Failure Criteria of Unreinforced Grouted Brick Masonry Based on a Biaxial Compression Test

To define failure under biaxial stress, a three-dimensional surface in terms of two principal stresses and their orientation to the bed joints is required. This article describes a series of biaxial compression tests on full-scale brick specimens. Tests were performed on square unreinforced grouted brick masonry specimens with the principal compressive stresses oriented at 0 and 90 degree angles to the bed joints, and a fail-are surface was obtained in terms of these parameters. Test results indicated that the masonry strength under equal biaxial compression is higher by about 36% on average than that under uniaxial compression: the influence of joint orientation is very insignificant and negligible for these models.