Fatigue Strength of Bolted Joints

Abstract

This paper summarizes the results of 400 fatigue tests of high‐strength bolted joints that were reported in eight domestic and six foreign studies. The following variables were investigated: type of bolt and washer, bolt pattern, bolts‐to‐member strength ratio, initial bolt tension, yield strength, skew, joint length, and partial connection of member elements. The analysis of the data showed that within the limits on maximum stress imposed by the American Association of State Highway and Transportation Officials (AASHTO) specifications on edge distance, bolt spacing, etc., both friction‐type and bearing‐type joints can be designed to Category B on the basis of the gross area stress range. The fatigue of long bolted joints with more than four bolt rows in a line of stress must be lowered from Category B to C. The stress range in members that transfer load through some, but not all, cross‐sectional elements must be calculated using a reduced effective gross area.