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Mehendale, Shashank Vasudeo, Abhay Namdev Bambole y S. Raghunath. "Development of pseudo interface element for modelling of reinforced brick masonry". Revista ALCONPAT 7, n.º 1 (31 de enero de 2017): 73–86. http://dx.doi.org/10.21041/ra.v7i1.147.
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Development of pseudo interface element for modelling of reinforced brick masonryABSTRACTStrength of reinforced masonry is influenced by interfaces between brick, mortar and reinforcement. Experimental protocol has been defined to characterise the behaviour of reinforced brick masonry joint, with reinforcement steel embedded in cement mortar 1:6. This is applicable for low-strength, low-stiffness brick masonry found. Experimental investigations show that bond between masonry and steel is not perfect. Considering critical bond mechanisms, an attempt is made to put-forth a novel approach for development of a pseudo interface element representing three different materials (viz. brick, mortar and reinforcement) and two interfaces (reinforcement-mortar (RM) interface and brick-mortar (BM) interface). Principles of classical Reinforced Concrete (RC) design can therefore be directly applied to reinforced masonry with the introduction of the proposed pseudo interface element.Keywords: reinforced masonry joint; interface element; masonry reinforcement bond behavior; pseudo interface material; stiffness of interface elements. Desarrollo de un pseudo-elemento de interfaz para el modelado de mampostería de ladrillo reforzado RESUMENLa resistencia de la mampostería reforzada está influenciada por las interfaces entre el ladrillo, el mortero y el refuerzo. Se ha definido un protocolo experimental para caracterizar el comportamiento de la junta de mampostería de ladrillo reforzado, con acero de refuerzo incrustado en mortero de cemento 1: 6. Esto es aplicable para la albañilería con ladrillos de baja resistencia y baja rigidez encontrada. Las investigaciones experimentales demuestran que el vínculo entre la mampostería y el acero no es perfecto. Teniendo en cuenta los mecanismos de enlace críticos, se intenta presentar un nuevo enfoque para el desarrollo de un elemento de pseudo-interfaz que represente tres materiales diferentes (ladrillo, mortero y refuerzo) y dos interfaces (de refuerzo y mortero (RM) y de mortero (BM)). Por lo tanto, los principios del diseño de concreto armado (RC) clásico pueden aplicarse directamente a la mampostería reforzada con la introducción del pseudo-elemento de interfaz propuesto.Palabras clave: articulación de mampostería reforzada; elemento de interfaz; comportamiento de enlace de refuerzo de mampostería; pseudo-material de interfaz; rigidez de los elementos de la interfaz. Desenvolvimento de um elemento pseudo-interface para modelagem reforçada alvenaria de tijoloRESUMOA resistência de alvenaria reforçada é influenciada pelas interfaces entre o tijolo, argamassa e de reforço. Definido um protocolo experimental para caracterizar o comportamento da placa reforçada alvenaria de tijolo com aço de reforço embebido em argamassa de cimento 1: 6. Isso se aplica a alvenaria de tijolo com baixa resistência e baixa rigidez encontrados. A pesquisa experimental mostra que a ligação entre a alvenaria e aço não é perfeito. Dada a mecanismos de ligação crítica, tenta apresentar uma nova abordagem para o desenvolvimento de um elemento de pseudo-relação representando três diferentes materiais (tijolos, argamassa e reforço) e duas interfaces (reforço e argamassa (RM) e argamassa (BM)). Portanto, os princípios de concepção de betão armado (RC) pode ser aplicado directamente sobre a alvenaria reforçada clássico com a introdução do elemento pseudo-interface proposta.Palavras-chave: alvenaria armada conjunta; elemento de interface; vinculativo de reforço comportamento da alvenaria; material de pseudo-relação; rigidez dos elementos de interface.
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Jing, Meng y Werasak Raongjant. "Durability Test on the Bond Strength between SFRP Layer and Masonry Surface". Materials Science Forum 976 (enero de 2020): 165–72. http://dx.doi.org/10.4028/www.scientific.net/msf.976.165.
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The mechanical properties of masonry structural members strengthened by FRP (Fiber Reinforced Polymer) are affected by the bond strength of the reinforcement interface, in addition to the strength of the material FRP itself. This project is aimed at the new technology of Sprayed Fiber Reinforced Polymer Composites (SFRP), which is currently attracting attention. The bond strength between SFRP layer and masonry surface under high-humidity condition during strengthening construction and dry-wet cycle conditions after reinforcement were studied by experimental method. Different masonry substrates and different reinforcement methods were set as the test parameters. It is concluded that, compared with the currently used GFRP (Glass Fiber Reinforced Polymer) sheets reinforcement method, the SFRP reinforcement method has an significant improvement in the bond strength and the durability.
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Leone, Marianovella, Margherita Stefania Sciolti, Francesco Micelli y Maria Antonietta Aiello. "The Interface Behavior between External FRP Reinforcement and Masonry". Key Engineering Materials 624 (septiembre de 2014): 178–85. http://dx.doi.org/10.4028/www.scientific.net/kem.624.178.
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The need to guarantee higher safety levels of masonry structures under both short and long term conditions, have led to the use of new materials and technologies, in conjunction or in place of traditional ones. In this context, fiber-reinforced composite materials have gained an increasing success, mostly for strengthening, retrofitting and repair existing structures. As well known, the analysis of the interface performance of FRP (Fiber Reinforced Polymer) composites and masonry substrate is a critical problem as it influences the effectiveness of the technique. The present paper reports part of a large research project, still in progress, focused on the analysis of the bond performance between FRP sheet and different type of masonry substrates. The obtained experimental data were analysed in terms of bond strength and the kind of failure. The influence of the deformability of the strengthening material as well as the mechanical performance of the substrates are also discussed.
