Concrete-Filled FRP Tubes: New Forms for Improved Confinement Effectiveness

2012 ◽  
Vol 256-259 ◽  
pp. 657-661
Author(s):  
Togay Ozbakkloglu
Keyword(s):  
Experimental Study ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Similar Material ◽  
Reinforced Polymer ◽  
Improved Performance ◽  
Frp Tube ◽  
Frp Tubes

This paper reports on the development and testing of a new concrete-filled fiber reinforced polymer (FRP) tube (CFFT) system. The CFFT system was designed to enhance the effectiveness of rectangular FRP tubes in confining concrete. The technique used in the development of the CFFT system involved the incorporation of an internal FRP panel as an integral part of the CFFT. The performance of the system was investigated experimentally through axial compression tests of six unique CFFTs. The results of the experimental study indicate that the new CFFT system presented in this paper offer significantly improved performance over conventional CFFTs with similar material and geometric properties. Examination of the test results have led to a number of significant conclusions in regards to confinement effectiveness of each new CFFT system. These results are presented and a discussion is provided on the parameters that influenced the compressive behavior of the new CFFT system.

scholarly journals Compressive Behavior of Circular Sawdust-Reinforced Ice-Filled Flax FRP Tubular Short Columns

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 957 ◽  
Author(s):  
Yanlei Wang ◽  
Guipeng Chen ◽  
Baolin Wan ◽  
Baoguo Han
Keyword(s):  
Ice Cores ◽  
Absorption Capacity ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Compressive Behavior ◽  
Composite Columns ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Frp Tube ◽  
Frp Tubes

Sawdust-reinforced ice-filled flax fiber-reinforced polymer (FRP) tubular (SIFFT) columns are newly proposed to be used as structural components in cold areas. A SIFFT column is composed of an external flax FRP tube filled with sawdust-reinforced ice. The compressive behavior of circular SIFFT short columns was systematically investigated. Four types of short columns with circular sections, including three plain ice specimens, three sawdust-reinforced ice specimens (a mixture of 14% sawdust and 86% ice in weight), nine plain ice-filled flax FRP tubular (PIFFT) specimens and nine SIFFT specimens, were tested to assess the concept of the innovative composite columns. The test variables were the thickness of flax FRP tubes and the type of ice cores. The test results indicated that the lateral dilation and the development of cracks of the ice cores were effectively suppressed by outer flax FRP tubes, thus causing a considerable enhancement in the compressive strength. Moreover, the compressive behavior, energy-absorption capacity, and anti-melting property of sawdust-reinforced ice cores were better than those of plain ice cores confined by flax FRP tubes with the same thicknesses. The proposed equations for estimating ultimate bearing capacities of PIFFT and SIFFT short columns were shown to provide reasonable and accurate predictions.

scholarly journals Compressive Behavior and Analytical Model of Ultra-Early Strength Concrete-Filled FRP Tube With Zero Curing Time

2022 ◽  
Vol 8 ◽  
Author(s):  
Yue Liu ◽  
Jia-Zhan Xie ◽  
Jing-Liang Yan
Keyword(s):  
Compressive Strength ◽  
Fiber Reinforced Polymer ◽  
Curing Time ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Early Strength ◽  
Frp Tube

Fiber-reinforced polymer (FRP) has been widely used in civil engineering due to its light weight, high strength, convenient construction, and strong corrosion resistance. One of the important applications of FRP composites is the concrete-filled FRP tube (CFFT), which can greatly improve the compressive strength and ductility of concrete as well as facilitate construction. In this article, the compressive performances of a normal concrete-filled FRP tube (N-CFFT) column with 5-hour curing time and an ultra-early strength concrete-filled FRP tube (UES–CFFT) column with zero curing time were studied by considering the characteristics of rapid early strength improvement of ultra-early strength concrete and the confinement effect of the FRP tube. Monotonic axial compression tests were carried out on 3 empty FRP tubes (FTs) without an internal filler and 6 CFFT (3 N-CFFTs and 3 UES-CFFTs) specimens. All specimens were cylinders of 200 mm in diameter and 600 mm in height, confined by glass fiber–reinforced polymer (GFRP). Test results indicated that the compressive bearing capacity of the specimens increased significantly by adopting the ultra-early strength concrete as the core concrete of the CFFT, although the curing time was zero. It was also shown that the compressive behavior of the UES–CFFT specimens with zero curing time increased significantly than that of the N-CFFT specimens with 5-hour curing time because the former was able to achieve rapid strength enhancement in a very short time than the latter. The ultimate compressive strength of UES–CFFT specimens with zero curing time reached 78.3 MPa, which was 66.2 and 97.2% higher than that of N-CFFT with 5-hour curing time and FT specimens, respectively. In addition, a simple confinement model to predict the strength of UES–CFFT with zero curing time in ultimate condition was introduced. Compared with the existing models, the proposed model could predict the ultimate strength of UES–CFFT specimens with zero curing time with better accuracy.

