AASHTO LRFD Bridge Design Specifications, 6th Edition .
Kirk T. Steudle, P.E., PresidentDirector, Michigan Department of TransportationJohn Horsley, Executive Director444 North Capitol Street NW, Suite 249, Washington, DC 20001(202) 624-5800 Fax: (202) 624-5806 www.transportation.orgERRATAJune 2012Dear Customer:Recently, we were made aware of some technical revisions that need to be applied to the AASHTO LRFDBridge Design Specifications, 6th Edition.Please replace the existing text with the corrected text to ensure that your edition is both accurate andcurrent.AASHTO staff sincerely apologizes for any inconvenience. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPageExisting TextCorrected TextSection 33-13The last row of Table 3.4.1-1, column 1, reads“Fatigue I II”Change “Fatigue I II” to “Fatigue II”.Eq. C4.6.2.5-3 reads:Revise denominator to read: E I Σ c c LG c Eg I c Σ Lg E I Σ c c LG c Eg I g Σ Lg 4-60through4-61Article includes the following extra content:Table 4.6.2.6.4-1, Figure 4.6.2.6.4-1, fourspecification paragraphs, and two commentaryparagraphs.In Article 4.6.2.6.4, delete the table, figure and lastfour paragraphs in the Article. In the commentaryto Article 4.6.2.6.4, delete the last two paragraphs.4-70In Article 4.6.3.2.4, the second sentence of thefirst paragraph reads “The structural model shouldinclude all components and connections andconsider local structural stress at fatigue pronedetails as shown in Table 6.6.1.2.3-3.”Change table number from “6.6.1.2.3-3” to“6.6.1.2.3-1”.In Article C4.6.3.2.4, FHWA citation is shown aspending.Update to “2012”.FHWA (2012) is cited (see above) but thereference is missing from Article 4.9.Add the following reference:The first bullet in Article 5.5.4.2.1 reads:Delete bullet.Section 44-514-93FHWA. 2012. Manual for Design, Construction,and Maintenance of Orthotropic Steel Bridges.Federal Highways Administration, U.S.Department of Transportation, Washington, DC.Section 55-26 For shear and torsion:normal weight concrete . 0.90lightweight concrete .0.805-39The fourth bullet reads:Change second value so bullet reads: For shear and torsion:normal weight concrete . 0.90lightweight concrete .0.70 For shear and torsion:normal weight concrete . 0.90lightweight concrete .0.80In Eqs. 5.7.3.1.1-3 and 5.7.3.1.1-4, the subscriptin “ β1 ” runs into the next variable in theexpression.Reformat the subscript so that it isn’t overlooked. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPage5-46Existing TextThe second to last paragraph of Article 5.7.3.4reads:The maximum spacing of the skin reinforcementshall not exceed either de /6 or 12.0 in.Corrected TextCorrect subscript from “e” to “ℓ” to read:The maximum spacing of the skin reinforcementshall not exceed either dℓ /6 or 12.0 in.5-80through5-82Most equations in Article 5.8.4.2 have the “ ”symbol.Reset in standard algebraic notation.5-81Eq. 5.8.4.2-2 reads:Revise to read:Vui vui Acv vui 12bvVui vui Acv vui 12bvi5-84The second bullet of Article 5.8.4.4 includes thephrase “ provisions of Article 5.8.1.1 is ”Revise the article number to read “ provisions ofArticle 5.8.2.5 is ”5-108Eq. 5.9.5.4.3b-1 reads:Revise flat bracket placement to read:Δf pCD 5-121Epf ψ t , t ψb ( td , ti ) K df Eci cgp b f iEp Δf ψ t , t KEc cd b f d df()Eq. C5.10.8-1 reads:As 1.3 AgPerimeter ( fy )Δf pCD Epf ψ t , t ψb ( td , ti ) K df Eci cgp b f iEp Δf ψ t , t KEc cd b f d df()Format the “Format the “y” as a subscript to read:As 1.3 AgPerimeter(f )ySection 66-326-346-34 and6-45In Article 6.6.1.2.1, the second sentence of thethird paragraph reads:Revise to read:In regions where the unfactored permanent loadsproduce compression, fatigue shall be consideredonly if the compressive stress is less than twicethe maximum tensile live load stress resultingfrom the fatigue load combination specified inTable 3.4.1-1.In regions where the unfactored permanent loadsproduce compression, fatigue shall be consideredonly if the compressive stress is less than themaximum live load tensile stress caused by theFatigue I load combination specified inTable 3.4.1-1.In Article 6.6.1.2.3, a paragraph after the secondparagraph is missing.Insert the following:Last paragraph of C6.6.1.2.3 is misplaced.Move paragraph just after the fifth paragraph.For components and details on fracture-criticalmembers, the Fatigue I load combination specifiedin Table 3.4.1-1 should be used in combinationwith the nominal fatigue resistance for infinite lifespecified in Article 6.6.1.2.5. