where

σ_tot,Ed is the design total direct stress, calculated on the relevant effective cross-section

k_y,θ is the reduction factor for the yield strenght of the steel at steel temperature θ_a reached at time t

f_ya is the average yield strenght according to EN 1993-1-3 and chapter 3.2.2

γ_M,fi is the partial factor for the relevant material property, for the fire situation

where

τ_tot,Ed is the design total shear stress, calculated on the gross cross-section

where

σ_N,Ed

is the design direct stress due to the axial force N_Ed (using effective cross-section);

σ_My,Ed

is the design direct stress due to the bending moment M_y,Ed (using effective cross-section);

σ_Mz,Ed

is the design direct stress due to the bending moment M_z,Ed (using effective cross-section);

κ₁

is an adaptation factor for non-uniform temperature in a cross-section;

κ₂

is an adaptation factor for non-uniform temperature along the beam;

σ_B,Ed

is the design direct stress due to bi-moment B_Ed (using gross cross-section);

τ_Vy,Ed

is the design shear stress due to the transverse shear force V_y,Ed (using gross cross-section);

τ_Vz,Ed

is the design shear stress due to the transverse shear force V_z,Ed (using gross cross-section);

τ_t,Ed

is the design shear stress due to uniform (St. Venant) torsion (using gross cross-section);

τ_w,Ed

is the design shear stress due to warping (using gross cross-section).