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Silva, D. S. y E. G. P. Antunes. "Analysis of different interface treatments between masonry of AAC blocks and reinforced concrete structure after uniaxial compression strength test". Materiales de Construcción 71, n.º 343 (30 de julio de 2021): e252. http://dx.doi.org/10.3989/mc.2021.09920.
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Autoclaved aerated concrete (AAC) masonry is widely used in civil construction but requires further investigation. Hence, this experimental study evaluated three types of interface treatment between the reinforced concrete structure and AAC masonry, in scale, after a uniaxial compression resistance test. The types of interface treatment considered are reinforcement with steel bars, with rough polymeric cementitious mortar, and without treatment. The maximum load capacity, displacements, and occurrence of cracks were analysed. The results showed that the maximum individual load capacity did not significantly differ among the examined groups. However, the analysis of the displacements and cracks showed that the group with steel reinforcement had the smallest displacements and largest cracks. This behaviour is owing to the greater solidarity of forces conferred by steel reinforcement.
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Gulinelli, Pietro, Alessandra Aprile, Raffaella Rizzoni, Yves Henri Grunevald, Frédéric Lebon, Roberto Lovisetto y Sergio Tralli. "A Fe Model for TRM Reinforced Masonry Walls with Interface Effects". Key Engineering Materials 817 (agosto de 2019): 57–64. http://dx.doi.org/10.4028/www.scientific.net/kem.817.57.
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We report on experimental and numerical investigations of textile reinforced mortar (TRM) strengthening systems, an innovative solution for reinforcing historical masonry structures. The experimental campaign presented in this paper is original and concerns two commercial TRM applications to single-leaf clay masonry panels. The proposed FE modelling is based on a multiscale approach with the possibility of simulating bed joints sliding and TRM-reinforcement debonding. This last phenomenon is frequently reported in the experimental literature and it has been observed also in our experimental tests. The numerical model is applied to study the behaviour of TRM reinforced masonry panels under diagonal compression tests.
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Corinaldesi, Valeria, Jacopo Donnini y Giorgia Mazzoni. "Experimental Study of Adhesion between FRCM and Masonry Support". Key Engineering Materials 624 (septiembre de 2014): 189–96. http://dx.doi.org/10.4028/www.scientific.net/kem.624.189.
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The use of composites with cement matrix seems to acquire an increasing interest in applications to masonry structures, due to their low impact, and a deeper understanding of the mechanical interaction between support and reinforcement is certainly necessary. The effectiveness of these interventions strongly depends on the bond between strengthening material and masonry, on the fibers/matrix interface, as well as on the mechanical properties of the masonry substrate [1]. In this work the attention was focused on the possible improvement of the bond between FRCM and masonry by means of an inorganic primer, which can be spread on the ceramic support before the application of FRCM reinforcement. Two different kinds of brick were tested, in order to simulate more or less porous masonry supports. Results obtained showed that, independently on the kind of brick used (more or less porous) the presence of an inorganic primer always improves bond between masonry support and the cementitiuos matrix of FRCM. In fact, the cementitous matrix of FRCM has been studied and optimized in order to guarantee the best fibers/matrix interface, while it is not necessarily the best option for improving the adhesion with the masonry support. In particular, very effective seems to be the use of very fine inorganic particles (at nanometric scale), which proved to be able to assure the best results in terms of bond strength. Also the fresh consistence of the primer seemed to influence the final result.
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Izquierdo, O. S., M. R. S. Corrêa y I. I. Soto. "Study of the block/grout interface in concrete and clay block masonry structures". Revista IBRACON de Estruturas e Materiais 10, n.º 4 (agosto de 2017): 924–36. http://dx.doi.org/10.1590/s1983-41952017000400009.
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ABSTRACT This work aims to study the behavior of the block/grout interface for concrete and clay block masonry. This was achieved by push-out and pull-out experimental tests including reinforcement bar in the latter one. The experimental result showed that there is a good bond between the concrete blocks internal faces and the grout, enough to prevent infill-slippage, and that the whole tensile strength of the usual reinforcement bars is achieved provided they are properly anchored. Nevertheless, for clay blocks there is a low bond between the clay blocks internal faces and the grout, allowing the infill-slippage before the reinforcement bars reach their yield stress.
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Bruggi, Matteo y Alberto Taliercio. "Topology Optimization of the Fiber-Reinforcement of No-Tension Masonry Walls". Key Engineering Materials 747 (julio de 2017): 36–43. http://dx.doi.org/10.4028/www.scientific.net/kem.747.36.
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An innovative approach is proposed to define the optimal fiber-reinforcement of in-plane loaded masonry walls, modeled as linear elastic no-tension (NT) bodies. A topology optimization formulation is presented, which aims at distributing a prescribed amount of reinforcement over the wall, so as to minimize the overall elastic energy of the strengthened element. Perfect bonding is assumed at the wall-reinforcement interface. To account for the negligible tensile strength of brickwork, the material is replaced by an equivalent orthotropic material with negligible stiffness along the direction (s) undergoing tensile principal stress (es). Compressive principal stresses in the reinforcement are not allowed. A single constrained optimization problem allows both the equilibrium of the NT body to be enforced, and the optimal reinforcing layout to be spotted out, without any demanding incremental approach. Some preliminary numerical examples are shown to assess the capabilities of the proposed procedure and to identify the optimal reinforcement patterns for common types of masonry walls with openings.
