Possibilities and challenges of NSM for the flexural strengthening of RC structures

Near surface mounted (NSM) is a technique that has been used to increase the flexural and the shear resistance of reinforced concrete (RC) structures. The performance of the NSM for the flexural strengthening of RC beams and slabs was already well proved, from research to case-studies. However, the influence of some variables that govern the effectiveness of the NSM, such is the case of the distance between consecutive bars, the reinforcement ratio of existing longitudinal steel bars, the relative position between longitudinal steel and FRP bars, the concrete strength class, and the type and layer thickness of the adhesive is still not well understood. Strengthening procedures need also some improvements in order to increase the effectiveness of this technique. These topics are discussed in the present work, based on the research already done. Specific issues that need extra and deep research are addressed.National Science Foundation(13-05-04-FDR-00031

Shear deformation and failure modes of the GFRP reinforced concrete beams without stirrups

The various shear-transfer actions due to: aggregate interlock effect, dowel action of the flexural reinforcement, the uncracked concrete in the compressive zone and the direct strut action for the point load close to the support, may provide different crack pattern in the shear span of the concrete beams without stirrups. The aim of this paper is to investigate the shear failure mechanisms in T-shape, single span and simply supported beams exclusively reinforced with longitudinal glass fiber reinforced polymer (GFRP) bars. The research of concrete beams flexurally reinforced with GFRP bars without stirrups indicated the possibility of occurring, besides the conventional shear-compression failure mode, another type of failure governed by the loss of bond between the ordinary reinforcement and concrete. Usually the critical shear crack in RC beams without stirrups develops through the theoretical compression strut preventing a direct transfer of the shear force to the support. The main parameter affecting the crack pattern and the shear strength of the beams is the shear span to depth ratio. However, the test results presented in this paper showed the formation of an arching effect due to the bond losing between the GFRP flexural reinforcement and concrete. This failure mode revealed unexpected critical crack pattern and failure mode. Digital image correlation (DIC) technique was used to better capture and analyse the cracking process up to the formation of the shear failure crac

CFRP flexural and shear strengthening technique for RC beams : experimental and numerical research

Near surface mounted (NSM) technique has proved to be a very effective technique for the flexural strengthening of RC beams. Due to the relatively small thickness of the concrete cover that several beams present, cutting the bottom arm of steel stirrups for the installation of NSM laminates might be a possible strategy, whose implications on the beam’s load carrying capacity need to be assessed. When steel stirrups are cut, however, the shear resistance can be a concern. This also happens when a strengthening intervention is carried out to increase the flexural resistance of a beam, since in certain cases it is also necessary to increase the shear resistance in order to avoid the occurrence of brittle shear failure. The present work assesses the effectiveness of a technique that aims to increase both the flexural and shear resistance of RC beams that have the bottom arm of the steel stirrups cut for the application of NSM laminates. This assessment is performed by experimental and numerical research. The main results of the experimental program are presented and analyzed, and the innovative aspects of a constitutive model implemented in a computer program are described, being their virtues and deficiencies discussed.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 second Author acknowledges the grant under the aforementioned research project. The third author acknowledges the financial support of FCT, PhD Grant number SFRH/BD/23326/2005

Effect of interventions to reduce potentially inappropriate use of drugs in nursing homes: a systematic review of randomised controlled trials

Background Studies have shown that residents in nursing homes often are exposed to inappropriate medication. Particular concern has been raised about the consumption of psychoactive drugs, which are commonly prescribed for nursing home residents suffering from dementia. This review is an update of a Norwegian systematic review commissioned by the Norwegian Directorate of Health. The purpose of the review was to identify and summarise the effect of interventions aimed at reducing potentially inappropriate use or prescribing of drugs in nursing homes. Methods We searched for systematic reviews and randomised controlled trials in the Cochrane Library, MEDLINE, EMBASE, ISI Web of Knowledge, DARE and HTA, with the last update in April 2010. Two of the authors independently screened titles and abstracts for inclusion or exclusion. Data on interventions, participants, comparison intervention, and outcomes were extracted from the included studies. Risk of bias and quality of evidence were assessed using the Cochrane Risk of Bias Table and GRADE, respectively. Outcomes assessed were use of or prescribing of drugs (primary) and the health-related outcomes falls, physical limitation, hospitalisation and mortality (secondary). Results Due to heterogeneity in interventions and outcomes, we employed a narrative approach. Twenty randomised controlled trials were included from 1631 evaluated references. Ten studies tested different kinds of educational interventions while seven studies tested medication reviews by pharmacists. Only one study was found for each of the interventions geriatric care teams, early psychiatric intervening or activities for the residents combined with education of health care personnel. Several reviews were identified, but these either concerned elderly in general or did not satisfy all the requirements for systematic reviews. Conclusions Interventions using educational outreach, on-site education given alone or as part of an intervention package and pharmacist medication review may under certain circumstances reduce inappropriate drug use, but the evidence is of low quality. Due to poor quality of the evidence, no conclusions may be drawn about the effect of the other three interventions on drug use, or of either intervention on health-related outcomes

Methodology for Implementing Scalable Run-Time Reconfigurable Devices

The aim of this paper is to present the implementation methodology for an ASIC constituting the fine-grained array of dynamically reconfigurable processing elements. This methodology was developed during the work on a device which can operate as a typical Field Programmable Gate Array (FPGA) with some bio-inspired features or as a multi-core Single Instruction Multiple Data (SIMD) processor. Such high diversity of possible operating modes makes the design implementation extremely demanding. As a consequence, the comprehensive study and analysis of the different possible implementation techniques in this case allowed us to formulate a consistent and complete methodology that can be applied to other systems of similar structure