Zur Torsionsbemessung von Stahlbeton‐ und Spannbetonbalken nach DIN 1045‐1

Torsion Design of reinforced and prestressed concrete Beams according to DIN 1045‐1 The DIN 1045‐1 provisions specify two different methods for torsion design regarding the concrete strut angle. The analysis of a database containing about 300 tests on reinforced and prestressed concrete beams under pure torsion or combined loading shows that under certain loading conditions the methods should not be used alternatively. In addition, the database also shows that the strength of the concrete strut according to DIN 1045‐1 overestimates the torsional capacity in general. On the basis of these results a suggestion for the definition of the concrete strut angle for torsion design in relation to DIN 1045‐1 is derived. Furthermore a design concept for the definition of the thickness of the shear flow zone is presented. Finally the database is analysed according to Eurocode 2 in its edition of April 2002.     

Querkraftbemessung nach DIN 1045‐1

Im vorliegenden Beitrag werden Arbeitshilfen für die Querkraftbemessung nach DIN 1045‐1 entwickelt. Unter Anwendung der vorgestellten Bemessungstabellen erfolgt die Bestimmung der Querkraftbewehrung auf sehr einfache Weise. Der Aufwand bei der Bemessung wird auf ein Minimum reduziert, positive Nebeneffekte bestehen in der Übersichtlichkeit und Wirtschaftlichkeit der Bemessungsergebnisse – auch bei Querkraft unter dem Einfluss von Längsspannungen. Aus dem vorgestellten Nomogramm für Vollplatten lässt sich in Abhängigkeit vom Rechenwert der bezogenen Querkraft – τ_Ed = V_Ed/z, der Betonfestigkeit und der statischen Höhe direkt bestimmten, welche Längsbewehrung erforderlich ist, um Querkraftbewehrung zu vermeiden. Die wichtigsten Bemessungshilfen – Diagramme für Bauteile ohne Querkraftbewehrung sowie eine Bemessungstabelle für die Querkraftbemessung ohne Längskraft – sind im Anhang als Arbeitsblatt zusammengefasst. Shear Force Design according to DIN 1045‐1. A simple procedure In the present paper are deduced worksheets for lateral force design according to DIN 1045‐1. By using the tabulars the amount of shear reinforcement can be determined in a very simple way. There are positive side effects in the clarity and economy of the calculation results – even with shear force under the influence of longitudinal stresses. Beside the tabulars a nomogram for the design of solid slabs is presented. It is possible to determine in a direct way the amount of main reinforcement, wich is required in order to eliminate the assembling of reinforcement stirrups in dependence on the related shear force – τ_Ed = V_Ed/z, the concrete strength and the effective depth. The basic measuring tools for the design without a longitudinal force are summarized in the annex as a worksheet.     

Teilfertigdecken nach DIN 1045‐1. Wichtige Punkte der Bemessung und Konstruktion

Partly pre‐fabricated reinforced concrete Floors/Ceilings according to DIN 1045‐1. Important Points of Design and Construction There are invasive changes in design and construction of partly pre‐fabricated reinforced concrete floors/ceilings connected with the application of DIN 1045‐1, July 2001 issue. This applies specifically to the verification of acceptance of thrust force in the joint between pre‐cast slab and the on‐site concrete. The basic elements will be gathered for this extensive verification and an example is given. Regulations for the arrangement of lattice girders as bond/shear force reinforcement as well as concrete covers will be shown in detail. Structures of support are easier to implement in the future.