Creep influence on buckling resistance of reinforced concrete shells

The influence of concrete creep on the response of shallow reinforced concrete shells is analyzed in this contribution in the context of time-dependent shell buckling. The classical time-invariant stability analysis is extended to account for the long-term creep buckling, which is characterized by a continuous increase of deformation and time-dependent stability failure, if a certain critical load factor is exceeded. For a systematic study of these phenomena on a cylindrical roof shell, a recently proposed time-invariant and a time-dependent material model for concrete are combined in the framework of the long-term multi-level simulation concept, taking into account elasto-plastic deformation, crack damage and nonlinear basic creep of concrete. The performed numerical analyses provide an insight into the mechanisms of creep buckling of reinforced concrete shells as well as its sensitivity with respect to main influence factors and emphasize the relevance of interaction mechanisms between short- and long-term loadings.