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The advantages of the computer enable us to simulate of complex structures subjected to dynamic loading. To come up to the necessity to know the real behavior of such material, we exploit these advantages basing on experimental data available in the literature. Since the response of the material depends on stress velocity, so it is essential to provide a computational code with dynamic behavior. To perform such simulations, we have elaborated a behavior law governed by loading velocity effect on concrete and their attitudes cyclic non elastic, for an approach of seismic behavior. This paper shows the processes we have followed to formulate this viscous damage law whose aim is behavior prediction for concrete under dynamic stresses. Then, the model is validated with experimental results and simulations of some available tests on Hopkinson’s bar

Saint-Rkmy-lis-Chevreuse R~SUM.!?. Dans cette itude, le modile de comporternent cyclique du be'ton est bas6 sur la thiorie de I'endornrnagement isotrope, sur la micanique des milieux continus ei la thermodynamique des processus irre'versibles. Ce modile tient compte des diformations re'siduelles et de la perte de raideur due a la fissuration. h e ame'lioration irnportante pour l'application du modsle a it6 de dijinir une mithode d'identifcation des paramitres ci partir des donne'es physiques obtenues dans les essais classiques de contr6le du biton et d'une expression analytique de la loi de comportement d'usage courant. Des essais de validation ont e'te' rialise's sur des e'prouvettes cylindriques sous charges cycliques de compression et sur des poteaux courts armb sous compression et traction cycliques alterne'es. La comparaison apporte des rksultats encourageants pour l'analyse des structures en be'ton anne' sous charges cycliques.ABSTRACT. In this study, the model for the concrete behavior is based on the theov of damage, on the mechanics of continuum media and the thermodynamics of irreversible processes. The model takes into account the inelastic strains and the loss of sti' ess due to cracking. An important improvement for the application of the model has been made in the method of identification of parameters; it is based on physical data obtained from concrete classical tests and from an analytical expression of a constitutive law of common use. Vaiidation tests have been carried out on standard cylinders subjected to repeated compressive loads and on short reinforced columns under compression-tension alternate cycles. The comparison between the model and tests gives promizing results for analysis of reinforced concrete structures under cyclic loading.