Symbol Meaning Section : Moment of inertia about the axis of bending, mm4. 10.14.3 : Moment of inertia, mm4 10.20.12 : Moment of inertia of a vertical boundary element (VBE) taken perpendicular to the direction of the web plate line, mm4 10.20.17 : Moment of inertia of the steel deck supported on secondary members, mm4 10.16.1 : Moment of inertia of primary members, mm4 10.16.1 : Moment of inertia of secondary members, mm4 10.16.1 :& , :% Moment of inertia about the principal axes, mm4 10.5.4 :% Out-of-plane moment of inertia, mm4 10.19.2 : Minor principal axis moment of inertia, mm4 10.6.10.2 :% Moment of inertia about y-axis referred to the compression flange, or if reverse curvature bending referred to smaller flange, mm4 10.6.1 ; Torsional constant, mm4 10.5.4 < Effective length factor determined in accordance with Sec 10.3 10.3.1.2 < Effective length factor for prismatic member 10.20.13 < Effective length factor for torsional buckling 10.5.4 < Effective length factor in plane of bending, calculated based on the assumption of no lateral translation set equal to 1.0 unless analysis indicates a smaller value to be used. 10.3.2.1 < Effective length factor in the plane of bending, calculated based on a sidesway buckling analysis 10.3.2.1
Story height, mm. 10.3.2.1
Laterally unbraced length of a member, mm. 10.5.2
Length of member between work points at truss chord centerlines,mm. 10.5.5Symbol Meaning Section
Length of the member, mm. 10.8.3
Actual length of end-loaded weld, mm. 10.10.2.2
Nominal occupancy live load 10.18.1.4
Span length, mm. 10.19.2
Span length of the truss, mm. 10.20.12
Distance between VBE centerlines, mm 10.20.17 = Distance between braces, mm. 10.19.2 = Length between points that are either braced against lateral displacement of compression flange or braced against twist of the cross section, mm. 10.6.2, 10.20.13 = Distance between plastic hinge locations, mm 10.20.9 = Clear distance, in the direction of the force, between the edge of the hole and the edge of the adjacent hole or edge of the material,mm. 10.10.3.10 = Link length, mm 10.20.15 = Clear distance between VBE flanges, mm 10.20.17 = Total effective weld length of groove and fillet welds to rectangular HSS,mm. 10.11.2.3 = Limiting laterally unbraced length for the limit state of yielding, mm. 10.6.2.2 = Column spacing in direction of girder, m 10.16 = Limiting laterally unbraced length for full plastic flexural strength, uniform moment case,mm. 10.20.12 = Limiting laterally unbraced length for plastic analysis, mm. 10.15.7 = Limiting laterally unbraced length for plastic analysis, mm 10.20.13 => Maximum unbraced length for (the required flexural strength),mm. 10.19.2
Limiting laterally unbraced length for limit state of inelastic lateral-torsional buckling, mm. 10.6.2.2Symbol Meaning Section = Column spacing perpendicular to direction of girder, m 10.16.1 = Length of the special segment, mm 10.20.12
Distance from maximum to zero shear force,mm. 10.7.6 ? Absolute value of moment at quarter point of the unbraced segment, N-mm. 10.6.1 Required flexural strength in chord, using ASD load combinations, N-mm. 10.11.2.2 Required flexural strength, using ASD load combinations, N-mm. 10.20.9 Additional moment due to shear amplification from the location of plastic hinge to the column centerline based on ASD load combinations, N-mm. 10.20.9 ! Absolute value of moment at centerline of the unbraced segment, N-mm. 10.6.1 Required bracing moment,N-mm. 10.19.2 @ Absolute value of moment at three-quarter point of unbraced segment, N-mm. 10.6.1 @(&,%) Available flexural strength determined in accordance with Sec 10.6,N-mm. 10.8.1.1 @& Available flexural-torsional strength for strong axis flexure determined in accordance with Sec 10.6,N-mm. 10.8.1.3 Elastic lateral-torsional buckling moment, N-mm. 10.6.10.2 D First-order moment under LRFD or ASD load combinations caused by lateral translation of the frame only, N-mm. 10.3.2.1 & Absolute value of maximum moment in the unbraced segment,N-mm. 10.6.1 Nominal flexural strength, N-mm. 10.6.1 Nominal flexural strength, N-mm. 10.20.11 Nominal flexural strength of the chord member of special segment, N-mm. 10.20.12 First-order moment using LRFD or ASD load combinations assuming there is no lateral translation of the frame, N-mm. 10.3.2.1 Symbol Meaning Section Plastic bending moment,N-mm. Table 6.10.1 Nominal plastic flexural strength, N-mm. Table 6.10.8 Nominal plastic flexural strength modified by axial load, N- mm. 10.20.15 Nominal plastic flexural strength of the beam, N-mm. 10.20.9 Nominal plastic flexural strength of the column, N-mm. 10.20.8 ,& Expected plastic moment, N-mm. 10.20.9 Required second-order flexural strength under LRFD or ASD load combinations, N-mm. 10.3.2.1 Required flexural strength using LRFD or ASD load combinations,N-mm. 10.8.1 Required