Stress-strain characteristics of brick masonry under uniaxial cyclic loading

A series of laboratory tests were carried out on half-scale sand plast brickwork panels subjected to uniaxial cycle loading. Forty-two square panels were tested under cycle loading until failure for two cases of loading: (1) Normal to the bed joint; and (2) parallel to the bed joint. Failure due to cyclic compressions was usually characterized by a simultaneous failure of brick units and head joints or by splitting in the bed joints depending on whether the panel was loaded normal or parallel to the bed joint, respectively. The characteristics of the stress-strain relationship of the two loading conditions are presented in this paper. Envelope, common point, and stability point stress-strain curves were established based on test data, and an exponential formula was found to provide a reasonable fit to the test data. It was concluded that the peak stress of the stability point curve can be regarded as the maximum permissible stress level that is found to be approximately equal to two-thirds of the failure stress. It was also observed that the permissible stress level depends on the plastic strain level present in the material due to cyclic loading.