ABSTRACT
As discussed in the introductory paragraph of Section 4, a small amount of slip will occur in shear-loaded connections prior to reaching the maximum strength load. (This may not be true for the case of failure by bearing against connected material with very small edge distances.) Slip may also occur prior to reaching the allowable load (maximum strength divided by a factor of safety) as determined by strength considerations. In a great preponderance of connections, strength is the primary concern governing the design or slip cannot occur because in the real world joint assembly procedures generally ensure that the bolts will be in bearing with either the dead weight of the piece bearing on the loose erection bolts prior to final tightening or to the application of any other load or where, due to numerous bolts in large connections and the in-tolerance misalignments of holes, bolts are in bearing at all stages of loading. Reports of slip at design loads have rarely if ever been reported; however, there are situations where a high degree of assurance is required that slip will not occur. Slip must be prevented to avoid even minor changes in the geometrical relationship between members to ensure the integrity of the structure subject under static loads or to ensure that back-and-forth slippage of connections does not occur when they are subjected to significant reversal of loading or for other reasons. Such connections are advisedly identified in the Specification as "slip-critical" connections to call attention to the fact that they are intended to be used where special performance characteristics are important and to emphasize that their installation and tensioning require special control and inspection at additional cost. Joints considered to be slip-critical are those subject to significant load reversal or to cyclic fatigue loading, those with bolts installed in oversize holes, those with bolts installed in slotted holes when the line of action of the applied loads is more or less parallel to the long axis of the slots, those in which bolts and welds share the applied loads, and those that the engineer of record thinks would be adversely affected by slip.
