23 research outputs found
Ătude du comportement de colonnes en bĂ©ton armĂ© dâarmature en PRFV soumises Ă des charges cycliques quasi-statiques
Abstract: Corrosion of the steel reinforcement in the conventional concrete structure is a serious and expensive problem which adversely affect the service life of the structure. The use of fiber-reinforced polymer (FRP) as internal reinforcing bar offers structurally safe alternative in concrete members such as beams, and slabs; due to its corrosion resistance, durability, and high strength-to-weight ratio when to compared to traditional steel bars. However, there is a lack of information concerning the performance of the reinforced-concrete columns confined with FRP bars under simulated seismic load. Study of reinforced concrete columns is useful for the construction of building, highway, and railway bridge columns. Currently, several highway and railway bridge columns and buildings need rehabilitation work due to deterioration of internal steel reinforcement (mainly transverse reinforcement) due to corrosion which affects the economy of the country. Thus, the experimental work is needed to verify the confinement effect of FRP bars on concrete columns subjected to quasi-static cyclic load to be use in new construction. The present study investigates the experimental performance of reinforced-concrete columns confined with glass fiber-reinforced polymers (GFRP) spiral and cross tie. Eight full-scale columns were constructed with entirely GFRP reinforcement. Four other columns were constructed with hybrid reinforcement consisting of longitudinal steel rebars and confined with GFRP spirals and cross ties. The columns had a cross section of 400 Ă 400 mm with an overall height of 1850 mm. The columns were tested to failure under combined constant axial compression and quasi-static reversed cyclic loading. Parameters under study were longitudinal bar type (GFRP and steel), longitudinal reinforcement ratio (1.48% and 2.14%), transverse reinforcement size (#3, #4, and #5) and spacing of transverse reinforcement (100, 120 and 150 mm). Overall performance of each specimen was examined in terms of cracking patterns, hysteresis response, strain developed in reinforcing bars, energy dissipation capacity, drift capacity, and strength capacity. Based on the test results, well-confined concrete columns showed a stable performance attending acceptable drift capacity which meets the recommendation of most design codes. The longitudinal reinforcement type significantly affected the column performance in terms of important seismic parameters. The hybrid-reinforced columns consisting of longitudinal steel and transverse GFRP reinforcement (spiral and cross tie) exhibited higher ductility and dissipated more energy than the GFRP-reinforced concrete columns. Failure progression of GFRP-reinforced column was more gradual with no strength degradation contrary to columns reinforced with longitudinal steel bars. The column behavior was patently influenced by longitudinal and transverse reinforcement ratio. The strain developed in transverse GFRP spirals and cross ties showed its effectiveness in confining the column core irrespective of the longitudinal bar type. Proposed displacement deformability index based on experiment showed reasonably good prediction for GFRP-reinforced concrete columns. The test results achieved comparable strength compared to North American design codes for columns reinforced with hybrid longitudinal steel and transverse GFRP reinforcement while the low elastic modulus of the GFRP longitudinal bar had a significant impact on the theoretical capacity of the concrete columns.La corrosion de l'armature dâacier dans les structures en bĂ©ton est un problĂšme sĂ©rieux et coĂ»teux et qui rĂ©duit la durĂ©e de vie de lâouvrage. L'utilisation des barres dâarmature composites en polymĂšre renforcĂ© de fibres (PRF) offre une trĂšs bonne alternative pour les