Axial Force and Bending Moment Interaction Design per EN 1993-1-1

The interaction of axial compression and biaxial bending, according to EN 1993-1-1, is explained in detail under this title.

Notations

N_Ed: Design norma] force
N_pl,Rd: Design plastic resistance to normal forces of the gross cross-section
M_Ed: Design bending moment
M_{y, Rd} : Design values of the resistance to bending moments, y-y
M_{z, Rd} : Design values of the resistance to bending moments, z-z axis
h_w: depth of a cross-section
t_w: web thickness
f_y: Strength of axial compressive force available according to Section E
Ϭ_x,Ed: Design value of the local longitudinal stress
Y_MO : Partial factor for resistance of cross-sections, whatever the class is
Y_MI : Partial factor for resistance of members to instability assessed by member checks
Y_M2 : Partial factor for resistance of cross-sections in tension to fracture

6.2.9 Bending and Axial Force

6.2.9.1 Class 1 and 2 cross-sections

For classes 1 and 2, the interaction of axial force and bending moment is considered according to Eq. 6.32.

• For a rectangular solid section without fastener holes M_N,Rd

• There is no interaction if the below equations are satisfied for doubly symmetrical I and H sections.

• There is an interaction if the below equation is satisfied for doubly symmetrical I and H sections

6.2.9.2 Class 3 cross-sections

The maximum longitudinal stress should satisfy Eq. 6.42.

6.2.9.3 Class 4 cross-sections

The maximum longitudinal stress should satisfy Eq. 6.43.

Alternatively,