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Hernoune, Houria, Benchaa Benabed, Antonios Kanellopoulos, Alaa Hussein Al-Zuhairi y Abdelhamid Guettala. "Experimental and Numerical Study of Behaviour of Reinforced Masonry Walls with NSM CFRP Strips Subjected to Combined Loads". Buildings 10, n.º 6 (31 de mayo de 2020): 103. http://dx.doi.org/10.3390/buildings10060103.
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Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) walls using the detailed micro-modelling approach (DMM) by means of ABAQUS software. In this analysis, the non-linearity behavior of brick and mortar was simulated using the concrete damaged plasticity (CDP) constitutive laws. The results proved that the application of the NSM-CFRP strips on the masonry wall influences significantly strength, ductility, and post-peak behavior, as well as changing the failure modes. The adopted DMM model provides a good interface to predict the post peak behavior and failure mode of unreinforced brick masonry walls.
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Borri, Anatonio, Giulio Castori y Marco Corradi. "Design Criteria for Masonry Reinforcement with Composite Reinforced Mortars (CRM)". Key Engineering Materials 916 (7 de abril de 2022): 498–504. http://dx.doi.org/10.4028/p-k031gd.
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There is an emerging need to upgrade historic masonry buildings and infrastructures which are most vulnerable to earthquakes. An objective of a long-term research program at Perugia University, Italy was developing design criteria for masonry reinforcement using a new class of materials, using Composite Reinforced Mortars (CRM). These are typically made of fiberglass meshes embedded into a cementitious or lime mortar, which offers higher sustainability features, in terms of vapour permeability and compatibility with masonry, lower costs, and better performance at high temperatures, compared to more traditional steel rebar jacketing or epoxy-bonded composites. These design criteria have been based on a comprehensive experimental and numerical research plan that included a study of the influence of reinforcing material, coating and wall thickness, and associated masonry strength and elastic properties, and the interaction of different stress states on bond behavior at interface masonry-to-coating. A design equation suitable for ultimate load design has been developed. Finally, analytical models regarding the lateral capacity of shear walls are briefly discussed.
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Maroušková, Aneta. "Masonry Column Reinforced by FRP Wrapping: Behavior and Numerical Analysis". Applied Mechanics and Materials 825 (febrero de 2016): 27–30. http://dx.doi.org/10.4028/www.scientific.net/amm.825.27.
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A numerical analysis for masonry columns is presented in this paper. The behavior and character of deformation of compressed unreinforced masonry columns is investigated and compared with the deformation of masonry columns reinforced by FRP wrapping. The experimental program is part of a research project NAKI [1]. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The contact between reinforcement and masonry support is considered as perfectly-adherent. Two different cases are simulated - the ratio of Young ́s modulus of brick and Young’s modulus of mortar is 5:1, respectively 1:5. For all simulations the commercial software package ABAQUS was used and the obtained numerical results are discussed.
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Maroušková, Aneta. "Reinforced Masonry Column’s Analysis: The Influence of Rounded Corners". Advanced Materials Research 1144 (marzo de 2017): 34–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1144.34.
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Numerical analysis of masonry structures is a complex task requiring deep knowledges about the problematics. This paper deals with concentrically compressed brick masonry column reinforced by fiber reinforced polymer (FRP) wrapping. The experimental research across the world has proved that FRP external sheets are an efficient tool for stabilization or strengthening of masonry structures. A combination of several types of column’s failure were observed during the experimental testing – failure in masonry, rupture of FRP sheet or failure at interface between reinforcement and masonry support. The rupture of sheet occurs close to sharp corners under the assumption of sheets’ perfect overlap. The rounded corners result in an enlargement of the FRP-masonry contact and reduction of the stress concentration. The increasing of an effective area causes a greater influence of FRP wrapping. For all 3D simulations the commercial software package ABAQUS was used and the obtained results are discussed.
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Bertolli, Veronica y Tommaso D'Antino. "Calibration of a Rigid-Trilinear Cohesive Material Law to Describe the Matrix-Fiber Bond Behavior in FRCM Composites". Key Engineering Materials 916 (7 de abril de 2022): 393–400. http://dx.doi.org/10.4028/p-z1kd07.
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Fiber-reinforced cementitious matrix (FRCM) composites have been increasingly adopted as externally bonded reinforcement (EBR) of existing concrete and masonry members. Being debonding at the matrix-fiber interface one of the most frequent failure mechanisms of externally bonded FRCM, the matrix-fiber bond behavior represents a fundamental aspect for the effectiveness of the external reinforcement. A cohesive material law (CML) that describes the interface where debonding occurs can be used to model the bond behavior observed. In this paper, a rigid-trilinear CML is used to solve the differential equation that governs the bond problem at the matrix-fiber interface of an FRCM composite. The CML adopted has peculiar characteristics that entail for a finite length of the bond stress transfer zone (BSTZ). Furthermore, it allows for a simple and accurate analytical solution of the bond problem. The analytical solution obtained is compared with the results of an experimental campaign comprising single-lap direct shear tests of a polyparaphenylene benzobisoxazole (PBO) FRCM composite specifically designed for masonry substrates. Different calibrations of the rigid-trilinear CML are proposed, also considering the matrix-fiber free end slip.
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Tamborrino, Ottavio, Daniele Perrone, Marianovella Leone y Maria Antonietta Aiello. "Experimental Study on the Fiber-Matrix Interface Behavior of FRCM/CRM Reinforcement Systems". Key Engineering Materials 916 (7 de abril de 2022): 409–16. http://dx.doi.org/10.4028/p-0484vd.
