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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-27A6.4.3.1—High-Strength StructuralFasteners6.4.3.1.1—High-Strength BoltsAdd a new 3rd paragraph as follows:ASTM F3125 Grade A490 and GradeF2280 bolts, ASTM A354 Grade BDfasteners, and ASTM A722 bars shall notbe galvanized. No cleaning process shallbe used that will introduce hydrogen intosteel.C6.4.3.1.1Replace the 2nd paragraph with thefollowing:Galvanizing is not an acceptable optionwithin ASTM F3125 for Grade A490 andGrade F2280 bolts, but Grade A490 boltsmay be coated with a zinc/aluminumcoating in accordance with ASTM F1136 orF2833. Galvanization of ASTM F3125Grade 490 and Grade F2280 bolts, ASTMA354 Grade BD fasteners, and ASTM A722bars is not permitted due to potentialhydrogen embrittlement.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-28A6.4.3.3—Fasteners for StructuralAnchorage6.4.3.3.1—Anchor RodsReplace thefollowing:1stparagraphC6.4.3.3.1withtheAnchor rods shall conform to ASTMF1554. ASTM F1554 Grade 105 anchorrods shall not be galvanized. No cleaningprocess shall be used that will introducehydrogen into steel.Replace thefollowing:1stparagraphwiththeFasteners for structural anchorage arecovered in a separate article so that otherrequirements for high-strength bolts are notapplied to anchor rods. The term anchorrods, which is used in these Specifications,is considered synonymous with the termanchor bolts which has been used.Galvanization of ASTM F1554 Grade 105anchor rods is not permitted due topotential hydrogen embrittlement. Theserods should be carefully evaluated beforeuse with applicable protective coatingsconforming to ASTM F1554 Specifications.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.6.1.2.5—Fatigue ResistanceReplace Table 6.6.1.2.5-2 with thefollowing:Table 6.6.1.2.5-2—Cycles per TruckPassage, n.Longitudinal MembersSimple Span Girders1.0Continuous Girders:1.5 (HL-93)1) near interior support6-52AC6.6.1.2.5Add a new last paragraph as follows:Cycles per Permit Truck (P9) passageare evaluated by the rainflow method. Thenumbers of cycles induced by Permit Truck(P9) passage are somewhat similar to thecycles induced by the HL-93 truck used forFatigue I Limit State.1.2 (P9)2) elsewhere1.0Cantilever Girders5.0Orthotropic Deck PlateConnections Subjected5.0to Wheel Load CyclingTrusses1.0Transverse MembersSpacing 20.0 ft1.0Spacing 20.0 ft2.0April 2019
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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.10.7.1.2—Nominal FlexuralResistance6-151AC6.10.7.1.2Replace Eq. 6.10.7.1.2-2 with thefollowing:Replace the 2nd paragraph with thefollowing:Dp- 0.1MyDtMn 1 - 1 MpMp0.32Eq. 10.7.1.2-2 defines the inelasticmoment resistance as a straight linebetween the ductility limits Dp/Dt 0.1 and0.42. It gives approximately the sameresults as the comparable equation inprevious Specifications, but is a simplerform that depends on the plastic momentresistance Mp, the yield moment resistanceMy, and the ratio Dp/Dt.(6.10.7.1.2-2)April 2019
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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.10.8.2.3—Lateral Torsional BucklingResistanceReplace Cb related Equations (6.10.8.2.36) and (6.10.8.2.3-7), and related symbolsas follows: For cantilevers where the free end isunbraced:Cb 1.0 (6.10.8.2.3-6)For all other cases:Cb 12.5 Mmax2.5 Mmax 3 MA 4 MB 3 MC(6.10.8.2.3-7)where:Mmax absolute value of maximummoment in the unbraced segment(kip-in.)MA absolute value of moment atquarter point of the unbracedsegment (kip-in.)MB absolute value of moment atcenterline of the unbracedsegment (kip-in.)MC absolute value of moment in threequarter point of the unbracedsegment (kip-in.) For reverse curvature bending:Rm 0.5 0.2 where:Iy,topIyIy,topIy 2(C6.10.8.2.3-3) moment of inertia of theflange above the geometric centroidof the section about an axis throughthe web (in.4) moment of inertia of the entiresection about an axis through theweb (in.4)6-160AC6.10.8.2.3Replace the 8th (Pages 6-159) to 16thparagraphs (Page 6-162) as follows:2Equation Cb 1.75 - 1.05 MM1 0.3 MM1 andf1f1 2f2f222have been usedin AISC Specification from 1961 to 1986,and in AASHTO LRFD Bridge DesignSpecifications since 