flexural strength in chord, N-mm. 10.11.2.2 Expected flexural strength, N-mm. 10.20.9 E Required in-plane flexural strength in branch,N-mm. 10.11.3.2 EF Required out-of-plane flexural strength in branch,N-mm. 10.11.3.2 Required flexural strength, using LRFD load combinations, N- mm. 10.20.9 Required flexural strength in chord, using LRFD load combinations,N-mm. 10.11.2.2 Additional moment due to shear amplification from the location of plastic hinge to the column centerline based on LRFD load combinations, N-mm. 10.20.9 ,& Expected required flexural strength, N-mm. 10.20.15 % Yield moment about the axis of bending, N-mm. Table 6.10.1 Smaller moment, calculated from a first-order analysis, at the ends of that portion of the member unbraced in the plane of bending under consideration, N-mm. 10.3.2.1 Larger moment, calculated from a first-order analysis, at the ends of that portion of the member unbraced in the plane of bending under consideration, N-mm. 10.3.2.1 Symbol Meaning Section Length of bearing (not less than k for end beam reactions),mm. 10.10.10.2 Bearing length of the load, measured parallel to the axis of the HSS member, (or measured across the width of the HSS in the case of the loaded cap plates), mm. 10.11.1.1 Number of stress range fluctuations in design life 10.17.3 3 Number of bolts carrying the Applied tension 10.10.3.9 3 Additional lateral load 10.3.2.2 3 Notional lateral load Applied at level , N. 10.14.3 3 Number of slip planes 10.10.3.8 G Overlap connection coefficient 10.11.2.2 H Pitch, mm per thread 10.17.4 H Required axial strength of a column using ASD load combinations, N. 10.20.8 H Required compressive strength using ASD load combinations, N. 10.20.9 H Required strength of lateral brace at ends of the link, N. 10.20.15 H Required brace strength, N. 10.19.2 H Available axial compressive strength, N. 10.8.1.1 H Available tensile strength, N. 10.8.1.2 H Available axial strength of a column, N. 10.20.9 HF Available compressive strength out of the plane of bending, N. 10.8.1.3 H,H Elastic critical buckling load for braced and unbraced frame, respectively, N. 10.3.2.1 H) Euler buckling load, evaluated in the plane of bending, N. 10.14.3 Symbol Meaning Section HD( ,) First-order axial force using LRFD or ASD load combinations as a result of lateral translation of the frame only (tension or compression, N. 10.3.2.1 H ( ,) First-order axial force using LRFD or ASD load combinations, assuming there is no lateral translation of the frame (tension or compression, N. 10.3.2.1 H Nominal axial strength, N. 10.4.2 H Nominal axial strength of a column, N. 10.20.8 H Nominal axial compressive strength of diagonal members of the special segment, N. 10.20.12 H Nominal axial tensile strength of diagonal members of special segment, N. 10.20.12 H Required compressive strength using ASD or LRFD load combinations, N. 10.20.9 H Required second-order axial strength using LRFD or ASD load combinations, N. 10.3.2.1 H Required axial compressive strength using LRFD or ASD load combinations, N. 10.3.2.2 H Required tensile strength using LRFD or ASD load combinations, N. 10.8.1.2 H Required strength, N. 10.10.10.6 H Required axial strength in chord, N. 10.11.2.2 H Required axial strength in branch, N. 10.11.3.2 H Required compressive strength, N. 10.20.15 H Required axial strength in compression, N. 10.15.4 H Required axial strength of a column or a link in LRFD load combinations, N. 10.20.8 H Required compressive strength using LRFD load combinations, N. 10.20.9 H% Member yield strength, N. 10.3.2.2 H% Nominal axial yield strength of a member, equal to % ,N. Table 6.10.8 Symbol Meaning Section H% Axial yield strength of steel core, N. 10.20.16 I Full reduction factor for slender compression elements 10.5.7 I Reduction factor for slender stiffened compression elements 10.5.7.2 I Maximum unbalanced vertical load effect applied to a beam by the braces, N. 10.20.13 I Axial forces and moments generated by at least 1.25 times the expected nominal shear strength of the link 10.20.15 I Chord-stress interaction parameter 10.11.2.2 I Reduction factor for slender unstiffened compression elements 10.5.7.1 R Seismic response modification coefficient 10.20.1 J Seismic response modification coefficient 10.1.1.1 J Nominal load due to rainwater or snow, exclusive of the ponding contribution, MPa. 10.16.2 J Required strength (ASD) 10.2.3.4 JKL) Reduction factor for joints using a pair of transverse fillet welds only 10.17.3 J Factor in Eq. 6.10.8 dependent on type of system 10.3.2.1 J Cross-section monosymmetry parameter 10.6.1 J Nominal strength, N. 10.2.3.3 J Nominal strength, N. 10.20.6 J Nominal slip resistance, N. 10.10.3.8 J Web plastification factor 10.6.4.1 JMNM Reduction factor for reinforced or unreinforced transverse partial-joint-penetration (PJP) groove welds 10.17.3 J Web