Laje sandwich em polímero reforçado com fibra de vidro e argamassa de ultra elevada ductilidade para a reabilitação estrutural

Estudo desenvolvido no âmbito do projeto PTDC/ECM/113041/2009 “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, financiado pela FCT - Fundação para a Ciência e Tecnologia.Neste trabalho apresenta-se um novo sistema estrutural em laje sandwich formada por camada inferior de tração e nervuras transversais em material polimérico reforçado com fibra de vidro (GFRP), núcleo em material leve e com propriedades de isolamento térmico, e camada de compressão em argamassa de ultra elevada ductilidade (UDFRM). Esta última aumenta a resistência à encurvadura local das nervuras transversais de GFRP, contribui para a resistência e ductilidade do comportamento estrutural da laje, aumenta a proteção às temperaturas elevadas e permite a instalação na face superior da laje de elementos cerâmicos ou outros materiais convencionais de acabamento. Dado tratar-se de um tipo de laje com peso próprio muito inferior a qualquer outra solução construtiva existente, a sua aplicação é especialmente vocacionada para a reabilitação estrutural de edifícios de cantaria onde se preservam as paredes resistentes e se pretende remodelar as lajes. Utilizando um programa de cálculo automático baseado no método dos elementos finitos que dispõe de modelos constitutivos apropriados, foi efetuado um estudo paramétrico de forma a otimizar este sistema estrutural.Fundação para a Ciência e a Tecnologia (FCT

New composite slab system for the structural rehabilitation of traditional buildings

The study presented in this paper is a part of the research project “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, with reference number of PTDC/ECM/113041/2009.In this paper, a new generation of composite sandwich panel slab is proposed as a solution for the rehabilitation of slabs in old masonry buildings. The new slab composite system is composed of four elements that include: High Performance Fiber Reinforced Concrete (HPFRC) layer, GFRP ribs, foam core and GFRP skin. An innovative GFRP-HPFRC hybrid solution has been developed, with a GFRP laminate on the bottom tension skin, and an HPFRC layer on the top compression skin, preventing the occurrence of buckling phenomena, improving the resistance to the effects of impact and fire, providing a ductile behavior and allowing for an easy application of floor covering materials. GFRP ribs and foam core are able to transfer shear stresses between skins. The design process of the proposed hybrid GFRP-HPFRC sandwich panel slab is presented. The effects of various parameters on the behavior of the slabs are investigated by using both linear and material nonlinear analysis, with the aid of the software FEMIX. According to the obtained results, some criteria are established in order to choose the best slab solutions, which include design codes recommendations, failure criteria, serviceability criteria and economic aspects.Fundação para a Ciência e a Tecnologia (FCT

Structural performance of hybrid sandwich slabs under shear loading

In a hybrid panel with glass fiber reinforced polymer (GFRP) bottom skin and ribs, and deflection hardening cementitious composites (DHCC) top layer, it is very important to provide good shear connection between these various components in order to increase the load carrying capacity of the resulting hybrid slabs and a larger increment of deflection before the occurrence of the structural softening of this panel. The effectiveness of the proposed hybrid sandwich panels strongly depends on the performance of the shear connectors. The efficiency of indented shear connectors in improving the flexural performance of hybrid sandwich panels is here demonstrated. Since the efficiency of indented shear connectors in the hybrid sandwich panels is unknown, efforts are made in this paper in investigating the shear performance of hybrid slabs. A special focus is given on the indented shear connector’s behavior, considering different shear span ratios in ranges of 2.00, 1.39, and 0.77. In this regard, six hybrid sandwich panels were manufactured and experimentally tested under different shear loads. Then, the results are interpreted comprehensively. The results obtained show that the GFRP rib thickness and height, and shear span ratios influence the damage events and the structural performance of the hybrid sandwich panels. Moreover, it was observed that using indented shear connectors in the hybrid slabs, regardless of the shear span ratios, provides high load capacity, high stiffness, and large residual deflection.The study presented in this paper is a part of the research project “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, with reference number of PTDC/ECM/113041/2009

FRCcalc - software for design of fiber reinforced concrete elements according to MC2010 recommendations

