AISC LRFD 1.pdf

128 DESIGN FOR CYCLIC LOADING (FATIGUE) [App. K3.DescriptionTABLE A-K3.1 (Cont’d)Fatigue Design ParametersStressCategoryConstantC fThresholdF THksi(MPa)Potential CrackInitiation PointSECTION 3 – WELDED JOINTS JOINING COMPONENTS OF BUILT-UP MEMBERS3.1 Base metal and weld metal inmembers without attachments built-upof plates or shapes connected bycontinuous longitudinal complete-jointpenetrationgroove welds, back gougedand welded from second side, or bycontinuous fillet welds.3.2 Base metal and weld metal inmembers without attachments built-upof plates or shapes, connected bycontinuous longitudinal completepenetration groove welds with backingbars not removed, or by continuouspartial-joint-penetration groove welds.3.3 Base metal and weld metaltermination of longitudinal welds at weldaccess holes in connected built-upmembers.B 120 x 10 8 16(110)B 61 x 10 8 12(83)D 22 x 10 8 7(48)From surface orinternaldiscontinuities inweld away fromend of weldFrom surface orinternaldiscontinuities inweld, includingweld attachingbacking barsFrom the weldtermination intothe web or flange3.4 Base metal at ends of longitudinalintermittent fillet weld segments.3.5 Base metal at ends of partial lengthwelded coverplates narrower than theflange having square or tapered ends,with or without welds across the ends ofcoverplates wider than the flange withwelds across the ends.Flange thickness 0.8 in. (20 mm)Flange thickness > 0.8 in. (20 mm)3.6 Base metal at ends of partial lengthwelded coverplates wider than theflange without welds across the ends.E 11 x 10 8 4.5(31)EE11 x 10 8 4.5(31)3.9 x 10 8 2.6(18)E 3.9 x 10 8 2.6(18)In connectedmaterial at startand stop locationsof any welddepositIn flange at toeof end weld or inflange attermination oflongitudinal weldor in edge offlange with widecoverplatesIn edge of flangeat end ofcoverplate weldSECTION 4 – LONGITUDINAL FILLET WELDED END CONNECTIONS4.1 Base metal at junction of axiallyloaded members with longitudinallywelded end connections. Welds shall beon each side of the axis of the memberto balance weld stresses.t 1 2-in. (13 mm)t > 1 2-in. (13 mm)EE11 x 10 8 4.5(31)3.9 x 10 8 2.6(18)Initiating fromend of any weldterminationextending intothe base metalLRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION