Bounding surface models applied to the fatigue of plain concrete

A survey was performed to find in the literature theoretical models capable of describing the fatigue behaviour of concrete, subjected to uni- and triaxial elevated stress. Four models were selected, which are based on the concept of «bounding surface». Several numerical simulations of fatigue tests were performed to assess the potentiality of these models in the domain of fatigue. Whereas the response of two of these models is consistent with the loading conditions in most simulations, the other ones are unable to take the effect of confining pressure into account. All of the models, however, require modifications to give realistic predictions of fatigue life and cyclic creep. The parameters that mostly seem to affect the model response under fatigue are devised and slightly modified; comparisons with available experimental data support the validity of this proposal. This preliminary research is intended to be the first step toward the incorporation of rate effects into the models considered, or other theoretical models.