Numerical simulation of serviceability, damage evolution and failure of reinforced concrete shells

The present paper deals with FE-simulations of damage and failure processes in reinforced concrete structures, with emphasis on the description of suitable material models. For concrete, the generally accepted equivalent strain concept (pseudo-1D) is applied, which allows consideration of arbitrary concrete qualities. In the case of cyclic processes, elastic, plastic as well as micro-damage material phases are considered in an empirical manner, as initially proposed by Bazant and Cedolin [ASCE J. Eng. Mech. 106 (1980) 1287]. Two-dimensionality has been considered by the application of a 2D failure model. Macro-cracking and debonding is treated on the meso-level through special crack elements as computational units of the length of the crack distance. This concept yields crack widths and crack distances with sufficient accuracy and it is also impervious to possible size effects due to the strain localization. The second main issue concentrates on simulation concepts for large structures, elucidating the applied shell elements and the required multi-level-simulation techniques. Finally, exemplary results are presented, demonstrating crack-damage induced response phenomena of a large cooling tower shell up to structural failure.