CONNECTED ELEMENTS
8 - 237
Other Elements in Connections
Shims
Shims are furnished to the erector for use in filling the spaces allowed for field clearance which might be present at connections such as simple shear connections, PR and FR moment connections, column base plates, and column splices. These shims, illustrated in Figure 8-63, may be either strip shims, with round punched holes, or finger shims, with slots cut through the edge. Whereas strip shims are less expensive to fabricate, finger shims may be laterally inserted and eliminate the need to remove erection bolts or pins already in place. Finger shims, when inserted fully against the bolt shank, are acceptable for slip-critical connections and are not to be considered as an internal ply with the slotted hole determining the design strength of the connection. This is because less than 25 percent of the contact surface is lost and this is not enough to affect the performance of the joint. Fillers
A filler is furnished to occupy spaces which will be present because of dimensional separations between elements of a connection across which load transfer occurs. Examples where fillers might be used are beams framing off center on a column and raised beams. From LRFD Specification Section J6, fillers in welded connections and fillers thicker than 3⁄4-in. in bolted bearing-type connections must be fully developed. In bolted bearing-type connections, fillers between 1⁄4-in. and 3⁄4-in. thick, inclusive, need not be developed, provided the design shear strength of the bolts is reduced by the factor 0.4(t − 0.25) where t is the total thickness of the fillers up to 3⁄4-in. In bolted slip-critical connections, fillers need not be fully developed.
Strip
Finger
Fig. 8-63. Shims. AMERICAN INSTITUTE OF STEEL CONSTRUCTION