Sensitivity to Material Modeling Choices in Seismic Demand Estimation for Reinforced Concrete Frames

This paper examines the sensitivity of computed seismic system demands to modeling choices made at the material level. Accurate constitutive models of the constituent materials in a reinforced concrete (RC) section, namely, unconfined concrete, confined concrete and reinforcing steel are necessary for direct use in fiber-section discretization of RC components. The characteristics of the cyclic constitutive model can also directly influence the efficiency and accuracy of the element model used in the analysis. An additional aspect of modeling sensitivity resulting from ground motion characteristics, in the context of material model sensitivity, is also explored in the study. A series of numerical simulations of a typical ductile RC frame building is conducted with a view to gaining additional insight into response sensitivity resulting from modeling choices at the material level. Results of the simulations indicate that proper choice of parameters representing the behavior of confined concrete and the post-elastic behavior of reinforcing steel can influence the computed inelastic response of RC structural systems.