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPageExisting TextCorrected Text6-35through6-36In Table 6.6.1.2.3-1, the descriptions forConditions 2.1 through 2.3 are incomplete.Add the following to the condition descriptions:6-36In Table 6.6.1.2.3-1, Condition 2.5 is missing.Add Condition 2.5.6-42In Table 6.6.1.2.3-1, the description forCondition 7.1 is incomplete.Add the following to the condition description:In Table 6.6.1.2.3-1, Condition 7.2 is missing.Add Condition 7.2.6-43through6-44In Table 6.6.1.2.3-1, the figures forConditions 8.1 through 8.9 display “Δσ”.Replace with figures that display “Δf”.6-46through6-47Table 6.6.1.2.3-3 is redundant.Delete table.6-93In the where list for Eq. 6.9.4.2.2-9, the definitionof Aeff ends with “ ( b be ) t ”.Revise the definition for Aeff as follows:(Note: see Condition 2.5 for bolted angle or teesection member connections to gusset orconnection plates.)(Note: see Condition 7.2 for welded angle or teesection member connections to gusset orconnection plates.)summation of the effective areas of the crosssection based on a reduced effective width foreach slender stiffened element in the cross-sectionA ( b be ) t (in.2)6-95In the open-circle bullet immediately above 80 ” is tooEq. 6.9.4.4-1, the expression “rxsmall.6-108The last sentence of the first paragraph ofArticle 6.10.1.7 reads as follows:Reword to read:The reinforcement used to satisfy this requirementshall have a specified minimum yield strength notless than 60.0 ksi and a size not exceeding No. 6bars.The reinforcement used to satisfy this requirementshall have a specified minimum yield strength notless than 60.0 ksi; the size of the reinforcementshould not exceed No. 6 bars.The last sentence of the second paragraph ofArticle 6.10.1.7 reads as follows:Reword to read:The individual bars shall be spaced at intervalsnot exceeding 12.0 in.The individual bars should be spaced at intervalsnot exceeding 12.0 in.6-109Remove the subscripting of “ 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law. 80 ”.rx
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPage6-134through6-140Existing TextCorrected TextThe last sentence of the third paragraph ofArticle C6.10.6.2.3 reads as follows:Revise the sentence and add to the end of theparagraph to read as follows:Research has not yet been conducted to extend theprovisions of Appendix A6.Research has not yet been conducted to extend theprovisions of Appendix A6 either to sections inkinked (chorded) continuous or horizontallycurved steel bridges or to bridges with supportsskewed more than 20 degrees from normal.Severely skewed bridges with contiguous crossframes have significant transverse stiffness andthus already have large cross-frame forces in theelastic range. As interior-pier sections yield andbegin to lose stiffness and shed their load, theforces in the adjacent cross-frames will increase.There is currently no established procedure topredict the resulting increase in the forces withoutperforming a refined nonlinear analysis. Withdiscontinuous cross-frames, significant lateralflange bending effects can occur. The resultinglateral bending moments and stresses areamplified in the bottom compression flangeadjacent to the pier as the flange deflects laterally.There is currently no means to accurately predictthese amplification effects as the flange is alsoyielding. Skewed supports also result in twistingof the girders, which is not recognized in plasticdesign theory. The relative vertical deflections ofthe girders create eccentricities that are also notrecognized in the theory. Thus, until furtherresearch is done to examine these effects in greaterdetail, a conservative approach has been taken inthe specification.6-174The text immediately under the where list forEq. 6.11.1.1-1 is shown as a new paragraph ratherthan a continuation.Remove the indent at the beginning of theparagraph immediately under the where list forEq. 