A 3D continuum FE-model for predicting the nonlinear response and failure modes of RC frames in pushover analyses

Compared to the commonly employed finite element models of RC structures in earthquake engineering, based on structural elements, refined finite element models, characterized by discretizing the concrete by 3D continuum elements together with an advanced nonlinear material model for concrete combined with 1D truss elements for the reinforcement together with an elastic–plastic material model for steel, allow valuable deeper insights into the stress distribution in RC structures and the evolution of concrete damage. As a first step towards the application of such refined finite element models in earthquake engineering, their capabilities and shortcomings are demonstrated for pushover analyses. For this purpose, pushover analyses of four RC frames were performed, for which well documented extensive test data from shaking table tests, conducted by Yavari, is available. The comparison of numerical and experimental results demonstrates the capability of refined FE-models to capture the lateral load carrying capacity as well as the location and evolution of concrete damage very well. However, the well-known shortcoming of pushover analyses of predicting a much larger lateral ductility compared to the observed one in the shaking table tests was also observed.