Zum Durchstanzen von Flachdecken nach Eurocode 2

Die Regelungen zur Durchstanzbemessung im Eurocode 2 basieren im Wesentlichen auf den Modellvorstellungen in Model Code 90, der die Durchstanztragfähigkeit auf die Querkrafttragfähigkeit zurückführt. Nach Versuchsauswertungen ist diese Analogie für punktgestützte Platten jedoch nicht in jedem Fall zutreffend. Insbesondere für bügelbewehrte Platten ist bei der Bemessung nach Eurocode 2 ein Sicherheitsdefizit möglich, und es erscheint eine Anpassung der Bemessungsgleichungen zwingend erforderlich. Dieser Beitrag erläutert die Sicherheitsdefizite und schlägt verbesserte Bemessungsgleichungen vor. Punching of Flat Slabs according to Eurocode 2 The punching shear provisions according to Eurocode 2 are based on the design recommendations in Model Code 90 where no differentiation between shear and punching shear design is made. This approach is not fully confirmed by test results for flat slabs. In particular for flat slabs with stirrups as shear reinforcement some design provisions according to Eurocode 2 do not achieve the required safety level. Therefore adjustments to the design equations seem to be necessary. In this paper the Eurocode 2 provisions are critically reviewed and improved design regulations are proposed.     

Tragverhalten von Stahlbetonbalken bei geneigter Querkraft

Bearing Behaviour of RC Beams Subjected to Biaxial Shear Forces The shear bearing behaviour of RC beams is still subject of expert's discussion and intensive research. Most investigations focus on uniaxial loading conditions parallel to one principal axis. More recently, biaxial shear – leading to inclined shear forces – was theoretically considered and integrated into new design concepts. However, its experimental basis is rather limited. Thus, extensive biaxial shear tests are carried out and analysed. Their main findings are presented in the paper. The design concept is elaborated to introduce inclination effects into all partitions of the resistances provided by the tensile and the compressive shear struts. Designs become more precise and more economic.     

Ganzheitliche Analyse von Stahl‐ und Verbundeisenbahnbrücken

Holistic analysis on steel‐ and composite railway bridges – Innovative solutions for strengthening durability and reducing construction times (Part 1). Investigations on sustainability on infrastructure projects differ from comparable investigations on building constructions through their longer life‐cycle of the objects. Questions regarding sustainability are thus accompanied by questions of durability and simple, mostly undisturbed maintenance through the whole life‐cycle. By the application of innovative railway bridges with steel and composite constructions blocking times induced by the construction time and maintenance actions within the usage phase, can be effectively reduced. Additionally the optimization of restrictive fatigue‐details can affect the whole life‐cycle of a bridge‐construction. In the frame of the FOSTA‐AiF‐research project „Holistic Assessment of steel‐ and composite railway bridges according to criteria of sustainability“ different innovative railway bridge types have been compared to their corresponding conventional bridge types and evaluated over their whole life‐cycle to quantify their advantageousness. While this article shows the investigated innovative bridge‐variants in constructive regards and optimization proposals and design approaches are explained, the second article is about the holistic approach and the results of the sustainability assessment of the investigated steel‐and composite railway bridge.