Damping identification and quantification: experimental evidences and first numerical results

International audienceThe way of quantifying energy dissipations in reinforced concrete (RC) structures during seismic events is still a complex issue to solve out. However, the designer would rather use simplified modelling for both the geometrical representation of the structure and its mechanical behaviour. To this end, the Rayleigh-type viscous damping based models are commonly used even if several studies have emphasized the inherent issues of this approach. Alternative solutions exist, but the target values of the damping themselves are still questionable since the dynamic properties of the structure evolve throughout the nonlinear time history analysis. To bring answers to the aforementioned issues, a set of experiments including seismic tests on RC beams is carried out by means of the TAMARIS experimental facility operated by the French Alternative Energies and Atomic Energy Commission (CEA). The results will be used to propose a new damping modelling strategy able to reproduce damping evolution throughout time history analysis while avoiding the use of complex constitutive laws. In this paper, the lacks of Rayleigh damping models are briefly reminded and a review of the advantages and disadvantages of various damping measurement experimental procedures is made. Then, the IDEFIX experimental campaign (not executed yet) is presented in contrast with the aforementioned review. Eventually, numerically simulated results of the tests are exposed and discussed. Preliminary numerical results in connection with the proposed damping modelling strategy will be shown and compared with the ones coming from existing approaches in order to demonstrate not only its relevance but also its efficiency