Behavior of interlocking grouted stabilized sand-fly ash brick masonry under uniaxial cyclic compressive loading

An experimental investigation of the behavior of interlocking grouted stabilized sand-fly ash brick masonry under unaxial cyclic compressive loading with different bed joint orientation is presented. Five cases of loading at 0, 22.5, 45, 67.5, and 90 degrees with the bed joints were considered. The brick units and masonry system developed by Professor S. N. Sinha are used in the present investigation. Eighteen specimens 500 mm X 100 mm X 700 mm and 27 specimens 500 mm X 100 mm X 500 mm were tested. The envelope stress-strain curve, common point curve, and stability point curve were established for all five cases of loading with respect to the bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. It was inferred that the peak stress of the stability point curve may be considered as the maximum permissible stress level and is found in the range of 0.745-0.775 times the masonry strength depending upon the load case. It was also inferred that the permissible stress level depends on the plastic (residual) strain present in the material under cyclic loading.