Connection of Rib Member on Surfaces with Different Thicknesses

You can connect a rib member to a line on two surfaces with different thicknesses.

To determine the stiffness or internal forces, the eccentricity of the rectangular cross-section is determined using the mean value of both connected surfaces in RFEM.

1 RFEM Model of Rib with Different Plate Thicknesses

For design in RF‑CONCRETE Members, the add-on module determines a special cross-section, which is displayed in Window "1.4 Ribs" of the add-on module.

2 Dialog Box "1.4 Ribs" in RF-CONCRETE Members

By clicking the "i" button (see Image 02), it is possible to open an info dialog box for the generated rib cross-section, where you can see all cross-section properties applied for the design in the add-on module, such as the position of the shear center and center of gravity, and so on.

3 Section Properties of Rib Cross-Section in RF-CONCRETE Members

When adjusting the "effective width" in Window "1.4 Ribs" (for example, to 0.50 m), this has an impact on the cross-section applied in RF‑CONCRETE Members and the cross-section properties of it.

4 Modified Section Properties of Rib Cross-Section

However, this does not affect the stiffness or the determination of internal forces in the 3D model in RFEM.