PSI - Issue 19

Helen Bartsch et al. / Procedia Structural Integrity 19 (2019) 395–404 Helen Bartsch, Benno Hoffmeister, Markus Feldmann / Structural Integrity Procedia 00 (2019) 000 – 000

403

9

6. Conclusion, design recommendations and Outlook In conclusion, using local stress concepts for the more economical determination of weld stresses proved to be helpful. Today, the advantages of modern computing power can be ideally used to extend experimental fatigue tests by detailed finite element simulations. Especially for the end plate connections with butt welds and overhanging end plate (Type C) the application of modified nominal stress ranges is useful. In general a classification in detail 2 of table 8.5 according to (Eurocode 3 1-9, 2005) under consideration of corrected nominal stress ranges due to stress concentrations in the bolt area is recommended. Connections with flush endplates (Type A) are definitely not recommended, since the bolts are subjected to large bending stresses and depict the most critical details in the connection, possibly leading to sudden complete failure of the connection due to high fatigue loading. For connections with overhanging end plate and fillet welds (Type B) primarily investigated in this paper, the following recommendations for fatigue design are proposed: a) A small end plate thickness has an unfavorable effect on bolt and weld stress ranges. Very large end plate thicknesses, on the other hand, are uneconomical. b) Since large bolt diameters lead to significantly smaller bolt stress ranges with only minor influence on the weld details, the choice of a larger bolt diameter is generally recommended. c) In conjunction with a), the approach "End plate thickness at least equal to bolt diameter" is proposed. d) The bolt spacing should be selected in accordance with (Eurocode 3-1-8, 2005). If the bolt becomes the decisive fatigue detail, the smallest possible bolt spacing to the tension flange is recommended. e) The nonlinear bolt forces should be determined by FE simulations. Simplified calculation models are suitable for estimations. f) End plate connections with overhanging end plate and butt welds (Type C) are recommended. In non-fully penetrated welds, in addition to the weld toe the detail of the weld root, which is decisive in most cases, must be considered. In future investigations, geometric influences on flush end plate connections with fillet welds (Type A) and overhanging end plate connections with butt welds (Type C) could also be investigated. Additionally, the differences between small-scale and large scale specimens could also be analyzed numerically. 7. Acknowledgements The presented investigations have been conducted in the framework of the Germ an research project “Re evaluation and enhancement of the detail catalogue in Eurocode 3 for future oriented design of steel construction under high loading ” (Enhancement detail catalouge, 2019). The financial contribution of the German Committee on Steel Construction (DASt) in cooperation with the Research Association for Steel Application (FOSTA) is greatly acknowledged. Many thanks also go to the AG der Dillinger Hüttenwerke, Peiner Träger GmbH, FREYLER Industriebau GmbH, August Friedberg GmbH and Adolf Würth GmbH & Co. KG for the provision of material and the manufacturing of the test specimens.