AISC LRFD 1.pdf

Sect. J8.] BEARING STRENGTH 69J6. FILLERSIn welded construction, any filler 1 4-in. (6 mm) or more in thickness shall extendbeyond the edges of the splice plate and shall be welded to the part on which it is fittedwith sufficient weld to transmit the splice plate load, applied at the surface of thefiller. The welds joining the splice plate to the filler shall be sufficient to transmit thesplice plate load and shall be long enough to avoid overloading the filler along thetoe of the weld. Any filler less than 1 4-in. (6 mm) thick shall have its edges madeflush with the edges of the splice plate and the weld size shall be the sum of the sizenecessary to carry the splice plus the thickness of the filler plate.When a bolt that carries load passes through fillers that are equal to or less than1 4 -in. (6 mm) thick, the design shear strength shall be used without reduction. Whena bolt that carries load passes through fillers that are greater than 1 4-in. (6 mm) thick,one of the following requirements shall apply:(1) For fillers that are equal to or less than 3 4-in. (19 mm) thick, the design shearstrength of the bolts shall be multiplied by the factor [1 - 0.4(t - 0.25)] [Metric:[1 - 0.0154(t - 6)]], where t is the total thickness of the fillers up to 3 4-in. (19mm).(2) The fillers shall be extended beyond the joint and the filler extension shall besecured with enough bolts to uniformly distribute the total force in the connectedelement over the combined cross-section of the connected element andthe fillers;(3) The size of the joint shall be increased to accommodate a number of bolts thatis equivalent to the total number required in (2) above; or(4) The joint shall be designed as a slip-critical joint.J7. SPLICESGroove-welded splices in plate girders and beams shall develop the full strength ofthe smaller spliced section. Other types of splices in cross sections of plate girdersand beams shall develop the strength required by the forces at the point of the splice.J8. BEARING STRENGTHThe strength of surfaces in bearing is R n ,where = 0.75R n is defined below for the various types of bearing(a) For milled surfaces, pins in reamed, drilled, or bored holes, and ends of fittedbearing stiffeners,R n = 1.8F y A pb(J8-1)whereF y = specified minimum yield stress, ksi (MPa)A pb = projected bearing area, in. 2 (mm 2 )(b) For expansion rollers and rockers,LRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION