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.

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

O objetivo principal deste trabalho é apresentar um modelo de análise probabilística do comportamento ao longo do tempo de estruturas de concreto. Para isso, é realizada a análise probabilística em conjunto com análise numérica. A análise numérica é realizada através de um programa computacional, baseado no método dos elementos finitos, que considera o comportamento não-linear e dependente do tempo dos materiais, assim como o processo evolutivo da construção. Para determinar o efeito das incertezas dos parâmetros é realizada uma análise probabilística, utilizando o método de amostragem por hipercubo latino. O modelo apresentado pode ser aplicado para a análise probabilística do comportamento ao longo do tempo das estruturas de concreto em geral. No entanto, foi aplicado na análise das flechas diferidas de lajes pré-moldadas formadas por vigotas com armação treliçada. Com esta análise, pôde-se propor um coeficiente multiplicador das flechas imediatas para a avaliação das flechas diferidas no tempo. O coeficiente multiplicador obtido para as lajes pré-moldadas formadas por vigotas com armação treliçada pode alcançar valores muito superiores ao fator 'alfa'f recomendado pela NBR 6118 (2003) para o caso de vigas de concreto armado. / The goal of this research is to present a probabilistic analysis model of the long-term behavior of concrete structures. For that, the probabilistic analysis is carried out together with numerical analysis. The numerical analysis is carried out using a software based on the finite element method that takes into account the nonlinear and time dependent behavior of the materials, as well as the evolutionary construction process. A probabilistic analysis is carried out in order to determine the effects of the uncertainties of the parameters, using latin hypercube sampling method. The presented model can be applied in the probabilistic analysis of the long-term behavior of concrete structures in general. However, it was applied in the analysis of the long-term deflections of precast slabs made by joist with lattice reinforcement. By this analysis, a multiplier coefficient of immediate deflections to evaluate long-term deflections could be proposed. The multiplier coefficient obtained for precast slabs made by joist with lattice reinforcement can reach values much higher than the factor 'alfa'f recommended by NBR 6118 (2003) for the case of reinforced concrete beams.

Byggnadstaktenav flerbostadshus i Sverige ligger på en hög nivå och ökar. Detta medför kravpå en snabb byggprocess. En lösning för att snabba på byggprocessen äranvändandet av prefabricerade delar. Författarnas uppgift, i samarbete med WSPSverige AB, är att utveckla ett hjälpmedel för konstruktörer som jämför fyraolika bjälklag, varav ett i korslimmat trä, två prefabricerade betongelementoch en platsgjuten konstruktion. Målet är att framställa en tabell som beaktarfaktorer som påverkar valet av stomsystem och som presenterar vilket avbjälklagen som är mest kostnadseffektivt. Rapporten sammanställdes under 10veckor och avgränsades till bjälklag i flerbostadshus upplagda på två stöd somuppfyller relevanta krav för dimensionering, beaktar torktid med fastaförutsättningar, leveranstid avseende produktionstid hos de prefabriceradeelementen och miljöpåverkan avseende CO2-ekvivalenta utsläpp iproduktionsskedet. Studiens resultat grundar sig på litteraturstudier ochintervjuer, kalkylhjälpmedel och beräkningsprogram som är vanliga i branschen.Resultatet visar att: · trä genererar lägst koldioxidutsläpp avbjälklagsalternativen · betong är, ur ett brand- och ljudperspektiv, detlämpligaste materialet · korslimmade träbjälklaget får den högsta byggnadshöjdenoch den högsta kostnaden per kvadratmeter · håldäcksbjälklag har den kortaste leveranstiden · det slakarmerade plattbärlag samt det platsgjutnabetongbjälklaget har längst torktid · den platsgjutna bjälklagskonstruktionen är detmest kostnadseffektiva bjälklaget av de fyra som har jämförts. / The building pace of multi apartment houses in Sweden is at a high leveland is increasing. This induces demands of a quick building process. Onesolution to quicken the building process is the use of prefabricated elements.The authors’ task, in collaboration with WSP Sverige AB, is to develop anaiding tool for engineers who compare different slabs, one cross laminatedwood, two precast concrete components and one construction cast in-place. Thegoal is to produce a table that considers factors that affects the choice ofstructure and presents which of the slabs that is most cost effective. Thepaper was compiled over a period of 10 weeks and limited to slabs inmulti-apartment buildings supported on two sides that meet relevantrequirements for dimensioning, consider hydration time with set conditions,delivery time regarding production time for the precast components andenvironmental effects considering CO2-equivalent emissions in the productionstage. The results of the study are founded on literature and interviews,calculation-aids and computational programs that are common in the industry.The outcome shows that: · woodgenerates the least amount of carbondioxide emissions of the slab alternatives · concrete is, from a fire- and acoustic perspective, the most suitable material · thecross laminated slab renders the highest cross-section and the highest cost persquare meter · hollow core slabs has the shortest delivery time · theconventionally reinforced precast slabs and the in-situ cast floor slabs havethe longest hydration times · thein situ slab is the most cost effective slab of the four that have beencompared. / <p>Betyg 170707, H14.</p>

