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Saad Mahmood Raoof - One of the best experts on this subject based on the ideXlab platform.
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trm versus frp in flexural strengthening of rc beams behaviour at high temperatures
Construction and Building Materials, 2017Co-Authors: Saad Mahmood Raoof, Dionysios A BournasAbstract:The flexural behaviour of RC beams strengthened with TRM and FRP composites was experimentally investigated and compared both at ambient and high temperatures. The investigated parameters were: (a) the strengthening material, namely TRM versus FRP, (b) the number of strengthening layers, (c) the Textile Surface condition (dry and coated), (d) the Textile material (carbon, basalt or glass fibres) and (e) the end-anchorage of the flexural reinforcement. A total of 23 half-scale beams were constructed, strengthened in flexure and tested to assess these parameters and the effectiveness of the TRM versus FRP at high temperatures. TRM exhibited excellent performance as strengthening material in increasing the flexural capacity at high temperature; in fact, TRM maintained an average effectiveness of 55%, compared to its effectiveness at ambient temperature, contrary to FRP which totally lost its effectiveness when subjected to high temperature. In specific, from the high temperature test it was found that by increasing the number of layers, the TRM effectiveness was considerably enhanced and the failure mode was altered; coating enhanced the TRM effectiveness; and the end-anchorage at high temperature improved significantly the FRP and marginally the TRM effectiveness. Finally, the formula proposed by the Fib Model Code 2010 was used to predict the mean debonding stress in the TRM reinforcement, and using the experimental results obtained in this study, a reduction factor to account for the effect of high temperature on the flexural strengthening with TRM was proposed.
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Bond between Textile reinforced mortar (TRM) and concrete substrate
2017Co-Authors: Saad Mahmood RaoofAbstract:There is a growing interest for strengthening and upgrading existing concrete structures both in seismic and non-seismic regions due to their continuous deterioration as a result of aging, degradation induced environment conditions, inadequate maintenance, and the need to meet the modern codes (i.e. Eurocodes). Almost a decade ago, an innovative cement-based composite material, the so-called Textile-reinforced mortar (TRM), was introduced in the field of structural retrofitting. TRM comprises high-strength fibres in form of Textiles embedded into inorganic matrices such as cement-based mortars. TRM offers well-established advantages such as: fire resistance, low cost, air permeability, and ability to apply on wet Surfaces and at ambient of low temperatures. It is well known that the effectiveness of any external strengthening system in increasing the flexural capacity of concrete members depends primarily on the bond between the strengthening material and member’s substrate. This PhD Thesis provides a comprehensive experimental study on the bond behaviour between TRM and concrete substrate and also provides a fundamental understanding of the flexural behaviour of RC beams strengthened with TRM. Firstly, the tensile properties of the Textile reinforcement were determined through carrying out tensile tests on bare Textiles, and TRM coupons. Secondly, the bond behaviour between TRM and concrete substrates both at ambient and, for the first time, at high temperature was extensively investigated. A total of 148 specimens (80 specimens tested at ambient temperature and 68 specimens tested at high temperatures) were, fabricated, and tested under double-lap shear. Parameters investigated at ambient temperature comprised: (a) the bond length; (b) the number of layers; (c) the concrete Surface preparation; (d) the concrete compressive strength; (e) the Textile Surface condition; and (f) the anchorage through wrapping with TRM jackets. Whereas, the parameters examined at high temperatures included: (a) the strengthening systems (TRM versus FRP); (b) the level of temperature at which the specimens were exposed; (c) the number of FRP/TRM layers; and (d) the loading conditions. The results of ambient temperature tests indicated that the bond at the TRM-concrete interface is sensitive to parameters such as: the number of layers, the Textile Surface condition, and the anchorage through wrapping with TRM. On the other hand, the results of high temperature tests showed that TRM exhibited excellent bond performance with concrete (up to 400 0C) contrary to FRP which practically lost its bond with concrete at temperatures above the glass trainset temperature (Tg). The flexural strengthening of RC beams with TRM at ambient and for the first time at high temperature was also examined carrying out 32 half-scale beams. The examined parameters were: (a) the strengthening system (TRM versus FRP); (b) the number of layers; (c) the Textile Surface condition; (d) the Textile fibre material; (e) the end-anchorage system of the external reinforcement; and (f) the Textile geometry. The results of ambient temperature tests showed that TRM was effective in increasing the flexural capacity of RC beams but its effectiveness was sensitive to the number of layers. Furthermore, a simple formula used for predicting the mean FRP debonding stress was modified for predicting the TRM debonding stress based on the experiment data available. The results of high temperature tests showed that TRM maintained an average effectiveness of 55%, of its effectiveness at ambient temperature, contrary to FRP which has totally lost its effectiveness when subjected to high temperature. Finally, a stress reduction factor of TRM flexural effectiveness (compared to its ambient effectiveness) when subjected to high temperature was also proposed.
