Dr Yuri Totoev

© 2015 by the authors. The behavior of dry stack masonry (DSM) is influenced by the interaction of the infill with the frame (especially the joints between bricks), which requires further research. This study investigates the compression and shear behaviors of DSM. First, a series of compression tests were carried out on both masonry prism with mortar (MP_m) and DSM prism (MP_ds). The failure mode of each prism was determined. Different from the MP_m, the stress-strain relationship of the MP_ds was characterized by an upward concavity at the initial stage. The compression strength of the MP_ds was slightly reduced by 15%, while the elastic modulus was reduced by over 62%. In addition, 36 shear-compression tests were carried out under cyclic loads to emphasize the influence of various loads on the shear-compression behavior of DSM. The results showed that the Mohr-Coulomb friction law adequately represents the failure of dry joints at moderate stress levels, and the varying friction coefficients under different load amplitudes cannot be neglected. The experimental setup and results are valuable for further research.

In order to increase the energy dissipation of wall/frame elements subjected to in plane shear loading a conceptually new system for masonry infilled RC frame has been proposed and proved as effective. The interaction between frame and infilled panel is considered as the major cause of the nonlinear behavior of structure. In this paper, the experimental results are briefly summarized and a micro finite element model is developed to simulate the monotonic response of the masonry infilled structure. A novel type of element called "initial gap element" is presented to simulate the gap between the frame and panel to allow the continual simulation of the response for the full load cycle. All the material parameters are experimentally evaluated. The initial testing included free vibration and cyclic tests on a bare RC frame followed by cyclic test on the RC frame infilled with a dry-stacked concrete brick panel. These results are used to verify the accuracy of the model. It is shown that the model is able to simulate the failure mechanisms exhibited by experiment including the crushing and cracking of the concrete frame and the diagonal compressive stress contribution of the masonry panel. The load-displacement response predicted by the model was also in good agreement with that obtained from the tests. Furthermore, the model was used for ultimate analysis, which discovered four typical stages of structural response of the dry-stack infilled RC frame and found the friction between bricks in the dry-stacked panel contributes significantly (about 50%) to the assembly. © 2014 Politechnika Wroclawska.