SMART 2008: Shaking table tests on an asymmetrical reinforced concrete structure and seismic margins assessment

The paper reports the main findings of a series of shaking table tests on a 3-story ¼-scale reinforced concrete model characterized by strong asymmetry, representative of a nuclear building. The specimen was subjected to 13 bi-directional input ground motions with increasing maximum acceleration from 0.05 to 1.0 g, which induced significant torsion and a nonlinear response. The tests were conducted on the AZALEE shaking table (Saclay, France) as part of a wide research program launched by the French Atomic Energy and Sustainable Energies Commission (CEA), Electricité De France (EDF) and the International Atomic Energy Agency (IAEA), titled, “Seismic design and best-estimate Methods Assessment for Reinforced concrete buildings subjected to Torsion and nonlinear effect (SMART).” Based on the analysis of the test results, the following conclusions were drawn: (a) moderate damage occurred on the specimen (mainly close to the geometric singularities) as revealed by the crack patterns observed at the end of the seismic test sequence; (b) the model responded mainly in the torsional mode; (c) an important specimen stiffness reduction was observed with a shift of the first peak frequency almost equal to 50%; (d) the seismic margins assessment carried out with two distinct failure criteria (frequency shift and inter-story drift) showed an important specimen robustness for high seismic amplitude as well.