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004352
2020-02-25

Question

Why is an opening not taken into account when determining the punching load due to shear forces in the critical perimeter?


Answer:

When determining the punching load from shear forces in the critical perimeter, a continuous perimeter is applied.

If an intermittent perimeter was to be used when determining the punching load, the load component (along the intermittent length) might not be considered. This would be the case, for example, if you have only defined the opening in RF‑PUNCH Pro, but not in the RFEM model. In the RFEM model, the shear force would be generated using the continuous cross-section. If the component was to be neglected, an insufficient punching load would be determined.

Therefore, the intermittent control perimeter is always applied in RF‑PUNCH Pro when determining the punching load from the shear forces within the critical perimeter.

During the design (on the resistance side), the opening is considered again and the perimeter section is reduced accordingly.