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Numerical Analysis of Reinforced Masonry Shear Walls Using the Nonlinear Truss ApproachWilliams, Scott A. 29 January 2014 (has links)
Reinforced masonry (RM) shear walls are a common lateral load-resisting system for building structures. The seismic design guidelines for such systems are based on relatively limited experimental data. Given the restrictions imposed by the capabilities of available experimental equipment, analytical modeling is the only means to conduct systematic parametric studies for prototype RM wall systems and quantify the seismic safety offered by current design standards. A number of modeling approaches, with varying levels of complexity, have been used for the analysis of reinforced concrete (RC) and masonry wall structures. Among the various methods, the truss analogy is deemed attractive for its conceptual simplicity and excellent accuracy, as indicated by recent studies focusing on RC walls.
This thesis uses an existing modeling method, based on nonlinear truss models, to simulate the behavior of fully grouted reinforced masonry shear walls. The modeling method, which was originally created and used for RC walls, is enhanced to capture the effect of localized sliding along the base of a wall, which may be the dominant mode of damage for several types of RM walls. The truss modeling approach is validated with the results of quasi-static cyclic tests on single-story isolated walls and dynamic tests on a multi-story, three-dimensional wall system. For the latter, the truss model is found to give similar results to those obtained using a much more refined, three-dimensional finite element model, while requiring a significantly smaller amount of time for the analysis.
Finally, truss models are used for the nonlinear static analysis of prototype low-rise walls, which had been analyzed with nonlinear beam models during a previous research project. The comparison of the results obtained with the two modeling methods indicates that the previously employed beam models may significantly overestimate the ductility capacity of RM squat walls, due to their inability to accurately capture the shear-flexure interaction and the effect of shear damage on the strength of a wall. / Master of Science
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A new methodology for detailed modelling of historical masonry walls in one-dimensional hygrothermal simulationsBottino-Leone, Dario 26 November 2024 (has links)
The hygrothermal analysis of building envelopes plays a crucial role in the renovation strategies for historical buildings. Dynamical hygrothermal simulations under realistic conditions are effective in predicting moisture-related damages, including the risk of mold growth or frost damage, which can arise when combining historical walls with modern insulation systems. However, accurately modeling and simulating historic walls, composed of brick/stone and mortar joints, using detailed two- or three-dimensional models, is a complex and time-consuming task. As a result, a common practice in hygrothermal simulations is to simplify old masonry into a one-dimensional layer of stone/brick, disregarding mortar joints. Nonetheless, in this study cases were identified where this simplification approach leads to unacceptable inaccuracies, particularly when historic masonry is combined with vapor-tight insulation systems. Also, this study investigated the influence of the internal geometry of mortar joints and the stone/mortar ratio in hygrothermal simulations. While the internal disposition of joints showed minimal influence, the stone/mortar ratio was found to play a significant role.
In light of these findings, this thesis proposes a method to replace the complex representation of historical masonry with a fictitious homogenized porous material that incorporates the influence of mortar joints. The hygrothermal properties of this newly developed ‘Homogenized Porous Material’ are averaged and optimized to closely approximate the behavior of the hygrothermal model for important applications. The proposed method was applied to various combinations of mortars, stones, and bricks. Furthermore, the behavior of the ‘Homogenized Porous Material’ was evaluated under dynamic conditions, specifically for the case of an internally insulated wall in different climates. A comparison was made with a two-dimensional fully described model to assess the performance of the developed method. The results demonstrate considerable improvements compared to the conventional one-dimensional stone/brick layer approximation, with the degree of improvement being more pronounced when the hygrothermal properties of the stone/brick and mortar differ significantly.
The developed method offers significant advantages: for example, the application to 3D building energy simulation tools which entangle moisture balances, allows for quick pre-checks for moisture damage. This can help pre-assessing the potential risks of moisture-related issues in a time-efficient manner also at building component level. Moreover, in time-critical studies where a large number of variant analyses are required, 1D models remain essential as they allow for efficient sensitivity analyses with a large number of simulations runs. This method facilitates a comprehensive exploration of different scenarios and parameter variations, aiding in the identification of critical factors affecting the hygrothermal performance of historic walls. Furthermore, the developed method has potential applications in situations where the inner structure of walls is unknown, such as forensic analysis of historical constructions. By providing a reliable and simplified representation of the hygrothermal behavior, this method can support investigations and assessments of moisture-related issues in historical buildings, even when detailed knowledge of the internal structure is limited.
