A Simple Design-Oriented Model for FRP-Confined High-Strength Concrete

2013 ◽  
Vol 743 ◽  
pp. 45-49
Author(s):  
Jian Chin Lim ◽  
Togay Ozbakkloglu
Keyword(s):  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Simple Design ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Strength Enhancement ◽  
Reinforced Polymer ◽  
Test Database

This paper presents a study on the axial compressive behavior of fiber reinforced polymer (FRP)-confined high-strength concrete (HSC). A large experimental test database assembled from the published literature was used to investigate and quantify factors influencing the compressive behavior of FRP-confined HSC. The database consisted of 976 test data having unconfined concrete strength ranging from 6.2 to 169.7MPa. Based on the analysis results of the database, it was found that the threshold confinement stiffness increases significantly with an increase in concrete strength, which in turn adversely affects the strength enhancement of confined concrete. It was also observed that the hoop rupture strain of FRP shell decreases with an increase in concrete strength. Existing confinement models that are applicable to FRP-confined HSC were assessed using the database. Finally, a new simple design-oriented model for FRP-confined HSC developed on the basis of the database is presented.

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.

Influence of Prestress on Axial Compressive Behavior of High-Strength Concrete-Filled FRP Tubes

2015 ◽  
Vol 744-746 ◽  
pp. 173-178
Author(s):  
Thomas Vincent
Keyword(s):  
Cross Sections ◽  
High Strength Concrete ◽  
Axial Strain ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Compressive Behavior ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Frp Tubes ◽  
Different Levels

This paper presents an experimental investigation on the influence of prestress on axial compressive behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs). A total of 12 aramid FRP- (AFRP) confined high-strength concrete (HSC) specimens with circular cross-sections were tested under monotonic axial compression. All specimens were cylinders with 152 mm diameter and 305 mm height and their unconfined concrete strengths were approximately 100 to 110 MPa. The influence of FRP prestress was examined by applying 3 different levels of lateral prestress ranging from 4.29 to 7.27 MPa. In addition to the prestressed specimens, companion specimens with no applied prestress were manufactured and tested to establish reference values. Results of the experimental study indicate that the influence of prestress on compressive strength is significant, with an increase in ultimate strength observed in all prestressed specimens compared to that of non-prestressed specimens. On the other hand, the influence of prestress on axial strain was found to be minimal, with prestressed specimens displaying a slight decrease in ultimate strain, compared to their non-prestressed counterparts. The results also indicate that prestressing the AFRP shell prevents the sudden drop in strength, typically observed in FRP-confined HSC specimens, that initiates at the transition point which connects the first and second branches of the stress-strain curves.

Experimental Studies on High Strength Concrete Beams Reinforced with Steel and GFRP Rebars

2012 ◽  
Vol 238 ◽  
pp. 669-673 ◽  
Author(s):  
Ying Hao Liu ◽  
Yong Yuan
Keyword(s):  
High Strength Concrete ◽  
Experimental Studies ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Structural Behavior ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Steel Rebars ◽  
Gfrp Rebars

The paper analyzes the structural behavior of high strength concrete (HSC) beams reinforced with hybrid glass fiber reinforced polymer (GFRP) and steel reinforcements. The analysis refers to HSC beams reinforced with GFRP rebars and steel rebars placed in different layers. Results of the experimental and theoretical investigation are represented and discussed. Significant features of the structural behavior regarding flexural strength, deflection, are pointed out.

An Experimental Study on the Compressive Behavior of CFRP-Confined High- and Ultra High-Strength Concrete

2013 ◽  
Vol 671-674 ◽  
pp. 1860-1864 ◽  
Author(s):  
Thomas Vincent ◽  
Togay Ozbakkloglu
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
Axial Stress ◽  
Concrete Strength ◽  
Experimental Studies ◽  
High Strength ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Strength Concrete ◽  
Ductile Behavior

It is well established that external confinement of concrete with fiber reinforced polymer (FRP) sheets results in significant improvements on the axial compressive behavior of concrete. This understanding has led to a large number of experimental studies being conducted over the last two decades. However, the majority of these studies have focused on normal strength concretes (NSC) with compressive strengths lower than 55 MPa, and studies on higher strength concretes have been very limited. This paper presents the results of an experimental study on the compressive behavior of FRP confined high- and ultra high-strength concrete (HSC and UHSC) with average compressive strengths of 65 and 100 MPa. A total of 29 specimens were tested under axial compression to investigate the influence of key parameters such as concrete strength and method of confinement. All specimens were cylindrical, confined with carbon FRP and were 305 mm in height and 152 mm in diameter. Results obtained from the laboratory testing were graphically presented in the form of axial stress-strain relationships and key experimental outcomes are discussed. The results of this experimental study indicate that above a certain confinement threshold, FRP-confined HSC and UHSC exhibit highly ductile behavior. The results also indicate that FRP-wrapped specimens perform similar to concrete-filled FRP tube (CFFT) specimens at ultimate condition, however notable differences are evident at the transition region when comparing stress-strain curves.

Load-deformation Behaviour of Eccentrically Loaded SSTT-confined High Strength Concrete Columns

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Ma Chau Khun ◽  
Abdullah Zawawi Awang ◽  
Wahid Omar
Keyword(s):  
High Strength Concrete ◽  
Deformation Behaviour ◽  
High Strength ◽  
Concrete Columns ◽  
Fiber Reinforced Polymer ◽  
Capacity Enhancement ◽  
Strength Concrete ◽  
Reinforced Polymer ◽  
Concentric Loading ◽  
Future Work

The application of steel-straps confinement or better known as steel-strapping tensioning technique (SSTT) has been proven to be effective in increasing the strength and ductility of High-Strength Concrete (HSC) column comparable to Fiber-Reinforced Polymer (FRP).  However, most of the research of confined HSC column has mainly concentrated on concentric loading. In actual practical condition, most of the columns are subjected to eccentric loading. The scarcity of the experimental data for eccentric loaded confined HSC column has prevented the potential use of this type of structure element. In this paper, five HSC columns were tested. The specimens were SSTT-confined and tested with 25mm and 50 mm eccentric loading. The results show that SSTT confinement can increase the strength and deformability of high-strength concrete column, although the strain gradient reduces the confining efficiency. Therefore, smaller capacity enhancement factor should be used in eccentrically loaded SSTT-confined HSC columns compared to concentrically loaded columns. Furthermore, the non-linear theoretical model established in this study can be used for templates for future work on SSTT-confined HSC columns.

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