Modelling the response of concrete structures from strain rate effects to shock-induced loading

In the regime between structural dynamics and stress wave loading, the response of concrete structures depends strongly on the loading rate. At low and medium loading rates, the influence of the strain rate-dependent response of the material (true strength) dominates. However, at high loading rates, the influences of inertia become more important. They cause a progressive increase in resistance (apparent strength), crack branching, and a change in failure mode. Structural simulations show that for larger structures subjected to high loading rates (impact, explosion), the rate sensitivity of the concrete is also important. If the structural discretization is fine, the influence of structural inertia on the structural response is automatically taken into account in dynamic analysis. Therefore, the inertia contribution should not be part of the rate-dependent constitutive law. In principle, all effects that cannot be automatically accounted for in the dynamic analysis should be included in the rate-dependent constitutive law.