Steifenlose Krafteinleitung bei Biegeträgern - Vorschlag einer vereinfachten Eurocode-konformen Nachweisführung

Transversal load introduction into unstiffened girder webs - Proposal for a simplified, Eurocode-compatible design check.

The introduction of concentrated transversal loads into the webs of hot-rolled or welded beams and girders, while avoiding the disposition of apposite stiffeners, is a common ingredient for a cost optimization of steel structures detailing, particularly in building structures. Practical design checks for this detailing solution were thus included in national standards - e. g. in DIN 18800. In this standard, a constant load distribution slope was assumed and an effective section in the web was used for the design checks. This procedure was simple and efficient, did however not consider all load-carrying mechanisms correctly. In Eurocode 3, the so-called general rules standard EN 1993-1-1 does not contain specific rules for design checks for this detailing solution. In other parts of EN 1993 (part 1-8 - connections and part 1-5 - plate buckling) a number of rules are given, which include the transversal load introduction into girder webs as part of design verifications for related cases (unstiffened frame joints, patch loading in welded (bridge) girders). In this paper, the different concepts found in the Eurocode are compared and discussed.
The study aims at identifying and discussing the key load-carrying behaviour at transversal load introduction points in order to derive an accurate, yet practical design check recommendation on the basis of the mentioned, existing Eurocode rules. This design recommendation is presented at the end of the paper in compact form.