Fibre reinforced polymers (FRP’s) are considered an alternative to steel reinforcement in concrete structures because of their noncorrosive nature and nonmagnetic properties. FRP materials are, however, brittle and have a lower stiffness compared to steel. The latter property can lead to deflection and crack control problems in FRP-reinforced concrete flexural members under service loads. A considerable amount of information is available for short-term deflection of FRP-reinforced concrete members, but data on long-term deflections are scarce. This study presents the results of monotonic (short-term) and sustained (long-term) loading tests of 12 concrete shallow beams reinforced with either steel or glass FRP (GFRP) bars. The short-term load-deflection responses of the members are evaluated using existing deflection prediction models (Branson’s and Bischoff’s), and the long-term deflection results (monitored over a period of one year) are used to evaluate the existing ACI code and CSA standard approaches for estimating long-term deflection. The GFRP-reinforced concrete beams exhibited greater amounts of both immediate deflection (under sustained load) and long-term deflections over time, than the steel-reinforced concrete beams. The long-term deflections of both the steel- and GFRP-reinforced concrete beams are overestimated when using the ACI and CSA approaches. Although ACI Committee 440 recommends use of lower values of the long-term deflection multiplier for GFRP-reinforced concrete beams, results obtained from this study suggest that the same longterm multiplier values may be used for GFRP- and steel-reinforced concrete beams loaded at between 115 to 157 days of concrete age.

Hollow-core flooring units are designed as simply supported members. However, frequently in construction, continuity is established between the units and supporting structure by the addition of insitu topping concrete and steel reinforcement. This change in structural form can result in negative bending moments and axial forces being induced in the floor by seismic and other structural actions. Significant negative moments are induced by load combinations that include the effects of seismic forces due to vertical ground motion. The focus of this research was two failure mechanisms possible under these loading conditions, a flexural failure and a shear failure. Both failure mechanisms were investigated analytically and experimentally. A brittle flexural failure was observed experimentally in a sub assembly test that contained starter bars and mesh reinforcement in the insitu topping concrete. The failure occurred at loads lower than those predicted using standard flexural theory. It appears that, due to the prestressing and low reinforcement ratio of the topping concrete, the assumption that plane sections remain plane is not appropriate for this situation. It is proposed that a strain concentration factor be introduced to account for the effects of tension stiffening. This factor improves the correlation between observed and predicted flexural strength. The second failure mode investigated was a flexure shear failure in a negative moment zone. Flexural cracks reduce the shear strength of a reinforced concrete member. Analytical predictions suggest that some hollow-core floor details could be prone to this type of brittle failure. A flexure shear failure was not observed experimentally; however, this does not eliminate the possibility of this failure mode. A summary of other failure mechanisms possible in hollow-core flooring is also presented. All failure modes should to be considered as part of establishing a hierarchy of failure in the design or retrofit of hollow-core floors.

The objectives of this study are to investigate the dynamic behavior of an apple slab subjected to drying at constant external conditions and under changing in the drying temperatures and to determine the effects of temperature and time combinations at different steps during drying on the process dynamics parameters, time constant and process gain of the system. For this purpose, a semi-batch dryer system was simulated by using integral method of analysis. Initially, the dynamic behavior of the drying temperature was investigated by using first order system dynamic model. Process dynamic parameters, time constant and process gain of the system, for change in drying temperature were determined. Secondly, investigation of the drying kinetics of the apple slab was carried out under constant external conditions in a semi-batch dryer. A mathematical model for diffusion mechanism assumed in one dimensional transient analysis of moisture distribution was solved by using explicit finite difference method of analysis. Thirdly, investigation of the drying kinetics of the apple slab was carried out under change in drying temperature at different time steps during drying. Inverse response system model was used for the representation of the dynamic behavior of drying. Process dynamic parameters, time constant and process gain of the system were determined. Model predicted results for apple slab drying under constant external condition and under step change in the drying temperature were compared with the experimental data.

