Blind Prediction of SMART 2008 Seismic Structural Response Test Results

This paper describes the numerical simulation contribution of Fortum Nuclear Services Ltd. to the round-robin blind prediction of SMART 2008 seismic structural response tests to be conducted by Commissariat Energie Atomique in France in spring 2008. In order to assess the seismic tri-dimensional effects (such as torsion) and non-linear response of reinforced concrete buildings, a reduced scaled model (scale of 1/4th) of a nuclear reinforced concrete building is going to be tested in 2008 on AZALEE shaking table at Commissariat a` l’Energie Atomique (CEA Saclay, France). This test, supported by Commissariat a` l’Energie Atomique (CEA) and Electricite´ de France (EDF), will be part of the “SMART-2008” project (Seismic design and best-estimate Methods Assessment for Reinforced concrete buildings subjected to Torsion and non-linear effects). The first part of the project is a blind prediction of the structure behavior under different seismic loadings. It is presented as a contest, opened to teams from the practicing structural engineering as well as the academic and research community, worldwide. This phase will result in the creation of a predictive benchmark, which should allow us to compare and validate approaches used for the dynamic responses evaluation of reinforced concrete structures subjected to earthquake and exhibiting both 3-D and nonlinear behaviors. The objectives of the predictive benchmark are to: 1) Assess different conventional design methods of structural dynamic analyses, including floor response spectra evaluation; 2) Compare best-estimate methods for structural dynamic response and floor response spectra evaluation. In the next analytical phase to be carried out during the year 2009, the prediction contest will be compared to test results at various levels of seismic excitation (including ‘under-design’ and high ‘over-design’ levels), in order to: 1) Quantify variability in the seismic response of the structure and identify contribution coming from uncertainties in input parameters and random variables; 2) Investigate and compare different methods for fragility curves elaboration. The numerical simulation gives the best estimate values for acceleration response spectra values in five specified response points of the model in two perpendicular horizontal directions for base excitation values from 0.05g up to 0.8 g. Also the maximum and minimum values of the stresses and strains in the concrete and in the reinforcement of four vertical walls of the model are to be simulated as well as the acceleration and displacement response time histories at the top of the model for base excitation values from 0.05g up to 0.8 g.