AISC LRFD 1.pdf

130 DESIGN FOR CYCLIC LOADING (FATIGUE) [App. K3.DescriptionTABLE A-K3.1 (Cont’d)Fatigue Design ParametersStressCategoryConstantC fThresholdF THksi(MPa)SECTION 5 – WELDED JOINTS TRANSVERSE TO DIRECTION OF STRESS5.1 Base metal and weld metal in oradjacent to complete joint penetrationgroove welded splices in rolled orwelded cross sections with weldsground essentially parallel to thedirection of stress.B 120 x 10 8 16(110)PotentialCrackInitiation PointFrom internaldiscontinuitiesin filler metal oralong thefusionboundary5.2 Base metal and weld metal in oradjacent to complete joint penetrationgroove welded splices with weldsground essentially parallel to thedirection of stress at transitions inthickness or width made on a slope nogreater than 8 to 20%.F y< 90 ksi (620 MPa)F y 90 ksi (620 MPa)5.3 Base metal with F yequal to orgreater than 90 ksi (620 MPa) andweld metal in or adjacent to completejoint penetration groove welded spliceswith welds ground essentially parallelto the direction of stress at transitionsin width made on a radius of not lessthan 2 ft. (600 mm) with the point oftangency at the end of the grooveweld.5.4 Base metal and weld metal in oradjacent to the toe of complete jointpenetration T or corner joints orsplices, with or without transitions inthickness having slopes no greaterthan 8 to 20%, when weld reinforcementis not removed.BB120 x 10 816(110)61 x 10 8 12(83)B 120 x 10 8 16(110)C 44 x 10 8 10(69)From internaldiscontinuitiesin filler metal oralong fusionboundary or atstart of transitionwhen F y 90 ksi (620MPa)From internaldiscontinuitiesin filler metal ordiscontinuitiesalong thefusionboundaryFrom surfacediscontinuity attoe of weldextending intobase metal oralong fusionboundary.5.5 Base metal and weld metal attransverse end connections of tension-loadedplate elements using partialjoint penetration butt or T or cornerjoints, with reinforcing or contouringfillets, F SRshall be the smaller of thetoe crack or root crack stress range.Crack initiating from weld toe:Crack initiating from weld root:CC44 x 10 8Eqn. A-K3.3or A-K3.3M10(69)NoneprovidedInitiating fromgeometricaldiscontinuity attoe of weldextending intobase metal or,initiating atweld root subjectto tensionextending upand then outthrough weldLRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION