Dimensioning and design of hollow section connections made of higher-strength steels using the example of N-joints

Eurocode 3 is currently under revision. Part 1-1 will regulate steels up to S700, Part 1-12 will regulate steels above S700 to S960. For hollow section nodes made of high-strength steels, the scientific and technical basis for a satisfactory normative regulation is currently missing. The currently valid Part 1-12 contains a general reduction of the joint load bearing capacities to 80 % of the values from the design formulae for normal-strength steels. The draft of the new Part 1-8 (prEN1993-1-8) additionally provides a limitation of the attachable strength which, depending on the yield strength, is reduced to up to 80 % of the tensile strength of the steel.
The aim of the research project is to create fundamentals that will lead to a significant improvement in the technical rules for the design and execution of hollow section joints made of high-strength steels. The following subsections are planned:

• Experimental and numerical investigation using N-joints with Q- and TM-steels in the strength range S500 to S960,
• Tests on T-joints welded on one side to develop optimized connection details of filler rods to belts,
• Simplification of the GMA-welding of HSS hollow section connections through parameter selection,
• Development of normative rules for the design and execution of welded hollow section joints.

The parallel development of design and execution rules opens up the possibility of improving the technical rules for both areas. Engineering offices and technical departments of steel construction companies, manufacturing companies, steel producers, manufacturers of welding consumables and developers of automation benefit from this.

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