plastification factor corresponding to the tension flange yielding limit state 10.6.4.4 Symbol Meaning Section J Ratio of the expected tensile strength to the specified minimum tensile strength , as related to overstrength in material yield stress J% 10.20.6 J Required strength (LRFD) 10.2.3.3 J Required strength 10.20.9 J Panel zone nominal shear strength 10.20.9 JD Total nominal strength of longitudinally loaded fillet welds, as determined in accordance with Table 6.10.8 10.10.2.4 J Total nominal strength of transversely loaded fillet welds, as determined in accordance with Table 6.10.8 without the alternate in Sec 10.10.2.4 (a) 10.10.2.4 J% Ratio of the expected yield stress to the specified minimum yield stress, % 10.20.6 O Elastic section modulus of round HSS, mm3 10.6.8.2 O Lowest elastic section modulus relative to the axis of bending, mm3 10.6.12 O Chord elastic section modulus, mm3 10.11.2.2 O Spacing of secondary members, m 10.16.1 O Elastic section modulus to toe in compression relative to axis of bending, mm3. 10.6.10.3 O Effective section modulus about major axis, mm3 10.6.7.2 O& , O& Elastic section modulus referred tension and compression flanges, respectively, mm3 Table 6.10.1 O&, O% Elastic section modulus taken about the principal axes, mm3 10.6.2.2, F6 O% For channels, taken as the minimum section modulus 10.6.6 P Nominal forces and deformations due to design-basis fire defined in Sec 4.2.1 10.18.1.4 P Tension force due to ASD load combinations, kN. 10.10.3.9 Symbol Meaning Section P Minimum fastener tension given in Table 6.10.9, kN. 10.10.3.8 P Available torsional strength, N-mm. 10.8.3.2 P Nominal torsional strength, N-mm. 10.8.3.1 P Required torsional strength, N-mm. 10.8.3.2 P Tension force due to LRFD load combinations, kN. 10.10.3.9 Q Shear lag factor 10.4.3.3 Q Utilization ratio 10.11.2.2 Q Reduction coefficient, used in calculating block shear rupture strength 10.10.4.3 Q Stress index 10.16.2 Q Stress index 10.16.2 R Required shear strength using ASD load combinations, N. 10.20.9 R Available shear strength, N. 10.7.3.3 R Nominal shear strength, N. 10.7.1 R Nominal shear strength of a member, N. 10.20.15 R Nominal shear strength of an active link, N. Table 6.10.8 R Nominal shear strength of an active link modified by axial load magnitude, N. 10.20.15 R Expected vertical shear strength of the special segment, N. 10.20.12 R Required shear strength at the location of the stiffener, N. 10.7.3.3 R Required shear strength using LRFD or ASD load combinations, N. 10.8.3.2 R Required shear strength using LRFD load combinations, N. 10.20.10 S Gravity load from the LRFD load combination or 1.6 times the ASD load combination Applied at level , N. 10.3.2.2 S Hole reduction coefficient, N. 10.6.13.1 Symbol Meaning Section T Plastic section modulus about the axis of bending, mm3 10.6.7.1 Z Plastic section modulus of a member, mm3. 10.20.9 T Branch plastic section modulus about the correct axis of bending, mm3 10.11.3.3 T Plastic section modulus of the beam, mm3. 10.20.9 T Plastic section modulus of the column, mm3. 10.20.9 T& Plastic section modulus x-axis, mm3. 10.20.8 T,!+ Minimum plastic section modulus at the reduced beam section, mm3. 10.20.9 T&,% Plastic section modulus about the principal axes, mm3 10.6.2, F6.1 U Shortest distance from edge of pin hole to edge of member measured parallel to direction of force, mm. 10.4.5.1 U Distance between connectors in a built-up member, mm. 10.5.6.1 U Clear distance between transverse stiffeners,mm. 10.6.13.2 U Half the length of the non-welded root face in the direction of the thickness of the tension-loaded plate, mm. 10.17.3 a Angle that diagonal members make with the horizontal 10.20.12 U Ratio of two times the web area in compression due to Application of major axis bending moment alone to the area of the compression flange components 10.6.4.2 Width of unstiffened compression element; for flanges of I-shaped members and tees, the width is half the full-flange width, ; for legs of angles and flanges of channels and zees, the width is the full nominal dimension; for plates, the width is the distance from free edge to the first row of fasteners or line of welds, or the distance between adjacent lines of fasteners or lines of welds; for rectangular HSS, width is the clear distance between the webs less the inside corner radius on each side, mm. 10.2.4.1, 10.2.4.2 Symbol Meaning Section Full width of longest angle leg, mm. 10.5.7.1 Outside width of leg in compression, mm. 10.6.10.3 Width of the angle leg resisting the shear force, mm. 10.7.4 b Width of compression element as defined in Specification Sec 10.2.4.1, mm. Table 6.10.8 Width of column flange, mm. 10.10.10.6 Width of column flange, mm. 10.20.9 Reduced effective width,mm. 10.5.7.2 Effective edge distance; the distance from the edge of the hole to the edge of the part measured in the direction normal to the applied force,mm. 10.4.5.1 F Effective width of the branch face welded to the chord 10.11.2.3 F Effective width of the branch face welded to the overlapped brace. 