The Mount Somers Volcanic Group (MSVG) and Mandamus Igneous Complex (MIC) are the magmatic manifestations of the transition from convergence to extension at the Gondwana margin, which culminated in the separation of New Zealand from Australia and Antarctica. The MIC has been correlated both geochemically and temporally with the Central Marlborough Igneous Province (CMIP). The MSVG and CMIP are located in the Eastern Province of New Zealand. The MSVG is restricted to the Rakaia terrane, whereas the CMIP is restricted to the Pahau terrane. The Rakaia and Pahau terranes are thick accretionary complexes, which were strongly deformed as a result of prolonged subduction at the Gondwana margin. The Pahau terrane is the younger of the two and continued to be deposited and deformed until the abrupt cessation of subduction, which in the Marlborough sedimentary record occurred in the Motuan (100 - 105 Ma). Following the cessation of subduction, after an interval of 2-7 Ma of relative quiescence and subsidence of the Pahau terrane, the MSVG and MIC were erupted/emplaced. The production of MSVG and MIC magmas occurred simultaneously and the activity was of short-lived duration. SHRIMP geochronology yielded crystallisation ages of 97.0 ± 1.5 Ma to 98.0 ± 1.2 Ma from zircons separated from MSVG rhyolites. The SHRIMP ages are within error of the previously published Rb-Sr age for the MIC. The SHRIMP geochronology also confirmed the presence of inherited zircons which yielded ages consistent with their derivation from the Rakaia terrane. Ar-Ar geochronology confirmed the coeval nature of the MSVG and MIC magmatism, but yielded consistently younger ages (94.5 ± 3 Ma for the MSVG and 94.2 ± 1.7 Ma for the MIC). The systematic differences in ages obtained by SHRIMP and Ar-Ar are believed to be method-dependent. The MSVG comprises a calc-alkaline volcanic assemblage, which ranges in composition from basaltic-andesite lavas (SiO₂ = 54.5%) to high-silica rhyolites and ignimbrites (SiO₂ ≤ 78.1%). The MSVG had an original extent of at least 18 000 km². The magmas from the MSVG had high LILE/HFSE, high LILE/REE and moderately high LREE/HFSE which are characteristic of subduction derived magmas. Geochemical modelling suggests that the MSVG magmas were formed from partial melting of a subduction-modified mantle wedge, with high degrees of crustal assimilation. The assimilant had an isotopic composition similar to that of the Rakaia terrane, which is consistent with the geological setting of the MSVG. The MSVG has ⁸⁷Sr/⁸⁶Sri from 0.7055 to 0.7100 and ¹⁴³Nd/¹⁴⁴Ndi from 0.51254 to 0.51230 (ɛNd +0.5 to -4.2), which reflects varying degrees of contamination by Rakaia terrane. Radiogenic isotope modelling suggests that the MSVG end-members were derived from the same parent magma, which evolved through AFC processes from basaltic-andesite to rhyolite. The modelling strongly suggests that assimilation played a lesser role in the petrogenesis of the Malvern Hills magmas than in the petrogenesis of the other units. AFC modelling requires the degree of assimilation to increase as the magmas evolved. Oxygen isotope data are consistent with high degrees of crustal assimilation, and may indicate that the assimilant had higher ¹⁸O characteristics than the Rakaia terrane samples analysed. The MIC is an alkaline suite which ranges in composition from basalt and gabbro to syenite, trachyte and phono-tephrite. The MIC is interpreted to have formed from enriched asthenospheric mantle, with a composition similar to HIMU (²⁰⁶Pb/²⁰⁴Pbi ranges from 19.2 to 20.3). The samples range in isotopic composition from ⁸⁷Sr/⁸⁶Sri = 0.7030 to 0.7036, ¹⁴³Nd/¹⁴⁴Ndi = 0.51275 to 0.51268 (ɛNd +4.6 to +3.3). The range in isotopic composition is due to varying degrees of contamination by Pahau terrane, which reaches a maximum of 25% but in most samples is < 10%. The MIC is contaminated to a much lesser extent than the MSVG which is interpreted to be related to the thinner nature of the Pahau crust in the mid-Cretaceous. The latest phases of activity in the MIC were subjected to lower degrees of contamination which is interpreted to reflect the passage of magmas through pre-existing pathways. The onset of MSVG and CMIP magmatism coincided with