Compressive behavior of unconfined and confined clay brick masonry

Presented in this paper are the results of an investigation of the compressive behavior of grouted clay brick masonry prisms. The objective is to experimentally capture the stress-strain characteristics of unconfined and confined clay brick masonry and compare the response with that predicted with the "modified" Kent-Park stress-strain curve. Based on the experimental results, five limit states for clay brick masonry in compression are proposed, as well as equivalent stress blocks for design. Thin galvanized steel plates placed in the mortar joints during construction provided prism confinement. The variables considered included volumetric ratio of confining steel (0, similar to0.015, and similar to0.03) and the presence of machined holes within the confinement plates to improve the bond between the masonry and steel plate. It is shown that confinement plates are extremely effective in enhancing the ultimate compressive strength as well as increasing the deformation capacity of the clay brick masonry prisms. The use of confinement plates in the test increased the ultimate compression strength by 40%. Failure of the confined masonry prisms occurred simultaneously or immediately after yielding of the confinement plates. Experimentally obtained stress-strain curves agreed reasonably well with the modified Kent-Park model.