 Shear | 121 |
| F. TESTS FOR SPECIAL CASES | 122 |
| F1 Tests for Determining Structural Performance | 122 |
| F1.1 Load and Resistance Factor Design and Limit States Design | 122 |
| F1.2 Allowable Strength Design | 126 |
| F2 Tests for Confirming Structural Performance | 126 |
| F3 Tests for Determining Mechanical Properties | 126 |
| F3.1 Full Section | 126 |
| F3.2 Flat Elements of Formed Sections | 127 |
| F3.3 Virgin Steel | 127 |
E3.3.1 Strength [Resistance] without Consideration of Bolt Hole Deformation.117
| LOADING (FATIGUE) | 128 |
| G1 General | 128 |
| G2 Calculation of Maximum Stresses and Stress Ranges | 129 |
| G3 Design Stress Range | 129 |
| G4 Bolts and Threaded Parts | 130 |
| G5 Special Fabrication Requirements | 131 |
| PREFACE TO APPENDIX A: | A2 |
| APPENDIX A: PROVISIONS APPLICABLE TO THE UNITED STATES | A3 |
| A1.1a Scope and Limits of Applicability | A3 |
| A2.2 Other Steels | A3 |
| A3 Loads | A3 |
| A3.1 Nominal Loads | A3 |
G. DESIGN OF COLD-FORMED STEEL STRUCTURAL MEMBERS AND CONNECTIONS FOR CYCLIC A4.1.2 Load Combinations for ASD............................................................................ A3
North American Cold-Formed Steel Specification
| A5.1.2 Load Factors and Load Combinations for LRFD | A4 |
| A9a Referenced Documents | A4 |
| C2 Tension Members | A4 |
| C3.1.4 Beams Having One Flange Fastened to a Standing Seam Roof System | A5 |
| E2a Welded Connections | A5 |
| E3a Bolted Connections | A6 |
| E3.1 Shear, Spacing and Edge Distance | A7 |
| E3.2 Fracture in Net Section (Shear Lag) | A8 |
| E3.4 Shear and Tension in Bolts | A9 |
| E4.3.2 Connection Shear Limited by End Distance | A14 |
| E5 Rupture | A14 |
| E5.1 Shear Rupture | A14 |
| E5.2 Tension Rupture | A14 |
| E5.3 Block Shear Rupture | A14 |
| PREFACE TO APPENDIX B: | B2 |
| APPENDIX B: PROVISIONS APPLICABLE TO CANADA | B3 |
| A1.2a Terms | B3 |
| A2.1a Applicable Steels | B3 |
| A2.2 Other Steels | B3 |
| A2.2.1 Other Structural Quality Steels | B3 |
| A2.2.2 Other Steels | B3 |
| A2.4a Delivered Minimum Thickness | B3 |
| A3 Loads | B4 |
| A3.1 Specified Loads | B4 |
| A3.2 Temperature Effects | B5 |
| A6.1.2 Load Factors and Load Combinations for LSD | B5 |
| A6.1.2.1 Load Factors (α) | B5 |
| A6.1.2.2 Load Combination Factor (ψ) | B5 |
| A6.1.2.3 Importance Factor (γ) | B5 |
| A9a Reference Documents | B6 |
| C2 Tension Members | B6 |
| C2.1 Yielding of Gross Section | B6 |
| C2.2 Fracture of Net Section | B6 |
| C3.1.4 Beams Having One Flange Fastened to a Standing Seam Roof System | B7 |
| D3a Lateral Bracing | B7 |
| D3.1a Symmetrical Beams and Columns | B7 |
| D3.1.1 Discrete Bracing | B8 |
| D3.1.2 Bracing by Deck, Slab, or Sheathing | B8 |
| D3.2a C-Section and Z-Section Beams | B8 |
| D3.2.3 Discrete Bracing | B8 |
| D3.2.4 One Flange Braced by Deck, Slab, or Sheathing | B8 |
| D3.2.5 Both Flanges Braced by Deck, Slab, or Sheathing | B9 |
| E2a Welded Connections | B9 |
| E2.2a Arc Spot Welds | B9 |
| E2.3a Arc Seam Welds | B9 |
December 2001 13 E3a Bolted Connections.....................................................................................................................B10
Table of Contents
| E3.1 Shear, Spacing and Edge Distance | B10 |
| E3.2 Fracture in Net Section (Shear Lag) | B10 |
| E3.3a Bearing | B11 |
| E3.4 Shear and Tension in Bolts | B11 |
| E4.3.2 Connection Shear Limited by End Distance | B12 |
| E5 Rupture | B12 |
| APPENDIX C: PROVISIONS APPLICABLE TO MEXICO | C3 |
