Investigação no âmbito da utilização de materiais compósitos no reforço de estruturas de betão

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. No Subgrupo de Estruturas do Departamento de Engª Civil da Escola de Engª da Universidade do Minho 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. Os resultados mais significativos obtidos na investigação efectuada são apresentados no presente trabalho

Near surface mounted CFRP-based technique for the strengthening of concrete structures

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.S&P®. Bettor MBT® Portugal. Secil. Nordesfer. Ferseque. Casais. Solusel. VSL. Unibetão (Braga). Cemacom

Nova abordagem no reforço de estruturas com materiais compósitos

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

Assessing the effectiveness of embedding CFRP laminates in the near surface for structural strengthening

The authors of the present work wish to acknowledge the support provided by the S&P, Bettor MBT Portugal, Secil, Nordesfer, Ferseque, Casais, Solusel, VSL, Unibetão (Braga) and the colaboration of Cemacom.Near Surface Mounted (NSM) is a recent strengthening technique based on bonding Carbon Fiber Reinforced Polymer (CFRP) bars (rods or laminate strips) into pre-cut grooves on the concrete cover of the elements to strength. 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 the failure strain of the (CFRP) laminates can be attained using the NSM technique. Beams failing in bending are 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 in this composite material, revealing that the NSM technique is also very effective to increase the flexural resistance of RC beams. The effectiveness of externally bonded reinforcing (EBR) and NSM techniques to increase the flexural resistance of masonry panels is also assessed. In the EBR technique the CFRP laminates are externally bonded to the concrete joints of the panel, while in the NSM technique the CFRP laminates are fixed into precut slits on the panel concrete joints. The NSM technique provided a higher increase on the panel load carrying capacity, as well as, a larger deflection at the failure of the panel. The performance of EBR and NSM techniques for the strengthening of RC beams failing in shear is also analyzed. The NMS technique was much more effective in terms of increasing the beam load carrying capacity, as well as, the beam deformability at its failure. The NSM technique was easier and faster to apply than the EBR technique.The first author wishes to acknowledge the grant SFRH/BSAB/291/2002-POCTI, provided by FCT and FSE

Biodiversity conservation gaps in the Brazilian protected areas

Although Brazil is a megadiverse country and thus a conservation priority, no study has yet quantified conservation gaps in the Brazilian protected areas (PAs) using extensive empirical data. Here, we evaluate the degree of biodiversity protection and knowledge within all the Brazilian PAs through a gap analysis of vertebrate, arthropod and angiosperm occurrences and phylogenetic data. Our results show that the knowledge on biodiversity in most Brazilian PAs remain scant as 71% of PAs have less than 0.01 species records per km2. Almost 55% of Brazilian species and about 40% of evolutionary lineages are not found in PAs, while most species have less than 30% of their geographic distribution within PAs. Moreover, the current PA network fails to protect the majority of endemic species. Most importantly, these results are similar for all taxonomic groups analysed here. The methods and results of our countrywide assessment are suggested to help design further inventories in order to map and secure the key biodiversity of the Brazilian PAs. In addition, our study illustrates the most common biodiversity knowledge shortfalls in the tropics.Fil: Oliveira, Ubirajara. Universidade Federal de Minas Gerais; BrasilFil: Soares-Filho, Britaldo Silveira. Universidade Federal de Minas Gerais; BrasilFil: Paglia, Adriano Pereira. Universidade Federal de Minas Gerais; BrasilFil: Brescovit, Antonio Domingos. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: De Carvalho, Claudio J. B.. Universidade Federal do Paraná; BrasilFil: Silva, Dasniel Paiva. Instituto Federal Goiano; BrasilFil: Teixeira de Rezende, Daniella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Leite, Felipe Sá Fortes. Universidade Federal de Vicosa; BrasilFil: Batista, João Aguiar Nogueira. Universidade Federal de Minas Gerais; BrasilFil: Barbosa, João Paulo Peixoto Pena. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Stehmann, João Renato. Universidade Federal de Minas Gerais; BrasilFil: Ascher, John S.. National University Of Singapore; SingapurFil: De Vasconcelos, Marcelo Ferreira. Instituto Prístino; BrasilFil: De Marco, Paulo. Universidade Federal de Goiás; BrasilFil: Löwenberg-Neto, Peter. Universidade Federal da Integração Latino-Americana; BrasilFil: Ferro, Viviane Gianluppi. Universidade Federal de Goiás; BrasilFil: Santos, Adalberto J.. Universidade Federal de Minas Gerais; Brasi

Reply to Biodiversity conservation gaps in Brazil: A role for systematic conservation planning

Previous article in issueNext article in issue Fonseca and Venticinque (2018) (hereafter FV) present a critical assessment of a paper in which we attempt to estimate the biodiversity coverage of the Brazilian conservation units (Oliveira et al., 2017). We appreciate their contribution to this important debate. We have no doubts that conservation planning should be based on a variety of information sources, including not only the coverage of species? ranges but also the contribution of each area to the preservation of ecosystem services, landscape features and socioeconomic and cultural aspects. This systematic and integrative conservation planning is certainly a complex process, which requires the contribution of experts from different fields. However, we have shown, in this reply, that our paper (Oliveira et al., 2017) aims to quantify the knowledge and protection gaps of biodiversity in protected areas, not to propose priority areas or to test whether the current proposal of priority areas is efficient. Objectives and the conclusions of our paper. We hope this short response can clarify this debate.Fil: Oliveira, Ubirajara. Universidade Federal de Minas Gerais; BrasilFil: Soares Filho, Britaldo Silveira. Universidade Federal de Minas Gerais; BrasilFil: Paglia, Adriano Pereira. Universidade Federal de Minas Gerais; BrasilFil: Brescovit, Antonio Domingos. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: de Carvalho, Claudio J. B.. Universidade Federal do Paraná; BrasilFil: Silva, Daniel Paiva. Instituto Federal Goiano; BrasilFil: Teixeira de Rezende, Daniella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Leite, Felipe Sá Fortes. Universidade Federal de Viçosa; BrasilFil: Batista, João Aguiar Nogueira. Universidade Federal de Minas Gerais; BrasilFil: Barbosa, João Paulo Peixoto Pena. Governo do Estado de Sao Paulo. Secretaria da Saude. Instituto Butantan; BrasilFil: Stehmann, João Renato. Universidade Federal de Minas Gerais; BrasilFil: Ascher, John S.. National University Of Singapore; SingapurFil: Vasconcelos, Marcelo Ferreira de. Instituto Prístino; BrasilFil: De Marco, Paulo. Universidade Federal de Goiás; BrasilFil: Löwenberg-Neto, Peter. Universidade Federal Da Integração Latino-americana; BrasilFil: Ferro, Viviane Gianluppi. Universidade Federal de Goiás; BrasilFil: Santos, Adalberto J.. Universidade Federal de Minas Gerais; Brasi