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Data Mining techniques and UPV tests for the assessment of damage level in concrete exposed to high temperatures and subject to compression   

A Data Mining (DM) process was applied, aiming to develop a numerical tool for the assessment of the level of damage (measured from a strain parameter) of concrete columns subject to high temperature exposure (or fire). The database used was obtained from an experimental program carried out with measurements of Ultrasonic Pulse Velocity (UPV) through concrete specimens of various steel reinforcement arrangements after exposure to different levels of high temperature (reference, 250 ºC, 500 ºC and 750 ºC). The UPV tests were performed during the execution of...

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Cost competitive steel fibre reinforced self-compacting concrete for structural applications   

A mix design for Steel Fibre Reinforced Self-Compacting Concrete (SFRSCC) was developed for application in lightweight panels as building facades. Concrete precast industry is one of the most suited industries for the use of SFRSCC, as it has the potential not only to use the mix composition but also other steps leading to make structural elements. Since precast elements’ demoulding should be carried out as soon as possible for economic reasons, the influence of age on mechanical properties of SFRSCC was assessed by compression and flexural tests....

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Innovative structural systems for industrial buildings using fibre reinforced concrete and material nonlinear FEM-based models   

Fibre Reinforced Concrete (FRC) can be very effective in precast pre-stressed high strength concrete structures, since shear reinforcement and passive longitudinal bars can be totally replaced by fibre reinforcement. To simulate adequately the fibre reinforcement benefits, material constitutive models, able of capturing the crack initiation and crack propagation need to be used, under the frame-work of FEM-based analysis. In the present work, the use of FRC was explored for the development of innovative structural systems for industrial buildings. The connections between...

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Numerical simulation of continuous RC slabs strengthened using NSM technique   

The effectiveness of the Near Surface Mounted (NSM) technique for the increase of the flexur-al resistance of reinforced concrete (RC) beams and slabs was already well proved. The NSM technique is es-pecially adapted to increase the negative bending moments of continuous (two or more spans) RC slabs. However, the influence of the NSM strengthening on the moment redistribution capability of RC structures should be investigated. Recently, an exploratory experimental program was conducted to assess the level of moment redistribution that can be obtained in two span RC slabs strengthened with NSM strips...

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Propagação de ondas ultra-sónicas em provetes de betão expostos a temperaturas elevadas   

O recurso a ensaios não destrutivos para avaliação da capacidade resistente de elementos estruturais danificados pela exposição acidental ao fogo ou a temperaturas elevadas apresenta algumas vantagens, nomeadamente, a rapidez de execução e a possibilidade de realização de inúmeras medições sem incremento do dano previamente ocorrido. Entre os diversos ensaios não destrutivos encontra-se o da determinação da velocidade de propagação de ondas ultra-sónicas. As correlações que podem ser estabelecidas entre os registos obtidos nos ensaios velocidade de propagação...

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Moradias de custo controlado em betão auto-compactável reforçado com fibras   

No presente trabalho é desenvolvido um betão auto-compactável reforçado com fibras (BACRF) para a construção de habitações de custo controlado. As principais propriedades são apresentadas e utilizadas na análise e dimensionamento do modelo estrutural proposto.Joaquim Barros, João Dias, Delfina Gonçalves, Lúcio Lourenço, Jorge Chaves....

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Total registos: 62
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