A damage model to predict the behaviour of masonry under sustained loading

The results of uniaxial creep tests to failure on rubble masonry samples are presented. These tests are meant to be representative of the stress conditions that may be responsible for the collapse of massive masonry structures. A theoretical damage model is proposed to simulate the experimental results. It is based on the theory of viscoelasticity coupled with two anisotropic damage variables, allowing, respectively, for damage induced by monotonically increasing stresses and by sustained stresses. The numerical simulations performed so far are quite encouraging, so that the applicability of the proposed model to structural analyses can be envisaged.