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fiber-reinforced-polymers
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Total 89 records
The effect of elevated temperatures on the tensile performance of GFRP and CFRP sheets
, Article Construction and Building Materials ; Volume 190 , 2018 , Pages 38-52 ; 09500618 (ISSN) ; Pournamazian Najafabadi, E ; Houshmand Khaneghahi, M ; Vatani Oskouei, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this study, the effects of fiber type (i.e., carbon and glass fibers) and intumescent paint on the tensile performance of fiber reinforced polymer (FRP) sheets at elevated temperatures are investigated. For this purpose, a series of tensile tests were conducted on the glass and carbon fiber reinforced polymer (GFRP and CFRP) sheets, with and without intumescent fire retardant paint, at different elevated temperatures. The studied temperatures ranged from 25 °C to 600 °C. Scanning electron microscopy was also used to examine the effects of elevated temperatures on FRP sheets and the fire protecting mechanism of the intumescent paint. Based on the test results, the tensile strength of the...
The tensile performance of FRP bars embedded in concrete under elevated temperatures
, Article Construction and Building Materials ; Volume 211 , 2019 , Pages 1138-1152 ; 09500618 (ISSN) ; Vatani Oskouei, A ; Khaneghahi, M. H ; Shoaei, P ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this research, the mechanical properties of glass and carbon fiber reinforced polymer (FRP) bars with epoxy resin matrices embedded in concrete were investigated under an extensive range of elevated temperatures (i.e., 25–800 °C). Embedded FRP bars with various bar diameters were studied in order to determine bar diameter influence on the results. In addition, analysis of variance (ANOVA) was performed on the experimental results to investigate the contribution of exposure temperature and bar diameter to the tensile behavior of embedded in concrete FRP bars at elevated temperatures. The results show that the tensile strength of embedded FRP bars generally decreases with increasing...
Effect of fibers configuration and thickness on tensile behavior of GFRP laminates subjected to elevated temperatures
, Article Construction and Building Materials ; Volume 202 , 2019 , Pages 189-207 ; 09500618 (ISSN) ; Bazli, M ; Ashrafi, H ; Vatani Oskouei, A ; Azhari, S ; Zhao, X. L ; Gholipour, H ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This study was aimed at gaining an improved understanding of the behavior of glass fiber-reinforced polymer laminates at elevated temperatures by means of testing laminate specimens with unidirectional, woven, and randomly distributed (chopped strand mat) fibers. The testing parameters were temperature, the type of fiber, and the thickness of the laminates. The failure modes of the specimens and their elasticity moduli at ambient temperature were investigated, and analysis of variance was conducted to determine the contribution of each parameter to the behavioral test results. The findings showed that among the parameters, an increase in temperature exerted the strongest effect on the...
Flexural behavior of timber beams strengthened with pultruded glass fiber reinforced polymer profiles
, Article Composite Structures ; Volume 241 , 2020 ; Vatani Oskouei, A ; Raftery, G. M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Timber is one of the materials widely used in construction and industry all over the world. In this paper, the behavior of strengthened timber beams made of beech wood (Fagus orientalis) were investigated experimentally. The composite timber beams were reinforced with flat, U-shaped, and L-shaped pultruded Glass Fiber Reinforced Polymer (GFRP) profiles. The GFRPs were attached to tensile or both tensile and compressive surfaces of beams. Altogether, 24 specimens, including 20 strengthened beams and 4 un-strengthened (control) beams, were tested under three-point bending test. Flexural behavior of specimens was evaluated through their load versus mid-span displacement curves, ultimate load...
Dynamic performance enhancement of RC slabs by steel fibers vs. externally bonded GFRP sheets under impact loading
, Article Engineering Structures ; Volume 213 , 2020 ; Khaloo, A ; Sadraie, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Recently, to improve the dynamic behavior of Reinforced Concrete (RC) slabs under impact load, the methods of externally bonding Glass Fiber Reinforced Polymer (GFRP) sheets to slab and internally reinforcing concrete by steel fibers have been proposed. Nevertheless, it is required to investigate the comparison between these two methods on response of RC slabs under impact loads. In this study, the influence of volume fraction of steel fibers, the number of GFRP sheet layers (one or two) and the arrangement of GFRP sheets (covering the whole or parts of surface), are examined. Performance of fourteen 1000 × 1000 × 75 mm concrete slabs including one plain slab, one steel RC slab, three steel...
Experimental investigation on the behavior of RC arches strengthened by GFRP composites
, Article Construction and Building Materials ; Volume 235 , 28 February , 2020 ; Moradi, H ; Kazemian, A ; Shekarchi, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
An experimental investigation on the behavior of RC arches strengthened by glass fiber-reinforced polymer (GFRP) composites is presented. Twelve samples were tested in order to determine influence of arrangement and number of GFRP layers on RC arches having different steel reinforcement ratios. The arches were tested under centrally concentrated point load using displacement control condition. Load-deflection behavior, failure mode, GFRP debonding, angle between hinge formation and supports and crack propagation pattern are studied extensively. Based on test results, extrados strengthening is much more effective than intrados strengthening in increasing ultimate load carrying capacity which...
The effects of elevated temperatures on the performance of concrete-filled pultruded GFRP tubular columns
, Article Thin-Walled Structures ; Volume 169 , 2021 ; 02638231 (ISSN) ; Khaloo, A ; Azizmohammadi, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Usage of concrete-filled pultruded glass fiber-reinforced polymer (GFRP) tubes (CFPGT) as columns can increase the service life of structures. However, marine structures such as oil platforms are always prone to fire because of the low resistance to the elevated temperatures. The purpose of this investigation is to evaluate the effects of concrete core strength (30 and 60 MPa), and exposure temperature (25, 100, 200, 300, and 400 °C) and time (60 and 120 min) on the compressive and bond behavior of CFPGTs. The properties of unexposed and exposed concrete core, pultruded GFRP hollow tubes, and CFPGTs were determined via compressive and disk-split tests. Also, the push-out test was used to...
Seismic behavior comparison of RC shear walls strengthened using FRP composites and steel elements
, Article Scientia Iranica ; Volume 28, Issue 3 A , 2021 , Pages 1-27 ; 10263098 (ISSN) ; Khaloo, A ; Abdoos, H ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
This paper aims at investigating the seismic behavior of strengthened reinforced concrete (RC) shear walls using a 3D finite element analysis. A series of four different configurations of carbon fiber reinforced polymer (CFRP) composites and four different schemes of steel elements are utilized to compare the two methods of retrofitting RC shear walls with similar dimensions and reinforcement ratios. Nonlinear simulations of the RC shear walls are conducted under the action of lateral cyclic loading in ABAQUS Explicit software. In addition, the numerical modeling for RC walls strengthened by CFRP composites as well as steel elements are validated according to the previous experimental...
Bond strength prediction of timber-FRP under standard and acidic/alkaline environmental conditions based on gene expression programming
, Article European Journal of Wood and Wood Products ; Volume 80, Issue 6 , 2022 , Pages 1457-1471 ; 00183768 (ISSN) ; Toufigh, V ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Timber is widely used as a construction material; however, the environmental deterioration of timber is a crucial problem for the construction industry. Fiber-reinforced polymer (FRP) has been considered appropriate and beneficial for the repair and rehabilitation of timber. This study proposes three empirical models using a supervised machine learning method called gene expression programming (GEP) to predict the bond strength between timber and FRP under various environmental conditions. The first empirical model is used to predict bond strength under standard conditions. The two other models are proposed to predict the strength reduction in acidic and alkali solutions. The formulation...