34 research outputs found
Flexural strengthening of RC continuous slab strips using NSM CFRP laminates
To assess the effectiveness of the near surface mounted (NSM) technique, in terms of load carrying and moment
redistribution capacities, for the flexural strengthening of continuous reinforced concrete (RC) slabs, an
experimental program was carried out. The experimental program is composed of three series of three slab strips of
two equal span length, in order to verify the possibility of increasing the negative (at the intermediate support
region) resisting bending moment in 25% and 50% and maintaining moment redistribution levels of 15%, 30% and
45%. Though the flexural resistance of the NSM strengthened sections has exceeded the target values, the moment
redistribution was relatively low, and the increase of the load carrying capacity of the strengthened slabs did not
exceed 25%. This experimental program is analyzed to highlight the possibilities of NSM technique for statically
indeterminate RC slabs in terms of flexural strengthening effectiveness, moment redistribution and ductility
performance. Using a FEM-based computer program, which predictive performance was appraised using the
obtained experimental results, a high effective NSM flexural strengthening strategy is proposed, capable of
enhancing the slabâs load carrying capacity and maintaining high levels of ductility.The study reported in this paper forms a part of the research program "CUTINEMO - Carbon fiber laminates applied according to the near surface mounted technique to increase the flexural resistance to negative moments of continuous reinforced concrete structures" supported by FCT, PTDC/ECM/73099/2006. The authors wish to acknowledge the support also provided by the S&P, Casais and Artecanter Companies. The first Author acknowledges the financial support of National Council for Scientific and Technological Development (CNPq) - Brazil, Ph.D. Grant no. 200953/2007-9. The second Author wishes to acknowledge the support provided by FCT, by means of the SFRH/BSAB/818/2008 and SFRH/BSAB/913/2009 sabbatical grants
Atividade elicitora de fitoalexinas em Soja e Sorgo por extratos e tinturas de espécies medicinais
A verificação da capacidade indutora de fitoalexinas a partir de extratos e tinturas de espĂ©cies vegetais pode representar uma forma potencial de controle de doenças em plantas cultivadas. O objetivo foi verificar a capacidade de indução de fitoalexinas em cotilĂ©dones de Soja e mesocĂłtilos de Sorgo a partir de extratos brutos aquosos (EBAs) e tinturas de espĂ©cies medicinais. As espĂ©cies utilizadas foram as plantas medicinais Arruda (Ruta graveolens), Manjerona (Origanum majorana) e Carqueja (Baccharis trimera). Os resultados obtidos mostraram que os EBAs sĂŁo eficientes na indução de fitoalexinas em cotilĂ©dones de Soja. Em mesocĂłtilos de Sorgo os EBAs das plantas medicinais Carqueja e Manjerona induzem a produção de fitoalexinas em concentraçÔes elevadas (15, 20, 25 e 50%). As tinturas sĂŁo capazes de induzir a produção de fitoalexinas em cotilĂ©dones de Soja nas concentraçÔes de 10 e 15%, porĂ©m, nĂŁo sĂŁo capazes de induzir acĂșmulo de fitoalexinas em mesocĂłtilos de Sorgo