ABSTRACT
The basic assumption of no-tension masonry model coincides with the hypothesis that the tensile resistance is null. Under this hypothesis, no-tension stress fields are selected by the body through the activation of an additional strain field, the fractures (see Baratta, 1991, Baratta et al. 1981, Baratta & Toscano 1982, Bazant 1996, Heyman 1966). The behavior in compression can be modeled in a number of different ways (elastic linear, elastic non-linear, elastic-plastic; isotropic, anisotropic; etc.), without altering substantially neither the results nor the mathematical treatment of the problem; some convenience exists for practical applications in assuming a isotropic linearly elastic model, in order to keep limited the number of mechanical parameters to be identified for masonry, since increasing the number of data causes increasing uncertainty in the results. Because of these reasons, and being clearly understood that there is no difficulty in introducing more sophisticated models, it is convenient to set up the fundamental theory on the basis of the assumption that the behavior in compression is indefinitely linearly elastic.