10.11.2.3 Flange width, mm. 10.2.4.1 Flange width, mm. 10.20.9 Compression flange width, mm. 10.6.4.2 Width of tension flange, mm. 10.7.3.1 D Longer leg of angle, mm. 10.5.5 Shorter leg of angle, mm. 10.5.5 Stiffener width for one-sided stiffeners, mm. 10.19.2 Full nominal depth of section, mm. 10.2.4.1 Pin diameter,mm. 10.4.5.1 Full nominal depth of tee, mm. 10.5.7.1 Depth of rectangular bar, mm. 10.6.11.2 Symbol Meaning Section Nominal fastener diameter, mm. 10.10.3.3 Diameter, mm. 10.10.7 Roller diameter,mm. 10.10.7 d Nominal fastener diameter, mm. 10.20.7 d Overall beam depth, mm. 10.20.15 Beam depth,mm. 10.10.10.6 Nominal diameter (body or shank diameter), mm. 10.17.4 Column depth, mm. 10.10.10.6 Overall column depth, mm. 10.20.9 Overall panel zone depth between continuity plates, mm. 10.20.9 V Eccentricity in a truss connection, positive being away from thebranches, mm. 10.11.2.1 e EBF link length, mm. 10.20.15 W Required axial stress at point of consideration of LRFD or ASD load combinations, MPa. 10.8.2 W(,) Required flexural stress at the point of consideration (major axis, minor axis) using LRFD or ASD load combinations, MPa. 10.8.2 W * Specified minimum compressive strength of concrete at elevated temperatures, MPa. 10.18.2 WF Stress due to D + R (the nominal dead load + the nominal load due to rainwater or snow exclusive of the ponding contribution, MPa. 10.16.2 W Required shear strength per unit area, MPa. 10.10.3.7 X Transverse center-to-center spacing (gage) between fastener gage lines, mm. 10.2.3.13 X Gap between toes of branch members in a gapped K- connection, neglecting welds, mm. 10.11.2.1 ℎ Clear distance between flanges less the fillet or corner radius for rolled shapes; for built-up sections, the distance between adjacent lines of fasteners or the clear distance between flanges when welds are used; for tees, the overall depth; for rectangular HSS, the clear distance between the flanges less the inside corner radius on each side, mm. 10.2.4.2, Table 6.10.8 Symbol Meaning Section ℎ Distance between centroids of individual components perpendicular to the member axis of buckling,mm. 10.5.6.1 h Distance between horizontal boundary element centerlines, mm. 10.20.17 ℎ Twice the distance from the centroid to the following: the inside face of the compression flange less the fillet or corner radius, for rolled shapes; the nearest line of fasteners at the compression flange or the inside faces of the compression flange when welds are used, for built-up sections, mm. 10.2.4.2 ℎF Distance between flange centroids, mm. 10.6.2.2 ℎF Distance between flange centroids, mm 10.20.9 ℎ Twice the distance from plastic neutral axis to the nearest line of fasteners at the compression flange or inside face of compression flange when welds are used, mm 10.2.4.2 ℎ Hole factor 10.10.3.8 Z Factor defined by Eq. 6.10.141 for minimum moment of inertia for a transverse stiffener 10.7.2.2 [ Distance from outer face of flange to the web toe of fillet, mm. 10.10.10.2 [ Outside corner radius of HSS, which is permitted to be taken as 1.5t if unknown, mm. 10.11.1.3 [ Coefficient for slender unstiffened elements, mm. Table 6.10.1 [ Slip-critical combined tension and shear coefficient 10.10.3.9 [ Web plate buckling coefficient 10.7.2.1Largest laterally unbraced length along either flange at the point of load, mm. 10.10.10.4
Length of bearing,mm. 10.10.7
Length of connection in the direction of loading,mm. Table 6.10.2 l Unbraced length between stitches of built-up bracing members,mm. 10.20.13 l Unbraced length of compression or bracing member, mm. 10.20.13 Symbol Meaning Section Number of nodal braced points within the span 10.19.2 Threads per mm. 10.17.4 ] Ratio of element i deformation to its deformation at maximum stress 10.10.2.4 ] Projected length of the overlapping branch on the chord 10.11.2.2 ^ Overlap length measured along the connecting face of the chord beneath the two branches 10.11.2.2 _ Governing radius of gyration, mm. 10.5.2 r Governing radius of gyration, mm. 10.20.13 _ Distance from instantaneous center of rotation to weld element with minimum`a b ratio, mm. 10.10.2.4 _ Minimum radius of gyration of individual component in a built- up member, mm. 10.5.6.1 _ Radius of gyration of individual component relative to its centroidal axis parallel to member axis of buckling, mm. 10.5.6.1 _Fc Polar radius of gyration about the shear center,mm. 10.5.4 _ Radius of gyration of the flange components in flexural compression plus one-third of the web area in compression due to application of major axis bending moment alone 10.6.4.2 _ Effective radius of gyration used