scholarly journals Experimental Study on Mechanical Properties of Novel FRP Bars with Hoop Winding Layer

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yue Liu ◽  
Hong-Tao Zhang ◽  
Hong-Hao Zhao ◽  
Lin Lu ◽  
Ming-Yang Han ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Outer Surface ◽  
Ultimate Load ◽  
High Strength ◽  
The Novel ◽  
Loading Test ◽  
Gfrp Bars ◽  
Gfrp Bar ◽  
Frp Bar ◽  
Frp Bars

Due to the fact that steel reinforcement is vulnerable to corrosion, FRP bars with light weight, high strength, and excellent durability have become a good substitute for ordinary steel bars. FRP bars have high tensile strength, but their compressive strength is relatively low and often neglected, so the application of FRP bars in compression members has been restricted. This paper proposes a new pultrusion-winding-pultrusion method to improve the compressive ability of FRP bars. A hoop FRP layer is winded on the outer surface of the pultruded FRP core, and a longitudinal pultruded layer and ribs are also added on the outermost surface. In this paper, mechanical properties of this novel FRP bar with hoop winding layer are investigated. First, monotonic tensile and compressive tests on traditional and novel GFRP bars were conducted. Then, cyclic tension-compression loading tests were also carried out on the two types of GFRP bars. Test results showed that the compressive ultimate bearing capacities of GFRP bars with winding layers were 10∼20 kN greater than those of the traditional GFRP bars, and the compressive ductility of the novel GFRP bars was also improved. Furthermore, the tensile stress-strain behaviors of both GFRP bars were linear-elastic and the added winding layer did not greatly influence the tensile properties of the GFRP bars. Moreover, for the cyclic loading test, the compressive ultimate load of GFRP bars was 80%∼90% of that under monotonic compressive test, and the tensile ultimate load was 45%∼65% of that under monotonic tensile test. Compared with the GFRP bar without winding layer, the overall stiffness of the novel GFRP bar was greater than that of the traditional one and the ultimate load of the novel GFRP bar was also greater. In addition, seeing that the residual displacement of the novel GFRP bar was greater than that of the traditional GFRP bar, winding hoop fibers on the outer surface of the core is a useful way to improve the energy dissipation capacity of the GFRP bar.

Microstructure and Mechanical Properties of High Strength Alloyed Steel for Aerospace Application

2018 ◽  
Vol 284 ◽  
pp. 351-356 ◽  
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Strength ◽  
Single Stage ◽  
The Novel ◽  
Tempering Temperature ◽  
Quenching And Partitioning ◽  
Aerospace Application ◽  
Cooling Conditions ◽  
Quenching And Tempering

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).

Surface Interaction Studies on Glass Fiber Reinforced Polymer Bars

2007 ◽  
Vol 345-346 ◽  
pp. 1217-1220
Author(s):  
Jung Yoon Lee
Keyword(s):  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Interfacial Bond ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Failure ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Frp Bars

The use of fiber reinforced polymer (FRP) bars has been gaining increasing popularity in the civil engineering community due to their favorable properties such as high-strength-to-weight ratio and good corrosion resistance. In order for concrete to be FRP reinforced, there must be interfacial bond between FRP bars and concrete. The interfacial bond behavior of FRP bars to concrete is expected to vary from that of conventional steel bars, since various key parameters that influence bond performance are different. This paper presents the results of an experimental and analytical study on the interfacial surface interaction of glass fiber reinforced polymer (GFRP) bars in high strength concrete cube. The experimental program consisted of testing 54 concrete cubes prepared according to CSA S802-02 standard 1). The split specimens showed that interfacial bond failure of the steel bar occurred due to concrete crushing in front of the bar deformations, while interfacial bond failure of the GFRP bars occurred partly on the surface of the bar and partly in the concrete by peeling of the surface layer of the bar.

scholarly journals Comparison of the Flexural Performance and Behaviour of Fly-Ash-Based Geopolymer Concrete Beams Reinforced with CFRP and GFRP Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Hemn Qader Ahmed ◽  
Dilshad Kakasor Jaf ◽  
Sinan Abdulkhaleq Yaseen
Keyword(s):  
Crack Width ◽  
Ultimate Load ◽  
Load Capacity ◽  
Reinforcement Ratio ◽  
Geopolymer Concrete ◽  
Ultimate Load Capacity ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