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Masonry existing buildings are subjected to significant structural damages when seismic events occur. Over the last decades, innovative techniques like composite materials based on inorganic mortar (FRCM – Fiber Reinforced Cementitious Matrices) have emerged as attractive solutions for the strengthening of civil structures. FRCM shows better compatibility with masonry substrates with respect to Fiber Reinforced Polymers. The effectiveness of FRCM reinforcement systems relies on the composite-substrate bond behavior which is affected by many parameters, leading to different failure mechanisms. Although numerous studies investigate the FRCM-substrate bond, few attentions have been paid to the study of fiber grid-matrix interface behavior. In this study, the preliminary results of a wider experimental campaign aimed at investigating the interface behavior between fiber and mortar accounting for the contribution of transversal grid wires are presented. Different typologies of fiber and mortar were tested and the results are compared and discussed.
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Bertolesi, Elisa, Mario Fagone, Ernesto Grande, Gabriele Milani y Tommaso Rotunno. "Advanced and Simplified Modeling Approaches for the Study of the Bond Behavior of FRP Systems on Curved Masonry Substrates". Key Engineering Materials 916 (7 de abril de 2022): 172–79. http://dx.doi.org/10.4028/p-f711n5.
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Curved masonry structures externally strengthened by Fiber Reinforced Polymer (FRP) systems exhibits failure mechanisms that emphasize a local bond behavior particularly influenced by the curved geometry of the substrate and the position of the strengthening (i.e. at the intrados or extrados). Indeed, together with tangential stresses, normal stresses in tension or compression also arise by leading to a combined mode I–mode II behavior of strengthening system at the reinforcement/masonry interface level. In recent studies, the Authors proposed different modeling approaches for FRPs applied to curved masonry structures. In particular, both micro-modeling detailed approaches and simplified approaches were generally proposed. The present paper critically analyzes these models by underlining the main differences among them, the assumptions and their ability to reproduce specific phenomena experimentally observed.
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Maroušková, Aneta. "Non-Linear Numerical Analysis of Unreinforced Masonry Column and Masonry Column Reinforced by FRP Wrapping". Applied Mechanics and Materials 827 (febrero de 2016): 279–82. http://dx.doi.org/10.4028/www.scientific.net/amm.827.279.
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A numerical model for unreinforced masonry columns and masonry columns reinforced by FRP wrapping is presented in this paper. Both, the bricks and the mortar are modeled as 3D continuum and to the interface between these two materials a non-linear contact law is assigned. The accurate 3D modeling of masonry units and mortar joints within the numerical model leads to high computational cost, but on the other hand, an appropriate analysis tool delivering detailed information about the behavior of masonry columns is obtained. A concrete damaged plasticity model was adopted for mortar and brick. External wrapping by a perfectly-adherent composite based strips and contact between strips and masonry is defined in the next step. The behavior of reinforcement was assumed isotropic and linearly elastic. The response and failure mechanism of masonry columns can be investigated. For all simulations the commercial software package ABAQUS was used. By comparison with results from experiments [1], the performance of the numerical model is evaluated and the obtained numerical results are discussed.
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Pantò, Bartolomeo, Marialaura Malena y Gianmarco de Felice. "Non-Linear Modeling of Masonry Arches Strengthened with FRCM". Key Engineering Materials 747 (julio de 2017): 93–100. http://dx.doi.org/10.4028/www.scientific.net/kem.747.93.
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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.
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Hatami, Kianoosh, Jaime E. Granados, Danial Esmaili y Gerald A. Miller. "Reinforcement Pullout Capacity in Mechanically Stabilized Earth Walls with Marginal-Quality Soils". Transportation Research Record: Journal of the Transportation Research Board 2363, n.º 1 (enero de 2013): 66–74. http://dx.doi.org/10.3141/2363-08.
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Pullout capacity of geotextile reinforcement is an important consideration in the analysis of internal stability of reinforced soil structures, especially those constructed with marginal soils. Precipitation, ground water infiltration, and seasonal variations of water content during the construction process or service life of the structure could result in significant reductions in the matric suction and lead to a reduction in the strength of the soil–geotextile interface. Consequently, the reinforced soil structure may experience unacceptable deformations or even failure during its construction or postconstruction periods. The loss of matric suction in the soil influences both the shear strength of the soil and the soil–reinforcement interface. However, the focus of this study was merely on the latter. Nine pullout tests and 18 interface shear tests were performed to measure the pullout resistance of a reinforcement geotextile in a marginal soil that was compacted at different gravimetric water contents (GWCs). The marginal soil was selected to meet the limiting requirements of the National Concrete Masonry Association guidelines for segmental retaining walls with respect to fines content, gradation, and plasticity. The range of GWC values investigated varied from the dry to the wet side of the optimum moisture content of the soil. The matric suction in the soil was measured to evaluate its influence on the soil–reinforcement interface shear strength. A moisture reduction factor is proposed to account for the reduction in the soil–geotextile interface strength as a result of the loss in matric suction.
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Jasiński, Radosław. "NUMERICAL ANALISIS OF THE STRAINS AND STRESS STATES REINFORCED CLAY BRICK MASONRY WALLS HORIZONTALLY SHEARED". International Journal of Engineering Technologies and Management Research 5, n.º 8 (21 de marzo de 2020): 20–37. http://dx.doi.org/10.29121/ijetmr.v5.i8.2018.277.
