Search results for "CFRP"

Debonding Phenomena in CFRP Strengthened Calcarenite Masonry Walls and Vaults

2009

In this paper the results of an experimental investigation on full-scale reinforced masonry elements like vaults and walls are presented. The masonry type is constituted by calcarenite ashlars and bed joint mortar and the reinforcement is constituted by Carbon Fibre Reinforced Polymer (CFRP) strips. Preliminary experimental results obtained in a previous research by the authors on the local behaviour at the interface CFRP-calcarenite are summarized. Tests with controlled displacement are carried out on out-of-plane loaded walls and cylindrical vaults loaded at a quarter of the span. Results of tests carried out before and after the application of the reinforcement made it possible to evalu…

Flexural behaviour of concrete corbels containing steel fibers or wrapped with FRP sheets

2005

In the present paper an analytical and experimental investigation referring to the flexural behaviour of reinforced concrete corbels subjected to vertical forces is presented. For fixed shape and dimensions of the corbels the experimental investigation analyses the effects of the following: longitudinal and transverse steel reinforcements; fiber reinforced concrete (FRC) with hooked steel fibers; external wrapping retrofitting technique with a thin layer of carbon fiber sheet (CFRP). The analytical model based on equivalent truss structures, allows one to determine the bearing capacity of corbels, distinguishing the different ultimate states reached. The analytical results are then compared…

Nonlinear FE analysis of out-of-plane behaviour of masonry walls with and without CFRP reinforcement

2014

Abstract The out-of-plane behaviour of unreinforced and CFRP reinforced masonry wall is studied by means of experimental investigation and numerical FE modelling. The latter is based on a linear constitutive law both for ashlars and mortar joints constituting masonry and the lines of potential delamination are taken into account by means of an interface element with bi-linear law, reproducing the opening failure mode. When reinforcement is introduced, an interface element with bi-linear law is also used, reproducing sliding failure mode. Comparison between numerical and experimental results show the reliability of the modelling. Moreover, a parametric analysis is carried out in order to inv…

Comportamento meccanico di una volta rinforzata con CFRP

2001

Il presente lavoro riguarda il progetto e l'esecuzione di un intervento di rinforzo di una volta a padiglione lunettata di una Villa di interesse storico-monumentale del 700. Tale volta è realizzata con conci di calcarenite inzeppati con cunei di legno e senza malta di connessione, tipologia molto diffusa in tutta l'area del mediterraneo. L’intervento è stato preceduto dallo studio del comportamento meccanico della volta in laboratorio e da prove dinamiche in sito. Particolare attenzione è stata rivolta al sistema di trasmissione dei carichi verticali allo scopo di rendere meno gravoso lo stato tensionale nella parte più alta della volta. Il sistema strutturale è stato analizzato per mezzo …

Sostenibilità di interventi di miglioramento sismico di strutture in c.a. non danneggiate

2012

Numerical analysis and experimental comparison on CFRP reinforced masonry walls subjected to transverse loads

2009

The out-of-plane behaviour of walls, unreinforced and reinforced by using CFRP strips, is studied by means of experimental investigation and numerical modelling. The FEM model is based on a linear constitutive law both for the ashlars and the mortar joints constituting the masonry and the lines of potential delamination are taken into account by means of an interface element with bi-linear law, reproducing the opening failure mode. When the reinforcement is introduced, an interface element with bi-linear law is also used, reproducing the sliding failure mode. Comparison between the numerical and experimental results shows the reliability of the modelling. Moreover, a parametric analysis is …

Analisi quantitativa dell'effetto termoelastico in materiali compositi CFRP

2008

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 …

Mode I fracture toughness behavior of hydro-thermally aged carbon fibre reinforced DGEBA-HHPA-PES systems

2012

In this work the Mode I fracture toughness behavior of unidirectional CFRP laminates is investigated by means of Double Cantilever Beam (DCB) tests. The composite samples were manufactured by thermal curing after impregnation of a Carbon fabric with a DGEBA epoxy and anhydride HHPA curing agent. One resin batch was also mixed with a PES thermoplastic monomer to enhance the matrix toughness. Two lots of samples, toughened and un-toughened, were then left to soak in hot water to achieve various degrees of aging. The influence of matrix toughening and hydrothermal aging on the delamination behavior of the composite have then been assessed and correlated with characterization data from Dynamic …

Interface behaviour of bonded CFRP-Calcarenite stone joints

2010

This paper presents the results of an experimental study investigating the interface behaviour between calcarenite stone and Carbon Fibre Reinforced Polymer (CFRP) reinforcement. The analysis of the results has allowed to deduce the local behaviour at the interface, which can be modelled by means of a bi-linear shear stress-slip law, according to several codes. The experimental investigation was carried out on specimens subjected to double shear pulling tests by varying the bond length of the CRFP strips. Tests enabled determination of the bond strength of the joint and the effective bond length. The parameters of the stress-slip law were calibrated on the experimental results in order to c…