The Effect of Confinement Method and Specimen End Condition on Behavior of FRP-Confined Concrete under Concentric Compression

2013 ◽  
Vol 351-352 ◽  
pp. 650-653 ◽  
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Experimental Investigation ◽  
Cross Sections ◽  
Fiber Reinforced Polymer ◽  
Confined Concrete ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Concrete Cylinders ◽  
Frp Tubes

This paper presents an experimental investigation on the influence of confinement method and specimen end condition on axial compressive behavior of fiber reinforced polymer (FRP)-confined concrete. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were tested. Half of these specimens were manufactured as concrete-filled FRP tubes (CFFTs) and the remaining half were FRP-wrapped concrete cylinders. The effect of specimen end condition was examined on both CFFTs and FRP-wrapped specimens. This parameter was selected to study the influence of loading the FRP jacket on the axial compressive behavior. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the performance of FRP-wrapped specimens is similar to that of CFFT specimens and the influence of specimen end condition is negligible.

Compressive behavior of circular and square concrete column externally confined by different types of basalt fiber–reinforced polymer

2020 ◽  
Vol 23 (8) ◽  
pp. 1534-1547 ◽  
Author(s):  
Jingting Huang ◽  
Tao Li ◽  
Dayong Zhu ◽  
Peng Gao ◽  
An Zhou
Keyword(s):  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced Polymers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Polymer Wrapping ◽  
Basalt Fiber Reinforced Polymer

This article studies the compressive behavior of concrete columns confined by different basalt fiber–reinforced polymers. A total of 30 columns were divided into 10 groups according to section shapes (circular and square), basalt fiber–reinforced polymer types (unidirectional basalt fiber–reinforced polymer, bidirectional basalt fiber–reinforced polymer, and hybrid basalt fiber–reinforced polymer/carbon fiber–reinforced polymers), and number of layers (0, 1, and 2). The test results showed that the compressive strengths of confined specimens increased by 20%–71% for circular columns and by 23%–41% for square columns. Similarly, the ultimate strains improved by 49%–296% for circular specimens and by 45%–145% for square specimens. The two-layer basalt fiber–reinforced polymer jacket had the best confinement effect, whereas the confining effect of bidirectional basalt fiber–reinforced polymer wrapping was relatively lower than that of unidirectional basalt fiber–reinforced polymer wrapping. Moreover, both the strength and ultimate strain of confined concrete improved with increasing number of basalt fiber–reinforced polymer layers. Finite element numerical models were also developed and verified by experimental results, and then the stress distributions of basalt fiber–reinforced polymer jackets and cross-sectional concrete were presented. Based on the test results and experimental data from several existing studies, modified strength and ultimate strain models were further developed for basalt fiber–reinforced polymer-confined circular and square columns.

Effect of Column Parameters on Axial Compression Behavior of Concrete-Filled FRP Tubes

2005 ◽  
Vol 8 (4) ◽  
pp. 443-449 ◽  
Author(s):  
Zhenyu Zhu ◽  
Iftekhar Ahmad ◽  
Amir Mirmiran
Keyword(s):  
Axial Compression ◽  
Experimental Program ◽  
Test Results ◽  
Compression Tests ◽  
Concrete Core ◽  
Compression Behavior ◽  
Reinforced Polymer ◽  
Dowel Action ◽  
Frp Tubes ◽  
Glass Frp

Axial compression tests have shown fiber reinforced polymer (FRP) tubes to significantly enhance both strength and ductility of concrete columns. However, most experiments and associated models typically do not account for the internal reinforcement, size effect of the column, and the end load-bearing conditions of the tube. An experimental program was undertaken to evaluate the effect of these parameters on the performance of CFFT columns. Glass FRP tubes filled with plain, steel-reinforced, and glass FRP-reinforced concrete were tested with and without end grooves, which would prevent the tube from directly bearing of the axial load. The experiments showed the dowel action of the internal reinforcement to improve the ductility of the columns by restraining the lateral dilation of concrete core. Anempirically derived confinement model, augmented with the stress-strain response of the internal reinforcement, showed close agreement with test results.

Influence of Slenderness on Behavior of High-Strength Concrete-Filled FRP Tubes under Axial Compression

2014 ◽  
Vol 501-504 ◽  
pp. 963-968
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkaloglu
Keyword(s):  
Cross Sections ◽  
High Strength Concrete ◽  
Axial Strain ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Strength Enhancement ◽  
Reinforced Polymer ◽  
Frp Tubes

This paper presents an experimental investigation on the influence of specimen slenderness on axial compressive behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs). A total of 18 aramid FRP- (AFRP) confined high-strength concrete (HSC) specimens with circular cross-sections were tested. Specimens with height-to-diameter ratios of 1, 2, 3 and 5 were manufactured and tested, with all specimens maintaining a nominal diameter of 150 mm. The results indicate that specimens with an H/D of 1 exhibit significantly higher strength and strain enhancements compared to specimens with H/D ratios of 2 to 5. The influence of slenderness on specimens with H/D ratios between 2 and 5 was found to be significant in regards to axial strain enhancement, with a decrease observed as specimen slenderness increased. On the other hand, the influence of slenderness on axial strength enhancement of specimens with H/D ratios between 2 and 5 was found to be negligible.

scholarly journals Evaluation Effects of the Short- and Long-Term Freeze-Thaw Exposure on the Axial Behavior of Concrete-Filled Glass Fiber-Reinforced-Polymer Tubes

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Hend El-Zefzafy ◽  
Hamdy M. Mohamed ◽  
Radhouane Masmoudi
Keyword(s):  
Environmental Effects ◽  
Salt Water ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Freeze Thaw ◽  
Reinforced Polymer ◽  
Short And Long Term

Previous studies have demonstrated the high performance of the concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) as a stay-in-place formwork and confining material for concrete structures. However, there are several concerns related to the behavior of CFFT as a protective jacket against harsh environmental effects. The environmental effects such as freeze-thaw cycles and deicing salt solutions may affect materials properties, which may affect the structural response of CFFT members as well. This paper presents the test results of experimental investigation on the durability of short- and long-term behaviors of CFFT members. Test variables included the effect of confining using GFRP tubes, freeze-thaw cycles exposure in salt water, and the number of freeze-thaw cycles. CFFT cylinders (150 × 300 mm) were prepared and exposed to 100 and 300 freeze-thaw cycles in salt water condition. Then, pure axial compression tests were conducted in order to evaluate the performance of specimens due to freeze-thaw exposure, by comparing the stress-strain behavior and their ultimate load capacities. Test results indicated that the confinement using CFFT technique significantly protected the concrete when subjected to freeze-thaw exposure.

Compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes as internal reinforcements

2019 ◽  
Vol 23 (4) ◽  
pp. 713-732 ◽  
Author(s):  
Shu Fang ◽  
Li-Juan Li ◽  
Tao Jiang ◽  
Bing Fu
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Small Diameter ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Fiber Reinforced ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Polymer Tubes

Concrete infilled in a small-diameter fiber-reinforced polymer tube is strongly confined, thus having a high compressive strength and excellent deformability. Such a feature is exploited in the development of two types of high-performance hybrid members at Guangdong University of Technology, China, by incorporating small-diameter (30 to 60 mm) concrete-filled fiber-reinforced polymer tubes as internal reinforcements. Understanding the compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes is essential to understanding the behavior of the proposed hybrid members and the development of their design approaches. This article therefore presents a systematic study on the axial compressive behavior of small-diameter concrete-filled fiber-reinforced polymer tubes with the test parameters being the thickness, diameter, and fiber type of fiber-reinforced polymer tubes and concrete strength. The test results show that the tested small-diameter concrete-filled fiber-reinforced polymer tubes have a compressive strength and an ultimate axial strain of up to 267 MPa and 10.3%, which are, respectively, about 6 and 34 times that of the corresponding unconfined specimens, demonstrating the great potential of small-diameter concrete-filled fiber-reinforced polymer tubes as internal reinforcements for use in high-performance hybrid members. The applicability of three widely accepted stress–strain models developed based on test results of fiber-reinforced polymer-confined concrete cylinders with a diameter of 150 mm or above is also examined. It is shown that the three models tend to predict a steeper second portion of stress–strain responses than the test results, revealing the need of a tailored stress–strain model for small-diameter concrete-filled fiber-reinforced polymer tubes.

Investigation of Key Column Parameters on Compressive Behavior of Concrete-Filled FRP Tubes

2012 ◽  
Vol 256-259 ◽  
pp. 779-783 ◽  
Author(s):  
Togay Ozbakkloglu ◽  
Wen Zhang
Keyword(s):  
Concrete Strength ◽  
Experimental Program ◽  
Apparent Difference ◽  
Compressive Behavior ◽  
Tube Material ◽  
Manufacturing Method ◽  
Reinforced Polymer ◽  
Frp Tube ◽  
The University ◽  
Frp Tubes

A comprehensive experimental program has been underway at the Structures Laboratory of the University of Adelaide to investigate the behavior of concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) under concentric compression. This paper presents the results from a group of selected circular CFFTs and discusses the influence of the critical column parameters on the compressive behavior of CFFTs. These parameters include: concrete strength, amount and type of FRP tube material, manufacturing method of the tubes, and size of the CFFTs. Results indicate that concrete strength and the amount and type of tube material significantly affect the behavior of CFFTs. The manufacture method of FRP tube also has some, but less significant, influence on the behavior of CFFTs. The influence of specimen size has been found to be small. No apparent difference has been found between the compressive behaviors of circular CFFTs and companion FRP-wrapped cylinders.

Sign in / Sign up

Export Citation Format

Share Document