The determination of the elastic critical load (buckling load) is an important element of the assessment of the ultimate load of plate girders. An analysis of the critical load of a plate corresponding to the web of an I-girder for different boundary conditions and the critical load of the I-girder itself is given in the paper. Conclusions regarding their correspondence are given. Also, experimentally determined ultimate loads of I-girders are compared with values according to Eurocode for the models used in this analysis
