SMART 2013

The SMART2008 mock-up
The AZALEE table (CEA Saclay)
CEA - credit : Philippe STROPA
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SMART 2013

Reinforced concrete (RC) structures exhibiting tri-dimensional (including torsion) effects such as torsion and non-linear response are a main concern in the field of earthquake research and regulation. In the last decade, several RC mock-ups were tested in Western Europe, on simple walls (a dozen campaign, including SAFE) or wall and floor structures (CASSBA, CAMUS, etc.). SAFE tests (“Structure Armées Faiblement Elancées”) that lied in pseudo-dynamic tests carried out between 1997 and 1998 at ISPRA CCR, were devoted to the experimental characterization of the dynamic behaviour of low span walls. The walls were subjected to series of earthquake loadings with increasing levels (up to fifteen times the design level). Some well-known phenomena have been confirmed by these tests: the failure modes, shape of the nonlinear load/displacement diagrams, allowable distortion described in guidelines. Other phenomena have been observed: an overestimation of the initial stiffness (may be due to boundary conditions), margins dependent on the frequency content of the solicitation, some ductility of the walls or cracking, which is limited until reaching the maximum bearing capacity. CASSBA tests (1990-1993) and Camus (1996-2002) have been performed at CEA/EMSI laboratory on multi-storey mock-ups. These tests have shown the good behaviour of the structures with bearing walls, only minor damages were observed at the design level. These campaigns have both helped improving the knowledge on structures behaviour and providing reference data for model development and validation.

SMART Mockup
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In order to assess the capability of buildings to withstand earthquake loading as well as seismic loads induced to their equipments, a reduced scaled model (1/4th scale) representative of a typical, simplified half part of an electrical nuclear building was designed, built and tested between June and October 2008 on AZALEE shaking table as part as “SMART-2008 project” (Seismic design and best-estimate Methods Assessment for Reinforced concrete buildings subjected to Torsion and non-linear effects). This project was supported by Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) and Electricité de France (EDF). The first part of this project lied in a blind predictive benchmark started in 2007. The objectives were (i) to evaluate conventional design methods for structural dynamic response and floor response spectra calculations and (2) to compare best-estimate methods for structural dynamic response and floor response spectra evaluation including various practices, depending on participant’s experiences. Results of this benchmark were presented in July 2008 during the 1st SMART workshop held in CEA Saclay.

To improve the knowledge of the seismic behavior of such reinforced concrete structures, a new research program was started in 2011, namely SMART 2013 project. It lies in an experimental program and in an international benchmark. Regarding the experimental part of the project, the main differences with respect to the SMART 2008 are related to the intensity of the seismic loading: (i) the input signals are real ones and not synthetic ones (excepted white noises and design signal), (ii) high intensity seismic loadings are applied at the beginning of the testing sequence and (iii) the effect of an aftershock is considered. Regarding the benchmark, a specific attention is paid to the characterization of the numerical models developed by the participants. Furthermore, additional data are provided to ensure an efficient control of the boundary conditions such as the time/history quantities at the actuator level.

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