| A1.1a Country Specific Scope and Limits of Applicability | C3 |
| A2.2 Other Steels | C3 |
| A3 Loads | C3 |
| A3.1 Nominal Loads | C3 |
| A4.1.2 Load Combinations for ASD | C3 |
| A5.1.2 Load Factors and Load Combinations for LRFD | C4 |
| A9a Referenced Documents | C4 |
| C2 Tension Members | C5 |
| C3.1.4 Beams Having One Flange Fastened to a Standing Seam Roof System | C5 |
| E2a Welded Connections | C5 |
| E3a Bolted Connections | C6 |
| E3.1 Shear, Spacing and Edge Distance | C7 |
| E3.2 Fracture in Net Section (Shear Lag) | C8 |
| E3.4 Shear and Tension in Bolts | C9 |
| E4.3.2 Connection Shear Limited by End Distance | C13 |
| E5 Rupture | C13 |
| E5.1 Shear Rupture | C13 |
| E5.2 Tension Rupture | C13 |
14 December 2001 E5.3 Block Shear Rupture ...................................................................................................... C13
North American Cold-Formed Steel Specification SYMBOLS AND DEFINITIONS
Symbol Definition Section
December 2001 15
A Full unreduced cross-sectional area of member C3.1.2.1, C4.2, C4.6, C5.2.1, C5.2.2, C6.2, D4.1 A Area of directly connected elements or gross area E2.7
Ab b1t + As, for transverse stiffeners at interior support and C3.6.1 under concentrated load, and b2t + As, for transverse stiffeners at end support
Ab Gross cross-sectional area of bolt E3.4 Ac 18t2 + As, for transverse stiffeners at interior support C3.6.1 and under concentrated load, and 10t2 + As, for transverse stiffeners at end support
Ao Reduced area due to local buckling C6.2
Ae Effective area at stress Fn C3.6.1, C4, C4.2, C5.2.1, C5.2.2, C6.2, D4, D4.1
Ae Effective net area E2.7, E3.2 Ag Gross area of element including stiffeners B5.1 Ag Gross area of section C2, E2.7, E3.2 Agt Gross area subject to tension E5.3 Agv Gross area subject to shear E5.3 Ant Net area subject to tension E5.3 Anv Net area subject to shear E5.3 An Net area of cross section C2, E3.2
As Reduced cross sectional area of edge or intermediate B4, B4.1, B4.2 stiffener
As Cross-sectional area of transverse stiffener C3.6.1 As Gross area of stiffener B5.1
A′s Effective area of stiffener B4, B4.1, B4.2 Ast Gross area of shear stiffener C3.6.2 At Net tensile area G4 Aw Area of web C3.2.1 Awn Net web area E5.1 a Shear panel length of unreinforced web element, or C3.2.1, C3.6.2 distance between transverse stiffeners of reinforced web elements a Intermediate fastener or spot weld spacing C4.5 a Fastener distance from outside web edge C4.6
Symbols and Definitions SYMBOLS AND DEFINITIONS
Symbol Definition Section
16 December 2001 a Length of bracing interval D3.2.2
B Stud Spacing D4
Bc Term for determining tensile yield point of corners A7.2 b Effective design width of compression element B2.1, B2.2, B3.1, B3.2,
B4.1, B4.2 b Flange width C4.6, D3.2.1 b length of web hole B2.4, C3.2.2, C3.4.2 bd Effective width for deflection calculation B2.1, B2.2, B3.1, B3.2, B4.1, B4.2, B5.2 be Effective with of elements, located at centroid of B5.1 element including stiffeners be Effective width B2.3 be Effective width either determined by Section B4.2 or B5.2 Section B5.1 depending on stiffness of stiffeners bo Dimension defined in Figure B4-1 B4, B4.1 bo Out-to-out width of compression flange as defined in B2.3 Figure B2.3-2 bo Total flat width of stiffened element B5.1 bo Total flat width of edge stiffened element B5.2 bp Largest sub-element flat width B5.1 b1, b2 Effective widths B2.3, B2.4 b1, b2 Effective widths of transverse stiffeners C3.6.1