in the determination of = for the lateral-torsional buckling limit state for major axis bending of doubly symmetric compact I-shaped members and channels 10.6.2.2 _& Radius of gyration about geometric axis parallel to connected leg, mm. 10.5.5 _% Radius of gyration about y-axis, mm. 10.5.4 _% Radius of gyration about y-axis, mm. 10.20.9 _$ Radius of gyration for the minor principal axis, mm. 10.5.5 Symbol Meaning Section Longitudinal center-to-center spacing (pitch) of any two consecutive holes, mm. 10.2.3.13 Thickness of element, mm. 10.2.4.2 t Thickness of element, mm. Table 6.10.8 Wall thickness, mm. 10.5.7.2 Angle leg thickness, mm. 10.6.10.2 Width of rectangular bar parallel to axis of bending, mm. 10.6.11.2 Thickness of connected material, mm. 10.10.3.10 Thickness of plate, mm. 10.4.5.1 Design wall thickness for HSS equal to 0.93 times the nominal wall thickness for ERW HSS and equal to the nominal wall thickness for SAW HSS, mm. 10.2.3.12 Total thickness of fillers, mm. 10.10.5 t Thickness of connected part, mm. 10.20.7 t Thickness of column web or doubler plate, mm. 10.20.9 Design wall thickness of HSS main member, mm. 10.11.3.1 Design wall thickness of HSS main member, mm. 10.11.2.1 Design wall thickness of HSS member, mm. 10.11.1.1 Design wall thickness of HSS branch member, mm. 10.11.2.1 Design wall thickness of HSS branch member, mm. 10.11.3.1 Thickness of beam flange, mm. 10.20.9 Thickness of the overlapped branch,mm. 10.11.2.3 Thickness of the column flange,mm. 10.10.10.6 Symbol Meaning Section Thickness of column flange, mm. 10.20.9 Thickness of the loaded flange, mm. 10.10.10.1 Thickness of flange, mm. 10.20.17 Compression flange thickness, mm. 10.6.4.2 Thickness of plate, mm. 10.11.1.1 Thickness of the attached transverse plate, mm. 10.11.2.3 Thickness of tension loaded plate, mm. 10.17.3 Thickness of panel zone including doubler plates, mm. 10.20.9 Web stiffener thickness, mm. 10.19.2 Web thickness, mm. Table 6.10.1 Thickness of web, mm. Table6.10.8 Thickness of element, mm. 10.5.7.1 Column web thickness, mm. 10.10.10.6 Beam web thickness, mm. 10.19.3 d Width of cover plate, mm. 10.6.13.3 d Weld leg size, mm. 10.10.2.2 d Plate width, mm. Table 6.10.2 d Leg size of the reinforcing or contouring fillet, if any, in the direction of the thickness of the tension-loaded plate, mm. 10.17.3 d$ Width of panel zone between column flanges, mm. 10.20.9 x Parameter used for determining the approximate fundamental period Appendix P.2 eF,fF Coordinates of the shear center with respect to the centroid, mm. 10.5.4 Symbol Meaning Section e̅ Connection eccentricity,mm. Table 6.10.2 f Subscript relating symbol to weak axis h Subscript relating symbol to minor principal axis bending T Minimum plastic section modulus at the reduced beam section, mm3 10.20.9 i Factor used in Eq. 6.10.2.2 10.3.2.1 i Separation ratio for built-up compression members =ℎ(2_) ⁄ 10.5.6.1 α Angle of diagonal members with the horizontal 10.20.12 α Angle of web yielding in radians, as measured relative to the vertical 10.20.17 m Reduction factor given by Eq. 6.10.159 10.10.2.2 m The width ratio; the ratio of branch diameter to chord diameter = / for round HSS; the ratio of overall branch width to chord width = / for rectangular HSS 10.11.2.1, 10.11.3.1 m Compression strength adjustment factor 10.20.16 m- Brace stiffness requirement excluding web distortion, N-mm/radian. 10.19.2 m Required brace stiffness 10.19.2 m Effective width ratio; the sum of the perimeters of the two branch members in a K-connection divided by eight times the chord width 10.11.2.1 mF Effective outside punching parameter 10.11.2.3 m Web distortional stiffness, including the effect of web transverse stiffeners, if any, N-mm/radian. 10.19.2 m Section property for unequal leg angles, positive for short legs in compression and negative for long legs in compression 10.6.10.2 Δ First-order interstory drift due to the design loads,mm. 10.3.2.2 Symbol Meaning Section Δ Design story drift 10.20.15 Δ Deformation quantity used to control loading of test specimen (total brace end rotation for the sub-assemblage test specimen; total brace axial deformation for the brace test specimen) Appendix R.2 Δ Value of deformation quantity, Δ, corresponding to the design story drift Appendix R.6 Δ% Value of deformation quantity, Δ, at first significant yield of test specimen Appendix R.6 Δ/ First-order interstory drift due to lateral forces,mm. 10.3.2.1 Δ Deformation of weld elements at intermediate stress levels, linearly proportioned to the critical deformation based on distance from instantaneous center of rotation,r,mm. 10.10.2.4 Δ Deformation of weld element at maximum stress,mm. 10.10.2.4 Δ Deformation of weld element at ultimate stress (fracture), usually in element furthest from instantaneous center of rotation, mm. 10.10.2.4 δ Deformation