A novel way to ensure stability of mortarless structures – topological interlocking – is examined. In this type of interlocking the overall shape and arrangement of the building blocks are chosen in such a way that the movement of each block is prevented by its neighbours. (The methodological roots of topological interlocking can be found in two ancient structures: the arch and the dry stone wall.) The topological interlocking proper is achieved by two types of blocks: simple convex forms such as the Platonic solids (tetrahedron, cube, octahedron, dodecahedron and icosahedron) that allow plate-like assemblies and specially engineered shapes of the block surfaces that also allow assembling corners. An important example of the latter – so-called Osteomorphic block – is the main object of this research with some insight being provided by numerical modelling of plates assembled from tetrahedra and cubes in the interlocking position. The main structural feature of the interlocking assemblies is the need of the peripheral constraint (for the Osteomorphic blocks this requirement can be relaxed to uni-directional constraint) to keep their integrity. We studied the least visible constraint structure – internal pre-stressed cables which run through pre-fabricated holes in Osteomorphic blocks. It is shown that the pre-stressed steel cables can provide the necessary constraint force without creating appreciable residual stresses in the cables, however the points of connection of the cables are the weakest points and need special treatment. The main mechanical feature of the interlocking structures is the absence of block bonding. As a result, the blocks have a certain freedom of translational and rotational movement (within the kinematic constraints of the assembly) and their contacts have reduced shear stresses which hampers fracture propagation from one block to another. These features pre-determine the specific ways the interlocking assemblies behave under mechanical and dynamic impacts. These were studied in this project and the following results are reported. As the blocks in the interlocking structure are not connected, the main issue is the bearing capacity. The study of the least favourable, central point loading in the direction normal to the structure shows elevated large-scale fracture toughness (resistance to fracture propagation). However when the central force imposes considerable bending the generated tensile membrane stresses assist fracturing of the loaded block. Prevention of bending considerably enhances the strength therefore the most efficient application of the interlocking structures would be in protective coatings and covers. Furthermore, proper selection of the material properties and the interface friction can increase the system overall strength and bearing capacity. The results of the computer simulations suggest that both Young’s modulus and the friction coefficient are the key parameters whose increase improves the bearing capacity of topologically interlocking assemblies.

A extração cada vez maior de recursos da natureza e o grande volume de lixo descartado nos aterros sanitários alertam para a necessidade de se promover a reciclagem e a reutilização de resíduos para se gerarem novos materiais, inclusive, no setor da construção civil. Com base nisso e a partir de um estudo sobre as obras arquitetônicas em que Shigeru Ban construiu painéis de vedação com tubos de papelão, este trabalho desenvolveu uma proposta de painéis de vedação vertical de tubos de papelão e fez uma avaliação do seu desempenho estrutural visando a sua utilização no Brasil. Foram realizados ensaios técnicos para avaliar o painel de vedação vertical de tubos de papelão proposto, no que se refere à sua resistência mecânica e ao seu comportamento quando submetido às principais ações sofridas por um painel de vedação vertical. Também foi construída uma célula-teste para avaliar o desempenho técnico e estrutural do painel de vedação vertical de tubos de papelão proposto quando submetido a situações reais de exposição. Os dados obtidos em ambas as avaliações foram levados em consideração para verificar o desempenho geral do painel que se propôs, possibilitando concluir se este é apto ao seu emprego na construção civil no Brasil, e sugerir alguns usos e aplicações para o mesmo. / The increasing extraction of nature resources and the large volume of waste discarded in landfills call for the need to promote recycling and reuse of waste to create new materials, inclusive in the construction industry. Considering this aspect and from a study of the architectural masterpieces where Shigeru Ban built sealing cardboard tubes panels, this study developed a proposal for vertical sealing cardboard tubes panels and assessed their structural performance having in mind their use in Brazil. Technical tests were conducted to evaluate the proposed vertical sealing cardboard tubes panel regarding its mechanical resistance and behavior when submitted to the main actions suffered by a vertical sealing panel. A test cell was also built to evaluate the structural and technical performance of the proposed vertical sealing cardboard tubes panel when submitted to real exposure situations. Data obtained in both evaluations were taken into consideration to verify the general performance of the proposed panel, allowing to conclude whether this is suitable for being used in civil construction in Brazil, and to suggest some usage and applications for it.

