Three different effects control the influence of the loading rate on structural response: creep of bulk material, rate dependency of growing microcracks and structural inertia. The first effect is important only at extremely slow loading rates whereas the second and…
Three different effects control the influence of the loading rate on structural response: creep of bulk material, rate dependency of growing microcracks and structural inertia. The first effect is important only at extremely slow loading rates whereas the second and third effects dominate at higher loading rates. In the present paper, a rate sensitive model, which is based on the energy activation theory of bond rupture, and its implementation into the microplane model for concrete are discussed. The rate sensitive microplane model is applied in a 3D finite element analysis of the pull-out of headed stud anchors from a concrete block. The results show that with an increase of the loading rate the pull-out resistance increases. For moderate loading rates, the rate of the micro crack growth controls the structural response. For much higher loading rates, how- ever, the structural inertia dominates. The numerical results are in good agreement with experimental evi- dence.