A new software, denominated FRCcalc, was developed for the analysis and design of fiber reinforced concrete (FRC) members based on the recommendations and design guidelines of MC2010. The software is guided for the analysis of FRC cross-sections with and without conventional steel reinforcements, submitted to bending and shear, in order to assess the ultimate and serviceability limit state safety verifications of structural members. A main feature of the software is the possibility to run a comparative analysis between FRC and reinforced concrete (RC) cross-sections from the technical aspects. Two examples of the analysis of FRC and RC cross-sections using FRCcalc are presented, having been explored the use of fiber reinforcement in members for increased structural performance and as a total or partial replacement of conventional steel reinforcement. Additionally, in order to appraise FRCcalc accuracy to evaluate the flexural response of FRC and RC cross-sections, a comparison with the results obtained with DOCROS software is presented, being DOCROS based on a layered model capable of attributing to each layer an aimed constitutive model, therefore adequate to predict the moment-curvature of cross sections composed of several types of cement, metallic and polymer materials.The first Author would like to acknowledge the grant SFRH/BDE/96381/2013 co-funded by CiviTest - Pesquisa de Novos Materiais para a Engenharia Civil, Lda. and by FCT - Portuguese Foundation for Science and Technology. The authors also acknowledge the support provided by the FCT project PTDC/ECM-EST/2635/2014

Development of innovative hybrid sandwich panel slabs: Advanced numerical simulations and parametric studies

The authors honestly appreciate the collaboration of the following institutions: Civitest for developing DHCC materials and PIEP for conducting VARTM process.An innovative hybrid sandwich slab for the rehabilitation of floors in old masonry buildings was conceived, designed, and tested. This structural system is a lightweight composite floor consisting of bottom skin and shear ribs in Glass Fiber Reinforced Polymer (GFRP), a top layer of Deflection Hardening Cement Composites (DHCC), and Polyurethane foam core. In the first part of this study, the material/structural performance of the panel’s concept was assessed by experimental tests. The second part is now dedicated to the execution of advanced numerical simulations, including parametric studies, for assisting on the optimization of this composite slab system and investigating the influence of the relevant characteristics of GFRP and DHCC components. The influence of considering isotropic or orthotropic behavior for the GFRP components and linear or nonlinear behavior for the DHCC are also investigated numerically in terms of accomplishing serviceability and ultimate limit state requisites for this structural system. The parametric studies show that the thickness of GFRP rib is the most important parameter to increase the load carrying capacity of this type of slabs. Based on the results of these parametric studies, two slabs are built and tested experimentally, and the obtained results are not only used to demonstrate the effectiveness of the developed structural system, but also to appraise the predictive performance of the constitutive models adopted in the FEM-based simulations.The study presented in this paper is a part of the research project “RehabGFRP - Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich Panels”, with reference number of PTDC/ECM/113041/2009. Furthermore, the authors honestly appreciate the collaboration of the following institutions: Civitest for developing DHCC materials and PIEP for conducting VARTM process

The Disease Burden Attributable to Smoking in the State Of Rio De Janeiro, Brazil in 2000

INTRODUCTION: Smoking is one of the main risk factors for morbidity and mortality. An estimated 59 million (4.4%) disability-adjusted life years were lost due to smoking throughout the world in 2000. OBJECTIVE: To estimate the disease burden attributable to smoking in the State of Rio de Janeiro, Brazil, for the year 2000. METHODS: Based on estimates of smoking prevalence and relative death risks, the smoking-attributable fraction was calculated for each selected cause, by age and gender. The disease burden attributable to smoking was estimated by multiplying the fractions by the corresponding disability-adjusted life years. RESULTS: In the State of Rio de Janeiro, 7% of all disability-adjusted life years were due to smoking. For individuals 30 or more years old, the fraction increased to 10.6% (13.6% in males and 7.5% in females). Chronic obstructive pulmonary disease, ischemic heart disease, cerebrovascular disease, and tracheal, bronchial, and lung cancer accounted for 32.2%, 15.7%, 13.2%, and 11.1% of the estimated total DALYs, respectively, amounting to 72.2% of the smoking-attributable disease burden. DISCUSSION: Limitations related to parameter estimates were not unique to this study, and therefore should not compromise the comparability of our results. Outcomes were similar to those obtained in other countries, despite methodological differences. CONCLUSION: Smoking is an important risk factor and places a significant disease burden on Rio de Janeiro, Brazil, showing a pattern similar to that observed in high income countries