quantity used to control loading of test specimen Appendix Q.6 δ% Value of deformation quantity δ at first significant yield of test specimen Appendix Q.6 ρ* Ratio of required axial force H to required shear strength R of a link 10.20.15 r The chord slenderness ratio; the ratio of one-half the diameter to the wall thickness = (2) ⁄ for round HSS; the ratio of one- half the width to wall thickness = (2) ⁄ for rectangular HSS 10.11.2.1, 10.11.3.1 s The gap ratio; the ratio of the gap between the branches of a gapped K-connection to the width of the chord = g/ B for rectangular HSS 10.11.2.1 Symbol Meaning Section t The load length parameter, applicable only to rectangular HSS; the ratio of the length of contact of the branch with the chord in the plane of the connection to the chord width = 3 ⁄ , where 3 = 2 sin 8 ⁄ 10.11.2.1, 10.11.3.1 x Slenderness parameter 10.6.3 λ Limiting slenderness parameter for compact element 10.2.4 λ Limiting slenderness parameter for compact flange 10.6.3 λ Limiting slenderness parameter for compact web 10.6.4 λ Limiting slenderness parameter for noncompact element 10.2.4 λ Limiting slenderness parameter for noncompact flange 10.6.3 λ Limiting slenderness parameter for noncompact web 10.6.4 λ,λ Limiting slenderness parameter for compact element 10.20.8 z Mean slip coefficient for class A or B surfaces, as Applicable, or as established by tests 10.10.3.8 { Resistance factor 10.2.3.3 { Resistance factor 10.20.6 { Resistance factor for flexure 10.6.1 { Resistance factor for flexure 10.20.8 { Resistance factor for compression 10.5.1 { Resistance factor for compression 10.20.8 { Resistance factor for shear on the failure path 10.4.5.1 {- Resistance factor for torsion 10.8.3.1 { Resistance factor for tension 10.4.2 { Resistance factor for shear 10.7.1 Symbol Meaning Section { Resistance factor for shear strength of panel zone of beam- to-column connections 10.20.9 { Resistance factor for shear 10.20.15 { F D Link rotation angle Appendix Q.2 | Safety factor 10.2.3.4 | Safety factor 10.20.6 | Safety factor for flexure 10.6.1 | Safety factor for flexure = 1.67 10.20.8 | Safety factor for compression 10.5.1 | Safety factor for compression = 1.67 10.20.8 | Safety factor for shear on the failure path
Safety factor for shear
10.7.1
|
Safety factor for shear strength of panel zone of beam-to-
column connections
10.20.9
|F
Horizontal seismic overstrength factor
10.20.4
Angle of loading measured from the weld longitudinal axis,
degrees
10.10.2.4
Acute angle between the branch and chord, degrees
10.11.2.1
Acute angle between the branch and chord, degrees
10.11.3.1
Interstory drift angle, radians
Appendix Q.3
}
Strain hardening adjustment factor
10.20.16
ε
Strain corresponding to compressive strength of concrete, W*
10.18.2
τ
Parameter for reduced flexural stiffness using the direct
analysis method
10.14.3
Symbol Meaning
Section
Σ∗
Moment at beam and column centerline determined by
projecting the sum of the nominal column plastic moment
strength, reduced by the axial stress H/
, from the top and
bottom of the beam moment connection
10.20.9
Σ∗ Moment at the intersection of the beam and column centerlines
determined by projecting the beam maximum developed
moments from the column face. Maximum developed
moments shall be determined from test results
10.20.9
10.1.2.2
Definitions
ACTIVE FIRE PROTECTION
Building materials and systems that are activated by
a fire to mitigate adverse effects or to notify people
to take some action to mitigate adverse effects.
ADJUSTED BRACE STRENGTH Strength of a brace in a buckling-restrained braced
frame at deformations corresponding to 2.0 times
the design story drift.
ALLOWABLE STRENGTH*
Nominal strength divided by the safety factor,
J /Ω.
ALLOWABLE STRESS
Allowable strength divided by the appropriate
section property, such as section modulus or cross-
section area.
AMPLIFICATION FACTOR
Multiplier of the results of first-order analysis to
reflect second-order effects.
AMPLIFIED SEISMIC LOAD
Horizontal component of earthquake load
multiplied by ΩF, where and the horizontal
component of are specified in the Code.
APPLICABLE BUILDING
CODE
Building Code under which the structure is
designed.
ASD(ALLOWABLE STRENGTH
DESIGN)
Method of proportioning structural components
such that the allowable strength equals or exceeds
the required strength of the component under the
action of the ASD load combinations.
ASD LOAD COMBINATION
Load combination in the Code intended for
allowable strength design (allowable stress design).
AUTHORITY HAVING
JURISDICTION
Organization, political subdivision, office or
individual charged with the responsibility of
administering and enforcing the provisions of the
Code.
AVAILABLE STRENGTH*
Design
strength
or
allowable
strength,
as
appropriate.
AVAILABLE STRESS*
Design stress or allowable stress, as appropriate.