the initiation of major rift-related depositional basins, and the eruption of the MSVG is demonstrably associated with normal faulting. The tectonic trigger responsible for the sudden onset of magmatism and rifting in the Eastern Province terranes was the detachment of the previously subducting slab following the cessation of subduction due to the arrival of the Hikurangi Plateau at the margin and the subsequent stalling of the Pacific spreading centre. The capture of the Gondwana margin led to the propogation of extension into the margin by the divergent Pacific plate. The ensuing extension aided the detachment of the subducting slab beneath the Eastern Province terranes. The slab-detachment promoted decompression melting of the sub-lithospheric mantle wedge to produce the MSVG magmas and triggered the ascent of asthenospheric mantle through the slab window, which melted through decompression to produce the CMIP magmatism. The asthenospheric mantle tapped by the slab detachment episode was highly enriched relative to N-MORB and is akin to the similar age HIMU-OIB affinity melts documented from Antarctica and Australia. The short-lived duration of activity is typical of slab-detachment related magmatism which occurs as a passive response to plate reconfiguration. The similarity in geochemistry of the MIC with OIB-affinity igneous centres in Australia and Antarctica implies an enriched mantle domain of large geographical extent. The distribution of relatively small volumes of OIB magmatism is suggestive of a fossil plume component, which was tapped in response to lithospheric extension producing relatively short-lived HIMU magmatism. The same fossil plume component has previously been implicated in the formation of the Cenozoic West Antarctic Rift System and may be responsible for the late Cretaceous magmatism in the Chatham Islands and Tertiary volcanics of the South Island of New Zealand.

Made available in DSpace on 2014-06-11T19:25:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-28Bitstream added on 2014-06-13T19:53:01Z : No. of bitstreams: 1 trigo_apm_me_ilha.pdf: 2296077 bytes, checksum: aa464f95de9d5130225ee4ae495722db (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No Brasil, o concreto armado é bastante empregado na confecção de pilares, vigas e lajes das estruturas de edificações. As lajes são utilizadas como piso ou forro e, considerandose que a laje de forro não demanda ações elevadas, quando comparada à laje de piso, pensa-se na possibilidade de substituir parcialmente o agregado do concreto por outros materiais que sejam, ecológica e economicamente, viáveis. Desses materiais, o resíduo de borracha se mostra promissor, por ser gerado em abundância. Este trabalho objetiva mostrar uma alternativa de reaproveitamento para o resíduo proveniente do processo de recauchutagem de pneu, utilizando-o como parte do agregado de concreto para lajes de forro. São ensaiadas, à flexão, duas lajes unidirecionais, sendo uma delas constituída parcialmente por resíduo de borracha de pneu, e a outra sem, ambas formadas por vigotas pré-moldadas treliçadas. Através dos deslocamentos verticais, das deformações no concreto e na armadura, medidos com auxílio de relógios comparadores e extensômetros elétricos, e dos modos de ruptura da estrutura, obtidos nos ensaios, avalia-se o comportamento dessas lajes. / In Brazil, the reinforced concrete is used for pillars, beams and slabs. The slabs are used as floor or lining and, as the lining slab do not demand raised actions, when compared with the floor slab, it is possible to replace partially the concrete aggregate for ecologically and economically viable materials. From these materials, the rubber residue is promising and abundant. The aim of this work is to show a recycling alternative for tire rubber from retreading process, using it as part of the concrete aggregate in lining slabs. Two unidirectional slabs are assayed to the flexure, one partially with tire rubber residue and another one without, both formed by precast lattice joist. The slabs behavior is evaluated through the vertical displacements, concrete and reinforcement deformations, measured with comparing clocks and electric strain gages, and structure rupture ways.

