When two or more bolts are assembled in a pattern to resist a tensile loading, deformations of the connected material may subject the bolts to a prying action as well as to a direct force. The effect on the prying action is to increase the total load that must be resisted by the bolts. Because the fatigue life of a bolt in tension is a function of the total force transmitted to the bolt and not simply the nominal applied load, the effect of prying action, if it exists, must be determined so that the actual load in the bolt may be known. It is very evident that the prying effect has a large influence on the fatigue resistance of a bolt. Tests executed, mainly in Delf, on very typical connections have clearly shown this problem. They also have the advantage to give general rules to design a connection keeping in mind the fatigue resistance. These tests have been very useful to change the 'philosophy' of the engineers concerning the conception of the connections. © 1993.
Piraprez, E. (1993). The effect of prying stress ranges on fatigue behaviour of bolted connections: The state-of-the-art. Journal of Constructional Steel Research, 27(1–3), 55–68. https://doi.org/10.1016/0143-974X(93)90006-E