In the RF‑/STEEL EC3 add-on module, I obtain an extremely high design ratio for a member in the case of "Biaxial bending, shear and axial force". Although the axial force is relatively high, the design ratio seems unrealistic. What can be the cause?

Question

Accepted Answer

According to DIN EN 1993‑1‑1, Section 6.2.9, the moment resistance is reduced due to a high axial force utilization; thus, the maximum design ratio for the cross-section design "biaxial bending, shear and axial force according to 6.2.10 and 6.2.9" is unusually high.By using Equation (6.2) from Section 6.2.1 for the cross-section design instead of Equation (6.41) from Section 6.2.9.1, the design ratio can be reduced significantly.In the RF‑/STEEL EC3 add-on module, you can activate the linear interaction of the axial force and moment loading in the Details tab.

N_Ed	Bemessungswert der vorhandenen Normalkraft
N_Rd	Bemessungswert der zulässigen Normalkraft
M_y,Ed	Bemessungswert des vorhandenen Biegemomentes um die lokale y-Achse
M_y,Rd	Bemessungswert des zulässigen Biegemomentes um die lokale y-Achse
M_z,Ed	Bemessungswert des vorhandenen Biegemomentes um die lokale z-Achse
M_z,Rd	Bemessungswert des zulässigen Biegemomentes um die lokale z-Achse

High Ratios in Cross-Section Design in RFEM 5 / RSTAB 8

In the RF‑/STEEL EC3 add-on module, I obtain an extremely high design ratio for a member in the case of "Biaxial bending, shear and axial force". Although the axial force is relatively high, the design ratio seems unrealistic. What can be the cause?