Os efeitos da cessação tabágica no tratamento periodontal não-cirúrgico da periodontite crónica

Objetivo: Abordar os efeitos da cessação tabágica na resposta ao tratamento periodontal não cirúrgico da periodontite crónica. Materiais e Métodos: Realizou-se uma pesquisa bibliográfica recorrendo às bases de dados PubMed, Scielo, B-On e Lilacs. Foram incluídas revisões sistemáticas, meta-análises, estudos prospetivos e transversais, realizados em humanos, entre 1997 e 2017, em língua inglesa ou portuguesa. A pesquisa resultou num total de 8 artigos. Resultados: A cessação tabágica parece diminuir o risco de incidência e progressão da periodontite, bem como melhorar a resposta ao tratamento periodontal não cirúrgico. No entanto, não está claro quanto tempo depois de parar de fumar, começa o ex-fumador a recuperar a capacidade de cicatrização e a recuperação da saúde oral, ainda que alguns resultados apontem para um efeito precoce e quase imediato. Conclusão: São necessários mais estudos clínicos randomizados, controlados, com amostras maiores, tempo maiores de acompanhamento e protocolos bem delineados, para suportar cientificamente os resultados encontrados.Objectives: To address the effects of smoking cessation on the response to non-surgical periodontal treatment of chronic periodontitis Material and Methods: A bibliographic search was done using the databases PubMed, Scielo, B-On and Lilacs. Only systematic reviews and meta-analyzes published between 1997 and 2017 published in English or Portuguese were included. The search resulted in a total of 8 items. Results: Smoking cessation appears to reduce the risk of incidence and progression of periodontitis, as well as to improve the response to non-surgical periodontal treatment Conclusion: Further randomized clinical trials with larger samples, longer follow-up times and well-designed protocols are required to scientifically support the effect of smoking cessation on the periodontium as well as non-surgical periodontal treatment of periodontitis

Os efeitos da cessação tabágica no tratamento periodontal não-cirúrgico da periodontite crónica

Objetivo: Abordar os efeitos da cessação tabágica na resposta ao tratamento periodontal não cirúrgico da periodontite crónica. Materiais e Métodos: Realizou-se uma pesquisa bibliográfica recorrendo às bases de dados PubMed, Scielo, B-On e Lilacs. Foram incluídas revisões sistemáticas, meta-análises, estudos prospetivos e transversais, realizados em humanos, entre 1997 e 2017, em língua inglesa ou portuguesa. A pesquisa resultou num total de 8 artigos. Resultados: A cessação tabágica parece diminuir o risco de incidência e progressão da periodontite, bem como melhorar a resposta ao tratamento periodontal não cirúrgico. No entanto, não está claro quanto tempo depois de parar de fumar, começa o ex-fumador a recuperar a capacidade de cicatrização e a recuperação da saúde oral, ainda que alguns resultados apontem para um efeito precoce e quase imediato. Conclusão: São necessários mais estudos clínicos randomizados, controlados, com amostras maiores, tempo maiores de acompanhamento e protocolos bem delineados, para suportar cientificamente os resultados encontrados.Objectives: To address the effects of smoking cessation on the response to non-surgical periodontal treatment of chronic periodontitis Material and Methods: A bibliographic search was done using the databases PubMed, Scielo, B-On and Lilacs. Only systematic reviews and meta-analyzes published between 1997 and 2017 published in English or Portuguese were included. The search resulted in a total of 8 items. Results: Smoking cessation appears to reduce the risk of incidence and progression of periodontitis, as well as to improve the response to non-surgical periodontal treatment Conclusion: Further randomized clinical trials with larger samples, longer follow-up times and well-designed protocols are required to scientifically support the effect of smoking cessation on the periodontium as well as non-surgical periodontal treatment of periodontitis