HOMOGENIZATION TECHNIQUE AND DAMAGE MODEL FOR OLD MASONRY MATERIAL

Masonry is a composite material realized by the inclusion of bricks in to the matrix of mortar. In the present paper, a micromechanical appro ach for defining the properties of a periodic masonry material is prop osed. A damage model for old masonries is presented. In fact, it is as sumed that the damage is due to the coalescence and growth of the frac tures only in the mortar. A repetitive unit cell is chosen and eight p ossible undamaged and damaged states for the masonry are identified. T he homogenization theory for material with periodic microstructure is used to define the overall moduli of the uncracked and cracked masonry . Variational formulations of the periodic problem are given. A numeri cal procedure for the computation of the elastic properties of the und amaged and damaged masonry material is developed. Then, the damage evo lution of the masonry, which accounts for the exact geometry and for t he mechanical properties of the constituents of the composite, is obta ined. Energy and local strength criteria for the mortar are proposed. The behavior of a typical masonry material is studied and the results are put in comparison with the ones available in the literature. Final ly, a simple structural application is developed. (C) 1997 Elsevier Sc ience Ltd.