scholarly journals Behavior of Cross Arms Inserted in Concrete-Filled Circular GFRP Tubular Columns

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2280 ◽  
Author(s):  
Fang Xie ◽  
Ju Chen ◽  
Qian-Qian Yu ◽  
Xinlong Dong
Keyword(s):  
Fiber Reinforced Polymer ◽  
Stress And Strain ◽  
Tubular Columns ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Structural Responses ◽  
The Cross ◽  
Experimental Findings ◽  
Glass Frp ◽  
Good Agreement

Fiber-reinforced polymer (FRP) materials nowadays have attracted much attention in both retrofitting of aged infrastructure and developing of new structural systems attributed to the outstanding mechanical properties. Extensive studies have been performed on concrete-filled glass FRP (GFRP) tubes for the potential application in piling, poles, highways overhead sign structures and bridge components. The new hybrid member also provides an alternative solution for traditional transmission structures. However, the connection between concrete-filled GFRP tubes and cross arms has not been fully understood. In this paper, an experimental study and theoretical analysis were conducted on the behavior of cross arms inserted in concrete-filled circular GFRP tubular columns. Steel bars with a larger stiffness in comparison with GFRP tubes were selected here for the cross arm to simulate a more severe scenario. The structural responses of the system when the cross arms were subjected to concentrated loads were carefully recorded. Experimental results showed that the concrete-filled GFRP tubes could offer a sufficient restraint to the deformation of the cross arm. No visible cracks were found on the GFRP tube at the corner of the cross arm where the stress and strain concentrated. Theoretical solutions based on available theories and equations were adopted to predict the displacement of the cross arms and a good agreement was achieved between the prediction results and experimental findings.

Comparative Study on Deflection Calculation for Concrete Flexural Members with Fiber Reinforced Polymer Reinforcement

2011 ◽  
Vol 183-185 ◽  
pp. 1979-1983
Author(s):  
Jiang Yong Cai ◽  
Xi Bo Zhou ◽  
Xiong Jia ◽  
Yan Tao He
Keyword(s):  
Concrete Beams ◽  
Reinforce Concrete ◽  
Fiber Reinforced Polymer ◽  
New Method ◽  
Flexural Members ◽  
Modified Method ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Frp Bars ◽  
Good Agreement

The application and development of FRP bars for reinforce concrete structures necessitates the need for either adopt the current code method or exploiting a new design one to account for the properties of FRP materials. The method for predicting deflection of concrete beams with FRP bars in ACI440 is based on the method for that with steel bars in ACI318. Similarly, a modified method based on GB50010 is proposed in this paper to estimate deflection of concrete beams with FRP bars. Furthermore, the new method, together with ACI318, ACI440 and GB50010 ones, are verified by nine test beams in three existing experiment and show a good agreement with the experimental data. Simultaneously, the new method is also proved to be of the most precise and accurate one and indicates the potential of the method to estimate deflection in Chinese code system.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

Deflection Prediction of FRP-Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 243-249 ◽  
pp. 621-624
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Test Results ◽  
Structural Members ◽  
Modified Model ◽  
Reinforced Polymer ◽  
Service Load ◽  
Good Agreement

Bonding fiber reinforced polymer (FRP) laminates to the tension face of RC members has been proven to be an effective method to improve the flexural strength. However, structural members are not only needed to have adequate strength, but also to have adequate performance of deformation at service load levels. To evaluate the deflection of externally FRP-strengthened RC beams, a total of 18 RC beams, including 16 beams strengthened with CFRP laminate under different preload levels and 2 control beams, were tested. Based on the assumption that the section of the beam behaves a tri-linear moment-curvature response characterized by pre-crack stage, post-crack stage and failure stage and the test results, this paper presents a modified model to evaluate the deflection of CFRP-strengthened RC beams. The present modified model was verified by the similar test results, and shows a good agreement with the test results.

Effect of fiber angles on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns under monotonic axial compression

2020 ◽  
Vol 23 (7) ◽  
pp. 1487-1504 ◽  
Author(s):  
Bing Zhang ◽  
Jun-Liang Zhao ◽  
Tao Huang ◽  
Ning-Yuan Zhang ◽  
Yi-Jie Zhang ◽  
...  
Keyword(s):  
Fiber Reinforced Polymer ◽  
Polymer Concrete ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Absolute Value ◽  
Tubular Columns ◽  
Reinforced Polymer ◽  
Double Skin ◽  
Polymer Tube ◽  
Hoop Direction

Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns are a novel form of hollow columns that combine two traditional construction materials (i.e. concrete and steel) with fiber-reinforced polymer composites. Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns consist of an inner tube made of steel, an outer tube made of fiber-reinforced polymer, and a concrete layer between the two tubes. Existing studies, however, are focused on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with fibers of the fiber-reinforced polymer tube oriented in the hoop direction or close to the hoop direction. In order to investigate the effect of fiber angles (i.e. the fiber angle between the fiber orientation and the longitudinal axis of the fiber-reinforced polymer tube), monotonic axial compression tests were conducted on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±45°, ±60°, or ±80° fiber angles. There were two types of steel tubes adopted for these hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns. The fiber-reinforced polymer tube thickness was also investigated as an important parameter. Experimental results showed that the confinement effect of the fiber-reinforced polymer tube increased with the increase of the absolute value of fiber angles, whereas the ultimate axial strain of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns decreased with the increase of the absolute value of fiber angles. An existing stress–strain model, which was developed on the basis of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±90° fiber angles, is verified using the test results of this study. For the compressive strength of the confined concrete in hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns, the existing model provides conservative predictions for specimens with a ±80° fiber-reinforced polymer tube, overestimated predictions for specimens with a ±60° fiber-reinforced polymer tube, and close predictions for specimens with a ±45° fiber-reinforced polymer tube.