A construction system with high sustainability, high durability, and appropriate strength can be supplied by geopolymer concrete (GPC) reinforced with glass fibre-reinforced polymer (GFRP) bars and carbon fibre-reinforced polymer (CFRP) bars. Few studies deal with a combination of GPC and FRP bars, especially CFRP bars. The present investigation presents the flexural capacity and behaviour of fly-ash-based GPC beam reinforced with two different types of FRP bars: six reinforced geopolymer concrete (RGPC) beams consisting of three specimens reinforced with GFRP bars and the rest with CFRP bars. The beams were tested under four-point bending with a clear span of 2000 mm. The test parameters included the longitudinal-reinforcement ratio and the longitudinal-reinforcement type, including GFRP and CFRP. Ultimate load, first crack load, load-deflection behaviour, load-strain curve, crack width, and the modes of failure were studied. The experimental results were compared with the equations recommended by ACI 440.1R-15 and CSA S806-12 for flexural strength and midspan deflection of the beams. The results show that the reinforcement ratio had a significant effect on the ultimate load capacity and failure mode. The ultimate load capacity of CFRP-RGPC beams was higher than that of GFRP-RGPC, more crack formations were observed in the CFRP-RGPC beams than in the GFRP-RGPC beams, and the crack width in the GFRP-RGPC beams was more extensive than that in the CFRP-RGPC beams. Beams with lower reinforcement ratios experienced a fewer number of crack and a higher value of crack width, while numerous cracks and less value of crack width were observed in beams with higher reinforcement ratio. Beams with the lower reinforcement ratios were more affected by the type of FRP bars, and the deflection in GFRP-RGPC beams was higher than that in CFRP-RGPC beams for the same corresponding load level. ACI 440.1R-15 and CSA S806-12 underestimated the flexural strength and midspan deflection of RGPC beams; however, CSA S806-12 predicted more accurately.

scholarly journals Bamboo as a Sustainable Building Material—Culm Characteristics and Properties

2021 ◽  
Vol 13 (13) ◽  
pp. 7376
Author(s):  
Kitti Chaowana ◽  
Supanit Wisadsatorn ◽  
Pannipa Chaowana
Keyword(s):  
Mechanical Properties ◽  
Ultimate Load ◽  
High Strength ◽  
Test Results ◽  
Sustainable Building ◽  
Bamboo Culm ◽  
Cross Section Area ◽  
Section Area ◽  
Culm Wall ◽  
Dendrocalamus Membranaceus

Bamboo culm is a renewable and lightweight material with high strength, particularly tensile strength. It is well accepted that bamboo culms have played a significant role in architecture because of their sustainable contribution. The culm characteristics and properties of three-year-old bamboo from five species (Dendrocalamus asper, Dendrocalamus sericeus, Dendrocalamus membranaceus, Thyrsostachys oliveri, and Phyllostachys makinoi) were investigated. The results show that each bamboo species has different culm characteristics along with culm length. Culm size, particularly the outer culm diameter and culm wall thickness, affects the ultimate load. These results confirm that a bigger culm with a thicker wall could receive more load. D. asper received the highest ultimate load, while T. oliveri received the lowest ultimate load. However, when calculating the test results for stress (load per cross-section area), P. Makinoi showed excellent mechanical properties, while D. asper showed the worst mechanical properties. This research promotes bamboo’s appropriate use for building applications and as a more sustainable material for architecture.

scholarly journals FLEXURAL BEHAVIOR OF NORMAL AND HIGH STRENGTH CONTINUOUS BEAMS REINFORCED BY GFRP BARS

2021 ◽  
Vol 25 (01) ◽  
pp. 15-30
Author(s):  
Muayad M. Abdullah ◽  
◽  
Hassan F. Hassan ◽  
Keyword(s):  
Ultimate Load ◽  
Weight Ratio ◽  
High Strength ◽  
Reinforcement Ratio ◽  
Flexural Behavior ◽  
Fiber Reinforced Polymers ◽  
Longitudinal Reinforcement ◽  
Fiber Reinforced ◽  
Gfrp Bars ◽  
Continuous Beams