In conclusion, this research can offer to architects and engineers practical benefits in terms of accurate prediction of moisture-related damages, efficient pre-checks, sensitivity analyses, and applications in cases with limited knowledge of wall structures. In future, an extended database of ‘Homogenized Porous Materials’, suitable to model masonry walls, can be built for the users.:Preface
Abstract
Kurzfassung
Table of Contents
Chapter 1 - Introduction and overview
1.1 Motivation
1.2 Problem statement
1.3 Thesis
1.4 Solution strategy and methodology
1.5 Structure of the study
Chapter 2 - Literature background
2.1 General concepts concerning historical masonry
2.2 Theory and tool for hygrothermal simulations
2.2.1 Balance equation of energy and mass for the porous medium
2.2.2 Flux of energy and mass for the porous medium
2.2.3 Climate and boundary conditions
Incident wind-driven rain
Radiation, short-wave and long-wave
Interior climate
2.3 Main hygrothermal properties of materials and experimental measurement procedures
2.3.1 Bulk density and porosity: helium pycnometer
2.3.2 Specific heat capacity: calorimeter
2.3.3 Thermal conductivity: the hot plate measurement
2.3.4 Vapour conductivity: the cup-tests
2.3.5 Moisture storage function: desiccator method and pressure plates
2.3.6 Liquid conductivity: water uptake and drying experiment
2.3.7 Vapor and liquid conductivity function: capillary condensation redistribution test (CCR)
2.4 Complexity and simplification for the hygrothermal modeling and simulation of historical masonry
Chapter 3 - Quantifying the Impact of Mortar Joints in Hygrothermal Simulations of Historical Masonry
3.1 Investigation through dynamical hygrothermal simulation in realistic condition
3.2 Evidence of mortar joints’ impact in hygrothermal simulations of historic walls
3.3 Dependence of the hygrothermal transport of a masonry wall on its internal geometry
3.4 Discrepancies due to assumptions on stone/mortar ratio
3.5 The case of a three-dimensional simulation
Chapter 4 - A fictitious ‘Homogenized Porous Material’ (HPM) to describe heat and moisture transport in a massive historic wall
4.1 Definition of the preliminary activities: choice of the reference model and of the materials
4.2 Homogenized porous material characterization
4.2.1 Phase 1: hygrothermal properties through analytical calculation
Bulk density, ρ
Porosity, θpor
Specific heat capacity, Cp
Moisture storage function, θl,HPMpc
4.2.2 Phase 2: hygrothermal properties through numerical experiment
Dry Thermal conductivity, λdry
Thermal conductivity function, λ(θl)
Dry water vapour resistance factor, μdry
Water vapour conductivity function, Kv(θl)
4.2.3 Phase 3: hygrothermal properties through optimization algorithm
4.3 Conclusions on the developed method
Chapter 5 - Application of the ‘Homogenized Porous Material’ (HPM) method
5.1 Preliminary activities and reading instructions
5.2 Homogenized Porous Material characterizations in three phases
5.3 Dynamical hygrothermal simulation in realistic condition with Homogenized Porous Materials
5.3.1 Simulations set-up
5.3.2 Analyzed Output
5.3.3 Result of the simulation in realistic design condition with Interior Insulation
5.4 Discussion on the obtained results
5.4.1 Discussion on HPM calibration results
5.4.2 Discussion on HPM dynamical hygrothermal simulation in realistic condition
5.5 Conclusions on the tests
Chapter 6 - Summary, conclusions and outlooks
6.1 Content summary
6.2 Achievements and conclusions
6.3 Future prospects
Appendix I
List of Figures (Appendix I)
List of Tables (Appendix I)
Appendix II
List of Figures (Appendix II)
Appendix III
List of figure (Appendix III)
List of Tables (Appendix III)
List of Abbreviations and Symbols
List of Figures
List of Tables
Acknowledgements
Bibliography
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Nonlinear Truss Analysis of Non-ductile Reinforced Concrete Frames with Unreinforced Masonry InfillsSalinas Guayacundo, Daniel Ricardo 03 May 2016 (has links)
Non-ductile Reinforced Concrete Frames (RCF) with and without Unreinforced Masonry (URM) infills can be found in many places around the world including the Western United States, Eastern Europe, Asia and Latin America. These structures can have an unsatisfactory seismic performance which may even lead to collapse due to brittle failure modes. Furthermore, the effect of the infills on the seismic response of the structural system is not always accounted for in analysis and design. At present, there is no consensus on whether masonry infills are beneficial (by increasing the resistance of the system) or detrimental (by leading to brittle failure modes) for RCF construction.
