Critical aspects of finite element modeling of RC structures for seismic performance assessment

Finite-element modeling of RC structures involves making a series of assumptions related to the distribution of forces and deformations within the structure. In an extensive variety of possible modeling strategies, the engineer is challenged to build an effective numerical model which can be used to quantify the performance of the structure in an efficient manner. In this study a fundamental component of the FE modeling which is the discretization of the model is discussed. The influence of the adopted discretization scheme on the simulated response is presented for a set of representative RC components. Both displacement-based and force-based beam-column finite-elements with two nodes are considered in the analysis. The results obtained using alternative meshing schemes are compared to estimates obtained using the empirical approach of the equivalent plastic hinge length method, as well as against experimental evidence. Additionally, the impact of the adopted meshing scheme on the predicted dynamic response of structures is investigated. The response of a series of RC columns and walls tested on shaking table are considered for this purpose. The simulated maximum and residual displacements are compared to the measured values. Based on the obtained results, preliminary recommendations are developed for the identification of appropriate meshing schemes.