6.11.1.1-1.6-183The text immediately under the bullet items inArticle 6.11.5 is shown as a new paragraph ratherthan a continuation.Remove the indent at the beginning of theparagraph immediately under the bullet items inArticle 6.11.5.The third sentence of the text immediately underthe bullet items in Article 6.11.5 is incomplete.Reword to read:In Article 6.11.8.2.2, the first paragraph reads:Add variable to read:The nominal flexural resistance of thecompression flange shall be taken as:The nominal flexural resistance of thecompression flange, Fnc, shall be taken as:6-190The allowables specified for nonredundantmembers are arbitarily reduced from thosespecified for redundant members due to the moresevere consequences of failure of a nonredundantmember. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPage6-191Existing TextEq. 6.11.8.2.2-1 reads:Fnc φ f Fcb f 1 v φv Fcv Corrected TextRemove “φf” just after equal sign to read:2Fnc Fcb f 1 v φv Fcv 2In Article 6.11.8.2.2, the variable descriptionunder “in which” reads:Add missing phrase to read:Fcb nominal axial compression bucklingresistance of the flange calculated asfollows:Fcb nominal axial compression bucklingresistance of the flange under compressionalone calculated as follows:Eq. 6.11.8.2.2-3 reads:Replace “1” with “Δ” in two places to read: Δ 0.3 λ f λ p Fcb Rb Rh Fyc 1 1 Rh λ r λ p Fcb Rb Rh F yc Δ The variable description followingEq. 6.11.8.2.2-4 reads:Add missing phrase to read:Fcv nominal shear buckling resistance of theflange calculated as follows:Fcv nominal shear buckling resistance of theflange under shear alone calculated asfollows:In the second paragraph of Article C6.11.8.2.2,the sentence following Eq. C6.11.8.2.2-1 reads asfollows:Revise to show the complete equation number asfollows:Rearranging Eq. C6.11.8.2.2-1 in terms of fc andsubstituting Fnc for fc facilitates the definition ofthe nominal flexural resistance of the compressionflange as provided in Eq. 6.11.8.2.2.Rearranging Eq. C6.11.8.2.2-1 in terms of fc andsubstituting Fnc for fc facilitates the definition ofthe nominal flexural resistance of the compressionflange as provided in Eq. 6.11.8.2.2-1.In Article C6.11.8.2.2, the first sentence of thethird paragraph reads as follows:Revise to include omitted phrase as follows:The nominal axial compression buckling resistanceof the flange, Fcb, is defined for three distinctregions based on the slenderness of the flange.The nominal axial compression bucklingresistance of the flange under compression alone,Fcb, is defined for three distinct regions based onthe slenderness of the flange. Δ 0.3 λ f λ p Δ Rh λ r λ p 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPage6-191(cont’d.)6-1926-202Existing TextCorrected TextIn Article C6.11.8.2.2, the fifth paragraph reads:Revise to include omitted phrase as follows:The equations for the nominal shear bucklingresistance of the flange, Fcv, are determined fromthe equations for the constant, C, given inArticle 6.10.9.3.2, where C is the ratio of theshear buckling resistance to the shear yieldstrength of the flange taken as Fyc / 3 .The equations for the nominal shear bucklingresistance of the flange under shear alone, Fcv, aredetermined from the equations for the constant, C,given in Article 6.10.9.3.2, where C is the ratio ofthe shear buckling resistance to the shear yieldstrength of the flange taken as Fyc / 3 .Eq. 6.11.8.2.2-13 reads:Revise to read:( Δ 0.3 ) Fyc Fyw( Δ 0.3 ) FycIn Eq. 6.12.2.2.1-4, there is an extra zero in thefirst term of equation, reading “0.038”.Delete zero to right of decimal point to read“0.38”.In the where list for Eq. 6.12.2.2.2-1, there areseparate definitions for b and t instead of one forb/t.Replace definitions for b and t with the following:b/t width of any flange or depth of any webcomponent divided by its thicknessneglecting any portions of flanges orwebs that overhang the box perimeter6-225First paragraph of Article 6.13.2.10.3 is notindented.Indent paragraph.6-263The second FHWA reference reads as follows:Revise year and title to read:FHWA. 2011. Manual for Design, Construction,and