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This paper presents the results: stress and strain of bed joints mortar, masonry units, reinforcement bars and mechanism of cracking of numerical simulations using ANSYS of reinforced brick wall in the horizontal shear. Willam-Warnke (WW-5) failure criterion for mortar and bricks and Huber-Mises-Hencky (HMH) plasticity surface for bed joints steel reinforcement (steel smooth bars and truss type reinforcement) has been used. Coulomb-Mohr (CM) criterion in the contact surfaces of mortar and bricks have been used in the interface elements. Numerical calculations showed satisfactory convergence of research in the patterns of cracking; and the load-strain relationship was similar to the results of research with regard only to the cracking time. Destructive force numerical models Hu,cal correspond to the forces observed at the first cracks in the walls Hu,mv. Reduction of transverse and longitudinal deformation of mortar bed joints have been reported in the immediate vicinity of the bars, and the reduction of the main stress of the bricks is reported in the case of the use reinforcement.
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Yuan, Yu y Gabriele Milani. "A Simple and Low-Cost Numerical Model for FRP-Masonry Interface Behavior". Key Engineering Materials 916 (7 de abril de 2022): 163–71. http://dx.doi.org/10.4028/p-h8cv80.
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In recent years, strengthening with Fiber Reinforced Polymers (FRPs) has emerged as an effective way for the structural upgrading of masonry elements. In such typology of external reinforcement, the bond quality is crucial for the increase of the load bearing capacity. The bond efficacy beyond the elastic limit can be studied analytically or numerically via several different models, where the most important issue to tackle is the reproduction of the typical brittle behavior of the substrate. In this paper, a simple numerical approach which models FRP as elastic and lumps all non-linearity on the FRP/masonry interface is proposed. The non-linear behavior of such interface is modeled in a simplified but effective way integrating numerically the differential equations deduced from equilibrium and compatibility (once that a non-linear constitutive relationship between tangential stress and slip is assumed at the interface). Such integration is carried out by means of a particularly simple forward scheme that requires the estimation of the slip value and its derivatives on specific knot points. A comparison against existing literature indicated that the proposed numerical procedure can adequately reproduce global load-displacement curves in standard single lap shear tests, as well predict the local slip behavior.
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Hernoune, Houria, Benchaa Benabed, Rajab Abousnina, Abdalrahman Alajmi, Abdullah M. GH Alfadhili y Abdullah Shalwan. "Experimental Research and Numerical Analysis of CFRP Retrofitted Masonry Triplets under Shear Loading". Polymers 14, n.º 18 (6 de septiembre de 2022): 3707. http://dx.doi.org/10.3390/polym14183707.
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This paper presents an experimental and numerical study into the shear response of brick masonry triplet prisms under different levels of precompression, as well as samples reinforced with carbon fiber-reinforced polymer (CFRP) strips. Masonry triplets were constructed with two different mortar mix ratios (1:1:3 and 1:1:5). In this study, finite element models for the analysis of shear triplets are developed using detailed micro-modelling (DMM) approach and validated with the experimental data. The failure mechanisms observed in the masonry triplets were simulated using a coupled XFEM-cohesive behaviour approach in ABAQUS finite element software. The nonlinear behaviour of mortar and brick was simulated using the concrete damaged plasticity (CDP) constitutive laws. The cohesive element with zero thicknesses was employed to simulate the behaviour of the unit–mortar interfaces. The extended finite element method (XFEM) was employed to simulate the crack propagation in the mortar layer without an initial definition of crack location. CFRP strips were simulated by 3D shell elements and connected to masonry elements by an interface model. The changes in failure mechanism and shear strength are calculated for varying types of mortar and fiber orientation of CFRP composite. Based on this study, it was concluded that the ultimate shear strength of masonry triplets is increased due to the external bonding of CFRP strips. The performance of masonry specimens strengthened with CFRP strips is assessed in terms of gain in shear strength and post-peak behaviour for all configurations and types of mortar considered. The comparison of FE and experimental results proved that the models have the potential to be used in practice to accurately predict the shear strength and reflect damage progression in unreinforced and CFRP-reinforced masonry triplets under in-plane loading, including the debonding of the CFRP reinforcement. Additionally, XFEM was found to be a powerful technique to be used for the location of crack initiation and crack propagation in the mortar layer.
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Al-Lami, Karrar, Angelo Savio Calabrese, Pierluigi Colombi y Tommaso D’Antino. "Effect of Wet-Dry Cycles on the Bond Behavior of Fiber-Reinforced Inorganic-Matrix Systems Bonded to Masonry Substrates". Materials 14, n.º 20 (18 de octubre de 2021): 6171. http://dx.doi.org/10.3390/ma14206171.
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In recent years, inorganic-matrix reinforcement systems, such as fiber-reinforced cementitious matrix (FRCM), composite-reinforced mortars (CRM), and steel-reinforced grout (SRG), have been increasingly used to retrofit and strengthen existing masonry and concrete structures. Despite their good short-term properties, limited information is available on their long-term behavior. In this paper, the long-term bond behavior of some FRCM, CRM, and SRG systems bonded to masonry substrates is investigated. Namely, the results of single-lap direct shear tests of FRCM-, CRM-, and SRG-masonry joints subjected to wet-dry cycles are provided and discussed. First, FRCM composites comprising carbon, polyparaphenylene benzobisoxazole (PBO), and alkali-resistant (AR) glass textiles embedded within cement-based matrices, are considered. Then, CRM and SRG systems made of an AR glass composite grid embedded with natural hydraulic lime (NHL) and of unidirectional steel cords embedded within the same lime matrix, respectively, are studied. For each type of composite, six specimens are exposed to 50 wet–dry cycles prior to testing. The results are compared with those of nominally equal unconditioned specimens previously tested by the authors. This comparison shows a shifting of the failure mode for some composites from debonding at the matrix–fiber interface to debonding at the matrix-substrate interface. Furthermore, the average peak stress of all systems decreases except for the carbon FRCM and the CRM, for which it remains unaltered or increases.