published_or_final_version / Architecture / Doctoral / Doctor of Philosophy

A extração cada vez maior de recursos da natureza e o grande volume de lixo descartado nos aterros sanitários alertam para a necessidade de se promover a reciclagem e a reutilização de resíduos para se gerarem novos materiais, inclusive, no setor da construção civil. Com base nisso e a partir de um estudo sobre as obras arquitetônicas em que Shigeru Ban construiu painéis de vedação com tubos de papelão, este trabalho desenvolveu uma proposta de painéis de vedação vertical de tubos de papelão e fez uma avaliação do seu desempenho estrutural visando a sua utilização no Brasil. Foram realizados ensaios técnicos para avaliar o painel de vedação vertical de tubos de papelão proposto, no que se refere à sua resistência mecânica e ao seu comportamento quando submetido às principais ações sofridas por um painel de vedação vertical. Também foi construída uma célula-teste para avaliar o desempenho técnico e estrutural do painel de vedação vertical de tubos de papelão proposto quando submetido a situações reais de exposição. Os dados obtidos em ambas as avaliações foram levados em consideração para verificar o desempenho geral do painel que se propôs, possibilitando concluir se este é apto ao seu emprego na construção civil no Brasil, e sugerir alguns usos e aplicações para o mesmo. / The increasing extraction of nature resources and the large volume of waste discarded in landfills call for the need to promote recycling and reuse of waste to create new materials, inclusive in the construction industry. Considering this aspect and from a study of the architectural masterpieces where Shigeru Ban built sealing cardboard tubes panels, this study developed a proposal for vertical sealing cardboard tubes panels and assessed their structural performance having in mind their use in Brazil. Technical tests were conducted to evaluate the proposed vertical sealing cardboard tubes panel regarding its mechanical resistance and behavior when submitted to the main actions suffered by a vertical sealing panel. A test cell was also built to evaluate the structural and technical performance of the proposed vertical sealing cardboard tubes panel when submitted to real exposure situations. Data obtained in both evaluations were taken into consideration to verify the general performance of the proposed panel, allowing to conclude whether this is suitable for being used in civil construction in Brazil, and to suggest some usage and applications for it.

Submitted by Biblioteca Central (biblioteca@unicap.br) on 2018-01-29T17:34:49Z No. of bitstreams: 1 maria_conceição_aguiar_nascimento.pdf: 3804537 bytes, checksum: aea07399e9de24f9fafa6060e4c467bd (MD5) / Made available in DSpace on 2018-01-29T17:34:49Z (GMT). No. of bitstreams: 1 maria_conceição_aguiar_nascimento.pdf: 3804537 bytes, checksum: aea07399e9de24f9fafa6060e4c467bd (MD5) Previous issue date: 2016-12-15 / Brazil is the world's largest non-sugar-alcohol complex that has been expanding in recent times, driven by the advent of bioenergy, exerting a leadership in all segments. The residue generated at the end of the sugarcane bagasse milling process is used for the generation of energy by burning in boilers. At the end of the burning as residual ash are released into the environment inadequately, and may cause environmental problems due to the generation of waste as a sugarcane bagasse ash. The interest of the research is to justify the demand through a job offer from the sugarcane bagasse ash (CBC) in concrete structures, due to the large volume of generation and the concern with the environment. The objective of this research is to evaluate the performance of the conventional contract made of sugar cane residues proved from mills. The results were reported with a 0%, 20% and 40% substitution of natural sand by BCC, where this mixture may contribute to a compound more difficult than conventional concrete. It is also concluded that although the use of CBC has not significantly reduced the final value of m³ of concrete, the gain in relation to the mechanical performance was higher. It can be concluded that the specimens produced have obtained sufficient mechanical strength to be dismantled, transported and conditioned prior to use, in the same way as the referents. / O Brasil é o maior produtor mundial no complexo sucroalcooleiro que vem se expandindo nos últimos tempos, impulsionado pelo advento da bioenergia, exercendo a liderança em todos os segmentos. O resíduo gerado ao final do processo de moagem do bagaço da cana-de-açúcar é utilizado para a geração de energia por meio da queima em caldeiras. Ao final da queima as cinzas residuais são lançadas no meio ambiente de forma inadequada, podendo causar problemas ambientais em decorrência da geração de resíduos como a cinza do bagaço de cana-de-açúcar. O interesse desta pesquisa justifica-se pela necessidade de se avaliar a possibilidade do emprego da cinza do bagaço da cana-de-açúcar (CBC) em estruturas de concreto, devido ao grande volume de geração e a preocupação com o meio ambiente. O objetivo desta pesquisa é avaliar o desempenho do concreto convencional confeccionado de resíduos de cana-de-açúcar proveniente de usinas. Os resultados foram apresentados com a substituição de 0%, 20% e 40% da areia natural por CBC, onde essa mistura pode contribuir para um composto mais durável que o concreto convencional. Conclui-se, também, que apesar do uso da CBC não ter diminuído significativamente o valor final do m3 do concreto, o ganho em relação ao desempenho mecânico foi maior. Pode-se concluir que os corpos-de-prova produzidos obtiveram resistência mecânica suficiente para serem desmoldados, transportados e acondicionados antes do uso, da mesma forma que os de referência.

