3685x
000655
2021-02-05

Determining Required Longitudinal Reinforcement for Shear Force Design According to EN 1992-1-1

The shear force resistance VRd,c without computational shear force reinforcement according to 6.2.2 of EN 1992-1-1 [1] or 10.3.3 of DIN 1045-1 [2] is calculated depending on the longitudinal reinforcement ratio. If the required longitudinal reinforcement from the bending design is used for the calculation of VRd,c, this leads to an underestimation of the shear force resistance without shear reinforcement in the vicinity of the hinged end supports. In contrast to the shear force, the required bending reinforcement decreases in the direction of the support. Furthermore, the actually inserted longitudinal reinforcement usually deviates significantly from the required bending reinforcement in the end support area (for example, in the case of non-staggered beam reinforcement).

In RF‑CONCRETE Members and CONCRETE, you can specify whether the shear force design is carried out with the required longitudinal reinforcement from the bending design, or with the existing longitudinal reinforcement of the reinforcement proposal from module Window 3.1. The application of the provided reinforcement is now performed at the location at which the shear resistance with the required bending reinforcement is insufficient. If the shear design without shear reinforcement cannot be performed with the provided reinforcement, the provided amount of reinforcement is also shown as statically required longitudinal reinforcement.

Furthermore, there is the option to increase the required longitudinal reinforcement automatically, to avoid shear reinforcement. Here, the longitudinal reinforcement is increased until the maximum reinforcement ratio of 0.02 is reached. If, in this process, it is found that VRd,c under the application of the maximum longitudinal reinforcement ratio is still less than the acting shear force VEd, the increase of the longitudinal reinforcement has no effect on the shear resistance VRd,c and is not used. In this case, VRd,c is determined with the required longitudinal reinforcement from the bending analysis, and then the required shear reinforcement is calculated.


Author

Mr. Meierhofer is the development leader of programs for concrete structures and is available for the customer support team in case of questions related to reinforced and prestressed concrete design.

Links
References
  1. Nationaler Anhang - National festgelegte Parameter - Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken - Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau; DIN EN 1992-1-1/NA:2013-04
  2. DIN 1045-1: Tragwerke aus Beton, Stahlbeton und Spannbeton Teil 1-1: Bemessung und Konstruktion, Kommentierte Kurzfassung. Beuth Verlag GmbH, Berlin, edition = 2. 2005.