Maintenance of Orthotropic Steel Bridges.Federal Highway Administration, U.S.Department of Transportation, Washington, DC.FHWA. 2012. Manual for Design, Construction,and Maintenance of Orthotropic Steel DeckBridges. Federal Highway Administration, U.S.Department of Transportation, Washington, DC.6-304In Figure C6.4.5-1, the decision branch on the rightside involving “Shored Construction” is incorrect.Replace with a singular box in flowchart reading“Concrete compressive stress 0.6f c”.6-315The figure immediately below Table D6.1-2 isincorrect.Replace figure.Articles 9.8.3.6 and 9.8.3.7 need revisions.After moving three paragraphs of Article C9.8.3.6to Article C9.8.3.7, delete the rest of Article9.8.3.6, renumber Article 9.8.3.7 as 9.8.3.6, andrenumber object references and article crossreferences as needed.Section 99-26through9-30 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionPage9-28Existing TextCorrected TextArticle 9.8.3.6.4, item d reads:Revise to read:Combined fillet-groove welds may have to beused in cases where the required size of filletwelds to satisfy the fatigue resistancerequirements would be excessive, if used alone.Combined fillet-groove welds may have to be used1) in cases where the required size of fillet weldsto satisfy the fatigue resistance requirementswould be excessive if used alone or 2) toaccomplish a ground termination.Eq. 12.12.2.2-2 is missing parentheses.Revise to read:9-44Section 1212-72Δt 12-74Eq. 12.12.3.5-1 is missing parentheses.()K B DL Psp CL PL Do(31000 E p I p R 0.061 M s) ε sc DRevise to read:(Pu ηEV γ EV K γE K 2VAF P sp γWA P w ηLL γ LL P L C L12-80Eq. 12.12.3.9-1 is missing parentheses.Revise to read:PL 12-83Eq. 12.12.3.10.1e-2 is missing parentheses.)P (1 IM /100 ) m[ L0 (12 H K 1) LLDF ][W0 (12 H K1 ) LLDF ]Revise to read:εbck (1.2Cn E p I pAeff E p)132 φ M (1 2ν ) 3 s s Rh2 (1 ν ) 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionSECTION 3: LOADS AND LOAD FACTORS3-13The load factor for settlement, γSE, should beconsidered on a project-specific basis. In lieu of projectspecific information to the contrary, γSE, may be taken as1.0. Load combinations which include settlement shall alsobe applied without settlement.For segmentally constructed bridges, the followingcombination shall be investigated at the service limit state:DC DW EH EV ES WA CR SH TG EL PS(3.4.1-2)Table 3.4.1-1—Load Combinations and Load FactorsUse One of These at a ————Strength IVStrength tremeEvent IExtremeEvent IIService ��———Service IIService IIIService LoadCombinationLimit StateStrength I(unless noted)Strength IIStrength IIIFatigue I—LL, IM & CEonlyFatigue II—LL, IM & CEonly 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth Edition3-14AASHTO LRFD BRIDGE DESIGN SPECIFICATIONSTable 3.4.1-2—Load Factors for Permanent Loads, γpLoad FactorMaximumMinimumType of Load, Foundation Type, andMethod Used to Calculate DowndragDC: Component and AttachmentsDC: Strength IV onlyDD: DowndragPiles, α Tomlinson MethodPiles, λ MethodDrilled shafts, O’Neill and Reese (1999) MethodDW: Wearing Surfaces and UtilitiesEH: Horizontal Earth Pressure Active At-Rest AEP for anchored wallsEL: Locked-in Construction StressesEV: Vertical Earth Pressure Overall Stability Retaining Walls and Abutments Rigid Buried Structure Rigid Frames Flexible Buried Structureso Metal Box Culverts and Structural Plate Culverts with Deep Corrugationso Thermoplastic culvertso All othersES: Earth .35N/A1.000.900.901.51.31.950.90.90.91.500.75Table 3.4.1-3—Load Factors for Permanent Loads Due to Superimposed Deformations, γpPS1.0CR, SHSee γP for DC, Table 3.4.1-21.01.0Substructures supporting non-segmental Superstructures using Ig using Ieffectuve0.51.00.51.0Steel Substructures1.01.0Bridge ComponentSuperstructures—SegmentalConcrete Substructures supporting SegmentalSuperstructures (see 3.12.4, 3.12.5)Concrete Superstructures—non-segmental 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionSECTION 4: STRUCTURAL ANALYSIS AND EVALUATION4-51For unbraced frames:2 π Ga Gb 36 K 6 (Ga Gb )πK π tan K (C4.6.2.5-2)where subscripts a and b refer to the two ends of thecolumn under considerationin which: E I Σ c c LG c Eg I g Σ Lg (C4.6.2.5-3)where:Σ EcIcLcEg Ig Lg K summation of the properties of componentsrigidly connected to an end of the column in theplane of flexuremodulus of elasticity of column (ksi)moment of inertia of column (in.4)unbraced length of column (in.)modulus of elasticity of beam or otherrestraining member (ksi)moment of inertia of beam or other restrainingmember (in.4)unsupported length of beam or other restrainingmember (in.)effective length factor for the column underconsiderationFigures C4.6.2.5-1 and C4.6.2.5-2 are graphicalrepresentations of the relationship among K, Ga, and Gbfor Eqs. C4.6.2.5-1 and C4.6.2.5-2, respectively. Thefigures can be used to obtain values of K directly.Eqs. C4.6.2.5-1, C4.6.2.5-2, and the alignmentcharts in Figures C4.6.2.5-1 and C4.6.2.5-2 are based onassumptions of idealized conditions. The developmentof the chart and formula can be found in textbooks suchas Salmon and Johnson (1990) and Chen and Lui(1991). When actual conditions differ significantly fromthese idealized assumptions, unrealistic designs mayresult. Galambos (1988), Yura (1971), Disque (1973),Duan and Chen (1988), and AISC (1993) may be usedto evaluate end conditions more accurately. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth Edition4-52AASHTO LRFD BRIDGE DESIGN SPECIFICATIONSFigure C4.6.2.5-1—Alignment Chart for DeterminingEffective Length Factor, K, for Braced FramesFigure C4.6.2.5-2—Alignment Chart for DeterminingEffective Length Factor, K, for Unbraced Frames 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionSECTION 4: STRUCTURAL ANALYSIS AND EVALUATION4-59Figure 4.6.2.6.2-4—Effective Flange Widths, bn, for NormalForces4.6.2.6.3—Cast-in-Place Multicell SuperstructuresThe effective width for cast-in-place multiwebcellular superstructures may be taken to be as specifiedin Article 4.6.2.6.1, with each web taken to be a beam,or it may be taken to be the full width of the deck slab.In the latter case, the effects of shear lag in the endzones shall be investigated.4.6.2.6.4—Orthotropic Steel DecksThe effective width need not be determined whenusing refined analysis as specified in Article 4.6.3.2.4.For simplified analysis, the effective width of the deck,including the deck plate and ribs, acting as the top flangeof a longitudinal superstructure component or atransverse beam may be taken as: L/B 5: fully effective 1L/B 5: bod L5where:L B bod span length of the orthotropic girder ortransverse beam (in.)spacing between orthotropic girder web platesor transverse beams (in.)effective width of orthotropic deck (in.)C4.6.2.6.4Consideration of effective width of the deck platecan be avoided by application of refined analysismethods.The procedures in Design Manual for OrthotropicSteel Plate Deck Bridges (AISC, 1963) may be used asan acceptable means of simplified analysis; however, ithas been demonstrated that using this procedure canresult in rib effective widths exceeding the rib spacing,which may be unconservative.Tests (Dowling et al., 1977) have shown that formost practical cases, shear lag can be ignored incalculating the ultimate compressive strength ofstiffened or unstiffened girder flanges (Lamas andDowling, 1980; Burgan and Dowling, 1985; Jetteur etal., 1984; and Hindi, 1991). Thus, a flange maynormally be considered to be loaded uniformly across itswidth. It necessary to consider the flange effectivenessin greater detail only in the case of flanges withparticularly large aspect ratios (L/B 5) or particularlyslender edge panels or stiffeners (Burgan and Dowling,1985 and Hindi, 1991) is it necessary to consider theflange effectiveness in greater detail.Consideration of inelastic behavior can increase theeffective width as compared to elastic analysis. At 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth Edition4-60AASHTO LRFD BRIDGE DESIGN SPECIFICATIONSfor strength limit states for positive and negative flexure.For service and fatigue limit states in regions of highshear, the effective deck width can be determined byrefined analysis or other accepted approximate methods.4.6.2.6.5—Transverse Floorbeams and IntegralBent CapsFor transverse floorbeams and for integral bent capsdesigned with a