Modeling of Collapse Mechanisms of Thin Reinforced Concrete Shells

Abstract

A numerical model based on an elasto-plastic–fracturing formulation is presented to predict the ultimate strength as well as the related mode of failure of thin reinforced concrete (RC) shells. The model defines a safe domain within which the shell would not collapse under the applied load. It predicts two possible modes of failure, which may be broadly classified into bending-type failure and buckling-type failure. Important issues are considered in the model: the effects of holes, reinforcing members, and concentrated loads; and shape deviations due to construction or modeling imperfections. By comparison with analytical solutions as well as experimental observations, the model is shown to lead to reasonably accurate predictions of the main events leading to the failure of RC shells, including the loading path relating the downward vertical displacement to the applied load. From detailed investigations, the relations between the actual mode of failure and the level of the bending force are explained. To provide a shell with the maximum ultimate strength can be dangerous if an inadequately safe domain results.