Flexural capacity and design of hybrid FRP-steel-reinforced concrete beams

2019 ◽  
Vol 23 (7) ◽  
pp. 1290-1304
Author(s):  
Yang Yang ◽  
Ze-Yang Sun ◽  
Gang Wu ◽  
Da-Fu Cao ◽  
Zhi-Qin Zhang
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Steel Reinforced Concrete ◽  
Reinforced Polymer ◽  
The Cross

This study presents a design method for hybrid fiber-reinforced-polymer-steel-reinforced concrete beams by an optimized analysis of the cross section. First, the relationships among the energy consumption, the bearing capacity, and the reinforcement ratio are analyzed; then, the parameters of the cross section are determined. Comparisons between the available theoretical and experimental results show that the designed hybrid fiber-reinforced-polymer-steel-reinforced concrete beams with a low area ratio between the fiber-reinforced polymer and the steel reinforcement could meet the required carrying capacity and exhibited high ductility.

Prior and post peaks compressive behavior of concrete-filled double-skin tubular columns with BFRP-punched-in outer steel and BFRP-circular inner steel

2020 ◽  
Vol 23 (13) ◽  
pp. 2911-2927
Author(s):  
Yung William Sasy Chan ◽  
Zhi Zhou ◽  
Zhenzhen Wang ◽  
Jinping Ou
Keyword(s):  
Load Capacity ◽  
High Energy ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Peak Performance ◽  
Design Parameters ◽  
Fiber Reinforced ◽  
Tubular Columns ◽  
Reinforced Polymer ◽  
Double Skin

Fiber-reinforced polymer composites have been widely used to design fiber-reinforced polymer–based confined concrete columns with potential benefits. However, it is critical to design a column with sufficient post-peak performance that can prevent its collapse at the rupture of the fiber-reinforced polymer tube. This article presents the experimental results on the prior and post peaks behavior of concrete-filled double-skin tubular columns with basalt fiber-reinforced polymer (BFRP)–punched-in outer steel and BFRP-circular inner steel (BFST-DSTCs). Twenty-two specimens were tested under axial compression to investigate the effects of design parameters on the behavior of the BFST-DSTC. The outcomes reveal that the BFST-DSTC exhibits the best performance in terms of load capacity, confinement ratio, failure and damage mechanisms, and ductility in prior and post peaks. The inner fiber-reinforced polymer jacket delays the buckling of the inner tube. The punched-in patterns of the outer steel improve the confinement effectiveness of the fiber-reinforced polymer jacket. The BFST-DSTC displays a good post-peak performance with high-energy dissipation capacity that prevents the concerned structure from collapse after the fiber-reinforced polymer jacket rupture. Finally, a new confinement model is proposed to predict the ultimate point of the confined concrete.

NUMERICAL ANALYSIS OF CONCRETE BEAM REINFORCED WITH GLASS FIBER REINFORCED POLYMER BARS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Osama A. Mohamed ◽  
Rania Khattab
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Reinforcing Bars ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Steel Bars ◽  
Frp Bars

The use of fiber reinforced polymer (FRP) bars to reinforce concrete beams has received significant attention in the past decade due to their corrosion resistance, high tensile strength, and excellent non-magnetic properties. Glass FRP (GFRP) reinforcing bars have gained popularity due to the relatively lower cost compared to carbon FRP (CFRP) bars. In this study, sixteen concrete beam finite element models were created using the finite element computer program ANSYS to perform linear and non-linear analyses. Twelve beams were longitudinally reinforced with GFRP bars, while the remaining four beams were reinforced with conventional steel bars as control specimens. In terms of mechanical properties, FRP reinforcing bars have lower modulus of elasticity compared to conventional reinforcing steel and remain linear elastic up to failure. This leads to lack of plasticity and a brittle failure of beams reinforced with FRP bars. The objective of this study is to investigate flexural behavior of concrete beams reinforced with GFRP reinforcing bars. Some of the parameters incorporated in the numerical analysis include longitudinal reinforcement ratio and compressive strength of concrete, both of which affect the flexural capacity of beams. It is shown in this study that replacement of traditional reinforcing steel reinforced bars by GFRP bars significantly decreases mid-span deflection and increases ultimate load. The strain distribution along GFRP longitudinal reinforcing bars is totally different from that of traditional steel bars.

Behaviors of Concrete Beam Prestressed with External CFRP Tendons

2008 ◽  
Vol 400-402 ◽  
pp. 559-566 ◽  
Author(s):  
Hong Fang Li ◽  
Chang Gong ◽  
Zhi Fang
Keyword(s):  
Point Load ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Reinforced Polymer ◽  
Initial Loading ◽  
External Tendons ◽  
Effective Depth ◽  
Ultimate Loading Capacity ◽  
Steel Rebars ◽  
Good Agreement

The purpose of present paper is to study the flexural behaviors of concrete T-beams prestressed with external carbon fiber reinforced polymer(CFRP) tendons. Tests were carried out on 5 beams under four-point load, of which four beams were reinforced with hybrid both external CFRP tendons and internal steel rebars and another one only reinforced with internal steel rebars. Such parameters as the different initial loading states at external CFRP tendon jacking and different jacking stress in tendon were considered in experiment. A program was developed to predict the behaviors of those beams prestressed with externally prestressed tendons and the parametric study was conducted using the program. The predicted results from the program were in good agreement with the test results. Such parameters as jacking stress, elastic modulus of external tendons, configuration of deviators and ratio of span to effective depth of beam were chosen as primary analytical factors for the study on the flexural behaviors of beams prestressed with external tendons. The initial loading state on the beam before tendon jacking has no significant influence on the ultimate loading capacity and deflection.

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