Concrete bridge superstructures typically consist of relatively thin slabs monolithically connected to each other along longitudinal joints. Although these systems satisfy the geometrical conditions for classification as thin shell structures, it is not appropriate to analyse them according to elastic shell theory. The use of elastic shell theory requires linear elastic, isotropic and homogeneous material behaviour, which is never the case in prestressed concrete bridge superstructures. At ultimate limit state, the superstructure is transformed into an inhomogeneous, fully cracked composite member. Moreover, self-equilibrating stresses of unknown magnitude and distribution are always present under service conditions, a result of differential creep and shrinkage as well as temperature gradients.