AISC LRFD 1.pdf

70 BEARING STRENGTH [Sect. J8.If d 25 in. (635 mm),R n = 1.2(F y – 13)ld / 20(Metric: R n = 1.2(F y –90)ld / 20)(J8-2)(J8-2M)If d >25 in. (635 mm),R = 6.0( F −13) l d / 20ny(J8-3)(Metric : R = 6.0( F −90) l d / 20)ny(J8-3M)whered = diameter, in. (mm)l = length of bearing, in. (mm)J9. COLUMN BASES AND BEARING ON CONCRETEProper provision shall be made to transfer the column loads and moments to thefootings and foundations.In the absence of code regulations, design bearing loads on concrete may be takenas c P p :(a) On the full area of a concrete supportP p = 0.85f c A 1(J9-1)(b) On less than the full area of a concrete supportP = 0.85 f′A A / Apc1 2 1(J9-2)where c = 0.60A 1 = area of steel concentrically bearing on a concrete support, in. 2 (mm 2 )A 2 = maximum area of the portion of the supporting surface that is geometricallysimilar to and concentric with the loaded area, in. 2 (mm 2 )A / A ≤2 1 2J10. ANCHOR RODS AND EMBEDMENTSSteel anchor rods and embedments shall be proportioned to develop the factoredload combinations stipulated in Section A4. If the load factors and combinationsstipulated in Section A4 are used to design concrete structural elements, the provisionsof ACI 318 shall be used with appropriate factors as given in ACI 318,Appendix C.LRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION