AISC LRFD 1.pdf

126 DESIGN FOR CYCLIC LOADING (FATIGUE) [App. K3.DescriptionTABLE A-K3.1Fatigue Design ParametersStressCategoryConstantC fThresholdF THksi(MPa)SECTION 1 – PLAIN MATERIAL AWAY FROM ANY WELDING1.1 Base metal, except non-coatedweathering steel, with rolled or cleanedsurface. Flame-cut edges with surfaceroughness value of 1,000 in. (25 m)or less, but without re-entrant corners.A 250 x 10 8 24(165)Potential CrackInitiation PointAway from allwelds or structuralconnections1.2 Non-coated weathering steel basemetal with rolled or cleaned surface.Flame-cut edges with surfaceroughness value of 1,000 in. (25 m)or less, but without re-entrant corners.B 120 x 10 8 16(110)Away from allwelds or structuralconnections1.3 Member with drilled or reamedholes. Member with re-entrant cornersat copes, cuts, block-outs or othergeometrical discontinuities made torequirements of Appendix K3.5, exceptweld access holes.B 120 x 10 8 16(110)At any externaledge or at holeperimeter1.4 Rolled cross sections with weldaccess holes made to requirements ofSection J1.6 and Appendix K3.5.Members with drilled or reamed holescontaining bolts for attachment of lightbracing where there is a smalllongitudinal component of brace force.C 44 x 10 8 10(69)At re-entrantcorner of weldaccess hole orat any small hole(may containbolt for minorconnections)SECTION 2 – CONNECTED MATERIAL IN MECHANICALLY FASTENED JOINTS2.1 Gross area of base metal in lapjoints connected by high-strength boltsin joints satisfying all requirements forslip-critical connections.B 120 x 10 8 16(110)Through grosssection nearhole2.2 Base metal at net section ofhigh-strength bolted joints, designed onthe basis of bearing resistance, butfabricated and installed to all requirementsfor slip-critical connections.B 120 x 10 8 16(110)In net sectionoriginating atside of hole2.3 Base metal at the net section ofother mechanically fastened jointsexcept eye bars and pin plates.D 22 x 10 8 7(48)In net sectionoriginating atside of hole2.4 Base metal at net section ofeyebar head or pin plate.E 11 x 10 8 4.5(31)In net sectionoriginating atside of holeLRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION