Masonry is a compos ite non-homogeneous structural material, whose mechanical properties depend on the properties of and the interaction between the composite components-brick and mortar, their volume ratio, the properties of their bond, and any cracking in the masonry. The mechanical properties of masonry depend on the orientation of the bed joints and the stress state of the joints, and so the values of the shear modulus, as well as the stiffness of masonry structural elements can depend on various factors. An extensive testing programme in several countries addresses the problem of measurement of the stiffness properties of masonry. These testing programs have provided sufficient data to permit a review of the influence of different testing techniques (mono and bi-axial tests), the variations caused by distinct loading conditions (monotonic and cyclic), the impact of the mortar type, as well as influence of the reinforcement. This review considers the impact of the measurement devices used for determining the shear modulus and stiffness of walls on the results. The results clearly indicate a need to reassess the values stated in almost all national codes for the shear modulus of the masonry, especially for masonry made with lime mortar, where strong anisotropic behaviour is in the stiffness properties.

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SIM (semi interlocking masonry) is a kind of innovative building system for mortar-less walls. It utilizes a special method of interlocking SIM bricks that allows relative sliding of brick courses in-plane of a wall and prevents out-of-plane relative movement of bricks. It has increased capacity to dissipate earthquake energy through friction between bricks compared with traditional masonry. It can be used in earthquake resistant frame structures as infill panels, which also act as EDD (energy dissipation devices). However, as a mortar-less system, it is not covered by masonry design standards. The purpose of this paper is to introduce SIM and also to develop an analytical design procedure for this innovative masonry system.

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.

Masonry is one of the most popular building materials. It has many excellent material properties and proven durability. Over time, masonry structures have evolved from massive walls, which work mainly through compression, to more slender walls, which could also experience tension and shear. Earthquake-induced tensile and shear stresses often exceed the capacity of traditional unreinforced masonry resulting in substantial damage and failure. A new mortar-less masonry system called semi-interlocking masonry (SIM) is presented in this paper. It has reduced stiffness and susceptibility to damage and utilized a special method of interlocking bricks that allows relative sliding of brick courses in-plane of a wall and prevents out-of-plane relative movement of bricks. The paper reviews the research on SIM to date and identifies new research opportunities in this area.

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