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Textile reinforced mortar trm versus fibre reinforced polymers frp in flexural strengthening of rc beams
Construction and Building Materials, 2017Co-Authors: L Koutas, Saad Mahmood Raoof, Dionysios A BournasAbstract:The aim of this paper is to compare the flexural performance of reinforced concrete (RC) beams strengthened with Textile-reinforced mortar (TRM) and fibre-reinforced polymers (FRP). The investigated parameters included the strengthening material, namely TRM or FRP; the number of TRM/FRP layers; the Textile Surface condition (coated and uncoated); the Textile fibre material (carbon, coated basalt or glass fibres); and the end-anchorage system of the external reinforcement. Thirteen RC beams were fabricated, strengthened and tested in four-point bending. One beam served as control specimen, seven beams strengthened with TRM, and five with FRP. It was mainly found that: (a) TRM was generally inferior to FRP in enhancing the flexural capacity of RC beams, with the effectiveness ratio between the two systems varying from 0.46 to 0.80, depending on the parameters examined, (b) by tripling the number of TRM layers (from one to three), the TRM versus FRP effectiveness ratio was almost doubled, (c) providing coating to the dry Textile enhanced the TRM effectiveness and altered the failure mode; (d) different Textile materials, having approximately same axial stiffness, resulted in different flexural capacity increases; and (e) providing end-anchorage had a limited effect on the performance of TRM-retrofitted beams. Finally, a simple formula proposed by fib Model Code 2010 for FRP reinforcement was used to predict the mean debonding stress developed in the TRM reinforcement. It was found that this formula is in a good agreement with the average stress calculated based on the experimental results when failure was similar to FRP-strengthened beams.
Dionysios A Bournas - One of the best experts on this subject based on the ideXlab platform.
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trm versus frp in flexural strengthening of rc beams behaviour at high temperatures
Construction and Building Materials, 2017Co-Authors: Saad Mahmood Raoof, Dionysios A BournasAbstract:The flexural behaviour of RC beams strengthened with TRM and FRP composites was experimentally investigated and compared both at ambient and high temperatures. The investigated parameters were: (a) the strengthening material, namely TRM versus FRP, (b) the number of strengthening layers, (c) the Textile Surface condition (dry and coated), (d) the Textile material (carbon, basalt or glass fibres) and (e) the end-anchorage of the flexural reinforcement. A total of 23 half-scale beams were constructed, strengthened in flexure and tested to assess these parameters and the effectiveness of the TRM versus FRP at high temperatures. TRM exhibited excellent performance as strengthening material in increasing the flexural capacity at high temperature; in fact, TRM maintained an average effectiveness of 55%, compared to its effectiveness at ambient temperature, contrary to FRP which totally lost its effectiveness when subjected to high temperature. In specific, from the high temperature test it was found that by increasing the number of layers, the TRM effectiveness was considerably enhanced and the failure mode was altered; coating enhanced the TRM effectiveness; and the end-anchorage at high temperature improved significantly the FRP and marginally the TRM effectiveness. Finally, the formula proposed by the Fib Model Code 2010 was used to predict the mean debonding stress in the TRM reinforcement, and using the experimental results obtained in this study, a reduction factor to account for the effect of high temperature on the flexural strengthening with TRM was proposed.
