Imperial College London, Department of Civil & Environmental Engineering

This paper presents an advanced numerical model for nonlinear analysis of unreinforced brick masonry, where 3D continuum solid elements and 2D nonlinear interface elements are employed to model bricks, mortar and brick-mortar interfaces. The proposed approach allows an accurate representation of any 3D arrangement for brick-masonry, as both the in-plane stacking mode and the through-thickness geometry are taken into account. A softening plasticity-base model is used to deal with material nonlinearity at the interface, while the co-rotational approach is employed to account for large displacements, which often characterise the out-of-plane response of masonry panels under seismic actions. A Coulomb slip criterion accounting for energy dissipation, de-cohesion and residual/frictional behaviour is used to simulate failure in shear and in tension, while a cap model is employed for failure in compression. The accuracy and reliability of the model is demonstrated in this paper through comparisons against experimental results, where consideration is given to both in plane shear and out-of-plane bending tests.

Key words
Unreinforced masonry, nonlinear analysis, interface element, cohesive model, geometric nonlinearity