How do I model and design an opening or a big opening in a reinforced concrete beam?


For modeling, a surface model with result beams is usually suitable (see Figure 01). With a result beam, the internal forces of a surface can be integrated and output as member internal forces. Another advantage is that it is possible to design result beams with the specification of a cross-section in the RF‑CONCRETE Members add‑on module.

In the upper model of the example file, the result beam was defined over the entire length of the beam (see Figure 02). In the lower model, on the other hand, the result beams were assigned exactly each to the individual area. Accordingly, the result diagrams shown in Figure 03 are obtained.

The design in RF‑CONCRETE Members results in the reinforcement drawings shown in Figure 04. For the upper model, the correct distribution of the reinforcement in the area of the opening would still have to be adjusted manually. In the lower model, however, the reinforcement is distributed exactly according to the cross-section dimensions of the result beams.

There is a technical article on this topic in our Knowledge Base, which you can find under Links below.


Opening Opening reinforced concrete beam




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RFEM 5.xx

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Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

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