This study focuses on the development of a simplified modeling approach for non-ductile RCF with URMI that combines the simplicity of strut-and-tie models with the accuracy of Nonlinear Finite Element Analysis (NLFEA). Despite the fact that NLFEA procedures are the most advanced way to address the structural analysis of RCF with URM infills, their conceptual complexity and computational cost may hinder their widespread adoption as an analysis and design tool. At the same time, simplified methods, such as those based on the equivalent strut concept, may be overly crude and neglect essential aspects of the nonlinear response. To address the need for an adequately accurate, but computationally and conceptually efficient analysis method, this study establishes a novel method for planar RCF with URM infills subjected to lateral loads. The method, which is based on the Nonlinear Truss Analogy (NLTA) is shown to have an accuracy comparable to that of NLFEA. Specifically, the method is shown to adequately capture the strength and stiffness degradation and the damage patterns while entailing a reduced computational cost (compared to that of NLFEA). The proposed method is expected to bridge the gap between overly crude equivalent strut models and computationally expensive NLFEA. / Ph. D.
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Advocating SilenceForth, Stephen 12 June 2013 (has links)
The buildings people inhabit everyday frame their existence and provide a backdrop for life. This relationship is inextricable and, as such, begs the question as to whether buildings can function as more than mere containers for life or whether they, at some point or in some capacity, can begin to bare influence over the life or quality of life of their patrons. This project is an intention to explore this qualitative, unquantifiable aspect of building. Through a manipulation of volume and mass, constriction and expansion, solid and void, light and shadow, and the qualities of interiority and exteriority an occupied space will begin to impress itself upon the user. The main objective of this project is to use these architectural properties to create a place that fosters introspection through self awareness. By choosing presence over practicality and content over convention, the construct proposed in this thesis attempts to create spaces that are imposing and unfamiliar yet somehow emotionally reminiscent. Confronted by these contradictions and juxtapositions, this building will stand as an object, in opposition to the occupant, and through that opposition inspire and promote a greater awareness of, and possibly a reflection upon, normally unconscious thought processes. / Master of Architecture
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Behaviour of interlocking mortarless hollow block walls under in-plane loadingSafiee, N.A., Nasir, N.A.M., Ashour, Ashraf, Bakar, N.A. 31 January 2018 (has links)
Yes / Experimental study of five full scale masonry wall panels subjected to prescibed pre-compressive vertical loading and increasing in-plane lateral loading is discussed. All five walls were constructed using interlocking mortarless load bearing hollow concrete blocks. The behaviour of wall in term of deflections along the wall height, shear strength, mortarless joint behaviour and local and overall failures under increasing in-plane lateral loading and pre-compressive vertical loading are reported and analysed. Simple strut-and-tie models are also developed to estimate the ultimate in-plane lateral capacity of the panel walls tested. The results indicate that, as the pre-compressive load increases, the in-plane lateral load capacity of walls increases. All walls tested failed due to diagonal shear and/or moderate toe crushing depending on the level of the pre-compressive load. The proposed strut-and-tie models were able to give reasonable predictions of the walls tested.
