Reassessment of fatigue detail categories of bolts and rods according to EC 3-1-9

摘要

The paper deals with the reassessment of fatigue detail categories of bolts and rods in EC 3-1-9 based on published fatigue test data and further conducted investigations. An elaborate database structure has been set up to evaluate the available fatigue test data in a differentiated way. Detail categories of bolts and rods in tension and shear have been investigated and re-evaluated based on the developed data base. Moreover, fatigue tests and numerical investigations on prestressed bolts in T-joints, L-joints and different types of end plate connections have been performed. Several influences on the fatigue strength (e.g. material influence, size effect, fabrication differences) have been analysed and design recommendations are given. The conducted fatigue tests on bolts in tension fit into the spreading band of 573 tests results conducted in the past, confirming fatigue class 50. However, bolts with rolled threads show a higher fatigue strength than those with cut threads, which has been included into the recommendations for fatigue details of bolts. Fatigue class 100 for bolts in shear has also been confirmed, however based on few data. Numerical investigations show, that bolts should be placed as close as possible to the tension flanges, while end plates should be dimensioned thick enough with an overhang including an additional bolt row. (C) 2021 Elsevier Ltd. All rights reserved.