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Verre, Salvatore, Alessio Cascardi, Maria Antonietta Aiello y Luciano Ombres. "Numerical Modelling of FRCMs Confined Masonry Column". Key Engineering Materials 817 (agosto de 2019): 9–14. http://dx.doi.org/10.4028/www.scientific.net/kem.817.9.
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The Fabric Reinforced Cementitious Matrices (FRCMs) are promising strengthening solution for existing masonry since the inorganic matrix is considerably compatible with historical substrates. Nevertheless, the matrix is responsible for the stress-transfer in composites so, in case of poor-quality mortar, the effectiveness of the strengthening can be limited or even compromised. For this reason, a few studies have been targeted to this aspect in the recent past, while numerical investigations are still limited. The present paper refers to a Finite Element (FE) analysis of masonry columns confined with FRCM composites developed by Abaqus-code and based on the macro-model approach. At this scope, available experimental results were used for the calibration regarding different types of the matrix (lime and cement based) for FRCM-confinement. The model was performed by using the Plastic (P) and the Concrete Damage Plasticity (CDP) material constitutive laws. The FRCM-strengthened system was preliminary modeled as a homogenous elastic material until failure. Typical failures of FRCM-systems are the detachment of the matrix from the substrate, slippage of the fibers within the embedding matrix, detachment of the composite strip at the fabric-matrix interface and fiber rupture. In this study, a perfect bond was considered for the interaction between the masonry column and the external reinforcement according to the experimental observations (calibration specimens). The parametric analysis allowed to evidence the influence of the mechanical and geometrical parameters on the structural performances of the FRCM-system in confining column.
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Leone, Marianovella y Maria Antonietta Aiello. "Bond Tests on Clay Bricks and Natural Stone Masonry Externally Bonded with FRP". Materials 14, n.º 23 (4 de diciembre de 2021): 7439. http://dx.doi.org/10.3390/ma14237439.
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Nowadays, the solution of durability problems of existing buildings has a key role in civil engineering, in which there is an ever-increasing need for building restorations. Over the past 50 years, there is a growing interest in a new composite material, fibre-reinforced polymer (FRP), suitable for increasing the resistance and the stability of existing buildings and, consequently, for extending their service life. In this context, the effectiveness of the strengthening system is related to the bond behaviour that is influenced by several parameters such as bond length, the stiffness of the reinforcement, the mechanical properties of the substrate, environmental conditions, etc. This paper aims to analyse the main experimental results from shear tests performed on two kinds of masonry substrates and different types of FRP reinforcements. The purpose is to highlight the role played by many parameters to the bond behaviour of these systems: the mechanical properties of substrates; the stiffness of reinforcements; the type of supports (i.e., unit or masonry unit). The obtained experimental results underlined that the specimens realised with masonry unit show an increase in debonding load and different stress transfer mechanisms along the bonded length with respect to the specimens with a unit substrate. The analysis of the data revealed that the presence of mortar joints cannot be neglected because it influences the interface global performance.
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Hou, Wei, Xinghua Dai, Zheyu Yang, Hanhuang Huang, Xiaoli Wang, Pandeng Zheng, Yixin Zhang y Zixiong Guo. "Seismic Behavior of Stone Masonry Joints with ECC as a Filling Material". Materials 14, n.º 21 (5 de noviembre de 2021): 6671. http://dx.doi.org/10.3390/ma14216671.
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This paper investigates the seismic behavior of novel stone masonry joints using ductile engineered cementitious composite (ECC) as a substitute for ordinary mortar. Ten stone masonry joints with different types of mortar/ECC were tested under axial and cyclic loads. The filling materials of mortar joints tested included ordinary mortar, polymer mortar, ECC, and composite mortar with two combination proportions of ECC and ordinary mortar. The test results indicated that ECC specimens exhibited a more stable hysteretic response as well as an improvement in strength, deformation, energy dissipation, and strength degradation. The ECC mortar joints maintained integrity during the entire loading process due to the “self-confinement” effect of ECC. A partial substitution of mortar with ECC could provide effective reinforcement and confinement to prevent mortar failure and peeling, thereby allowing such specimens to approach the seismic performance of ECC specimens. Based on the trend of shear strength variations, a corresponding failure process is defined for ECC/mortar joints under cyclic and axial compressive loads, including four distinct stages: linear elastic, crack-developing stage, interface debonding, and friction sliding. New equations are proposed for predicting the shear strength and residual shear strength of the ECC/mortar joints on the basis of the test results, which are validated in the composite mortar specimens.
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Donnini, Jacopo, Giovanni Lancioni, Tiziano Bellezze y Valeria Corinaldesi. "Bond Behavior of FRCM Carbon Yarns Embedded in a Cementitious Matrix: Experimental and Numerical Results". Key Engineering Materials 747 (julio de 2017): 305–12. http://dx.doi.org/10.4028/www.scientific.net/kem.747.305.