1994, respectively.Those equations are only applicable tolinearly varying moment diagrams betweenthe braced points – a condition that is rarein bridge girder design. Those equationscan be easily misinterpreted andmisapplied to moment diagrams that arenot linear within the unbraced segment.AISC Specification (1993) and CaltransBDS (2004) have adopted Eq. (6.10.8.2.37) originally developed by Kirby andNethercot (1979) with slight modifications.Eq. (6.10.8.2.3-7) provides a moreaccurate solution for unbraced lengths inwhich the moment diagram deviatessubstantially from a straight line, such asthe case of a continuous bridge girder withno lateral bracing within the span,subjected to dead and live loads.Cb 1.75 - 1.05 0.3 Eq. (6.10.8.2.3-7) is applicable fordoubly symmetrical sections. For singlysymmetrical I-shaped sections, thefollowing expression developed by Heldwiget al. (1997) may be used:Cb 12.5 Mmax2.5 Mmax 3 MA 4 MB 3 MC Rm 3.0(C6.10.8.2.3-1)For single curvature bending:Rm 1.0(C6.10.8.2.3-2)April 2019
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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-176A6.10.10.4.2—Nominal Shear ForceReplace Eq. (6.10.10.4.2-8) with thefollowing:P2n Fyrs Ars(6.10.10.4.2-8)where:Ars total area of the longitudinalreinforcement within the effectiveconcrete deck width (in.2)Fyrs specified minimum yield strength oflongitudinal reinforcement within theeffective concrete deck width (ksi)April 2019
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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-177A6.10.11.1—Transverse Stiffeners6.10.11.1.1—GeneralReplace the 2nd paragraph with thefollowing:Stiffeners not used as connection platesshall be welded to the compression flangeand fitted tightly to the tension flange.Single-sided stiffeners on horizontallycurved girders shall be attached to bothflanges.Replace thefollowing:4thparagraphwiththeThe distance between the end of theweb-to-stiffener weld and the near edge ofthe adjacent web-to-flange or longitudinalstiffener-to-web weld shall not be less than4tw, nor more than 6tw. In no case shall thedistance exceed 4.0 in.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-177BThis page intentionally left blank.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-234A6.13—CONNECTIONS AND SPLICES6.13.1—GeneralReplace thefollowing:1stC6.13.1paragraphwiththeExcept as specified herein, connectionsand splices for primary members subjectonly to axial tension or compression shallbe designed at the strength limit state fornot less than 100 percent of the factoredaxial resistance of the member or element.Replace the 2nd paragraph with thefollowing:Connections and splices for primarymembers subjected to combined forceeffects, other than splices for flexuralmembers, shall be designed at the strengthlimit state for not less than 100 percent ofthe factored axial resistance of the memberdetermined as specified in Articles 6.8.2 or6.9.2, as applicable.Replace the 1st paragraph with thefollowing:For primary members subjected to forceeffects acting in multiple directions due tocombined loading, such as members inrigid frames, arches, and trusses, aclarification of the design requirements isprovidedhereinrelatedtothedetermination of the factored resistance ofthe member. Connections and splices forsuch members are to be designed for 100percent of the factored axial resistance ofthe member. The 100 percent resistancerequirement is retained to provide aminimum level of stiffness and to beconsistent with past practice for the designof connections and splices for axiallyloaded members.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-234BReplace the 4th paragraph of the articlewith the following:Where diaphragms, cross-frames,lateral bracing, stringers, or floorbeams forstraight or horizontally curved flexuralmembers which are non-primary membersare included in the structural model used todetermine force effects, or alternatively, aredesigned for explicitly calculated forceeffects from the results of a separateinvestigation, end connections for thesebracing members shall be designed for thecalculated factored member force effects.Otherwise, the end connections for thesemembers shall be designed for 75 percentof the factored resistance of the member.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.13.6.1.3b—Flange SplicesDelete the 3rd paragraph6-256AC6.13.6.1.3bDelete the 3rd and 4th paragraphsApril 2019
