Determining Required Longitudinal Reinforcement for the Shear Force

Tips & Tricks

The shear force resistance VRd,c without the calculational shear reinforcement according to, for example, Section 6.2.2 of EN 1992‑1‑1 is calculated depending on the ratio of longitudinal reinforcement.

Up until now, the required longitudinal reinforcement was used from the bending analysis in the modules RF‑CONCRETE Members or CONCRETE for the calculation of VRd,c. This resulted in an underestimation of the shear resistance without shear reinforcement near the hinged end supports, because there the required bending reinforcement, unlike the shear action, decreases in the direction of the supports. In addition, the actually used longitudinal reinforcement in the end support area differs significantly from the required bending reinforcement (for example in the case of uncurtailed beam bars).

In RF‑CONCRETE Members and CONCRETE, you can now specify whether to perform the shear force design with the required longitudinal reinforcement from the bending analysis or with the provided longitudinal reinforcement of the proposed reinforcement from 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, you have the option to increase the required longitudinal reinforcement to avoid a shear reinforcement automatically. 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, then the increase of the longitudinal reinforcement has no effect on the shear resistance VRd,c and it 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.


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