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The use of inorganic cement based composite systems, known as Fiber Reinforced Cementitious Matrix (FRCM), is a very promising technique for retrofitting and strengthening the existing masonry or concrete structures. The effectiveness of FRCM systems is strongly related to the interface bond between inorganic matrix and fabric reinforcement, and, since the major weakness is often located on this interface, the study of stress-transfer mechanisms between fibers and matrix becomes of fundamental importance.FRCM are usually reinforced with uni-directional or bi-directional fabrics consisting of multifilament yarns made of carbon, glass, basalt or PBO fibers, disposed along two orthogonal directions. The difficulty of the mortar to penetrate within the filaments that constitute the fabric yarns and the consequent non-homogeneous stress distribution through the yarn cross section makes difficult to access the characterization of the composite material. The use of polymer coatings on the fibers surface showed to enhance the bond strength of the interface between fibers and mortar and, as a consequence, to improve the mechanical performance of the composite. The coating does not allow the mortar to penetrate within the filaments while is able to improve the bond between the two materials and to increase the shear stress transfer capacity at the interface.An experimental session of several pull out tests on carbon yarns embedded in a cementitious matrix was carried out. Different embedded lengths have been analyzed, equal to 20, 30 and 50 mm. The carbon yarns object of this study were pre-impregnated with a flexible epoxy resin enhanced with a thin layer of quartz sand applied on the surface.A variational model was proposed to evaluate the pull-out behaviour and failure mechanisms of the system and to compare numerical results to the experimental outcomes. Evolution of fracture in the yarn-matrix system is determined by solving an incremental energy minimization problem, acting on an energy functional which account for brittle failure of matrix and yarn, and for debonding at the yarn-matrix interface. The model was able to accurately describe the three phases of the pull-out mechanism, depending on the embedded length.
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Baraldi, Daniele, Giosuè Boscato, Antonella Cecchi y Claudia Brito de Carvalho Bello. "An Updated Discrete Element Model for the In-Plane Behaviour of NFRCM Strengthened Masonry Walls". Key Engineering Materials 916 (7 de abril de 2022): 249–55. http://dx.doi.org/10.4028/p-1853qe.
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Abstract. Masonry strengthened with natural fabric-reinforced cementitious matrix (NFRCM-strengthened masonry) is investigated by updating an existing discrete element model. Masonry walls are modelled by rigid blocks and elastoplastic interfaces that are able to account for mortar joints and block cracking. The reinforcement is modelled in a simplified manner considering perfect adhesion between wall and reinforcement and by adopting further spring elements connecting block centres. The model is validated by comparing it with an existing FEM based on a multi-step homogenization, where reinforced masonry is considered as a whole. Both approaches are used for performing nonlinear pushover tests with an increasing shear action applied to unreinforced and reinforced panels. The updated discrete model turns out to be able to represent the strength increment given by the reinforcement, but it is less able to represent the corresponding ductility increment.
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Baraldi, Daniele, Giosuè Boscato, Claudia Brito de Carvalho Bello, Antonella Cecchi y Emanuele Reccia. "Discrete and Finite Element Models for the Analysis of Unreinforced and Partially Reinforced Masonry Arches". Key Engineering Materials 817 (agosto de 2019): 229–35. http://dx.doi.org/10.4028/www.scientific.net/kem.817.229.
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In this work the behavior of masonry arches, without reinforcement and with partial reinforcement, is investigated by means of three different numerical models. The first one is a Discrete Element model based on rigid blocks, and elastic-plastic interfaces; the second one is a standard heterogeneous Finite Element Model, which is adopted for a detailed micro-modelling of arch voussoirs, joints, and reinforcements. The third model is analytic-numerical, and it is adopted for validating the other numerical results. The aim of the work is the comparison and validation of the numerical Finite and Discrete Element models for the correct simulation of masonry arch behavior, together with the evaluation of the effectiveness of these models in simulating the behavior of the partially reinforced arch.
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Chiozzi, Andrea, Gabriele Milani, Nicola Grillanda y Antonio Tralli. "Fast and Reliable Limit Analysis Approach for the Structural Assessment of FRP-Reinforced Masonry Arches". Key Engineering Materials 747 (julio de 2017): 196–203. http://dx.doi.org/10.4028/www.scientific.net/kem.747.196.
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This contribution is devoted to assess the capability of a new upper-bound approach for the limit analysis of FRP-reinforced masonry arches by comparing it to both experimental tests and a number of existing numerical procedures. The approach is based on an idea previously presented by the Authors and relies on the representation of the geometry of both the arch and of FRP reinforcement through Non Uniform Rational B-Spline (NURBS) functions. This allows generating a rigid body assembly starting from the assigned geometry composed by very few elements which still provide an exact representation of the original shape. A homogenized kinematic formulation for the limit analysis of the obtained rigid blocks assembly is derived, which accounts for the main properties of masonry material. FRP material is included exploiting the Italian CNR Recommendations for the design of FRP based reinforcing interventions. The approach is capable of accurately predicting the load bearing capacity of masonry arches of arbitrary geometry, provided that the initial mesh is adjusted by means of a suitably devised Genetic Algorithm (GA) until the active interfaces among blocks (e.g. hinges) closely approximate the actual failure mechanism.
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Hong, Sung Gul y Woo Young Lim. "Flexural and Shear Strength of Granite Reinforced by Metal Rods". Advanced Materials Research 133-134 (octubre de 2010): 417–22. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.417.
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This paper investigates feasibility of reinforcement method for fractured granite of slab type and beam members used as components of old stone masonry pagodas. Investigation of the effect of reinforcement to flexural and shear strength is performed using the concept for the high strength concrete since the mechanical properties of granite are similar to properties of high strength of concrete. In this experimental program two types of notched specimens are intended for failures with shear and flexural cracks. Intended fractured specimens are reinforced by metal rods, so called pinning method. The rods are inserted in holes and bonded with inorganic cement. The metal rods are supposed to transfer forces by tensile resistance in flexure and dowel action in shear. Increase in shear and flexural capacities and ductile behavior after sudden yielding of the metal rods are observed. The final failure cracks in reinforced specimens occurred different from interfaces along the original cracks. Locations of metal rods, their numbers, and construction of anchored rod are main variables to be examined for guidelines for reinforcement methods.
