Search results for "frp"
showing 10 items of 92 documents
Seismic evaluation of ordinary RC buildings retrofitted with externally bonded FRPs using a reliability-based approach
2020
International audience; Despite the extensive literature on reinforced concrete (RC) members retrofitted with fiberreinforced polymer (FRP) composites, few studies have employed a reliability-based approach to evaluate the seismic performance of RC buildings in terms of their collapse capacity and ductility. In this study, the performance of a poorly-confined RC building structure is investigated for different FRP retrofitting schemes using different configurations and combinations of wrapping and flange-bonded FRPs, as two well-established techniques. A nonlinear pushover analysis is then implemented with a computational reliability analysis based on Latin Hypercube Sampling (LHS) to deter…
Stress-Strain Law for Confined Concrete with Hardening or Softening Behavior
2013
This paper provides a new general stress-strain law for concrete confined by steel, fiber reinforced polymer (FRP), or fiber reinforced cementitious matrix (FRCM), obtained by a suitable modification of the well-known Sargin’s curve for steel confined concrete. The proposed law is able to reproduce stress-strain curve of any shape, having both hardening or softening behavior, by using a single closed-form simple algebraic expression with constant coefficients. The coefficients are defined on the basis of the stress and the tangent modulus of the confined concrete in three characteristic points of the curve, thus being related to physical meaningful parameters. It will be shown that if the v…
Effectiveness of BFRP confinement on the compressive behaviour of clay brick masonry cylinders
2020
Abstract This paper presents the results of an experimental and analytical study on the compressive behaviour of small clay brick masonry cylinders reinforced with a basalt fibre reinforced polymer (BFRP) composite. Fourteen cylinders, manufactured using two assembling schemes and confined using either one or two layers of BFRP grids, were tested under monotonic compression loading. Traditional strain measuring systems were integrated with digital image correlation (DIC) technique. The BFRP confined masonry cylinders showed a ductile behaviour characterised by a softening branch of the stress–strain curve. The experimental strains, strength, and full stress–strain curves were modelled using…
Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: II. Post-cure testing
2007
In this paper the use of fiber optic sensors embedded into GFRP laminates for structural health monitoring of thermo-mechanical loads is presented. The proposed sensing system, consisting of two coupled fiber Bragg grating (FBG) sensors, allows the simultaneous measurement of both temperature and strain by decoupling the change in reflected wavelength induced by temperature variations from that induced by either mechanical or apparent strain, with significant advantages either for monitoring the composite cure kinetics, as described in the accompanying paper (Part I), or for assessing the structural response to thermo-mechanical loads. Both thermal ramp and mechanical static/dynamic bending…
Speckle Interferometry Analysis of Full-bending Behavior of GFRP Pultruded Material
2016
Abstract The use of Glass Fiber Reinforced Polymer materials (GFRP) has increased in the last years even among civil structural engineering due to their high specific strength, lightweight and excellent corrosion resistance. With application of the pultrusion method, the manufacture of large-scale profiles with various cross-section forms became potentially possible with relatively low costs. Usually two different technological approaches are available to realize the element: in the first one a mat-roving-mat sequence is adopted, in the second one only roving is present. Continuous filament mat (CFM, fibers distributed randomly in all directions) is often used to build up laminate thickness…
Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets
2017
This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip-off failure of the concrete cover. The CFRP sheets were fixed to the concrete surface by epoxy adhesive as well as combined with various configurations of small-diameter steel pins for mechanical fastening to form a hybrid connection. Such hybrid jointing techniques were found to be particularly adva…
Numerical and Experimental Study of Defects Evolution in a Composites Wing Box Under Compressive Loads
2013
Due to their high specific strength and stiffness, Carbon Fibres Reinforced Plastics (CFRP) are commonly considered suitable for aerospace structural applications. However, their failure mechanisms are not completely predictable and this is the main reason why the CFRP integration in the aerospace industry has been generally slow in the last twenty years. Indeed, the lack of robust numerical tools, able to take into account the damage tolerance of composite structures, has led to over-conservative designs, not fully realising the promised economic benefits of composites materials. The Project MACMES (Damage Management of Aircraft Composite Structures Monitored by Embedded Sensors), funded b…
Strengthening of steel-reinforced concrete structural elements by externally bonded FRP sheets and evaluation of their load carrying capacity
2014
Abstract The paper proposes a preliminary design tool for reinforced concrete (RC) elements strengthened by fiber-reinforced-polymer (FRP) sheets to be used in civil engineering applications and in particular in medical buildings. The design strategy is based on limit analysis theory and utilizes a numerical procedure which provides a direct method to determine peak load, failure mode and critical zones of the structural elements of interest.
Effect of FRP Wraps on the Compressive Behaviour of Slender Masonry Columns
2017
In the last decade, Fibre Reinforced Polymer (FRP) wrapping technique has become a common method to retrofit masonry piers or columns with poor structural performances. The passive confinement effect induced by the external wrap allows increasing the compressive strength and ductility of the member. Several studies highlighted as the efficacy of this technique is affected by several key parameters, including the shape of the transverse cross section, stress intensification at the strength corner of sharp sections, amount and mechanical properties of adopted composite. Despite this technique has been widely studied from both theoretical and experimental point of view, most of studies focused…
Finite element modelling of slipage between FRP rebar and concrete in pull-out test
2014
The paper presents numerical results of direct pull-out test of glass fiber-reinforced polymer (GFRP) rebars embedded in concrete. Rebars of three different cross-sections are considered: circular without longitudinal ribs and with two and four ribs. The design analyses of the rebar configurations embedded in concrete are investigated by the 3D finite element method (FEM), which takes into account the non-linearity using ANSYS software. The results of the numerical model with two ribs were compared with the experimental results. Then, the effect of different rebar geometries to the load-slip pull-out curves was studied. It is concluded that the influence of rib height and width on the pull-…