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Desenvolvimento de blocos de concreto para construção de silos circulares de alvenaria sem função estrutural. / Development of concrete blocks for the construction of masonry circular silos without structural function.MACIEL, Kuelson Rândello Dantas. 01 July 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-01T14:50:29Z
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Previous issue date: 2002-08 / CNPq / Atualmente estima-se que 25% da produção de grãos produzidos no Brasil, são perdidos nas fases de colheita e pós-colheita, parte desta perda referente ao armazenamento, pode ser minimizada, caso o país estimule a estocagem da produção nas próprias fazendas. Para isso é necessário ter disponível tecnologia simples, entre as quais, a de construção de silos para que se possa construir nos locais de produção. Com intuito de colaborar para uma política de armazenagem de grãos em fazendas, o presente
trabalho tem o objetivo de estudar blocos de concreto para serem utilizados na construção de silos cilíndricos de alvenaria. Logo foi desenvolvido um bloco com geometria especial para se utilizar em silos cilíndricos, e analisando-se a absorção de água , as resistência à
compressão e tração dos blocos confeccionados com traço de 1:3, 1:4 e 1:6 submetendo-os a dois tipos de cura: natural e submersa. Dentre os traço estudados para confecção de blocos de concreto o único que não atingiu resistência à compressão exigida pela NBR 7173 foi o traço 1:6, mas a resistência dos blocos em todos os traços foram superior aos esforços atuante no silo com dimensões estudadas. Enquanto que para resistência à tração não há norma especifica, com isso foi desenvolvida uma metodologia para simular o esforço de tração que as paredes dos silos cilíndricos estão submetidos e o blocos que foram moldados com traço 1:3 e 1:4 obtiveram resistência superior a necessária para um silo de 4m de altura e relação altura /diâmetro igual a 1. / Nowaday it's estimated that 25% o f the grains produced in Brazil are lost in the crop and
post-crop phases, some of this refer to storage, but it can be minimized if the country
stimulate stocking up the production in the farms. So it's neccssary to havc a simple
technology available, as the construction of bin in the production places. In order to help a crop storage politic in the farms, in the prcscnt work we studied concrcte blocks that can be used to build masonry cylindrical bin. We developed a block with a special geometry to use in these bin, the water absorption, compression and traction resistances of the
blocks were analyzed they were made with 1:3, 1:4 and 1:6 mixture and then submitted to two types o f cure: natural and submerged. Among the mixture studied to build the blocks the 1:6 mixture didn't reach the required resistance by the NBR 7173, but the resistance of the block with ali mixture was superior to the efforts in a bin with the same dimensions.
There isn't an specilic norm for traction resistance, so we developed a methodology to
simulate the traction efforts that the cylindrical bin walls were submitted, the blocks were
moulded with 1:3 and 1:4 mixture, we get a superior resistance to the onc required to an bin with 4 metros in height and height/diameter relation equal to one.
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Etude expérimentale et numérique du comportement des voiles en maçonnerie soumis à un chargement hors plan / Masonry walls submitted to out-of-plane loading : experimental and numerical studyBui, Tan Trung 28 June 2013 (has links)
Cette contribution, en s’appuyant sur expérimentation et modélisation numérique, vise à une meilleure compréhension du comportement de structures en maçonnerie. Nous traitons tout d’abord le cas des murs soumis à un chargement hors plan de type pression uniforme. Les applications en ingénierie sont multiples, par exemple le cas de la maison individuelle construite en montagne en zone bleu, zone où les structures sont susceptibles de subir un impact de type avalanche de neige ; ou encore le cas de la maçonnerie soumise à une pression latérale induite par une charge accidentelle telle qu’une explosion dans une zone Seveso ou plus généralement en ville suite à l’explosion d’une conduite de gaz. Notre étude se confine au cas quasi-statique, l’objet étant une meilleure compréhension du comportement d’un mur en maçonnerie soumis à pression latérale uniforme. Nous avons aussi testé différentes configurations de renforcement par matériau composite. Puis nous évaluons pas à pas, les possibilités de la modélisation via la méthode des éléments discrets (DEM). Des essais judicieusement choisis, maçonnerie à joint sec ou mortier, nous permettent d’en évaluer les pertinences et les limites. Nous abordons ensuite sur maquettes, les essais sous charge ponctuelle hors plan en quasi-statique et le cas de l’impact en