Ă©lĂ©ments en bĂ©ton tels que les poutres et les dalles notamment en raison de leur rĂ©sistance Ă la corrosion, de durabilitĂ© et de son rapport rĂ©sistance / poids Ă©levĂ© par rapport aux barres d'acier traditionnelles. Cependant, il y a un manque d'information technique sur le comportement des colonnes en bĂ©ton armĂ© avec des barres en PRF sous charges sismiques. L'Ă©tude des colonnes en bĂ©ton armĂ© est utile pour la construction de nombreux ouvrages dont les bĂątiments et les ponts. Actuellement, plusieurs colonnes dâouvrages nĂ©cessitent des travaux de rĂ©habilitation en raison de la dĂ©tĂ©rioration des armatures dâacier (principalement des armatures transversales) due Ă la corrosion. Ainsi, des travaux expĂ©rimentaux sont nĂ©cessaires pour vĂ©rifier lâutilisation de barres en PRF comme armature longitudinale et transversale dans des colonnes en bĂ©ton armĂ© soumises Ă des charges latĂ©rales cycliques. La prĂ©sente Ă©tude examine les performances expĂ©rimentales de colonnes en bĂ©ton armĂ© avec armature transversale en composite de polymĂšre renforcĂ© de fibres de verre (PRFV) de forme spirale en spirale et en Ă©pingle. Huit colonnes Ă pleine Ă©chelle ont Ă©tĂ© construites avec un renforcement entiĂšrement en PRFV (armature longitudinale et transversale). Quatre autres colonnes ont Ă©tĂ© construites avec une armature hybride constituĂ©e dâarmature dâacier longitudinale et dâarmature transversale constituĂ©e de spirales et dâĂ©pingles en PRFV. Les colonnes ont une section transversale de 400 mm x 400 mm avec une hauteur totale de 1850 mm. Les colonnes ont Ă©tĂ© testĂ©es jusqu'Ă la rupture sous une charge axiale constante combinĂ©e Ă un chargement cyclique latĂ©ral. Les paramĂštres dâĂ©tude considĂ©rĂ©s sont : le type de barre longitudinale (PRFV et acier), le taux de renforcement longitudinal (1,48% et 2,14%), la grosseur des armatures transversales (#3-10 mm, #4-13 mm et #5-15 mm) et l'espacement des armatures transversales (100, 120 et 150 mm). Les performances globales de chaque colonne ont Ă©tĂ© examinĂ©es en termes de rĂ©seaux de fissuration, de la courbe d'hystĂ©rĂ©sis, de dĂ©formation dans les barres d'armature, de capacitĂ© de dissipation d'Ă©nergie, de taux de dĂ©placement latĂ©ral et de rĂ©sistance. Sur la base des rĂ©sultats des essais, les colonnes en bĂ©ton bien confinĂ©es avec de lâarmature transversale en PRFV ont montrĂ© une performance stable correspondant Ă une capacitĂ© de dĂ©placement latĂ©ral acceptable qui rĂ©pond aux recommandations de la plupart des codes de conception. Le type de renforcement longitudinal (acier ou PRFV) a eu un impact significatif sur les performances des colonnes en termes de paramĂštres sismiques. La colonne renforcĂ©e avec de lâarmature hybride constituĂ©e dâacier (armature longitudinale) et de PRFV (armature transversale) prĂ©sentait une ductilitĂ© plus Ă©levĂ©e et dissipait plus d'Ă©nergie que la colonne en bĂ©ton armĂ© entiĂšrement en PRFV. La progression de la rupture dans les colonnes en bĂ©ton armĂ© dâarmature en PRFV (armature longitudinale et transversale) Ă©tait plus progressive et sans dĂ©gradation de la rĂ©sistance contrairement aux colonnes en bĂ©ton armĂ© avec des barres d'acier longitudinales. Aussi, le comportement des colonnes a Ă©tĂ© clairement influencĂ© par le taux dâarmature longitudinale et transversale. La dĂ©formation dĂ©veloppĂ©e dans les spirales transversales et les Ă©pingles en PRFV a montrĂ© l'efficacitĂ© de la spirale et des Ă©pingles en PRFV quel que soit le type de barre longitudinale de la colonne (acier ou PRFV). L'indice de dĂ©formabilitĂ© proposĂ© en se basant sur les rĂ©sultats expĂ©rimentaux obtenus a montrĂ© une bonne prĂ©diction pour les colonnes en bĂ©ton armĂ© de PRFV. Les rĂ©sistances des colonnes testĂ©es concordent trĂšs bien avec les prĂ©dictions des normes de conception nord-amĂ©ricains aussi bien pour les colonnes avec armature hybride ou entiĂšrement en PRFV. Le module d'Ă©lasticitĂ© rĂ©duit de la barre longitudinale de GFRP a eu un impact significatif sur la capacitĂ© des colonnes de bĂ©ton armĂ© de PRFV
