Search results for "FRP"
showing 10 items of 92 documents
Rinforzo sismico di elementi strutturali in muratura con l’uso di FRP
2011
Con riferimento al rinforzo di elementi strutturali in muratura in conci di calcarenite e malta viene descritta brevemente una sperimentazione su: - capacità portante del giunto di incollaggio tra FRP e calcarenite; - domini di interazione M-N della sezione muraria rinforzata; pareti rinforzate caricate fuori piano; volte cilindriche rinforzate all'estradosso caricate ad un quarto della luce.
Influenza del confinamento del calcestruzzo con FRP sulla stabilità delle barre di elementi in c.a.
2009
Analisi teorico-sperimentale dell'efficacia degli interventi di rinforzo di murature in conci di calcarenite mediante l'applicazione di FRP
2012
Analisi quantitativa dell'effetto termoelastico in materiali compositi CFRP
2008
DELAMINAZIONE INTERLAMINARE DI COMPOSITI CFRP AL VARIARE DELLE CONDIZIONI DI CURA DELLA MATRICE
2012
In questo lavoro si è condotto uno studio sperimentale del comportamento a delaminazione interlaminare in Modo I di laminati compositi unidirezionali in fibra di carbonio e matrice epossidica (CFRP), al variare delle condizioni di cura della matrice. Tutti i sistemi analizzati hanno utilizzato lo stesso tessuto e lo stesso monomero epossidico DGEBA. Variando il processo di cura (cura termica o mediante radiazioni), gli agenti di cura (ammine o anidridi per i sistemi curati termicamente), e l’impiego di additivi tenacizzanti (es. il PES per i sistemi irradiati), è stato possibile controllare e modificare sia il grado di adesione fibra/matrice, che il grado di fragilità della matrice (monitor…
Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation
2012
In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …
Numerical Calibration of a Simplified Model for FRP Confinement of Columns
2018
This paper presents the calibration of a simplified analytical model for concrete columns confined by fiber reinforced polymer (FRP) jackets. The model allows evaluating the increase of strength, ductility and dissipated energy without defining the lateral confinement pressure and it can be easily extended for the assessment of FRP confinement in design applications. This model was obtained by a simplified procedure based on the best fit of experimental data available in the literature and the coefficient of determination (R2) was evaluated in order to estimate the accuracy of the regression analysis. A numerical database resulting from finite element (FE) analyses was compiled and reported…
Simplified analytical models for compressed concrete columns confined by FRP and FRCM system
2017
In order to consider the response of concrete columns confined by FRP and FRCM system, proper models have to be formulated. In this context the present paper shows a generalized criterion for the determination of the increase in strength, in ductility and in dissipated energy for varying corner radius ratio of the cross section and fiber volumetric ratio. The procedure is based on the best fitting of several experimental data and unlike the usual empirical approaches available in the literature, the proposed technique relates the confinement effectiveness to a single parameter representative of the relative stiffness between the original concrete core and the reinforcement system. Furthermo…
Strength and strain enhancements of concrete columns confined with FRP sheets
2004
The compressive behavior up to failure of short concrete members reinforced with fiber reinforced plastic (FRP) is investigated. Rectangular cross-sections are analysed by means of a simplified elastic model, able also to explain stress-concentration. The model allows one to evaluate the equivalent uniform confining pressure in ultimate conditions referred to the effective confined cross-section and to the effective stresses in FRP along the sides of section; consequently, it makes it possible to determine ultimate strain and the related bearing capacity of the confined member corresponding to FRP failure. The effect of local reinforcements constitute by single strips applied at corners bef…
Adhesive debonding detection of FRP reinforcement by the ultrasonic non-destructive technique
2015
Fiber reinforced polymer (FRP) composite systems are extensively used for repairing and reinforc- ing structurally inefficient concrete structures. The performance of an FRP rehabilitation system is highly influenced by its integrity. In particular, the presence of defects, e.g. voids, inclusions, debonds, improper cure and delaminations, caused by an inaccurately manufacture and installation, may affect the capability of the rehabilitated structure. For this reason, non-destructive (ND) meth- ods could be used to assess the quality of the reinforcement [1,2]. In this work an ultrasonic ND technique for detecting delamination defects in FRP reinforcement is presented. The technique couples …