C For compression members, ratio of total corner cross A7.2 -sectional area to total cross-sectional area of full section; for flexural members, ratio of total corner cross -sectional area of controlling flange to full cross
-sectional area of controlling flange
C Coefficient C3.4.1 C Bearing factor E3.3.1
Cb Bending coefficient dependent on moment gradient C3.1.2.1, C3.1.2.2 Cf Constant from Table G1 G1, G3, G4 Ch Web slenderness coefficient C3.4.1 Cm End moment coefficient in interaction formula C5.2.1, C5.2.2 Cms Coefficient for lateral bracing of Z-section D3.2.1 Cmx End moment coefficient in interaction formula C5.2.1, C5.2.2
North American Cold-Formed Steel Specification SYMBOLS AND DEFINITIONS
Symbol Definition Section
December 2001 17
Cmy End moment coefficient in interaction formula C5.2.1, C5.2.2 CN Bearing length coefficient C3.4.1 Co Initial column imperfection D4.1 Cp Correction Factor F1.1 CR Inside bend radius coefficient C3.4.1 Cs Coefficient for lateral-torsional buckling C3.1.2.1 CTF End moment coefficient in interaction formula C3.1.2.1 Cth Coefficient for lateral bracing of Z-sections D3.2.1 Ctr Coefficient for lateral bracing of Z-sections D3.2.1 Cv Shear stiffener coefficient C3.6.2 Cw Torsional warping constant of cross-section C3.1.2.1, D4.1 Cy Compression strain factor C3.1.1
C1 Term used to compute shear strain in wall board D4.1 C1, C2, Axial buckling coefficients C4.6
| C3 |
Cφ Calibration coefficient F1.1 c Distance C3.2.2 cf Amount of curling displacement B1.1 ci Horizontal distance from edge of element to centerline B5.1, B5.1.2 of stiffener
D Outside diameter of cylindrical tube C6, C6.1, C6.2 D Overall depth of lip B1.1, B4, B4.2 D Shear stiffener coefficient C3.6.2 D Dead load A3.1, A6.1.2
Do Initial column imperfection D4.1 d Depth of section B1.1, C3.1.2.1, C3.1.3, C4.6, D3.2.1, D3.2.2, D4, D4.1 d Nominal screw diameter E4, E4.1, E4.2, E4.3.1, E4.4.1 d Flat depth of lip defined in Figure B4-2 B4 d Width of arc seam weld E2.3
Symbols and Definitions SYMBOLS AND DEFINITIONS
Symbol Definition Section
18 December 2001 d Visible diameter of outer surface of arc spot weld E2.2.1, E2.2.2 d Diameter of bolt E3a, E3.2, E3.3.1, E3.3.2, E3.4 da Average diameter of arc spot weld at mid-thickness E2.2.1, E2.2.2 of t da Average width of seam weld E2.3 db Nominal diameter (body or shank diameter) G4 de Effective diameter of fused area E2.2, E2.2.1, E2.2.2 de Effective width of arc seam weld at fused surfaces E2.3 dh Diameter of standard hole B2.2, E3a, E3.1, E3.2, E5.1 d0 Depth of web hole B2.4, C3.2.2, C3.4.2 ds Reduced effective width of stiffener B4, B4.2 d′s Effective width of stiffener calculated according to B3.1 B4, B4.2 dwx Screw head or washer diameter E4.4 dw Larger value of screw head or washer diameter E4, E4.4, E4.4.2
E Modulus of elasticity of steel, 29,500 ksi (203,0 MPa, A2.3.2, B1.1, B2.1, B4, B5.1, or 2,070,0 kg/cm2) C3.1.1, C3.1.2.1, C3.1.2.2, C3.2.1, C3.5.1, C3.5.2, C3.6.1, C3.6.2, C4.1, C4.6, C5.2.1, C5.2.2, C6, C6.1, C6.2, D1.2, D4.1, E2.2.1
E Live load due to earthquake A3.1, A6.1.2
Eo Initial column imperfection; a measure of initial D4.1 twist of stud from initial, ideal, unbuckled shape
E1 Term used to compute shear strain in wallboard D4.1 E′ Inelastic modulus of elasticity D4.1 e Distance measured in line of force from E3.1, E3.1a center of a standard hole to nearest edge of an adjacent hole or to end of connected part toward which force is directed e Distance measured in line of force from center E4.3.2 of a standard hole to nearest end of connected part emin Minimum allowable distance measured in line of E2.2.1, E2.2.2 force from centerline of a weld to nearest edge
