Limit analysis of masonry structures: upper bound approach based on homogenization and local mesh refinement

We present an upper bound limit analysis tool for plane stress problems in masonry. A given masonry construction is discretized into planar rigid-perfectly plastic finite elements, whose kinematics is described by rigid body velocities and plastic strain rates. To properly represent the collapse behaviour of the heterogeneous masonry material, the plastic strain rates must follow the homogenized kinematic conditions derived for running bond masonry textures. For a given load configuration, a rigid-plastic limit analysis problem can be defined and solved to find a mechanism and an associated collapse load. Local mesh refinement is finally applied to optimize the representation of the mechanism and minimize the collapse load.