[pt] Neste trabalho apresenta-se ferramentas computacionais para o projeto de lajes maciças de concreto armado. O projeto de lajes é feito utilizando-se uma análise elástica, elasto- plástica perfeita, um dimensionamento ótimo utilizando programação matemática e um projeto pela análise plástica. O projeto convencional de lajes de concreto armado tem sido feito a partir de esforços solicitantes determinados pela hipótese de comportamento linear elástico do material. Utilizando-se as ferramentas computacionais desenvolvidas neste trabalho é proposto um procedimento de projeto de lajes maciças de concreto armado que utiliza esforços solicitantes obtidos através de uma análise elasto-plástica perfeita desenvolvida pelo método dos elementos finitos. O dimensionamento das armaduras ortogonais, positivas e negativas, em cada ponto da laje é feito de modo a atender aos critérios de resistência definidos em função dos momentos de flexão e de torção e de maneira a se ter o menor consumo de aço. Os estados limites de utilização correspondentes à flecha da laje e à abertura de fissuras também são considerados no projeto. A análise elástica e elasto-plástica perfeita das lajes, descritas pelo seu plano médio e discretizadas pelo método dos elementos finitos, são feitas em regime de pequenos deslocamentos com formulação consistente em deslocamentos. Na análise elasto- plástica perfeita é utilizado o algoritmo de Newton-Raphson para solução das equações de equilíbrio a nível global da estrutura. As relações da Teoria da Plasticidade são resolvidas a nível local, ou seja, para cada ponto de Gauss da estrutura discretizada. O problema de retorno das tensões na análise elasto-plástica perfeita é formulado como um problema de Programação Matemática (PM). O Método dos Pontos Interiores proposto por Herskovits (HERSKOVITS, 1995) é utilizado como algoritmo de retorno das tensões na análise elasto-plástica perfeita. / [en] In this work it is presented computational methodologies for the design of reinforced concrete massive slabs. The design of the slabs is made using an elastic and perfect elastoplastic analysis, an optimum design using mathematical programming and a plastic analysis project. The conventional project of reinforced concrete slabs has been made starting from efforts determined by the hypothesis of linear elastic behavior of the material. Using the computational methodologies developed in this work, it is proposed a procedure of design of reinforced concrete massive slabs that uses efforts obtained through a perfect elasto-plastic analysis developed by the finite element method. The design of the orthogonal reinforcements, positive and negative, in each point of the slab is made in order to assist the yield criteria defined in function of the bending and torsion moments and in order to obtain the lowest consumption of reinforcement. The limit states of serviceability corresponding to the slab deflection and crack opening are also considered in the design.The elastic and perfect elasto-plastic analyses of the slabs, described by their medium plan and discretized by the finite element method, are performed under the hypothesis of small displacements with consistent formulation in displacements. In the perfect elasto-plastic analysis, the Newton-Raphson algorithm is used to solve the equilibrium equations at global level of the structure. The relationships of the Plasticity Theory are resolved at local level,that is, for each Gauss point of the iscretized structure. The return mapping problem in the perfect elasto- plastic analysis is formulated as a problem of Mathematical Programming (PM). The Method of the Interior Points proposed by Herskovits (HERSKOVITS, 1995) is used as a return mapping algorithm in the perfect elasto-plastic analysis.

The current research focuses on the environmental comfort in the civil construction and refers to a comparative analysis related to the acoustic isolation of reinforced concrete pavement which is submitted to noise of impact. According to thestandards ISO-140/VII, the measurements were taken in situ by using appropriate equipment for this purpose. In order to achieve the aims of this dissertation, unfinished constructions which used different typologies of floor-support (slab) in their structural system were chosen as the object of measurement and, this way, uncovered slabs could be measured. Therefore a better evaluation of their performance was possible and the sound isolation was related to the impact noise, providing evidence of the acoustic isolation. The analysis and interpretation of the results were undertaken through tables and graphs that, according to ISO 717-2, show the performance of each slab and a possible comparison among them. This is also a contributing factor to civil construction professionals as being a working instrument and it serves as a data base for a better understanding towards these materials performance. In this way, minimal values of acoustic comfort may be estimated in a near future. / A presente pesquisa concentra-se na área de conforto ambiental na construção civil e refere-se a uma análise comparativa quanto ao desempenho do isolamento acústico de tipologias de lajes submetidas a ruído de impacto. Os ensaios foram realizados in situ , em conformidade com as normas da ISO-140/VII, utilizando equipamentos adequados para este fim. Para o desenvolvimento desta dissertação, escolheram-se como objetos de medição obras ainda em fase de construção que tivessem utilizado como sistema estrutural as lajes maciça, nervurada, pré-moldada convencional e pré-moldada treliçada, possibilitando assim a medição das lajes em osso , ou seja, sem o revestimento de piso. Dessa forma, foi permitida uma melhor avaliação do desempenho dessas, relacionando o isolamento sonoro ao ruído de impacto, evidenciando assim o desempenho acústico deste sistema. A análise e interpretação dos resultados foram realizadas através de tabelas e gráficos que, de acordo com a ISO 717-2, demonstram o desempenho de cada laje, permitindo-nos assim traçar um comparativo entre essas, o que contribui como ferramenta de trabalho para os profissionais da construção civil e serve como base de dados para um melhor conhecimento do desempenho destes materiais. Desse modo, valores mínimos de conforto acústico ao usuário da construção civil podem vir a serem traçados futuramente.

Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-09-23T12:46:32Z No. of bitstreams: 1 DissFLR.pdf: 3397805 bytes, checksum: 748cef78a5c04d386df8100510a2b742 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:36:55Z (GMT) No. of bitstreams: 1 DissFLR.pdf: 3397805 bytes, checksum: 748cef78a5c04d386df8100510a2b742 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-09-26T20:37:01Z (GMT) No. of bitstreams: 1 DissFLR.pdf: 3397805 bytes, checksum: 748cef78a5c04d386df8100510a2b742 (MD5) / Made available in DSpace on 2016-09-26T20:37:08Z (GMT). No. of bitstreams: 1 DissFLR.pdf: 3397805 bytes, checksum: 748cef78a5c04d386df8100510a2b742 (MD5) Previous issue date: 2015-08-24 / Não recebi financiamento / The civil construction more than ever is challenged by the circumstances faced by the country, the economic crisis experienced in these last few years puts into perspective the necessity of more rational choices avoiding unnecessary dispenses and wastes. In face of this scenario the pre-cast elements became vital to guarantee the conclusion in less time and trying to reduce constructive bottlenecks. The latticed pre-cast concrete slabs are one of the many types of pre-cast parts which can be used at the construction sites, however the national standards are confuse and vague about some aspects contained especially in the European standards. Even the last review of the NBR 6118 of 2014 adds little about the issue and the more specific standard (NBR 14680) has few constructive details regarding the connection between elements and the calculus procedures, therefore this work tries to discuss the main questions related to this kind of pavement, introduces knowledge coming from other standards trying to answer some less usual doubts, but extremely pertinent ones such as, for example, the concept of self-portance, the use of this material in bridge floors and also the type connective reinforcement needed to attain the effective monolithism at the interface between beamstructure. This dissertation also presents some examples of pre- and post-constructive deflection limits, fissured deformation and a full example of calculation for a common pavement. Some data from the experiments realized at the NEPRE in the University of São Carlos and their practical application are shown as well. / A construção civil mais do que nunca se vê desafiada pelas circunstâncias enfrentadas pelo país, a crise econômica vivida nos últimos anos coloca a necessidade de escolhas mais racionais evitando gastos e desperdícios desnecessários. Em face deste cenário as peças prémoldadas se tornaram vitais para garantir prazos menores e redução de gargalos construtivos. As lajes pré-moldadas do tipo painel treliçado são um dos muitos tipos de peças pré-fabricadas que podem ser utilizadas nos canteiros de obra, porém as normas vigentes são confusas e vagas em relação a alguns aspectos celebrados principalmente nas normas europeias. Mesmo a última revisão da NBR 6118 de 2014 acrescenta pouco sobre o assunto e a norma mais específica (NBR 14860) possui poucos detalhes construtivos relativos à ligação entre elementos e a procedimentos de cálculo, portanto este trabalho tenta abordar as principais questões relativas a esse tipo de pavimento, introduz conhecimento vindo de outras normas na tentativa de responder a algumas dúvidas menos usuais, porém extremamente pertinentes como, por exemplo, o conceito de autoportância, o uso desse material em pavimentos de pontes e também o tipo de ancoragem necessário para se atingir o monolitismo adequado da interface vigaestrutura. O trabalho ainda apresenta exemplos de cálculo de flecha limite pré e pós-construtiva, deformação fissurada e um dimensionamento completo de um pavimento. São apresentados também os dados coletados durante os ensaios realizados no NETPRE da Universidade Federal de São Carlos e sua aplicação prática para aqueles resultados.