O objetivo principal deste trabalho é apresentar um modelo de análise probabilística do comportamento ao longo do tempo de estruturas de concreto. Para isso, é realizada a análise probabilística em conjunto com análise numérica. A análise numérica é realizada através de um programa computacional, baseado no método dos elementos finitos, que considera o comportamento não-linear e dependente do tempo dos materiais, assim como o processo evolutivo da construção. Para determinar o efeito das incertezas dos parâmetros é realizada uma análise probabilística, utilizando o método de amostragem por hipercubo latino. O modelo apresentado pode ser aplicado para a análise probabilística do comportamento ao longo do tempo das estruturas de concreto em geral. No entanto, foi aplicado na análise das flechas diferidas de lajes pré-moldadas formadas por vigotas com armação treliçada. Com esta análise, pôde-se propor um coeficiente multiplicador das flechas imediatas para a avaliação das flechas diferidas no tempo. O coeficiente multiplicador obtido para as lajes pré-moldadas formadas por vigotas com armação treliçada pode alcançar valores muito superiores ao fator 'alfa'f recomendado pela NBR 6118 (2003) para o caso de vigas de concreto armado. / The goal of this research is to present a probabilistic analysis model of the long-term behavior of concrete structures. For that, the probabilistic analysis is carried out together with numerical analysis. The numerical analysis is carried out using a software based on the finite element method that takes into account the nonlinear and time dependent behavior of the materials, as well as the evolutionary construction process. A probabilistic analysis is carried out in order to determine the effects of the uncertainties of the parameters, using latin hypercube sampling method. The presented model can be applied in the probabilistic analysis of the long-term behavior of concrete structures in general. However, it was applied in the analysis of the long-term deflections of precast slabs made by joist with lattice reinforcement. By this analysis, a multiplier coefficient of immediate deflections to evaluate long-term deflections could be proposed. The multiplier coefficient obtained for precast slabs made by joist with lattice reinforcement can reach values much higher than the factor 'alfa'f recommended by NBR 6118 (2003) for the case of reinforced concrete beams.

Punching shear is a failure mechanism caused by concentrated loads, creating a crack pattern that resembles a cone shape or piece of pie starting from the top surface of the slab and prolongs downwards. When the total shear force is greater than the shear resistance of the slab, it may eventually lead to punching shear failure. It can be visualized as the column punches through the slab. Punching shear is very brittle and occurs all of a sudden. It is believed that the slab is subjected to hogging moments over the column in both directions, i.e. parallel and perpendicular to the free edge. Non-linear finite element analyses (NLFEA) has been used to study the cracking and failure mechanism for the reinforced slab. It is a slab over the edge support without clamping stiffness, therefore simulating the slab shear mechanism over a slender steel column is carried out in this study. The analyses has been performed using the software ATENA 3D Engineering developed by Červenka Consulting. Since the symmetry has been taken into account over an edge column, only one half of the cross-section has been modeled, with a symmetry line passing vertically through the slab and column. It can be summarized that the failure encountered around the column has a conical shape crack pattern similar to the ones encountered when punching shear occurs. However, it is important to note that this failure is not due to classic punching shear, but instead due to shear cracks developing around the column in both directions, both parallel and perpendicular to the free-edge. Three models (C1, C2, and C3) are studied to evaluate the impact that the length of the lower leg of the c-bar reinforcement has during failure. As mentioned earlier above, the crack propagation during punching shear begins from the upper surface of the slab and prolongs downwards diagonally towards the bottom of the slab and adjacent to the column. However, the crack propagation in the strip perpendicular to the free edge in all three models initiate from the bottom and propagate upwards. It can be concluded that the length reduction of the lower leg of the c-bars as a consequence reduced the shear strength capacity of the slab around the steel-plate. The reason for this is due to a reduction in maximum peak load when the lower leg of the c-bars were reduced. Consequently, this leads to a decrease in shear strength capacity of the slab and an earlier failure, where the inner-span was not able to take additional loads which could have led to greater deflections. / Genomstansning är en brottmekanism orsakad av koncentrerade laster, vilket skapar ett sprickmönster i likhet med en konfrom ellet en bit av paj som börjar från den övre ytan av plattan och förlängs nedåt. När den totala skjuvkraften är större än skjuvmotståndet i plattan , kan det så småningom leda till ett genomstansningsbrott. Det kan visualiseras som att pelaren stansar eller slår igenom plattan. Genomstansning är ett mycket sprött brott och inträffar helt plötsligt. Det antas att plattan utsätts för negativt moment ovanför pelaren i båda riktningarna, d.v.s såväl parallellt som vinkelrät mot den fria kanten. Icke-linjära finita elementanalyser (NLFEA) har använts för att studera sprickbildnings och brottmekanismen för den förstärkta plattan. Det är en platta över kantstödet utan någon fast inspänd styvhet, därför simuleras skjuvmekanismen för plattan över en slank stålpelare i denna studie. Analyserna har utförts med programvaran ATENA 3D Engineering som utvecklats av Červenka Consulting. Eftersom hänsyn har tagits till symmetrin över en kantpelare har endast halva tvärsnittet modellerats, med en symmetrilinje som går vertikalt genom plattan och pelaren. Det kan sammanfattas att brottet som påträffas runt pelaren har en konisk form med ett sprickamönster som liknar de som påträffas vid genomstansning. Det är dock viktigt att notera att detta brott inte orsakats av klassisk genomstansning, utan istället på grund av skjuvsprickor som utvecklast runt pelaren i båda riktningarna, såväl parallellt som vinkelrät mot den fria kanten. Som det tidigare nämnts ovanför börjar sprickan vid genomstansning från plattans övre yta och förlängs nedåt diagonalt mot bottenplattan och intill pelaren. Sprickmönstret i remsan vinkelrät mot den fria kanten i alla tre modellerna (C1, C2 och C3) initierar dock från botten och sprids uppåt. Slutsatsen kan dras att längdminskningen av c-stängernas underben minskade skjuvhållfastheten hos betongplattan runt pelaren. Anledningen till detta beror på en minskning av maximal toppbelastning när c-stängernas underben reducerades. Följaktligen leder detta till en minskning av skjuvhållfastheten och ett tidigare brott, där den inre spännvidden inte kunda ta ytterligare belastningar som kunde ha lett till större nedböjningar.