The design code checks performed per Eurocode 3 have been updated to include checks for shear buckling in I Sections and PFC Sections. Eurocode 3 – Part 1 (EN 1993-1-1:2005) states in Cl.6.2.6 that the checks for Shear buckling are to be based on the procedure in EN 1993-1-5. STAAD.Pro performs checks based on the methods Section 5 of EN 1993-1-5:2006.

In the case of an unstiffened web, the program will check the unstiffened web capacity. If the demand due to applied loads is greater than this capacity, the program will calculate a suitable spacing for transverse stiffener plates in order to meet the demand.

In the case of a web with transverse stiffeners, the program will check the capacity of the web considering the provided stiffener spacing. The program will consider both the buckling capacity of the web as well as the flange. If the demand due to applied loads is greater than this capacity, the program will calculate a reduced stiffener spacing for transverse stiffener plates in order to meet the demand.

The distance between transverse stiffeners is specified by the STIFF parameter, in the current units of length. If no value is specified, the program assumes a spacing equal to either the member length or depth of beam, whichever is greater.

The output file provides recommendations on the evaluation of stiffeners (e.g., adding stiffeners at a spacing or increasing the web thickness).

Refer to D5.C.5.3 Members Subject to Shear for additional information.