Under which conditions are washers necessary for pretensioned and slip critical joints?

Washers are necessary in pretensioned and slip-critical joints under specific conditions that ensure optimal performance and integrity of the bolted connection. When utilizing calibrated wrench pretensioning, the application of a washer is beneficial primarily to distribute the load more evenly and prevent damage to the mating surfaces. Oversized holes can lead to variations in load distribution and the potential for relative movement, making washers crucial for achieving the desired tension and fit.

In these scenarios, washers serve several functions: they provide a larger surface area to bear the load, minimize the risk of surface degradation, and help maintain the bolt tension by compensating for any slight misalignments that might arise from the oversized hole condition. This ensures that the joint remains tight and effective over its service life, crucial for both the performance and safety of the structure being assembled.

The other conditions presented do not universally require washers as a necessity. Standard bolting connections do not inherently need washers unless specified for particular applications or conditions. Similarly, while lubricated bolts can affect tensioning and may require specific considerations, they do not automatically make washers necessary unless other factors, such as hole size or the method of pretensioning, are in play. Thus, the combination of calibrated wrench pretensioning and oversized