Experimental and numerical insights on the diagonal compression test for the shear characterisation of masonry

摘要

The masonry tensile strength and shear modulus play a key role in the definition of the shear capacity of masonry structures. These properties are often determined experimentally by means of the diagonal compression test on square walls, which is regulated by the ASTM E519 standard. In spite of its wide use, the interpretation of the test is still controversial and no universal criterion exists on how to derive the masonry mechanical properties from the wall overall strength. Aiming to contribute in the improvement of the test's reliability and interpretation, this paper presents an investigation on the use of the diagonal compression test to characterise the shear properties of masonry. First, an experimental campaign on brickwork walls is described. The walls were built in laboratory in Flemish bond, a pattern that has been scarcely investigated in the available research studies on this type of test. Second, an advanced numerical model is used for the analysis of walls subjected to the diagonal compression test. The adopted numerical model, enhanced by a crack-tracking algorithm to reproduce accurately the tensile damage localization, constitutes a very useful and powerful tool to interpret correctly the behaviour during the test. Finite element analysis was executed to interpret the walls’ response in the linear and nonlinear ranges with models properly calibrated by comparison with the experimental results. As a result, a criterion was determined for the calculation of the tensile strength from the outcomes of the diagonal compression test. A sensitivity analysis was carried out with regard to the most influent material properties of the material, the geometrical dimensions of the panel, and the loading conditions of the testing setup. The findings of this research were finally applied and validated by means of simulations of diagonal compression tests from eight experimental campaigns performed by other authors on different masonry typologies.