Plane Elements with Intermediate Stiffeners

The procedure for determining the effective width/thickness of elements with intermediate stiffeners is given in EN 1993-1-3 art. 5.5.3.3 and art. 5.5.3.1.

This applies to elements of type RI

The stiffness K of the internal stiffener is determined from formula (5.11):

The reduced effective area of the stiffener A_s,red according to art 5.5.3.3(10) is calculated using σ_com,Ed = f_yb/γ_M0.