dynamique, puis nous traitons des essais vibratoires et des sollicitations dynamiques harmoniques. La modélisation DEM est aussi évaluée dans certains cas tels que les vibrations et les sollicitations modales, voir l’application d’une sollicitation sismique unidirectionnelle. L’étude des sollicitations dynamiques est limitée à la vibration et l’impact, plus facile à gérer en laboratoire que les essais dynamiques de « type souffle », non ici abordés mais que nous mettons en perspective. / The study, based on experiments and numerical modeling, discusses the behavior of masonry walls in the loading case of a uniform out of plane pressure. Engineering applications are multiple, for example the case of detached house built on mountain in blue area, where structures are liable to undergo an impact of snow avalanche type; or the case of masonry subjected to lateral pressure induced by accidental load such as an explosion in Seveso area or more generally in city following the explosion of a gas pipeline. Our study allows, first to quantify the bearing capacity in the case of uniform pressure in quasi-static loading case, and thus to highlight the associated modes of rupture, and secondly to estimate the improvements in terms of global behavior when the structure is reinforced by Carbon Fiber Reinforced Polymer (CFRP) layers. Then, discrete element method (DEM) is illustrated by applications to various masonry problems from simple to more complicated, where in plane loading, out of plane loading, or both, are considered. This modeling allows us to evaluate the pertinence and limitations of DEM in masonry structure. Finally we discuss the dynamic tests, with the case of impact, easier to manage in laboratory than the testing dynamic "blast type" that we will put into perspective.
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Experimental and numerical study of confined masonry walls under in-plane loads : case : guerrero State (Mexico) / Étude expérimentale et numérique des murs en maçonnerie confinée chargés dans leur plane : cas : état de Guerrero (Mexique)Sánchez Tizapa, Sulpicio 10 December 2009 (has links)
Cette recherche propose des méthodes d’amélioration de résistance et d’évaluation du comportement de murs en maçonnerie confinée construits en briques solides d’argile cuite. Ces éléments sont largement utilisés dans la construction des bâtiments à l’État du Guerrero (Mexique) lesquels doivent résister charges séismiques importantes. Ainsi, un programme expérimental a été développé pour évaluer les propriétés mécaniques des briques et de la maçonnerie, qui sont nécessaires dans la conception et analyse des constructions. Pour augmenter la résistance de la maçonnerie et compenser la variabilité de la résistance à la compression des briques, un mortier à haute résistance et un renfort métallique dans les joints ont été utilisés. Certaines propriétés mécaniques sont égales à celles communément citées, cependant, les autres ont des valeurs deux fois plus grandes. Dans cette région du pays, les trois premiers tests de murs à échelle réelle construits en briques solides d’argile cuite ont été réalisés sous charge latérale alternée afin d'évaluer son comportement. Un renfort métallique et une couche du mortier ont été placés dans les surfaces de deux murs. Ceux-ci ont présenté un bon comportement et le renfort a eu un comportement structural adéquat. Avec les données expérimentales, plusieurs modèles numériques de panneaux et de murs ont été mis au point afin de reproduire l'enveloppe de résistance et le mode de défaillance. Ces modèles ont également évalué l'influence des propriétés mécaniques des briques et des joints sur le comportement global des spécimens. Aussi, un renfort métallique a été placé à l’intérieure des joints dans deux modèles. D'un autre côté, à partir de résultats expérimentaux obtenus et cités, une loi de comportement de la maçonnerie a été définie pour construire un modèle simple qui donne des résultats concordants à la fois avec les résultats expérimentaux et ceux obtenus par la méthode des éléments finis. Finalement, deux modèles simplifiés ont été proposés afin d’évaluer la résistance de murs en maçonnerie en supposant que le plan de rupture est suivant la diagonale du mur. L'un suppose la rupture de la maçonnerie par effet de cisaillement tandis que l'autre suppose la rupture par effet de tension induite. Le ratio entre résistance théorique et résistance expérimentale a été acceptable pour 27 murs faits de matériaux différents et testés sous différents types de chargement où le ratio hauteur sur longueur varie entre 0,7 et 1,26 / This research work proposes methods to rises the resistance and to evaluate the behavior of confined masonry walls built from clay solid bricks. These elements are widely used in Guerrero State (México) to build masonry structures, which should resist high lateral loads because of the serious seismic