Energy based load-impulse diagrams with multiple failure modes for blast-loaded reinforced concrete structural elements

An energy based load-impulse diagram is an alternative of damage assessment tool for protective structures. By defining energy flow relationships, the entire domain of structural responses and corresponding damage can be characterized. The damage level or failure type of a reinforced concrete element under a specific threat or hazard (e.g. impact and blast) can be determined by examining the corresponding combination of energy input and its rate. An energy balance approach for deriving energy based load-impulse diagrams with multiple failure modes for structural elements are presented in this paper. Two different structural behaviors of reinforced concrete elements subjected to blast loads were considered (i.e. flexure and direct shear), and the energy flow in a structural system were described by proposing an energy tank analogy. The application of these approaches to the damage assessment of tested structural elements is illustrated.