Effect of Loading Pattern on Performance of FRP-HSC-Steel Double Skin Tubular Columns

2014 ◽  
Vol 919-921 ◽  
pp. 83-87
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu

This paper reports on part of an ongoing experimental program at the University of Adelaide on FRP-concrete-steel double-skin tubular columns (DSTCs). The main emphasis of the study reported in this paper was to investigate the influence of loading pattern on the axial compressive behavior of DSTCs. To this end, 12 hollow and concrete-filled DSTCs were manufactured and tested under monotonic or cyclic axial compression. All of the specimens were manufactured using high-strength concrete (HSC). The results of the experimental study indicate that that concrete in cyclically loaded hollow DSTCs exhibits slightly larger strength and strain enhancement ratios than concrete in companion monotonically loaded DSTCs. The results also indicate that concrete in filled DSTCs exhibit slightly larger strength enhancement ratios than and similar strain enhancement ratios to concrete in monotonically loaded DSTCs.

2013 ◽  
Vol 838-841 ◽  
pp. 535-539 ◽  
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu

This paper reports on a part of an ongoing experimental program at the University of Adelaide on the behavior of fiber reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs). Influence of concrete-filling inner steel tube on the compressive behavior of FRP-concrete-steel DSTCs was investigated experimentally through the test of 8 normal-and high-strength concrete DSTCs. The results of the experimental study indicate that concrete-filling inner steel tubes of DSTCs results in a slightly increase in the compressive strength and decrease in the ultimate strain of concrete in DSTCs, compared to companion DSTCs with hollow inner steel tubes. The results also indicate that concrete in both types of DSTCs is confined effectively by FRP and steel tubes.


2013 ◽  
Vol 838-841 ◽  
pp. 525-529 ◽  
Author(s):  
Yunita Idris ◽  
Togay Ozbakkaloglu

This paper reports on part of an ongoing experimental program at The University of Adelaide on the flexural behavior of FRP-high-strength concrete (HSC)-steel double-skin tubular beams (DSTBs). The results from three circular DSTBs that were tested as simply supported beams in a four-point bending setup under monotonic loading are presented. The experimental study investigated the influences of the inner steel tube diameter and the use of mechanical connectors on the steel tube on the flexural behavior of DSTBs. The results indicate that DSTBs are capable of developing very high inelastic flexural deformations. However, the results also indicate that slip between the concrete and the steel tube of the DSTB can be relatively large, unless the bond between concrete and steel tube is enhanced through the use of mechanical connectors. It was also observed that the flexural behavior of DSTBs is influenced significantly by the diameter and thickness of the inner steel tube.


2016 ◽  
Vol 705 ◽  
pp. 323-331 ◽  
Author(s):  
Togay Ozbakkaloglu

This paper presents the results of 20 hollow and concrete-filled double-skin tubular columns (DSTCs), which were tested as part of a comprehensive experimental program that was undertaken at The University of Adelaide on FRP-concrete steel DSTCs. The paper is aimed at providing important insights into the influence of two key parameters, namely the diameter of inner steel tube and presence/absence of a concrete-filling inside the inner steel tube, which play major roles in the column behavior through their influences on a series of interacting mechanisms that govern the complex system behavior. A detailed examination of the results yielded a number of important insights into the mechanisms that influence the compressive behavior of DSTCs.


2014 ◽  
Vol 501-504 ◽  
pp. 3-7
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu

This paper reports on part of an ongoing experimental program at the University of Adelaide on FRP-concrete-steel composite columns. The results from twenty specimens including 12 double skin tubular columns (DSTCs), two solid concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs), and six CFFTs with inner voids (H-CFFTs) are presented. The specimens were manufactured using high-strength concrete (HSC) and their FRP tubes were fabricated using unidirectional S-glass fiber sheets. The results of the experimental study indicate that that H-CFFTs perform significantly worse than DSTCs and CFFTs and their performance further degrades with an increase in the diameter of inner void. Comparison of the results from DSTC and CFFT specimens indicate that both hollow and concrete-filled DSTCs exhibit improved compressive behavior compared to CFFTs.


2013 ◽  
Vol 438-439 ◽  
pp. 701-705
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu

This paper reports on part of an ongoing experimental program at The University of Adelaide on FRP-concrete-steel composite columns. A total of eight high-strength concrete double-skin tubular columns (DSTCs) were tested under axial compression. The column parameters examined included the diameter, thickness, and shape of inner steel tube. The results of the experimental study show that increasing the inner steel tube diameter leads to an increase in the ultimate axial stress and strain of concrete in DSTCs. The results also show that increasing inner steel tube thickness leads to an increase in the ultimate axial stress and strain of DSTCs. Furthermore, it is observed that concrete inside DSTCs with square inner steel tubes is not confined as effectively as concrete inside DSTCs with circular inner steel tubes.


2013 ◽  
Vol 743 ◽  
pp. 45-49
Author(s):  
Jian Chin Lim ◽  
Togay Ozbakkloglu

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.


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