Simulating experimentally observed nonlinear response of large-scale concrete structure to understand the selection of damping: A case of minor nonlinearities

Abstract

Recent studies conducted by the US Nuclear Regulatory Commission and its collaborators have explored the use of limit-state C for SDCs 5 and 4, unlike the conventional design of concrete shear walls in nuclear power plants. Consideration of the limit-state C allows minor nonlinearity in the behavior of structural systems when subjected to design earthquakes. In the context of the nonlinear behavior in concrete structures, the selection of appropriate parameters for the concrete’s constitutive material model is important. In addition, there are some concerns with using Rayleigh damping in nonlinear seismic analysis because, many studies have shown that an improper use of Rayleigh damping in the nonlinear seismic analysis can lead to unintended large damping forces thereby resulting in an underestimation of response parameters. In this study, response data from a large-scale shake table experiment of a 3-story concrete shear wall structure is used to understand these effects. A finite element analysis of the test specimen using concrete damage plasticity model and its reconciliation with the experimental data is used to understand two aspects discussed above, i.e., (i) selection of model parameters in the Concrete Damage Plasticity Model for nonlinear seismic analysis of concrete structures, and (ii) selection of an appropriate damping model. Both of these aspects are studied for the case of minor damage (nonlinearity) in the structure corresponding to ASCE-43′s guidelines for risk-informed performance-based design.