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SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.13.6.1.3c—Web Splices6-258AC6.13.6.1.3cReplace the 1st to 3rd paragraphs with thefollowing:Replace the 3rd to 4th paragraphs with thefollowing:As a minimum, web splice plates andtheir connections shall be designed at thestrength limit state for a design web forcetaken equal to the following two cases:Figure C6.13.6.1.3c-1 shows stressdistribution of web in the plastic momentstate. The portion of the flexural momentcarried by the web can be expressed by thecombination of a design moment, Muw, anda design horizontal force resultant, Huw,applied at the mid-depth of the web at thepoint of the splice. This horizontal forceresultant may be assumed distributedequally to all web bolts. Thesmallerfactoredshearresistance of the web at the point ofsplice determined according to theprovisions of Article 6.10.9 or 6.11.9,as applicable.The portion of the smaller totalfactored plastic moment carried bythe web.FywYPNAMuwyoMid-Depthof WebD/2FywHuwDFigure C6.13.6.1.3c-1—StressDistribution of Web at Plastic MomentStateMuw ϕftw Fyw4(D 2 - 4yo2 )(C6.13.6.1.3c-1)Huw ϕf (2tw yo Fyw )(C6.13.6.1.3c-2)If the plastic neutral axis is within the web,yo D2- Ȳ(C6.13.6.1.3c-3)Otherwise:yo D2April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-258Bwhere:tw web thickness (in.)D web depth (in.)Fyw specified minimum yield strength ofthe web at the point of splice (ksi)yo distance from the mid-depth of theweb to the plastic neutral axis (in.)̄Y distance from the plastic neutral axisto the top of the element where theplastic neutral axis is located (in.)φf resistancefactorforflexurespecified in Article 6.5.4.2April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.13.6.1.3c—Web SplicesReplace As a minimum, bolted connections forweb splices shall be checked for slip underLoad Combination Service II, as specifiedin Table 3.4.1-1, or due to the deck castingsequence, at the point of splice, whichevergoverns, for the following two cases: Shear. Portion of the moment carried bythe web.Add the following after the 4th paragraph:Figure C6.13.6.1.3c-2 shows flexuralstress distribution of web under LoadCombination Service II or due to deckcasting sequence. The portion of theflexural moment carried by the web can beexpressed by the combination of a designmoment, Muw, and a design horizontal forceresultant, Huw, applied at the mid-depth ofthe web at the point of the splice. Thishorizontal force resultant may be assumeddistributed equally to all web bolts.fosD/2Mid-Depthof WebMuwHuwD/2fsFigure C6.13.6.1.3c-2—StressDistribution of Web at FactoredMoment StateMuw Huw where:tw D212tw D2 fs - fos (fs fos )(C6.13.6.1.3c-4)(C6.13.6.1.3c-5)fs larger flexural stress at the innerfiberoftheflangeunderconsideration for the smaller sectionat the point of splice (positive fortensionandnegativeforcompression) (ksi)April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6-259Bfos flexural stress at the inner fiber ofthe other flange of the smallersection at the point of spliceconcurrent with fs (positive fortensionandnegativeforcompression) (ksi)Flexural stress, fs and fos are to becomputed considering the application ofthe moments due to the appropriatefactored loadings to the respective crosssections supporting those loadings.April 2019
SECTION 6: STEEL STRUCTURESCALIFORNIA AMENDMENTS TO AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS – 8TH EDITION6.13.6.2—Welded Splices6-261AC6.13.6.2Add the following as the 2nd paragraph:Unnecessary field splices should beavoided. Welded field splices are subject toless control over the welding conditions and
F1554. ASTM F1554 Grade 105 anchor rods shall not be galvanized. No cleaning process shall be used that will introduce hydrogen into steel. C6.4.3.3.1 Replace the 1 st paragraph with the following: Fasteners for structural anchorage are covered in a separate article so that other requirements for high- strength bolts are not applied to anchor rods. The term anchor rods, which is used in these .