composite concrete deck slab, the effectiveflange width overhanging each side of the transversefloorbeam or bent cap web shall not exceed six times theleast slab thickness or one-tenth of the span length. Forcantilevered transverse floorbeams or integral bent caps, thespan length shall be taken as two times the length of thecantilever span.ultimate loading, the region of the flange plate above theweb can yield and spread the plasticity (and distributestress) outward if the plate maintains local stability.Results from studies by Chen et al. (2005) on compositesteel girders, which included several tub-girder bridges,indicate that the full slab width may be consideredeffective in both positive and negative moment regions.Thus, orthotropic plates acting as flanges areconsidered fully effective for strength limit stateevaluations from positive and negative flexure when theL/B ratio is at least 5. For the case of L/B 5, only awidth of one-fifth of the effective span should beconsidered effective. For service and fatigue limit statesin regions of high shear, a special investigation intoshear lag should be done.C4.6.2.6.5The provisions for the effective flange width fortransverse floorbeams and integral bent caps are basedon past successful practice, specified by Article 8.10.1.4of the 2002 AASHTO Standard Specifications.[This space is intentionally left blank. —ed.] 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionSECTION 4: STRUCTURAL ANALYSIS AND EVALUATION[This page is intentionally left blank. —ed.] 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.4-61
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth Edition4-62AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS4.6.2.7—Lateral Wind Load Distribution inMultibeam Bridges4.6.2.7.1—I-SectionsC4.6.2.7.1In bridges with composite decks, noncomposite deckswith concrete haunches, and other decks that can providehorizontal diaphragm action, wind load on the upper half ofthe outside beam, the deck, vehicles, barriers, andappurtenances shall be assumed to be directly transmitted tothe deck, acting as a lateral diaphragm carrying this load tosupports. Wind load on the lower half of the outside beamshall be assumed to be applied laterally to the lower flange.For bridges with decks that cannot provide horizontaldiaphragm action, the lever rule shall apply for distributionof the wind load to the top and bottom flanges.Bottom and top flanges subjected to lateral wind loadshall be assumed to carry that load to adjacent brace pointsby flexural action. Such brace points occur at wind bracingnodes or at cross-frames and diaphragm locations.The lateral forces applied at brace points by theflanges shall be transmitted to the supports by one of thefollowing load paths: Truss action of horizontal wind bracing in the planeof the flange; Frame action of the cross-frames or diaphragmstransmitting the forces into the deck or the windbracing in the plane of the other flange, and then bydiaphragm action of the deck, or truss action of thewind bracing, to the supports; Lateral bending of the flange subjected to the lateralforces and all other flanges in the same plane,transmitting the forces to the ends of the span, forexample, where the deck cannot provide horizontaldiaphragm action, and there is no wind bracing in theplane of either flange.Precast concrete plank decks and timber decks arenot solid diaphragms and should not be assumed toprovide horizontal diaphragm action unless evidence isavailable to show otherwise.Unless a more refined analysis is made, thewind force, wind moment, horizontal force to betransmitted by diaphragms and cross-frames, andhorizontal force to be transmitted by lateral bracingmay be calculated as indicated below. Thisprocedure is presented for beam bridges but may beadapted for other types of bridges.The wind force, W, may be applied to the flanges ofexterior members. For composite members andnoncomposite members with cast-in-place concrete ororthotropic steel decks, W need not be applied to the topflange.W ηi γPD d2(C4.6.2.7.1-1)where:W factored wind force per unit length applied tothe flange (kip/ft)design horizontal wind pressure