AVERAGE RIB WIDTH
Average width of the rib of a corrugation in a
formed steel deck.
AUTHORITY HAVING
JURISDICTION (AHJ)
Organization, political subdivision, office or
individual charged with the responsibility of
administering and enforcing the provisions of this
Code.
BATTEN PLATE
Plate rigidly connected to two parallel components
of a built-up column or beam designed to transmit
shear between the components.
BEAM
Structural member that has the primary function of
resisting
bending
moments.
Beam-column.
Structural member that resists both axial force and
bending moment. Bearing. In a bolted connection,
limit state of shear forces transmitted by the bolt to
the connection elements.
BEARING (LOCAL
COMPRESSIVE YIELDING)
Limit state of local compressive yielding due to the
action of a member bearing against another
member or surface.
BEARING-TYPE CONNECTION Bolted connection where shear forces are
transmitted by the bolt bearing against the
connection elements.
BLOCK SHEAR RUPTURE
In a connection, limit state of tension fracture along
one path and shear yielding or shear fracture along
another path.
BRACED FRAME
An essentially vertical truss system that provides
resistance to lateral forces and provides stability for
the structural system.
BRANCH FACE
Wall of HSS branch member.
BRANCH MEMBER
For HSS connections, member that terminates at a
chord member or main member.
BUCKLING
Limit state of sudden change in the geometry of a
structure or any of its elements under a critical
loading condition.
BUCKLING STRENGTH
Nominal strength for buckling or instability limit
states.
BUCKLING-RESTRAINED
BRACED FRAME (BRBF)
Diagonally
braced
frame
safisfying
the
requirements of Section16 in which all members of
the bracing system are subjected primarily to axial
forces and in which the limit state of compression
buckling of braces is precluded at forces and
deformations corresponding to 2.0 times the design
story drift.
BUCKLING-RESTRAINING
SYSTEM
System of restraints that limits buckling of the steel
core in BRBF. This system includes the casing on
the steel core and structural elements adjoining its
connections. The buckling-restraining system is
intended to permit the transverse expansion and
longitudinal contraction of the steel core for
deformations corresponding to 2.0 times the design
story drift.
BUILT-UP MEMBER, CROSS-
SECTION, SECTION, SHAPE
Member, cross-section, section or shape fabricated
from structural steel elements that are welded or
bolted together.
CAMBER
Curvature fabricated into a beam or truss so as to
compensate for deflection induced by loads.
CASING
Element that resists forces transverse to the axis of
the brace there by restraining buckling of the core.
The casing requires a means of delivering this force
to the remainder of the buckling-restraining system.
The casing resists little or no force in the axis of the
brace.
CHARPY V-NOTCH IMPACT
TEST
Standard dynamic test measuring notch toughness
of a specimen.
CHORD MEMBER
For HSS, primary member that extends through a
truss connection.
CLADDING
Exterior covering of structure.
COLD-FORMED STEEL
STRUCTURAL MEMBER
Shape manufactured by press-braking blanks
sheared from sheets, cut lengths of coils or plates,
or by roll forming cold-or hot-rolled coils or sheets;
both forming operations being performed at
ambient room temperature, that is, without manifest
addition of heat such as would be required for hot
forming.
COLUMN
Structural member that has the primary function of
resisting axial force.
COLUMN BASE
Assemblage of plates, connectors, bolts, and rods at
the base of a column used to transmit forces
between
the
steel
superstructure
and
the
foundation.
COMBINED SYSTEM
Structure comprised of two or more lateral load-
resisting systems of different type.
COMPACT SECTION
Section capable of developing a fully plastic stress
distribution and possessing a rotation capacity of
approximately three before the onset of local
buckling.
COMPARTMENTATION
The enclosure of a building space with elements that
have a specific fire endurance.
COMPLETE-JOINT-
PENETRATION GROOVE
WELD (CJP)
Groove weld in which weld metal extends through
the joint thickness, except as permitted for HSS
connections.
COMPOSITE
Condition in which steel and concrete elements and
members work as a unit in the distribution of
internal forces.
CONCRETE CRUSHING
Limit state of compressive failure in concrete
having reached the ultimate strain.
CONCRETE HAUNCH
Section of solid concrete that results from stopping
the deck on each side of the girder in a composite
floor system constructed using a formed steel deck.
CONCRETE-ENCASED BEAM
Beam totally encased in concrete cast integrally
with the slab.
CONNECTION
Combination of structural elements and joints used
to transmit forces between two or more members.
CONVECTIVE HEAT
TRANSFER
The transfer of thermal energy from a point of
higher temperature to a point of lower temperature
through the motion of an intervening medium.
CONTINUITY PLATES
Column stiffeners at the top and bottom of the panel
zone; also known as transverse stiffeners.
CONTRACTOR
Fabricator or erector, as applicable.
COPE
Cutout made in a structural member to remove a
flange and conform to the shape of an intersecting
member.
COVER PLATE
Plate welded or bolted to the flange of a member to
increase cross-sectional area, section modulus or
moment of inertia.
