Multiscale failure analysis of periodic masonry structures with traditional and fiber-reinforced mortar joints

Abstract

In this paper, a novel adaptive multiscale model is proposed for accurately predicting the nonlinear mechanical response of periodic brick masonry due to crack initiation and propagation under general in-plane loading histories. Such a model relies on a two-level domain decomposition technique, used in conjunction with an adaptive strategy able to automatically zoom-in the zones incipiently affected by damage localization, with the aim of reducing the typically high computational effort associated with fully microscopic models. The proposed switching criterion is based on the numerical determination of microscopically informed first failure surfaces taking into account higher-order deformation effects. In order to assess the validity of the proposed strategy, a sensitivity analysis is carried out on a shear wall sample by varying the required input numerical parameters. An additional application of the proposed multiscale model is then presented for investigating the role of the fiber content in fiber-reinforced mortars (FRMs), recently introduced for masonry construction and rehabilitation, on the overall response of a deep beam sample. 1 Introduction: an overview of modeling approaches for masonry structures In the last decades, the need of mitigating impacts of natural hazards on cultural heritage artefacts has inspired a huge number of repair and strengthening techniques for traditional masonry structures, also relying on the adoption of fiber-reinforced composite materials [1-4]. Fabric-reinforced cementitious matrix (FRCM) composite systems have emerged as a more sustainable alternative to the most used fiber-reinforced polymer (FRP) materials for restoration and rehabilitation of existing masonry buildings, especially those of historical and architectural interest [5-7]. The use of a cementitious matrix allows for a better chemical, mechanical and aesthetical compatibility with the masonry substrate and offers a potential fire protection. Nowadays, reinforcing fibers are available in a wide variety of materials and may be grouped into four classes: steel (low carbon or stainless), mineral (glass, basalt, etc.), synthetic organic (carbon, aramid, PBO, etc.) and natural organic, including both plant and animal fibers. Among them, natural fibers are gaining more and more attention by virtue of their low cost and low environmental impact, in terms of levels of embodied energy and CO2 production. However, in the presence of exposed brickworks, strengthening of masonry with externally bonded composite materials is often not desirable and/or allowed, so that less intrusive rehabilitation techniques should be used. Considering that the mortar joints are at the same time the weakest and the easiest

A refined diffuse cohesive approach for the failure analysis in quasibrittle materials—part II: Application to plain and reinforced concrete structures

“…Application of the proposed integrated fracture approach to other quasi‐brittle materials, as mortars, rocks, fiber‐reinforced or particle‐reinforced composites, some types of ceramics, masonries, etc. In particular, the in‐plane response of masonry structures (of both unreinforced and reinforced type) could be easily predicted by the adopted DIM, allowing different failure mechanisms of individual phases (eg, mortar and bricks) to be correctly captured, involving a priori unknown complex crack patterns, whose influence of the overall nonlinear mechanical behavior has been extensively demonstrated in the literature (see, for instance,).…”

Micromodels for the in-plane failure analysis of masonry walls: Limit Analysis, FEM and FEM/DEM approaches

“…The variational formulation for the equilibrium problem at the microscopic scale is rather classic and, thus, not reported here for the sake of brevity. However, with the aim to find more theoretical and computational details, the reader is referred to the works [13,16,17], in which this formulation is embedded within a more general multiscale framework. In this paper the following mixed-mode TSL of the type   = T T  , proposed by [50], is chosen (see Fig.…”

“…These models are often derived by considering only two material scales: a micro-scale where, after deducing the mechanical properties of the components, preferably through experimental tests, a material representative volume element (RVE) is defined and a macro-scale continuum model, is obtained by performing a homogenization procedure in most cases based on the solution of notable boundary conditions problems for the RVE. Among these approaches, both concurrent and semiconcurrent multiscale models have been proposed in the literature for masonry-like materials, the first ones referring to a strong coupling between the micro-and macro-levels [13][14][15][16], the latter ones, often referred to as computational homogenization models, characterized by an only weak (although two-way) coupling between them [17][18][19][20]. Most of the existing approaches are devoted to the mechanical behavior of periodic (i.e.…”

“…It must be pointed out that a limitation of Limit Analysis (both associated and not associated) concerns ductility that is assumed infinite, and this hypothesis not always fits well the softening behaviour of masonry [39]. A validation of the proposed model is provided, via suitable comparisons with two models that finely describe the microstructure and already adopted to the evaluation of the in-plane failure behavior of masonry panels: (i) a discrete model based on a combined Finite/Discrete Element method (FEM/DEM) [40,41], and (ii) a heterogeneous nonlinear Finite Element model (FEM), derived from the works [13,15,16]. The three models are used to reproduce the analysis performed in [42] -here regarded as a benchmark -on several masonry panels with different height-to-width ratio and with or without openings.…”

Strengthening of Unreinforced Masonry with Fibre Reinforced Concrete

“…The previous research paper developed in the masonry structures and related to the fibre. Samuel et al investigated these properties make fibre reinforced polymer materials, reinforced and unreinforced masonry structures are attractive for rehabilitating and strengthening [1], FRP materials are using of masonry structures to increase the shear and ductility and flexural strength [2].Fabrizio Greco et al have studied the microscopically first failure surfaces takes higher-order deformation effects [3], a sensitivity analysis is carried out on the shear wall sample the different input numerical parameters [4].Ornela Lalaj et al have studied the control specimen compared to increase in shear strength capacity up to 412%, mortar plaster are ferrocement, and polypropylene [5], the stiffness change and failure mode are more varied for strengthening techniques [6].Deniz Ucer et.al. The compression test of brick and mortar separately as well as wall prisms indicated that their strength was still higher than standard limits these wall pieces could be reused under appropriate conditions [7], the bed mortar was tested under shear loads to understand bed joints reliability [8].…”