C-J5J5 Fillers

As noted in Commentary Section J3.9, research reported in Borello et al. (2009) resulted in significant changes in the design of bolted connections with fillers. Starting with the 2010 AISC Specification (AISC, 2010), bearing connections with fillers over $\frac{3}{4}$ in. (19 mm) thick were no longer required to be developed provided the bolts were designed by multiplying the shear strength by a 0.85 factor. A test has shown that fillers welded to resist their proportion of the load will prevent a loss of shear strength in the bolts (Borello et al., 2009).

Filler plates may be used in lap joints of welded connections that splice parts of different thickness, or where there may be an offset in the joint.