Stress-Strain Characteristics of Brick Masonry under Cyclic Biaxial Compression

Tests on half-scale and plast brick masonry specimens subjected to cyclic biaxial compression were conducted for five principal stress ratios. An interaction curve for the principal stresses at failure was obtained experimentally and expressed mathematically in terms of stress invariants. The failure under biaxial compression was characterized by midthickness splitting of the bearing area. The failure was quantified by the critical orthogonal strain that governed the failure, which in turn defines the critical stress-strain envelope curves. The critical envelope curve and the corresponding common point and stability point curves were expressed in mathematical form by general exponential formulas. The stability point curves can be used to establish the permissible stress level under in-plane cyclic loading.