A theoretical investigation has been performed on reinforced concrete beams subjected to air blast loading. The investigation involved numerical simulations with the use of Autodyn and the purpose was to study deformations, failure modes, support reactions and crack patterns. The long-term goal is to generate and achieve the knowledge necessary to enable response predictions of complicated structures. The RHT material model was used for the concrete and the Johnson & Cook material model was used for the reinforcement. Here, the work focused on the influence of concrete strength, amounts of reinforcement, bond between concrete and reinforcement, bilinear strain softening of concrete, strain rate dependence of the reinforcement and boundary conditions at the supports. The results from this investigation show the abilities to predict the dynamic response of dynamically loaded concrete beams with varying concrete strength and amount of reinforcement. The knowledge obtained has contributed to a good foundation for further studies on dynamic structural response. A continuation of this investigation should focus on investigating different cross-sectional geometries, different boundary conditions, size effects, other structural elements such as slabs or columns and also other structural materials. Future work should also involve analyses of the residual strength of elements, upgrading of elements as well as connections and parts of a structure. The generation of fragments should also be considered and simplified methods may be of interest to investigate and compare with experiments and simulations.