Resumo: No Brasil, o concreto armado é bastante empregado na confecção de pilares, vigas e lajes das estruturas de edificações. As lajes são utilizadas como piso ou forro e, considerandose que a laje de forro não demanda ações elevadas, quando comparada à laje de piso, pensa-se na possibilidade de substituir parcialmente o agregado do concreto por outros materiais que sejam, ecológica e economicamente, viáveis. Desses materiais, o resíduo de borracha se mostra promissor, por ser gerado em abundância. Este trabalho objetiva mostrar uma alternativa de reaproveitamento para o resíduo proveniente do processo de recauchutagem de pneu, utilizando-o como parte do agregado de concreto para lajes de forro. São ensaiadas, à flexão, duas lajes unidirecionais, sendo uma delas constituída parcialmente por resíduo de borracha de pneu, e a outra sem, ambas formadas por vigotas pré-moldadas treliçadas. Através dos deslocamentos verticais, das deformações no concreto e na armadura, medidos com auxílio de relógios comparadores e extensômetros elétricos, e dos modos de ruptura da estrutura, obtidos nos ensaios, avalia-se o comportamento dessas lajes. / Abstract: In Brazil, the reinforced concrete is used for pillars, beams and slabs. The slabs are used as floor or lining and, as the lining slab do not demand raised actions, when compared with the floor slab, it is possible to replace partially the concrete aggregate for ecologically and economically viable materials. From these materials, the rubber residue is promising and abundant. The aim of this work is to show a recycling alternative for tire rubber from retreading process, using it as part of the concrete aggregate in lining slabs. Two unidirectional slabs are assayed to the flexure, one partially with tire rubber residue and another one without, both formed by precast lattice joist. The slabs behavior is evaluated through the vertical displacements, concrete and reinforcement deformations, measured with comparing clocks and electric strain gages, and structure rupture ways. / Orientador: Jorge Luís Akasaki / Coorientador: José Luiz Pinheiro Melges / Banca: Jefferson Sidney Camacho / Banca: Roberto Chust Carvalho / Mestre

Este trabalho trata da evolução natural do modelo de cálculo em regime elástico linear, largamente empregado no dimensionamento de pavimentos de concreto armado, para um modelo com maior capacidade de representação. A consideração da não-linearidade física do material concreto armado é incorporada a um sistema computacional em elementos finitos segundo modelos não-estratificados, através da generalização das formulações para o campo dos esforços. O elemento de barra é abordado em campo uniaxial, verificando-se o escoamento produzido pela flexão. Para o elemento de placa, estabelece-se o critério de escoamento de Von Mises com leis associativas particularizado ao estado plano de tensões (EPT). Essas tensões são integradas ao longo da espessura do elemento, permitindo escrever o critério em função do terno de valores de momentos atuantes. Por fim, os modelos de barra e placa são integrados ao sistema computacional, resultando um sistema de análise não-linear de pavimentos de concreto armado. A caracterização do comportamento físico da seção transversal é feita segundo um diagrama momento-curvatura trilinear. A aplicação do modelo proposto a elementos estruturais isolados, e a um pavimento convencional, confirma a melhoria do sistema computacional, e os tempos de processamento requeridos evidenciam a viabilidade do emprego do modelo não-linear físico em projetos usuais de pavimentos de concreto armado. / This work deals with the natural evolution of the design model based on linear elasticity, widely employed on reinforced concrete slabs designs, to a improved design model. The consideration of physical nonlinearity of the reinforced concrete is introduced into a finite element computational system by nonlayered models with generalization of the formulation to the bending moment field. The beam element is treated in a uniaxial field, with bending moment yielding. In the plate element it is established the Von Mises yield criterion with associative laws particularized to the plane stress. These stresses are integrated along the element depth, enabling to write the criterion with plate bending moments. At last, the beam and the plate models are incorporated into a computational system, resulting in a reinforced concrete slabs analysis system. The characterization of the cross section physical behavior is made by a trilinear bending moment-curvature diagram. The application of the proposed model to isolate structural elements and to a conventional slab confirms the improvement of the finite element system and the required computational analysis times show the feasibility of the nonlinear model application into usual reinforced concrete slab design.