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Textile reinforced mortar trm versus fibre reinforced polymers frp in flexural strengthening of rc beams
Construction and Building Materials, 2017Co-Authors: L Koutas, Saad Mahmood Raoof, Dionysios A BournasAbstract:The aim of this paper is to compare the flexural performance of reinforced concrete (RC) beams strengthened with Textile-reinforced mortar (TRM) and fibre-reinforced polymers (FRP). The investigated parameters included the strengthening material, namely TRM or FRP; the number of TRM/FRP layers; the Textile Surface condition (coated and uncoated); the Textile fibre material (carbon, coated basalt or glass fibres); and the end-anchorage system of the external reinforcement. Thirteen RC beams were fabricated, strengthened and tested in four-point bending. One beam served as control specimen, seven beams strengthened with TRM, and five with FRP. It was mainly found that: (a) TRM was generally inferior to FRP in enhancing the flexural capacity of RC beams, with the effectiveness ratio between the two systems varying from 0.46 to 0.80, depending on the parameters examined, (b) by tripling the number of TRM layers (from one to three), the TRM versus FRP effectiveness ratio was almost doubled, (c) providing coating to the dry Textile enhanced the TRM effectiveness and altered the failure mode; (d) different Textile materials, having approximately same axial stiffness, resulted in different flexural capacity increases; and (e) providing end-anchorage had a limited effect on the performance of TRM-retrofitted beams. Finally, a simple formula proposed by fib Model Code 2010 for FRP reinforcement was used to predict the mean debonding stress developed in the TRM reinforcement. It was found that this formula is in a good agreement with the average stress calculated based on the experimental results when failure was similar to FRP-strengthened beams.
Hisanaga Fujiwara - One of the best experts on this subject based on the ideXlab platform.
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Textile Surface Inspection by Using Translation Invariant Wavelet Shrinkage
IEEJ Transactions on Industry Applications, 2006Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant Wavelet Shrinkage is presented. The Wavelet transform, while it can be computed efficiently by the Mallat algorithm, has the translation variance problem. To deal with this problem, we use RI-Spline wavelets which are pseudo Complex wavelets consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant Wavelet Shrinkage realized using 2D RI-Spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
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CIRA - Textile Surface inspection by using translation invariant wavelet transform
Proceedings 2003 IEEE International Symposium on Computational Intelligence in Robotics and Automation. Computational Intelligence in Robotics and Aut, 1Co-Authors: Hisanaga Fujiwara, Zhong Zhang, H. Toda, H. KawabataAbstract:It is known that texture can be modeled better using both deterministic and random components. The wavelet transform, which can be computed efficiently, is a well-know multiresolution analysis method. However, when it is applied to texture analysis method. However, then it is applied to texture analysis, the wavelet transform has the problem that the transformed result of the deterministic component of the texture is no longer translation invariant. In this paper, we will constitute 2D RI-spline wavelets, which can be considered to be one variation of complex wavelets, we can obtain translation invariance. Then, we apply the translation invariant 2-D RI-spline wavelets to the automated inspection of Textile Surfaces. In our approach, first to remove Textile textures from Textile Surfaces we use the 2-D RI-spline wavelets. Once the textural information is removed from Textile Surfaces, the remaining inspection process becomes a tractable problem, which we can handle using a standard statistical method. The experimental results show that our inspection method is effective for real Textile Surfaces.