specified inArticle 3.8.1 (ksf)depth of the member (ft)load factor specified in Table 3.4.1-1 for theparticular group loading combinationload modifier relating to ductility, redundancy, andoperational importance as specified in Article 1.3.2.1PD dγ ηi For the first two load paths, the maximum wind momenton the loaded flange may be determined as:Mw WLb 210(C4.6.2.7.1-2)where:Mw maximum lateral moment in the flange due tothe factored wind loading (kip-ft)factored wind force per unit length applied tothe flange (kip/ft)spacing of brace points (ft)W Lb For the third load path, the maximum wind momenton the loaded flange may be computed as:Mw WLb 2 WL2 108 Nb(C4.6.2.7.1-3)where:Mw total lateral moment in the flange due to thefactored wind loading (kip-ft) 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
LRFDUS-6-E1: June 2012 Errata to LRFD Design, Sixth EditionSECTION 4: STRUCTURAL ANALYSIS AND EVALUATIONA structurally continuous railing, barrier, or median,acting compositely with the supporting components,may be considered to be structurally active at serviceand fatigue limit states.When a refined method of analysis is used, a tableof live load distribution coefficients for extreme forceeffects in each span shall be provided in the contractdocuments to aid in permit issuance and rating of thebridge.4-69 The longitudinal location of the design vehicularlive load in each lane, The longitudinal axle spacing of the designvehicular live load, The transverse location of the design vehicular liveload in each lane.This provision reflects the experimentally observedresponse of bridges. This source of stiffness hastraditionally been neglected but exists and may beincluded, provided that full composite behavior isassured.These live
Recently, we were made aware of some technical revisions that need to be applied to the AASHTO LRFD Bridge Design Specifications, 6th Edition. Please replace the existing text with the corrected text to ensure that your edition is both accurate and current. AASHTO staff sincerely apologizes for any inconvenience.File Size: 2MBPage Count: 104Explore furtherAASHTO LRFD 2012 Bridge Design Specifications 6th Ed ( US .archive.orgAASHTO Issues Updated LRFD Bridge Design Guideaashtojournal.orgAASHTO Publishes New Manual for Bridge Element Inspection .aashtojournal.orgAASHTO LRFD Bridge Design Specifications. Eighth Edition .trid.trb.orgSteel Bridge Design Handbook American Institute of Steel .www.aisc.orgRecommended to you b
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AASHTO LRFD Bridge Design Specifications, 7th Edition, 2014 (AASHTO LRFD) v. AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals, First Edition, 2015 (AASHTO Signs) vi. Washington State Department of Transportation Bridge Design Manual (LRFD), 2016 (BDM) vii. American Institute of Steel .
AASHTO LRFD Bridge Design Specifications, 8th Edition (LRFD-8) May 2018 . Dear Customer: Recently, we were made aware of some technical revisions that need to be applied to the AASHTO LRFD Bridge Design Specifications, 8th Edition. Please scroll down to see the full erratum.File Size: 2MB
Sep 05, 2021 · Development of the LRFD Specifications. LRFD Specifications were adopted by AASHTO in 1996 Period of transition – Two specifications were in use – AASHTO did not eliminate the Standard Specifications – Most States continued to use the Standard Specifications in early 2000s Maintain
bridge structures using the AASHTO Standard Specifications for Highway Bridges, and it is expected that TxDOT will make transition to the use of the AASHTO LRFD Bridge Design Specifications before 2007. The objectives of this portion of the study are to evaluate the current LRFD Specifica
Detailed design examples for an AASHTO Type IV girder and a Texas U54 girder using both the AASHTO Standard Specifications and AASHTO LRFD Specifications were also developed and compared. Volume 2 of this re port contains these examples. 17. Key Words Prestressed Concrete, LRFD, Design, Bridge Girders, U54
Cambridge IGCSE and O Level Accounting 1.4 The statement of financial position The accounting equation may be shown in the form of a statement of financial posi
