Multilevel approach for brick masonry walls - Part I: A numerical strategy for the nonlinear analysis

A numerical strategy based on a multilevel approach is presented for the nonlinear analysis of brick masonry walls as in-plane prototypes of large masonry structures. The strategy is based on an iterative scheme which uses two different, local and global, modelings of the masonry mechanics contemporarily. The former is the reference mechanical model and is defined at the fine scale of the bricks and mortar joints and describes their nonlinear mechanical interaction including damage evolution and friction toughness phenomena. The latter is a linearized Finite Element approximation of the previous model, defined at the rough scale of the wall and used to accelerate the iteration. The proposed iterative scheme proves to be efficient and robust in both linear and nonlinear contexts.