CROSS CONNECTION
HSS connection in which forces in branch members
or connecting elements transverse to the main
member are primarily equilibrated by forces in
other branch members or connecting elements on
the opposite side of the main member.
DEMANDCRITICAL WELD
Weld so designated by these Provisions.
DESIGNEARTHQUAKE
The earthquake represented by the design response
spectrum as specified in the Code.
DESIGNSTORYDRIFT
Amplified story drift (drift under the design
earthquake, including the effects of inelastic
action), determined as specified in the Code.
DESIGN-BASIS FIRE
A set of conditions that define the development of
a fire and the spread of combustion products
throughout a building or portion thereof.
DESIGN LOAD*
Applied load determined in accordance with either
LRFD
load
combinations
or
ASD
load
combinations, whichever is applicable.
DESIGN STRENGTH*
Resistance factor multiplied by the nominal
strength, {J .
DESIGN STRESS RANGE
Magnitude of change in stress due to the repeated
application and removal of service live loads. For
locations subject to stress reversal it is the algebraic
difference of the peak stresses.
DESIGN STRESS*
Design strength divided by the appropriate section
property, such as section modulus or cross section
area.
DESIGN WALL THICKNESS
HSS wall thickness assumed in the determination
of section properties.
DIAGONAL BRACING
Inclined structural member carrying primarily axial
force in a braced frame.
DIAGONAL STIFFENER
Web stiffener at column panel zone oriented
diagonally to the flanges, on one or both sides of
the web.
DIAPHRAGM PLATE
Plate possessing in-plane shear stiffness and
strength, used to transfer forces to the supporting
elements.
DIAPHRAGM
Roof, floor or other membrane or bracing system
that transfers in-plane forces to the lateral force
resisting system.
DIRECT ANALYSIS METHOD
Design method for stability that captures the effects
of residual stresses and initial out-of-plumbness of
frames by reducing stiffness and applying notional
loads in a second-order analysis.
DIRECT BOND INTERACTION
Mechanism by which force is transferred between
steel and concrete in a composite section by bond
stress.
DISTORTIONAL FAILURE
Limit state of an HSS truss connection based on
distortion of a rectangular HSS chord member into
a rhomboidal shape.
DISTORTIONAL STIFFNESS
Out-of-plane flexural stiffness of web.
DOUBLE CURVATURE
Deformed shape of a beam with one or more
inflection points within the span.
DOUBLE-CONCENTRATED
FORCES
Two equal and opposite forces that form a couple
on the same side of the loaded member.
DOUBLER
Plate added to, and parallel with, a beam or column
web to increase resistance to concentrated forces.
DRIFT
Lateral deflection of structure.
DUAL SYSTEM
Structural system with the following features (1) an
essentially complete space frame that provides
support for gravity loads; (2) resistance to lateral
load provided by moment frames (SMF, IMF or
OMF) that are capable of resisting atleast 25 percent
of the base shear, and concrete or steel shearwalls,
or steel braced frames (EBF,S CBF or OCBF); and
(3) each system designed to resist the total lateral
load in proportion to its relative rigidity.
DUCTILE LIMIT STATE
Ductile limit states include member and connection
yielding, bearing deformation at bolt holes, as well
as buckling of members that conform to the width-
thickness limitations of Table 6.10.18. Fracture of a
member or of a connection, or buckling of a
connection element, is not a ductile limit state.
ECCENTRICALLY BRACED
FRAME (EBF)
Diagonally braced frame meeting there quirements
of Section 15 that has at least one end of each
bracing member connected to a beam a short
distance from another beam-to-brace connection or
a beam-to-column connection.
EFFECTIVE LENGTH
FACTOR, K
Ratio between the effective length and the unbraced
length of the member.
EFFECTIVE LENGTH
Length of an otherwise identical column with the
same strength when analyzed with pinned end
conditions.
EFFECTIVE NET AREA
Net area modified to account for the effect of shear
lag.
EFFECTIVE SECTION
MODULUS
Section modulus reduced to account for buckling of
slender compression elements.
EFFECTIVE WIDTH
Reduced width of a plate or slab with an assumed
uniform stress distribution which produces the
same effect on the behavior of a structural member
as the actual plate or slab width with its nonuniform
stress distribution.
ELASTIC ANALYSIS
Structural analysis based on the assumption that the
structure returns to its original geometry on
removal of the load.
ELEVATED TEMPERATURES
Heating conditions experienced by building
elements or structures as a result of fire, which are
in excess of the anticipated ambient conditions.
ENCASED COMPOSITE
COLUMN
Composite column consisting of a structural
concrete column and one or more embedded steel
shapes.
END PANEL
Web panel with an adjacent panel on one side only.
ENGINEER OF RECORD
Engineer having authority or license from
government approved Authority to sign and seal
engineering and contract documents.
END RETURN
Length of fillet weld that continues around a corner
in the same plane. Engineer of record. Licensed
professional responsible for sealing the contract
documents. Expansion rocker. Support with curved
surface on which a member bears that can tilt to
accommodate expansion.
EXPANSION ROLLER
Round steel bar on which a member bears that can
roll to accommodate expansion.
EXEMPTED COLUMN
Column not meeting the requirements of Eq.