Our experience in second line Anti Retroviral Therapy (ART) At State Aids Clinical Expert Panel (SACEP) Clinic, Centre of Excellence (CoE), Art Centre, B. J. Medical College, Civil Hospital, Ahmedabad
NRTIs (ZDV and d4T) side effects in PLHAs attending the antiretroviral treatment centre of B. J. Medical College Aad Civil Hospital At Ahmedabad, Gujarat, India
Outcome of first line antiretroviral therapy (art) with respect to treatment Failure at ART CENTRE, B. J. Medical College, Civil Hospital, Ahmedabad
Service outcome of antiretroviral Post-Exposure Prophylaxis (PEP) for occupational HIV exposure among health care personnel
Health-related quality of life in patients with hepatitis C virus infection in Brazil
OBJECTIVE: To quantify the health-related quality of life (HRQoL) burden of hepatitis C virus (HCV) infection among a broad sample of adults in Brazil, particularly among those 40 years of age and older. METHODS: This was a retrospective observational study of data from the 2011 Brazil National Health and Wellness Survey, a large (n = 12 000) cross-sectional survey that includes information on medical conditions and health outcomes, including the Medical Outcomes Study Short-form 12 health questionnaire, version 2 (SF-12v2). Respondents who reported a physician diagnosis of HCV infection were compared with those who reported never experiencing HCV on the Mental (MCS) and Physical (PCS) Component Summary scores and SF-6D health utility scores. Unadjusted comparisons were conducted with chi-square tests for categorical variables and t-tests for continuous variables. Regression was used to adjust outcomes for potential confounds. Subgroup analyses were conducted on those 40 years of age and older. RESULTS: Unadjusted comparisons between respondents infected with HCV (n = 100) and controls (n = 11 694) revealed similar MCS and PCS scores, but HCV patients had lower SF-6D utility scores (0.70 vs. 0.73, P < 0.05). Regressions adjusting for demographic and health characteristics provided similar results to unadjusted comparisons. Subgroup analyses of respondents 40 years of age and older revealed decrements in both MCS (45.95 vs. 49.72, P < 0.05) and SF-6D (0.71 vs. 0.76, P < 0.05). PCS scores were comparable in HCV patients and controls. CONCLUSIONS: HCV infection in Brazil causes significant HRQoL burden, especially among the older population. Prevention measures to curtail the spread of the virus in Brazil should provide societal benefits in terms of quality of life, in addition to preventing morbidity and mortality from chronic infection
PSInSAR and GNSS derived deformation study in the west part of Narmada Son Lineament (NSL), western India
The Narmada Son Lineament located in the middle part of the Indian plate is to be considered seismically active part and already experienced six moderate earthquakes in the last century. The geological studies summarize that the reactivation of existing faults of the paleo-rift are the main source of the tectonic deformation in this part. In the present study the PSInSAR technique with Sentinel 1A dataset, 2016â2019, is being applied for the measurement of deformation pattern of NSL. The derived results were collectively analyzed with the time-series dataset (2009â2019) of a GNSS site located in the study area. The results reveal association of very low amount of deformation along the Son Narmada Fault (SNF). The area towards south of the SNF portrays approximately 2.0âŻmm of annual Line of Sight (LoS) displacement, which we believe is significant for this region. The estimated deformation lies mainly along the Tapti North Fault (TNF) and Barwani Sukta Fault (BSF) and represented by the existence of a number of transverse faults in the area. The presence of seismic activity in this part justifies the area of maximum deformation accumulation