North American Cold-Formed Steel Specification SYMBOLS AND DEFINITIONS
Symbol Definition Section
December 2001 19 of an adjacent weld or to end of connected part toward which the force is directed ey Yield strain = Fy/E C3.1.1
F Fabrication factor F1.1 F Nominal tensile or shear strength E3.4
FSR Design stress range G3 FTH Threshold fatigue stress range G1, G3, G4
Fc Critical buckling stress B2.1, C3.1.2.1, C6.1 Fcr Plate elastic buckling stress B2.1, B5.1
Fe Elastic buckling stress C3.1.2.1, C3.1.2.2, C4, C4.1, C4.2, C4.3, C4.4, C6.2, D4.1
Fm Mean value of fabrication factor C3.1.5, F1.1
Fn Nominal buckling stress B2.1, C4, C5.2.1, C5.2.2, C6.2, D4, D4.1
Fn Nominal strength of bolts E3.4 Fnt Nominal tensile strength of bolts E3.4 Fnv Nominal shear strength of bolts E3.4
F′nt Nominal tensile strength for bolts subject to combination E3.4 of shear and tension
Fsy Yield point as specified in Section A2.1, A2.2 or A2.3.2 A1.2, A2.3.2, E2.2.1, E3.1 Ft Nominal tensile stress in flat sheet E3.2
Fu Tensile strength as specified in Section A2.1, A2.2 A2.3.2, C2, E2.2.1, E2.2.2, E2.3, or A2.3.2 E2.4, E2.5, E2.7, E3.1, E3.2,
E3.3.1, E3.3.2, E4.3.2, E5.1, E5.3
Fuv Tensile strength of virgin steel specified by Section A2 A7.2 or established in accordance with Section F3.3
Fwy Yield point for design of transverse stiffeners C3.6.1
Fxx Tensile strength of electrode classification E2.1, E2.2.1, E2.2.2, E2.3, E2.4, E2.5
Fu1 Tensile strength of member in contact with screw head E4, E4.3.1, E4.4.2
Fu2 Tensile strength of member not in contact with screw E4, E4.3.1, E4.4.1 head
Symbols and Definitions SYMBOLS AND DEFINITIONS
Symbol Definition Section
20 December 2001
Fv Nominal shear stress E3.2.1
Fy Yield point used for design, not to exceed specified A1.2, A2.3.2, A7.1, A7.2, yield point or established in accordance with Section F3, B2.1, C2, C3.1.1, C3.1.2.1, or as increased for cold work of forming in Section C3.1.2.2, C3.1.3, C3.2.1, A7.2 or as reduced for low ductility steels in Section C3.1.4, C3.4.1, C3.5.1, C3.5.2, C3.6.1, C3.6.2, C4, C4.2, C5.1.1, C5.1.2, C5.2.1, C5.2.2, C6, C6.1, C6.2, D1.2, D4.1, E2.1, E2.2.2, E5.2, G1
Fya Average yield point of section A7.2 Fyc Tensile yield point of corners A7.2 Fyf Weighted average tensile yield point of flat portions A7.2, F3.2 Fys Yield point of stiffener steel C3.6.1
Fyv Tensile yield point of virgin steel specified by Section A7.2 A2 or established in accordance with Section F3.3 f Stress in compression element computed on B2.1, B2.2, B2.4, B3.1, B3.2, basis of effective design width B4, B4.1, B4.2, B5.1, B5.1.1, B5.1.2, B5.2 fav Average computed stress in full unreduced flange B1.1 width fc Stress at service load in cover plate or sheet D1.2 fd Computed compressive stress in element being B2.1, B2.2, B3.1, B4.1, B4.2, considered. Calculations are based on effective B5.1.1, B5.1.2, B5.2 section at load for which deflections are determined.
fd1, fd2 Computed stresses f1 and f2 as shown in Figure B2.3-1. B2.3 Calculations are based on effective section at load for which serviceability is determined.
fd3 Computed stress f3 in edge stiffener, as shown in Figure B3.2 B4-2. Calculations are based on effective section at load for which serviceability is determined.