hazard. Therefore, a large experimental program to evaluate the mechanical properties of bricks and masonry currently required in the design process and masonry analysis was developed. To rises the masonry resistance and to counteract the influence of the compressive strength of the pieces on the masonry behavior, a high compressive strength mortar and a metallic reinforcement inside the joints were used. With respect to referenced values of the mechanical properties, some were similar and others were twice bigger. In this country zone, the first three tests under lateral load on full-scale confined masonry walls built from clay solid bricks were carried out in order to evaluate its behavior. A reinforcement composed by metallic hexagonal mesh-mortar coat was placed on the faces of two walls to rise or to restore the resistance. The walls showed good behavior and the reinforcement had adequate structural efficiency. Numerical models of panels and walls built by using the experimental data evaluated the envelope resistance, the failure mode and showed the influence of the mechanical properties of the pieces and joints on the global behavior. Two models had metallic reinforcement inside the joints. In addition, a constitutive law of the masonry defined from experimental results allowed to elaborate a simple model, which results were concordant with respect to the experimental results and similar to those calculated by complex models. Finally, two simplified models to evaluate the resistance of confined masonry walls by considering the failure plane on the wall diagonal were developed. One supposes the masonry failure by shear effect and the other supposes the masonry failure by induced tension. The ratio theoretical resistance vs. experimental resistance was adequate for walls built from different materials and tested under different loads, which had ratio Height/Length ranging from 0.74 to 1.26
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Statická rekonstrukce barokního vinného sklepa / Static reconstruction of the baroque wine cellarKešiar, Szabolcs January 2018 (has links)
The diploma thesis is focused on the design of structural support and construction modifications of a baroque wine cellar, which is part of a double-storeyed house. The first part deals with the statical analysis and structural support of a masonry barrel vault, which was loaded with a new building. The second part deals with the reconstruction of the double-storeyed object, which is in a state of disrepair with heavily developed cracks. The thesis contains a technical report, analysis of statics, drawing documentation and the work progress. The calculation of internal forces were executed by the software Scia Engineer 2017. The drawing documentation contains a formwork and reinforcement drawing, maping of cracks, leading of tensions in the walls and vault including of floor plans, sections and elevations, production plans of base plates and deviators, reinforcement drawing of concrete bond beam and finally the construction process of upper construction.
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Gelový infuzní clonový systém pro dodatečnou hydroizolaci různých druhů zdiva s využitím druhotných surovin / Gel infusion screen system for additional waterproofing of various types of masonry with share of secondary raw materialsMelichar, Jindřich Unknown Date (has links)
Virtually any construction project in our climate zone is facing some form of moisture. Older and historical buildings are mostly affected by the negative impact of water. Previously, the additional reduction of the moisture was executed only by mechanical methods, pushing insulating sheets or breaking through and cutting of masonry. Over time chemical methods were also invented, which are compared to the mechanical considerably simpler and user friendly applications to statics of treated buildings, making them ideal for the treatment of historical buildings or buildings that would not bear significant disruption. The main principle of chemical methods of redevelopment of wet masonry is the application of special material into the line of drilled holes with a given pitch. Subsequent penetration of the grouting material is believed to intersect an arc of individual drill holes, and thus to create so-called grout curtain that prevents the accumulation of water above it. Injection material may also contain a proportion of secondary raw materials, thereby reducing the influence of the impact of production on the environment. Efficiency infusion materials in masonry affected by many factors, such as temperature, humidity, or the type of material treated. It is also an important factor to determine the effectiveness of the remediation of the material, proving its ability to penetrate the building material by identifying its presence in it.
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