AISC LRFD 1.pdf

Sect. B4.] STABILITY 11(a) When the tension load is transmitted only by fastenersA e = A n UwhereU = reduction coefficient= 1 −( x/ l) ≤0.9x = connection eccentricity, in. (mm)l = length of the connection in the direction of loading, in. (mm)(B3-1)(b) When the tension load is transmitted only by longitudinal welds to other than aplate member or by longitudinal welds in combination with transverse weldsA e = A g U(B3-2)whereU = 1 −( x/ l) ≤0.9A g = gross area of member, in. 2 (mm 2 )(c) When the tension load is transmitted only by transverse weldsA e = AU(B3-3)whereA = area of directly connected elements, in. 2 (mm 2 )U = 1.0(d) When the tension load is transmitted to a plate only by longitudinal weldsalong both edges at the end of the plateA e = A g U(B3-4)whereFor l 2w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . U = 1.00For 2w>l 1.5w . . . . . . . . . . . . . . . . . . . . . . . . . U = 0.87For 1.5w>l w . . . . . . . . . . . . . . . . . . . . . . . . . . U = 0.75wherel = length of weld, in. (mm)w=plate width (distance between welds), in. (mm)Larger values of U are permitted to be used when justified by tests or other rationalcriteria.For effective area of connecting elements, see Section J5.2.B4. STABILITYGeneral stability shall be provided for the structure as a whole and for each of itselements.Consideration shall be given to the significant effects of the loads on the deflectedshape of the structure and its individual elements.LRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION