Abstract: It is required to consider the strain rate effect of concrete and steel reinforcement appropriately in order to conduct simplified analysis of reinforced concrete （RC) members under blast loading, while there is a lack of concrete uniaxial constitutive model that can be used to model strain rate effect in LSDYNA. In this paper, based on Faria 's uniaxial plastic damage model, the strain rate effect is considered by adjusting the damage thresholds of rate-independent model through viscous regularization, and then the model is worked out as a user defined material subroutine VUMAT. The basic ratedependent properties are tested by a single element model and the dynamic response of RC beams under blast and impact loading are modeled on the basis of fiber model.Resultsshow that the constitutive model can reflect the fact that strain rate effect under tension is higher than that under compression, and can model the dynamic response of RC beams under blast and impact loading accurately.