6. Shape instabilities under concentrated load

6.1 Description of phenomena and verification principles

Under the effect of a concentrated load F _Sd applied through a footing, there are three possible modes of failure for an unstiffened web:

• plasticization of the core in the immediate vicinity of the baseplate, with or without plastic deformation of the baseplate (figure a );

• localized buckling of the web in the immediate vicinity of the base plate, accompanied by plastic deformation of the latter (figure