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Christopher K Y Leung - One of the best experts on this subject based on the ideXlab platform.
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effect of shear span Depth Ratio on mechanical performance of rc beams strengthened in shear with u wrapping frp strips
Composite Structures, 2017Co-Authors: Christopher K Y LeungAbstract:Abstract Shear span-to-effective Depth Ratio ( a v / d ) is well known to affect the shear performance of reinforced concrete (RC) members. However, this effect has not been properly addressed in existing design guidelines for fiber-reinforced polymer (FRP) strengthening structures. This paper focuses on the effect of a v / d on behaviors of RC beams shear-strengthened with U-wrapping CFRP strips. A total of six shear-strengthened and six normal beams, with a v / d Ratios ranging from 1.0 to 3.5, were tested. The test results indicate that FRP shear contribution increases initially with a v / d Ratio, but decreases slightly when the Ratio is beyond 2.0. The distribution of FRP strain along the critical shear crack shows different trends for different a v / d Ratios. Results of the present study and data collected from the literature with different a v / d Ratios are compared with predictions from various design guidelines. The comparison indicates a potential risk of overestimating the FRP shear contribution for beams with low a v / d Ratios (especially in deep beam). Further work is required to better understand the a v / d Ratio effect so it can be properly incorporated into the design equations.
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Shear Span–Depth Ratio Effect on Behavior of RC Beam Shear Strengthened with Full-Wrapping FRP Strip
Journal of Composites for Construction, 2016Co-Authors: Weiwen Li, Christopher K Y LeungAbstract:AbstractShear span-to-effective Depth Ratio (av/d) is known to affect the shear behavior of RC members. However, this effect has not been appropriately addressed in existing design guidelines for the fiber-reinforced polymer (FRP) strengthening of RC structures. This paper focuses on the effect of av/d on the behaviors of RC beams shear strengthened with full-wrapping FRP strips. A total of six strengthened beams and six normal beams are tested, with av/d Ratios ranging from 1.0 to 3.5. The experimental results indicate that the FRP shear contribution increases initially with the av/d Ratio, but decreases when the Ratio is beyond 2.5. The FRP strain along the critical shear crack distributes in different manners for different av/d Ratios. The authors’ experimental results and the test results from the literature are compared with predictions from available design guidelines. Although some recent design guidelines always provide a safe value, it can be overconservative. Conversely, other recent design guid...
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shear span Depth Ratio effect on behavior of rc beam shear strengthened with full wrapping frp strip
Journal of Composites for Construction, 2016Co-Authors: Christopher K Y LeungAbstract:AbstractShear span-to-effective Depth Ratio (av/d) is known to affect the shear behavior of RC members. However, this effect has not been appropriately addressed in existing design guidelines for the fiber-reinforced polymer (FRP) strengthening of RC structures. This paper focuses on the effect of av/d on the behaviors of RC beams shear strengthened with full-wrapping FRP strips. A total of six strengthened beams and six normal beams are tested, with av/d Ratios ranging from 1.0 to 3.5. The experimental results indicate that the FRP shear contribution increases initially with the av/d Ratio, but decreases when the Ratio is beyond 2.5. The FRP strain along the critical shear crack distributes in different manners for different av/d Ratios. The authors’ experimental results and the test results from the literature are compared with predictions from available design guidelines. Although some recent design guidelines always provide a safe value, it can be overconservative. Conversely, other recent design guid...
Weiwen Li - One of the best experts on this subject based on the ideXlab platform.
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Shear Span–Depth Ratio Effect on Behavior of RC Beam Shear Strengthened with Full-Wrapping FRP Strip
Journal of Composites for Construction, 2016Co-Authors: Weiwen Li, Christopher K Y LeungAbstract:AbstractShear span-to-effective Depth Ratio (av/d) is known to affect the shear behavior of RC members. However, this effect has not been appropriately addressed in existing design guidelines for the fiber-reinforced polymer (FRP) strengthening of RC structures. This paper focuses on the effect of av/d on the behaviors of RC beams shear strengthened with full-wrapping FRP strips. A total of six strengthened beams and six normal beams are tested, with av/d Ratios ranging from 1.0 to 3.5. The experimental results indicate that the FRP shear contribution increases initially with the av/d Ratio, but decreases when the Ratio is beyond 2.5. The FRP strain along the critical shear crack distributes in different manners for different av/d Ratios. The authors’ experimental results and the test results from the literature are compared with predictions from available design guidelines. Although some recent design guidelines always provide a safe value, it can be overconservative. Conversely, other recent design guid...
