Stress analysis of the effects of mortar thickness in masonry structures using an anisotropic model

The aim of this study is to investigate the effect of mortar/brick thickness ratio, brick configuration on the masonry stresses and on masonry structure modelling. Different mortar/brick thickness ratios are micro-modelled by using stress-strain relationship. The results of these models are used to obtain the material properties of anisotropic macro-models in vertical and horizontal directions. The sample unreinforced masonry structures are simulated by the SAP2000 software using anisotropic material properties. In general masonry structures are composite materials that consists of brick and mortar. The main goal in modelling is to simulate a model that behaves close to the real structure as much as possible. Micro-modelling of masonry structure by considering its components individually is more realistic but not practical for large scale structures. In order to overcome this problem, macro-modelling is used in literature. Macro-model is obtained by smearing out the material properties of the micro-model to an anisotropic continuum material. Currently, most engineers simply analysis masonry structures with isotropic modelling in practice. However, presence of head and bed mortar joints in the construction of masonry causes the masonry to be anisotropic. Anisotropic modelling of a large scale structure does not need unreasonable effort as in micro-modelling and can be used instead of isotropic modelling easily in practice. Considering the horizontal and vertical loads in the plane, some wall types with rectangular cross-section, rectangular and arches cross-sections cavities were modeled as anisotropic and the effect of anisotropic material was investigated. In terms of displacements, an isotropic model and anisotropic models were found to be close to each other. However, when examined in terms of stresses, the maximum and minimum stresses in the masonary structure were changed.