In the reinforced concrete structures, fiber reinforced polymer (FRP) has been considered an alternative material to steel reinforcement with the advantages of corrosion resistance, non-conductivity, and high strength to weight ratio. This work is devoted to study the flexural behavior of normal and high strength concrete continuous beams reinforced with glass fiber reinforced polymers (GFRP) bars. Ten continuous beams, with dimensions 150 mm wide × 250 mm deep × 2300 mm long consisting of two equal spans were investigated in this study . The beams were divided into three groups according to the compressive strength of concrete (30, 50 and 70) MPa. Each group consists of three beams with different longitudinal reinforcement ratio (ρfmin, ρfb and 1.5ρfb; where ρfmin and ρfb are the reinforcement ratio at a minimum and balanced condition, respectively). The ultimate load, mid-span deflection, cracks size, concrete strains, GFRP reinforcement strains of the tested beams were verified and contrasted. The experimental results indicate that the increase in the longitudinal reinforcement ratio increases the ultimate load by 125% and decreases the crack size and mid-span deflection by 78% and 57%, respectively. The experimental data were compared with the proposed ACI 440.1R-15 and CSA S806-12 equations. the ultimate load were greater than the calculated results according to (ACI 440.1R-15) by (20%) for beams with (ρmin), while beams with (ρb and 1.5ρb) the ultimate load were less than the calculated results by (9%), cracks size were close to the results according to (ACI 440.1R-15) for normal strength beams, while for high strength beams results were less than the results according to (ACI 440.1R-15), while ISIS-Canada 07 showed good agreement for all tested beams.

scholarly journals A study of the bond behavior of FRP bars in MPC seawater concrete

2020 ◽  
pp. 136943322095681
Author(s):  
Wen Sun ◽  
Yu Zheng ◽  
Linzhu Zhou ◽  
Jiapeng Song ◽  
Yun Bai
Keyword(s):  
Bond Strength ◽  
Potassium Phosphate ◽  
Fiber Reinforced Polymer ◽  
Reinforcing Bars ◽  
Bond Behavior ◽  
Reinforced Polymer ◽  
Steel Bar ◽  
Gfrp Bar ◽  
Frp Bar ◽  
Frp Bars

Using magnesium potassium phosphate cement (MPC) and fiber-reinforced polymer (FRP) bar to produce reinforced concrete can overcome the durability problems facing conventional steel reinforced PC concrete. In addition, FRP bar reinforced MPC concrete can also mitigate the CO2 emission issues caused by Portland cement (PC) production and the shortage of natural resources such as virgin aggregates and freshwater. This paper, therefore, is aimed at investigating the bond behavior of the FRP bars in MPC seawater concrete. The direct pullout tests were conducted with a steel bar, BFRP bar, and GFRP bar embedded into different concretes. The effects of reinforcing bars, type of concrete and mixing water on the bond behavior of FRP and steel bars were investigated and discussed. The results showed that the MPC concrete increases the bond strength of BFRP and GFRP bars by 51.06% and 24.42%, respectively, compared with that in PC concrete. Using seawater in MPC concrete can enhance the bond strength of GFRP bar by 13.75%. The damage interface of the FRP bar -MPC is more severe than that of PC with a complete rupture of the FRP ribs and peeling-off of the resin compared to that in steel reinforced MPC specimens. Moreover, the bond stress-slip models were developed to describe the bond behavior of MPC-FRP specimen, and the analytical results match well with the experimental data. In conclusion, the FRP bars showed better bond behavior in the MPC seawater concrete than that in the PC counterparts.

scholarly journals The Ultimate Load Estimation of Welded Joints of High-Strength Steels subject to Mechanical and Geometric Heterogeneity

2020 ◽  
pp. 99-108
Author(s):  
S B Sapozhnikov ◽  
M A Ivanov ◽  
I A Shcherbakov
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Base Metal ◽  
Welded Joints ◽  
Stress Concentrator ◽  
Ultimate Load ◽  
Welded Joint ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Wire

