This work is a development of constitutive model for concrete by the
theory of plasticity at high temperature. In this model, non-uniform work
hardening plasticity model adopts the most sophisticated failure model of
Willam - Warnke five-parameter model. This model was modified to
include the effect of the temperature on concrete structures. The
developed model can predict the effect of the fire on concrete structures at
diffirent types of temperature loading from room temperature to very high temperature