A damage model for triaxial fatigue of concrete: theoretical formulation and parametric investigation

A theoretical model for the description of the behaviour of concrete submitted to uni- and triaxial fatigue tests has been developed. It is based on damage mechanics and can be seen as extension of models formulated by other authors for static or quasi-static load histories. Special attention is devoted to the influence of the parameters defining the damage evolution law on the material fatigue life. In particular, some of the parameters are found to play a negligible role, at least in the range of values usually encountered for concrete. In the case of triaxial tests on cylinders, the effect of lateral confinement is carefully examined. The results obtained are discussed and possible further improvements are foreseen. The presented model also gives indications about the type of experimental information needed to forecast the fatigue lire of concrete under general load histories.