Does fatigue occur in non-preloaded bolts under varying compressive load?

[siberiankhatru]

Bolts are seldom under compressive load, but what if we had an situation, where a non-preloaded bolt was under varying compressive load (load ratio R>1, i.e the loading is fully compressive).

For example, the situation could be a column base connection without grout where the anchor bolts and nuts carry the compressive load from the column.

Details and FAT classes are presented in the design standards Eurocode 1993-1-9 and DNVGL RP C203 but the details are meant for bolts which are mainly or somewhat under tension. How much better FAT class would a non-preloaded bolt have if the load range was fully compressive?

 

[hydtools]

Yes, if the stress exceeds the bolt material fatigue stress limit. Seems the bolt could see both tensile and compressive stress, full reversing cycles. I'm assuming the base plate is captured between nuts on the bolt.

Ted

 

[siberiankhatru]

Yes of course. And there is base plate naturally.. But isn't the fatigue life longer when the load range is completely on the compression side compared to alternating or pulsating tension load? And how much bolt's FAT class increases when the varying load is fully compressive?