Browsing by Author "Fortes, Adriano S."
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- Assessing the effectiveness of embedding CFRP laminates in the near surface for structural strengtheningPublication . Ferreira, Débora; Barros, Joaquim; Fortes, Adriano S.; Dias, SalvadorThe Near Surface Mounted (NSM) technique is a recent strengthening strategy, using Fiber Reinforced Polymer (CFRP) systems, that is being developed to increase the bending and the shear resistance of structural elements. To assess the effectiveness of the NSM technique, an experimental program is carried out involving reinforced concrete (RC) columns, RC beams and masonry panels. In columns failing in bending the present work shows that CFRP failure strain can be attained using the NSM technique. In this study, beams of distinct steel reinforcement ratio failing in bending are strengthened with CFRP laminate strips in order to double their load carrying capacity. This goal was attained and maximum strain levels of about 90% of the CFRP failure strain were recorded. The effectiveness of externally bonded reinforcing (EBR) and NMS techniques are compared by carrying out three-point-bending tests with masonry panels failing in bending. The NMS technique has provided a higher increase of the load carrying capacity, deflection at panel failure and more homogeneous behavior during panel deformability. Performance of both EBR and NMS techniques are also compared for strengthening RC beams failing in shear. NMS is shown to be much more effective, not only in terms of the increase of the load carrying capacity and deformability at beam failure, but also with respect to the time consuming nature of the corresponding strengthening procedures.
- Investigação no âmbito da utilização de materiais compósitos no reforço de estruturas de betãoPublication . Barros, Joaquim; Cruz, Sena; Dias, Salvador; Ferreira, Débora; Fortes, Adriano S.Nos últimos anos tem sido crescente a utilização de materiais compósitos no reforço de estruturas de betão armado. Para tal contribui as melhores propriedades mecânicas destes materiais, a sua maior resistência à acção de agentes agressivos e a sua maior leveza e facilidade de aplicação, quando se tem por base de comparação materiais convencionais tais como o aço e o betão. Nos últimos tempos tem-se efectuado investigação experimental e numérica no âmbito da utilização de laminados em fibra de carbono (CFRP) no reforço de estruturas de betão. Estes materiais compósitos têm sido utilizados no reforço à flexão e ao corte de pilares e vigas. A ligação CFRP-adesivo-betão tem sido caracterizada por forma a ser estabelecida a lei que define a transferência de tensões entre os materiais constituintes desta ligação, lei esta a ser implementada num modelo de interface, no quadro do método dos elementos finitos.
- Near surface mounted CFRP-based technique for the strengthening of concrete structuresPublication . Barros, Joaquim; Cruz, Sena; Dias, Salvador; Ferreira, Débora; Fortes, Adriano S.To assess the effectiveness of the Near Surface Mounted (NSM) strengthening technique, an experimental program was carried out involving reinforced concrete (RC) columns and beams. In columns failing in bending the present work shows that the failure strain of the Carbon Fiber Reinforced Polymer (CFRP) laminates can be attained using the NSM technique. Beams failing in bending were also strengthened with CFRP laminates in order to double their load carrying capacity. This goal was attained and maximum strain levels of about 90% of the CFRP failure strain were recorded. Performance of externally bonded reinforcing (EBR) and NMS techniques was compared for strengthening RC beams failing in shear. NMS was much more effective, not only in terms of the increase of the load carrying capacity and deformability at beam failure, but also with respect to the time consuming nature of the corresponding strengthening procedures. To assess the bond behavior of CFRP to concrete, pulloutbending tests were carried out. The influences of bond length and concrete strength on the bond behavior were analyzed
- Nova abordagem no reforço de estruturas com materiais compósitosPublication . Ferreira, Débora; Barros, Joaquim; Cruz, José Sena; Fortes, Adriano S.Neste trabalho apresentam-se os resultados mais significativos da investigação experimental realizada para avaliar o desempenho de uma técnica de reforço baseada na fixação de laminados de CFRP em ranhuras efectuadas no betão de recobrimento de elementos estruturais. Com esta técnica foram reforçados e ensaiados elementos de pilar e de viga de betão armado com rotura por flexão, e vigas de betão armado com rotura por corte. De modo a caracterizar a ligação betão-adesivo-CFRP procedeu-se à realização de ensaios de aderência.