In this paper we consider the problems arising in the numerical estimation of the ultimate load of welded joints of high-strength steels with slight hardening. The stress concentrator in the transition node from the deposited to the base metal is modeled based on the example of welding a roller wire on a plate made of high-strength steel. The use of welding wire with a yield point lower than that of the base metal allowed to simulate areas of the welded joint with heterogeneous mechanical properties. The geometry of three areas of the welded joint is studied, i.e. weld metal, heat-affected zone (HAZ) and the base metal. Mechanical properties of all three areas are determined by calculation and experimentally. For this purpose, it is proposed to consider the material in all sections as ideally elastic-plastic, and the yield strength is uniquely associated with the hardness in the indentation zone (a Rockwell diamond cone is used). Calculations of the inelastic indentation process by the finite element method (FEM) in axis-symmetric formulation allowed obtaining a linear relationship between the hardness and the yield strength with a coefficient of 0.418. Tests at a quasi-static three-point bend (with stretching in the surfacing area) were carried out on sample beams cut perpendicular to the direction of welding. The “force-deflection” diagrams are obtained and compared with the calculated curves (FEM in a three-dimensional formulation with an explicit consideration of the complex configuration of all sections and different yield stress in the areas determined by local hardness values). There is a good agreement between the calculated and experimental ultimate loads. The proposed method of the three-stage study (determination of local hardness, yield strength in the areas and the ultimate load) can be effectively used to assess the ultimate loads of the welded joints due to the low parametricity of the proposed models of materials inelastic deformation in areas for which it is impossible to manufacture standard samples for the study of mechanical properties. The experimental study of the strengthening effect of the seam with a stress concentrator in the form of an angle of 90 degrees on the value of the ultimate bending load showed that the removal of the deposited metal does not lead to an increase in the ultimate load of the welded joint when using the welding wire of low-carbon high-plastic steel.

Experimental Method Study on Tensile Properties of GFRP Bar

2013 ◽  
Vol 438-439 ◽  
pp. 365-368
Author(s):  
Fei Mo ◽  
Pu Zhang ◽  
Dan Ying Gao ◽  
Yu Yang Pang ◽  
Ke Zhao
Keyword(s):  
Tensile Strength ◽  
Large Diameter ◽  
Testing Machine ◽  
Test Method ◽  
Internal Thread ◽  
Test Results ◽  
Anchor Length ◽  
Gfrp Bar ◽  
Frp Bar ◽  
Frp Bars

The GFRP bar has good mechanical properties and durability, but it is hard to test the tensile strength of large diameter FRP bar. Its test method given by ACI is too conservative, especially for large diameter FRP bar, and the length of test specimen will be too long and beyond the range of most testing machine. This article tested the tensile strength of GFRP bar using new methods, meanwhile, analyzed its stress distribution along the length of the specimens. The test results show that the use of bond anchor with steel plug or internal thread to measure the tensile strength of GFRP bar is feasible, and it can reduce the free length and the anchor length of the specimens, thus simplifying the test method of the tensile strength of FRP bars.

Behavior of Cantilever RC Beam Support Strengthened with Near-Surface-Mounted FRP Bars

2011 ◽  
Vol 243-249 ◽  
pp. 1762-1766
Author(s):  
Xing Guo Wang ◽  
Jun Hui Yue ◽  
Li Li ◽  
Yu Zhou Zheng
Keyword(s):  
Ultimate Load ◽  
Fiber Reinforced Polymer ◽  
Cantilever Beams ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Sustained Loading ◽  
Steel Bar ◽  
Frp Bar ◽  
Near Surface Mounted ◽  
Frp Bars

Several parameters, including typical loads, deflection, strains of steel bar and fiber- reinforced-polymer(FRP) bar under different sustained loading, were studied. The yield load and ultimate load of cantilever beams strengthened with near-surface-mounted(NSM) FRP bars are improved by 6.0%~15.2% and 55.7%~64.5% compared with non-strengthened beams, respectively. For strengthened beams,sustained loading can weaken the reinforced effect.The flexural behaviors of mounted beams were influenced by the lateral groove .

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

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