Deformation characteristics of interlocking grouted concrete masonry under uniaxial cyclic compressive loading

A series of laboratory test were conducted to evaluate the behaviour of interlocking grouted concrete masonry under uniaxial cyclic compressive loading. The brick units and masonry system developed by Prof. S.N. Sinha were used in the present investigation. Eighteen specimens of size 500 mm x 100 mm x 700 mm were tested. Two cases of loading parallel and perpendicular to the bed joints were considered. The envelope stress-strain curves, common point stress-strain curves, stability point stress-strain curves were proposed for both the cases of loading. Analytical expressions are proposed for the envelope, common point and stability point curves. The loops of stress-strain hysterisis obtained from cyclic loading tests were used to determine the energy dissipation characteristics of the masonry. The variation of envelope strain with plastic strain has been plotted. It was inferred that the deterioration of masonry starts at about 0.73 to 0.75 times of peak stress for specimens loaded parallel and perpendicular to the bed joints respectively.