fv Computed shear stress on a bolt E3.4 f1, f2 Web stresses defined by Figure B2.3-1 B2.3, B2.4
North American Cold-Formed Steel Specification SYMBOLS AND DEFINITIONS
Symbol Definition Section
December 2001 21 f3 Edge stiffener stress defined by Figure B4-2 B3.2
G Shear modulus of steel, 1,300 ksi (78,0 MPa or C3.1.2.1, C3.1.2.2, D4.1
795,0 kg/cm2)
G′ Inelastic shear modulus D4.1 g Vertical distance between two rows of connections D1.1 nearest to top and bottom flanges g Transverse center-to-center spacing between fastener E3.2 gage lines h Depth of flat portion of web measured along plane B1.2, B2.4, C3.1.1, C3.2.1, of web C3.2.2, C3.4.1, C3.4.2, C3.5.1, C3.5.2, C3.6.2 h Width of elements adjoining stiffened element B5.1 h Lip height as defined in Figures E2.5-4 to E2.5-7 E2.5 ho Out-to-out depth of web as defined in Figure B2.3-2 B2.3 ho Depth of web hole B2.4 hwc Coped flat web depth E5.1
Ia Adequate moment of inertia of stiffener, so that each B1.1, B4, B4.1, B4.2 component element will behave as a stiffened element
Is Actual moment of inertia of full stiffener about its own B1.1, B4, B4.1, centroidal axis parallel to element to be stiffened B4.2, C3.6.2
Ismin Minimum moment of inertia of shear stiffener(s) with C3.6.2 respect to an axis in plane of web
Isp Moment of inertia of stiffener about centerline of flat B5.1, B5.1.1, B5.1.2 portion of element
Ix, Iy Moment of inertia of full unreduced section about C3.1.2.1, C3.1.2.2, C5.2.1, principal axis C5.2.2, D3.2.2
Ixy Product of inertia of full unreduced section about major D3.2.2, D4.1 and minor centroidal axes
Iyc Moment of inertia of compression portion of section C3.1.2.1 about centroidal axis of entire section parallel to web, using full unreduced section i Index of stiffener B5.1, B5.1.2
Symbols and Definitions SYMBOLS AND DEFINITIONS
Symbol Definition Section
2 December 2001
J Saint-Venant torsion constant C3.1.2.1, C3.1.2.2, D4.1 j Section property for torsional-flexural buckling C3.1.2.1
K Effective length factor C4.1, C4.5, D4.1 K′ A constant D3.2.2
Kt Effective length factor for torsion C3.1.2.1 Kx Effective length factor for buckling about x-axis C3.1.2.1, C5.2.1, C5.2.2
Ky Effective length factor for buckling about y-axis C3.1.2.1, C3.1.2.2, C5.2.1, C5.2.2 k Plate buckling coefficient B2.1, B2.3, B3.1, B3.2, B4, B4.1, B4.2, B5.1, B5.2 kd Plate buckling coefficient for distortional buckling B5.1, B5.1.1, B5.1.2 kloc Plate buckling coefficient for local sub-element buckling B5.1, B5.1.1, B5.1.2 kv Shear buckling coefficient C3.2.1, C3.6.2, L Full span for simple beams, distance between inflection B1.1 points for continuous beams, twice length for cantilever beams
L Span length D3.2.1, D1.1
L Length of weld E2.1, E2.5 L Length of longitudinal welds E2.7 L Length of seam weld not including circular ends E2.3 L Length of fillet weld E2.4 L Length of connection E3.2 L Unbraced length of member C4.1, C4.5, C5.2.1, C5.2.2, D4.1
L Overall length D4.1 L Live load A3.1, A6.1.2, A6.1.2.2
Lbr Unsupported length between brace points or other B5.1, B5.1.1, B5.1.2 restraints which restrict distortional buckling of element
Lst Length of transverse stiffener C3.6.1 Lt Unbraced length of compression member for torsion C3.1.2.1
North American Cold-Formed Steel Specification SYMBOLS AND DEFINITIONS
Symbol Definition Section
December 2001 23
Lx Unbraced length of compression member for bending C3.1.2.1, C5.2.1, C5.2.2 about x-axis
Ly Unbraced length of compression member for bending C3.1.2.1, C3.1.2.2, C5.2.1, about y-axis C5.2.2
Lu Limit of unbraced length by which lateral-torsional C3.1.2.2 buckling is not be considered
Mmax, Absolute value of moments in unbraced segment, C3.1.2.1 MA, MB, used for determining Cb
Mm Mean value of material factor C3.1.5, F1.1
Mn Nominal flexural strength [resistance] B2.1, C3.1, C3.1.1, C3.1.2.1, C3.1.2.2, C3.1.3, C3.1.4,
C3.3.1, C3.3.2, C6.1
M Required allowable flexural strength, ASD C3.3.1, C3.5.1
Mnx, Nominal flexural strengths [resistances] about C5.1.1, C5.1.2, C5.2.1,
(Parte 2 de 6)