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Visual inspection of Textile Surfaces with translation invariant wavelet shrinkage
30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 1Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant wavelet shrinkage is presented. The wavelet transform, while the Mallat algorithm can compute it efficiently, has the translation variance problem. To deal with this problem, we use RI-spline wavelets, which are pseudo complex wavelets, consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant wavelet shrinkage realized using 2D RI-spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
Hiroyasu Koshimizu - One of the best experts on this subject based on the ideXlab platform.
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Textile Surface Inspection by Using Translation Invariant Wavelet Shrinkage
IEEJ Transactions on Industry Applications, 2006Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant Wavelet Shrinkage is presented. The Wavelet transform, while it can be computed efficiently by the Mallat algorithm, has the translation variance problem. To deal with this problem, we use RI-Spline wavelets which are pseudo Complex wavelets consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant Wavelet Shrinkage realized using 2D RI-Spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
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Visual inspection of Textile Surfaces with translation invariant wavelet shrinkage
30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 1Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant wavelet shrinkage is presented. The wavelet transform, while the Mallat algorithm can compute it efficiently, has the translation variance problem. To deal with this problem, we use RI-spline wavelets, which are pseudo complex wavelets, consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant wavelet shrinkage realized using 2D RI-spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
Zhong Zhang - One of the best experts on this subject based on the ideXlab platform.
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Textile Surface Inspection by Using Translation Invariant Wavelet Shrinkage
IEEJ Transactions on Industry Applications, 2006Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant Wavelet Shrinkage is presented. The Wavelet transform, while it can be computed efficiently by the Mallat algorithm, has the translation variance problem. To deal with this problem, we use RI-Spline wavelets which are pseudo Complex wavelets consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant Wavelet Shrinkage realized using 2D RI-Spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
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CIRA - Textile Surface inspection by using translation invariant wavelet transform
Proceedings 2003 IEEE International Symposium on Computational Intelligence in Robotics and Automation. Computational Intelligence in Robotics and Aut, 1Co-Authors: Hisanaga Fujiwara, Zhong Zhang, H. Toda, H. KawabataAbstract:It is known that texture can be modeled better using both deterministic and random components. The wavelet transform, which can be computed efficiently, is a well-know multiresolution analysis method. However, when it is applied to texture analysis method. However, then it is applied to texture analysis, the wavelet transform has the problem that the transformed result of the deterministic component of the texture is no longer translation invariant. In this paper, we will constitute 2D RI-spline wavelets, which can be considered to be one variation of complex wavelets, we can obtain translation invariance. Then, we apply the translation invariant 2-D RI-spline wavelets to the automated inspection of Textile Surfaces. In our approach, first to remove Textile textures from Textile Surfaces we use the 2-D RI-spline wavelets. Once the textural information is removed from Textile Surfaces, the remaining inspection process becomes a tractable problem, which we can handle using a standard statistical method. The experimental results show that our inspection method is effective for real Textile Surfaces.
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Visual inspection of Textile Surfaces with translation invariant wavelet shrinkage
30th Annual Conference of IEEE Industrial Electronics Society 2004. IECON 2004, 1Co-Authors: Hisanaga Fujiwara, Zhong Zhang, Hiroyuki Hatta, Hiroyasu KoshimizuAbstract:A visual inspection method of Textile Surfaces using the translation invariant wavelet shrinkage is presented. The wavelet transform, while the Mallat algorithm can compute it efficiently, has the translation variance problem. To deal with this problem, we use RI-spline wavelets, which are pseudo complex wavelets, consist of a pair of a symmetric bi-orthogonal spline wavelet and an anti-symmetric bi-orthogonal spline wavelet, for Textile Surface inspection. In our approach, we remove the regular information which consists of the Textile textures and the shading effects caused by uneven lighting from the Textile Surfaces to be inspected, using the translation invariant wavelet shrinkage realized using 2D RI-spline wavelets. The experimental results show that our inspection method is effective for detecting tiny defects as well as global defects such as dyeing unevenness.
