Academic literature on the topic 'Zero bond masonry'

The aim of the paper is to propose and assess the reliability of a modeling strategy which combines the homogenization of the masonry material and the use of zero-thickness interface elements. This strategy is specifically proposed for numerically investigating the structural response of FRP-reinforced curved masonry structures. Indeed, in order to consider the influence of the geometry curvature of the masonry substrate on the local bond behavior of the FRP-strengthening system, bond-slip laws which specifically account for the geometric curvature of the substrate are introduced at the FRP/substrate interface layer. Numerical analyses concerning masonry arches selected from the current literature are presented in the paper in order to assess the reliability of the proposed modelling approach.

The presented research focuses on masonry shells with dry (cohesionless) contacts. In the mechanical analysis of such structures, the material is often assumed to have zero resistance to tension. This simplification can be questioned in light of the fact that due to the frictional resistance between masonry layers compressed to each other, significant tension can be carried perpendicularly to the direction of the compression. The effect can be so considerable that the typical orange-slice cracking of masonry domes can be prevented purely by choosing a suitable brick shape and bond pattern. Based on preliminary 3DEC discrete element simulations with realistic and experimentally validated material parameters in order to understand the failure modes, the phenomenon is quantified in the present paper for the two main types of bond patterns applied in masonry shells: (i) different versions of the running bond pattern, and (ii) two versions of the herringbone pattern. The theoretically predicted failure tensile stresses are checked and validated with 3DEC discrete element simulations.

In this work the performances of the Discrete Element Method (DEM) applied to kinematic limit analyses of the out-of-plane behavior of masonry wall panels (with different textures) are investigated. A discrete model of masonry is proposed, which assumes that rigid blocks are connected by a mortar interface: this is ap-propriate for historical masonry, where mortar is much more deformable than blocks and joints thickness is negligible. Therefore blocks can be modeled as rigid bodies connected by zero thickness Mohr-Coulomb-type interfaces. The applied method is known as FEM/DEM, which combines finite and discrete element models. A comparison with well-known and meaningful examples presented by Giuffrè has been carried out in order to validate this method for studying the behavior of masonry. For this purpose, 2D DEM models reproducing walls sections have been considered: they reproduce masonry walls with different staggered blocks, in particular stack bond and running bond patterns, subjected to lateral loads.

Excessive consumption of cement in construction materials has resulted in a negative impact on the environment. This leads to the need of finding an alternative binder as a sustainable construction material. Different wastes that are rich in aluminosilicates have proved to be a valuable material for alkali-activated product development, which contains zero cement. Alkali-activated products are claimed to be sustainable and cost-effective. In the present study, alkali-activated reinforced masonry mortar was developed using locally available industrial waste (co-fired blended ash—CBA). Appropriate mortar design is one of the key challenges as connections between two structural elements play a significant role in building construction. The mortar designed with suitable fiber reinforcement shall significantly help to enhance the fresh, mechanical, durability, and dynamic properties. Chopped basalt fibers (CBFs) obtained from basalt rock are one of the eco-efficient fibers applied as a reinforcing material. The present study checked the feasibility of novel industrial waste-co-fired blended ash (CBA) in the development of alkali-activated masonry mortar and reinforced alkali-activated mortar. In view of sustainable construction material design, the study elaborated the application of chopped basalt fibers (CBFs) in alkali-activated mortar design. The mortar cubes were cast and tested for various properties with varying percentages of chopped basalt fibers (0.5%, 1%, and 1.5%). The results suggest that developed mortars were able to achieve higher compressive strength (10–18 MPa) and flexural strength (3–3.5 MPa). Further, based on the properties of developed alkali-activated reinforced mortar, masonry prisms were cast and evaluated for the bond strengths (flexural and shear) of masonry. The optimum properties of alkali-activated mortar were found for the mix design of alkali activator to solid ratio of 0.40 and 0.5% CBF percentage. Application of CBF in CBA alkali-activated reinforced masonry mortar proved to be an efficient construction material with no cement.

Recent seismic events, such as the Central Italy (2016), the Emilia (2012) and L’Aquila (2009) earthquake, have demonstrated the high vulnerability of cultural heritage represented by historical and monumental buildings. These structures are often characterized by the presence of elements with a curved geometry such as arches and vaults, which interact with the vertical elements (walls or columns) during the earthquake motion, producing a significant effect on the seismic response of the entire structure. Aiming at the reduction of the seismic vulnerability of curved masonry elements, several techniques of reinforcing based on composite fiber materials, have been recently developed and widely investigated by means of experimental tests and numerical simulations. The using of fiber reinforced systems, applied through cementitious mortar (FRCM), is becoming a very common technique of retrofitting for historical and monumental masonry buildings. This technique, if compared to the using of fiber polymeric materials (FRP), is more compatible with the mechanical properties of the masonry and more appropriate with the preservation needs of cultural heritage, associated to the historical constructions. A discrete macro-modeling approach, already available in the literature for modeling masonry structures with plane and curved geometry, is here employed to predict the non-linear behaviour of masonry arches strengthened with FRCM. In that approach the reinforcement is explicitly modeled by using a rigid plate, while the interaction between the reinforcement and the masonry support is governed by a discrete zero thickness interface. In this paper the interfacial behavior is updated with a more sophisticated bond-slip constitutive law specifically conceived for FRCM reinforcement within the framework of fracture mechanics; in particular the proposed calibration takes into account both the pure opening mode (mode I) and the in plane shear mode (mode II). The obtained numerical results are compared with an analytical closed form solution of the problem and validated by mean of experimental tests on prototypes, available in the literature.