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Anggreni, Made Yani, I. K. Sudarsana y M. Sukrawa. "PERILAKU TEKAN DAN LENTUR DINDING PASANGAN BATAKO TANPA PLESTERAN, DENGAN PLESTERAN DAN DENGAN PERKUATAN WIREMESH". Jurnal Spektran, 2 de julio de 2015. http://dx.doi.org/10.24843/spektran.2015.v03.i02.p02.
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Concrete blocks are one of the common materials used in construction practice because they are quite easy to get and the price is relatively cheap. Masonry (either concrete blocks or bricks) is a structure consisting of a binding material (mortar) and a filler material (such as concrete blocks). In general, masonry is very good at resisting gravity loads, but not quite good at resisting shear loads such as loads generated by earthquakes, so it requires reinforcement in the form of plaster and additional wire mesh in the plaster of the masonry. Due to several problems of the masonry frame structure, it is necessary to conduct a research on the quality of the masonry to find out the compressive and flexural behavior of the masonry with reinforcement namely plaster and wire mesh. The method used in this study was laboratory testing by creating specimens of concrete block masonry. Variations of masonry for compressive tests in this study 3 specimens varied based on the orientation namely Type A (Horizontal), Type B (Vertical) and Type C (Diagonal), and 3 specimens varied based on the treatment: masonry without plaster (TP), masonry with plaster (DP), and masonry with wire mesh reinforcement (DPW). Variations of masonry for bending tests perpendicular to the bed joint (LA) and parallel to the bed joint (LB). Based on the results the crack patterns occurring in the specimens were relatively the same, where the initial cracks occurred predominantly in the interface area between the mortar and concrete blocks. The compressive strength of the concrete block masonry with plaster had a higher value than that of with wire mesh reinforcement. This was due to adhesion between the mortar and wire mesh and poor density so the performance of wire mesh was less effective. The concrete block masonry of Type C had the highest modulus of elasticity value. This was because the propagation of cracks that occurred in the masonry of Type C was slowed down by the position of the concrete blocks, which were installed with a slope of 45o. Meanwhile, the propagation of cracks of Type A and Type B occurred vertically in the interface between the mortar and concrete blocks. Flexural strength values ??of specimens that were perpendicular to the bed joint (LTPA, LDPA, and LDPWA) were much higher than that of parallel to the bed joint (LTPB, LDPB and LDPWB). The addition of the wire mesh reinforcement to the compressive load did not contribute much to the stiffness of the masonry. Meanwhile in the bending tests, the addition of wire mesh reinforcement resulted in an increase in the flexural strength values of the concrete block masonry.
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Izquierdo, Orieta Soto, Márcio Roberto Silva Corrêa, Indara Soto Izquierdo y Iván Gómez Araújo. "Numerical and parametric study of the yield stress limits of reinforcement bars in clay block masonry structures". Revista IBRACON de Estruturas e Materiais 14, n.º 6 (2021). http://dx.doi.org/10.1590/s1983-41952021000600011.
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abstract: The Brazilian Standard Structural Masonry considers for the maximum tensile stress (fs) of the reinforcements embedded in the grout in clay blocks with smooth surfaces several limits of the yield stress for the reinforcement (fyk). This work aims to analyze the limits of the yield stress of reinforcement bars in clay block masonry structures by numerical and parametric analysis in push-out and pull-out tests, varying the type of grout and reinforcement diameter. A numerical study was performed using a 3D-model with the DIANA® software based on the Finite Element Method. The parametric study confirmed that the limits obtained in this research for reinforcement diameter of 8 mm, 10 mm, 12.5 mm and 16 mm are in agreement with the limits specified by the Brazilian Standard, with exception of the 20 mm diameter, which limit was lower than indicated by the Standard. The tensile stress limits of the embedded reinforcement progressively reduce with increasing rebar diameter, being the failure is dominated by the bond strength of the block/grout interface.
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Soti, Rajendra, Andre R. Barbosa y Andreas Stavridis. "Numerical Assessment of URM Infilled RC Frames Retrofitted With Near-Surface Mounted Reinforcing Steel Bars". Frontiers in Built Environment 6 (27 de noviembre de 2020). http://dx.doi.org/10.3389/fbuil.2020.590302.
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This paper presents a study on a retrofit technique for masonry infilled reinforced concrete (RC) frames. The proposed retrofit technique involves the addition of reinforcing steel bars into epoxy-filled pre-cut grooves on the surface of infill walls. The feasibility of the developed technique is initially investigated experimentally through pull-out tests conducted on near-surface mounted (NSM) reinforcing steel bars. The experimental results are used to augment an existing nonlinear finite element modeling approach used to simulate the response of RC frames with the retrofitted infill panels and to calibrate the numerical models developed. The nonlinear finite element models employ smeared-crack and zero-thickness cohesive-crack interface elements to model the RC members and masonry infills, while nonlinear truss elements are used to model the reinforcing steel bars. The modeling scheme is used to numerically simulate the performance of one- and two-bay infilled RC frames with a variety of reinforcing steel retrofit configurations under lateral loads. The results indicate that the retrofit solution can improve the deformation capacity of existing infilled frames, and its effectiveness depends on the orientation and the distribution of the NSM reinforcement steel bars that are added to the infill panels.