The paper shows a investigation of masonry components in a complex state of streses. In the mortar and brick material model the Willam-Warnke failure criteria are used. All parameters of failure criteria are obtained from mortar and brick samples investigations. To estimate the position of the meradians of the failure surface, the triaxial and uniaxial tests of mortar and brick were made.

Keywords: masonry unit, mortar. Willam-Warnke failure criteria. triaxial and uniaxial investigations of load slate.