This thesis deals with buckling of ax-
ially compressed thin cylindrical steel
shells. Through state-of-the-art review, it
is shown that a slightly imperfect cylin-
der has a load-carrying capacity (critical
buckling resistance), that is significantly
reduced compared to a perfect cylinder.
Therefore, three different imperfection pat-
terns is analysed through the most complex
of the recommended procedures in the Eu-
rocode, namely the geometrically and ma-
terially non-linear analysis with imperfec-
tion. Furthermore, the reliability of the im-
perfect models, as well as semi-empirical
mathematical models from the Eurocode
and DNV is estimated along with a cali-
bration of partial coefficients.