Hamid Gualous - One of the best experts on this subject based on the ideXlab platform.
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Tidal farm analysis using an analytical model for the flow velocity prediction in the wake of a tidal turbine with small diameter to Depth Ratio
Renewable Energy, 2016Co-Authors: Ottavio Lo Brutto, Van Thinh Nguyen, Sylvain Guillou, Jérôme Thiebot, Hamid GualousAbstract:A tidal turbine is a device converting hydrodynamic power into electrical power. Lately, more and more projects have been developed in order to optimize the productivity of this kind of energy. In such research with industrial interest, under the impact of the wake effect on the output power, the analysis of a tidal farm layout is regarded as the first priority. Simple approaches such as those developed for wind farms could be used in tidal turbine arrangement optimization. These methodologies can be improved by taking into account the turbulence in tidal farms and tidal turbines' mechanical characteristics. The goal of this work is to propose a predictive analytical model to estimate the tidal speed in the far wake of tidal turbines with small diameter to Depth Ratio (20% here). It is a first step prior to integrate the wake model in a tidal farm layout optimization algorithm. The wake model development is achieved reanalyzing the far wake's equations used in wind farm applications. A turbine represented by an Actuator Disc (AD) in conjunction with a Computational Fluid Dynamics (CFD) numerical model is used as a reference for this purpose. The CFD-AD model has been validated with experimental results from literature. The novelty of the present work consists in expressing the far wake's radius expansion as a function of the ambient turbulence and the thrust coefficient. The proposed equation is used in conjunction with the Jensen's model in a manner that the velocities downstream a tidal turbine can be estimated. The velocity distribution in the far wake of a single turbine obtained by the proposed model is in good agreement with the CFD numerical model. As a matter of fact, the model provides satisfactory accuracy in the cases of two parks: one with five aligned turbines and one with ten staggered turbines.
Dionysios A Bournas - One of the best experts on this subject based on the ideXlab platform.
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shear strengthening of concrete members with trm jackets effect of shear span to Depth Ratio material and amount of external reinforcement
Composites Part B-engineering, 2018Co-Authors: Zoi C Tetta, L Koutas, Dionysios A BournasAbstract:Abstract An experimental work on reinforced concrete (RC) rectangular beams strengthened in shear with textile reinforced mortar (TRM) jackets is presented in this paper, with focus on the following investigated parameters: (a) the amount of external TRM reinforcement Ratio, ρf, by means of using different number of textile layers and different types of textile fibre materials (carbon, glass, basalt); (b) the textile geometry, and (c) the shear span-to-Depth Ratio, a/d. In total, 22 tests were conducted on simply supported rectangular RC beams under (three-point bending) monotonic loading. The experimental results revealed that: (1) TRM is very effective when the failure is attributed to debonding of the TRM jacket from the concrete substrate; (2) the trend of effective strains for carbon, glass and basalt TRM jackets is descending for increasing values of the TRM reinforcement Ratio, ρf, when failure is associated to debonding of the jacket; (3) the effect of textile geometry is significant only for low values of ρf, resulting in variances in the capacity enhancement and the failure modes, and (4) the shear span-to-Depth Ratio has practically no effect to the failure mode nor to the TRM jacket contribution to the total shear resistance of the RC beams.
Bekir Cihad Bal - One of the best experts on this subject based on the ideXlab platform.
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The effect of span-to-Depth Ratio on the impact bending strength of poplar LVL
Construction and Building Materials, 2016Co-Authors: Bekir Cihad BalAbstract:Abstract In this study, it was studied the effect of span-to-Depth Ratio on the impact bending strength of laminated veneer lumber (LVL). For the study, LVL boards were produced from rotary-cut poplar veneer using phenol formaldehyde (PF) adhesive. Test samples were prepared from the boards to determine impact bending strength, density, moisture content, and tensile-shear strength. In addition, the compression Ratio and densification Ratios of LVL for each panel was determined. The impact bending strengths were tested in flatwise and edgewise directions for different span-to-Depth Ratios, i.e., 7.5, 10, 12.5, 15, 17.5, and 20. The highest impact bending strength was measured when the span-to-Depth Ratio was 20. The lowest impact bending strength was measured when the span-to-Depth Ratio was 10. There was a parabolic relationship between impact bending strength and the span-to-Depth Ratio. In addition, the test results showed that the impact bending strength of all of the samples tested in the flatwise direction were significantly higher than those tested in the edgewise direction.