Thesis (MPhil)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In this thesis I examine the natural building movement in South Africa in an attempt to determine the systemic influences that appear to confine it to a small market operating at the very edge of the mainstream building sector. I make use of the conceptual framework of the multi-level perspective to explore the interrelationships between natural building as a technological niche and the mainstream building sector as the dominant regime. I extend the concept of a technological niche by appending the term 'latent' to form the term 'latent technological niche', to describe a technology with sustainability credentials that fails to break into the mainstream market, despite achieving technological maturity and constant though minimal market share. The research objectives of this thesis are to: identify pathways for the natural building niche to move beyond its latent state; to determine how the translations of natural building practices to the building sector might occur; and how this might transform the building sector regime. I explore how action research involving knowledge sharing between multi-stakeholder, niche and regime actors might stimulate debate and subsequent action to overcome entry barriers; and serve as a catalyst to advance a latent technological niche beyond its confined market. I present an action research method, a 'latent technological mediation', of facilitated 1st and 2nd order social learning. This is used as a mechanism of tapping into the immediate knowledge of actors in the socio-technical regime. The purpose being to identify the external forces and internal processes of a latent technological niche. The status of a latent technological niche is assessed by comparing these processes in the context of external forces against seven processes, presented in this thesis. These seven processes are considered crucial for a technology to break into the mainstream market and are adapted from the internal processes of success, described in the literature on strategic niche management and the characteristics of a successful 'bounded socio-technical experiment' (BSTE) described in the conceptual work on BSTE's. The potential for natural building systems to enter the mainstream building sector, particularly in South Africa, is used as a case study to apply the latent technological mediation method. The findings of this research suggest that the mainstream building sector is undergoing a transition following the path of socio-techical transformation. The uncertainty introduced by the parallel system of informal settlement, which may drive transition along the more dramatic technological substitution or de-alignment and re-alignment transition pathways is briefly explored. / AFRIKAANSE OPSOMMING: In hierdie tesis ondersoek ek die natuurlike gebou beweging in Suid-Afrika in 'n poging om die sistemiese invloede te bepaal, wat neig om dit te beperk tot 'n klein mark teen die rand van die hoofstroom gebou sektor. Ek maak gebruik van die konseptuele raamwerk van die multi-vlak perspektief om die onderlinge verband tussen natuurlike geboue, as 'n tegnologiese nis, en die hoofstroom gebou sektor, as die dominante regime, te verken. Ek brei die konsep van 'n tegnologiese nis uit, deur die aanbring van die word 'latente' om die term 'latente tegnologiese nis' te vorm. 'n Latente tegnologie nis het volhoubaarheid potensiaal maar slaag nie daarin om in die hoofstroom mark in te breek nie, ten spyte van die bereiking van tegnologiese volwassenheid en 'n konstante maar minimale mark aandeel. Die navorsing doelwitte van hierdie tesis is om: roetes te identifiseer waarlangs die natuurlike gebou nis buite sy latente toestand kan beweeg; om te bepaal hoe die 'vertalings' van natuurlike gebou praktyke aan die gebou sektor kan voorkom; en hoe dit die gebou sektor regime kan verander. Ek bestudeer hoe aksie navorsing waarby kennis tussen verskeie belanghebbendes, nis en regime betrokkenes gedeel is, kan debatteer en die daaropvolgende aksie stimuleer inskrywing hindernisse te oorkom; en dien as 'n katalisator om 'n latente tegnologiese nis te bevorder buite sy beperkte mark. Ek bied 'n aksie-navorsing metode, 'n 'latente tegnologiese bemiddeling' van gefasiliteerde 1st en 2de order sosiale leerervaring aan. Dit dien as 'n meganisme van deling in die onmiddellike kennis van die spelers in die sosio-tegniese regime. Die doel is om die eksterne kragte en interne prosesse van 'n latente tegnologiese nis te identifiseer. Die status van 'n latente tegnologiese nis is beoordeel deur hierdie prosesse te vergelyk in die konteks van eksterne kragte teen sewe prosesse, wat in hierdie tesis aangebied is. Hierdie sewe prosesse word beskou as noodsaaklik vir 'n tegnologie om in die hoofstroom mark in te breek en is aangepas uit die interne prosesse van sukses, soos beskryf in die literatuur oor strategiese nis bestuur en die eienskappe van 'n suksesvolle 'begrensde sosio-tegniese eksperiment' (BSTE) beskryf in die konseptuele literatuur oor BSTE. Die potensiaal vir natuurlike gebou stelsels om die hoofstroom gebou sektor te betree, veral in Suid-Afrika, word gebruik as 'n gevallestudie om die latente tegnologiese bemiddeling metode toe te pas. Die bevindinge van die navorsing dui daarop dat die hoofstroom gebou sektor 'n verandering ondergaan op die pad van n sosio-tegniese transformasie. Die onsekerheid veroorsaak deur die parallelle informele nedersetting, wat 'n meer dramatiese tegnologiese substitusie, of ontsporing en herbelyning kan veroorsaak, word kortliks ondersoek.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Business Administration / Master / Master of Business Administration

published_or_final_version / Civil Engineering / Master / Master of Philosophy

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