scholarly journals Effect of Cross-Sectional Aspect Ratio on Rectangular FRP-Concrete-Steel Double-Skin Tubular Columns under Axial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Bing Zhang ◽  
Xia-Min Hu ◽  
Wei Wei ◽  
Qian-Biao Zhang ◽  
Ning-Yuan Zhang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
Axial Stress ◽  
Axial Strain ◽  
Steel Tube ◽  
Confined Concrete ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Double Skin ◽  
Frp Tube

Hybrid FRP-concrete-steel double-skin tubular columns (hybrid DSTCs) are novel hollow columns consisting of an outer FRP tube, an inner steel tube, and the concrete between the two tubes. Hybrid DSTCs possess important advantages, such as excellent corrosion resistance as well as remarkable seismic resistance. However, existing studies are mainly focused on hybrid DSTCs with a circular cross section or a square cross section. When a column is subjected to different load levels in the two horizontal directions, a rectangular column is preferred as it can provide different bending stiffness and moment capacity around its two axes of symmetry. This paper presents an experimental study on rectangular DSTCs with a particular focus on the effect of the cross-sectional aspect ratio (i.e., the ratio of the breadth to the width of the rectangular cross section). The effect of the cross-sectional shape of the inner steel tube (i.e., both elliptical and rectangular inner steel tubes were used) and the effect of FRP tube thickness were also investigated experimentally. Experimental results show that a larger aspect ratio will have no negative effect on the confinement effect in rectangular DSTCs; a rectangular DSTC with a larger aspect ratio generally has a larger ultimate axial strain and a higher axial stress at the ultimate axial strain; rectangular DSTCs with an elliptical steel tube generally have better performance than corresponding specimens with a rectangular steel tube. An existing model, which was developed based on a model for rectangular FRP-confined concrete columns and a model for circular DSTCs, is verified using the test results of the present study. The model generally provides close predictions for the peak axial stress of the confined concrete but yields conservative predictions for the ultimate axial strain for rectangular DSTCs.

scholarly journals Elliptical FRP-Concrete-Steel Double-Skin Tubular Columns under Monotonic Axial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Bing Zhang ◽  
Gui-Sen Feng ◽  
Yan-Lei Wang ◽  
Cong-Cong Lai ◽  
Chen-Chen Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
Steel Tube ◽  
Confined Concrete ◽  
Stress Strain ◽  
Tubular Columns ◽  
Strength Enhancement ◽  
Double Skin ◽  
The Cross ◽  
Frp Tube

Hybrid FRP-concrete-steel double-skin tubular columns (hybrid DSTCs) are a novel form of hollow columns consisting of an outer FRP tube, an inner steel tube, and an annular layer of concrete between the two tubes. Due to the effective confinement of the two tubes, the concrete in hybrid DSTCs is well confined, leading to excellent ductility and strength enhancement. Hybrid DSTCs also have excellent corrosion resistence due to the effective protection of the outer FRP tube. However, existing studies mainly focused on hybrid DSTCs with a circular cross-section. When subjecting to different loads in the two horizontal directions, elliptical columns are preferred as they can provide different bending stiffness and moment capacity around two axes of symmetry without significantly reducing the confining effect of the FRP tube. This paper extends the existing work on circular DSTCs to elliptical DSTCs with a particular focus on four issues: the effect of elliptical aspect ratio (i.e., the ratio of the major axis to the minor axis of the outer elliptical cross-section), the effect of the FRP tube thickness, the effect of void area ratio (i.e., the ratio of the area of concrete void to the area of the outer elliptical section), and the effect of the cross-section of the inner steel tube (i.e., both rectangular and elliptical steel tubes were used). Experimental results show that, the averaged peak stress of the confined concrete in elliptical DSTCs increases with the increase in the elliptical aspect ratio, whereas the elliptical aspect ratio has no obvious effect on the ultimate axial strain; the cross-section shape of the inner steel tube has significant effect on the axial stress-strain behavior of the confined concrete in elliptical DSTCs; elliptical DSTCs with an elliptical steel tube exhibit much better ductility and strength enhancement than those specimens with a rectangular steel tube. A simple stress-strain model of confined concrete was proposed for elliptical DSTCs to account for the effects of the elliptical aspect ratio, the inner void, and the shape of the inner steel tube, which can provide reasonably accurate but conservative predictions.

Influence of Inner Steel Tube Diameter on Compressive Behavior of Square FRP-HSC-Steel Double-Skin Tubular Columns

2015 ◽  
Vol 1119 ◽  
pp. 688-693 ◽  
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkloglu
Keyword(s):  
Axial Compression ◽  
Axial Stress ◽  
Steel Tube ◽  
Tube Diameter ◽  
Experimental Program ◽  
Composite Columns ◽  
Tubular Columns ◽  
Column System ◽  
Double Skin ◽  
The University

FRP-concrete-steel double-skin tubular columns (DSTCs) are a new form composite column system that effectively combines the advantages of the constituent materials. The performance of this column system has been experimentally investigated in a number of recent studies. However, apart from a single study reported on square DSTCs, all of the existing studies have been concerned with DSTCs with circular external tubes. This paper reports on part of an ongoing experimental program at the University of Adelaide on FRP-concrete-steel composite columns. The results from 12 square hollow and concrete-filled DSTCs and six companion hollow concrete-filled FRP tubes (H-CFFTs) that were tested under axial compression are presented. Results of the experimental study indicate that hollow DSTCs with larger inner steel tube diameters develop similar ultimate axial stresses to but significantly larger axial strains than companion DSTCs with smaller inner steel tubes. The results also show that, in concrete-filled DSTCs with similar Ds/ts ratios, an increase in the steel tube diameter leads to an increase in both axial stress and strain of concrete. It was observed that H-CFFTs perform significantly worse than both hollow and filled DSTCs under axial compression, and their behavior further degrades with an increase in the diameter of their inner voids.

scholarly journals OFBG-Based Smart Double-Skin Tubular Confined-Concrete Column with Basalt FRP-Steel Composite

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3572
Author(s):  
Yung William Sasy Chan ◽  
Zhi Zhou ◽  
Wanqiu Liu ◽  
Jinping Ou
Keyword(s):  
Axial Stress ◽  
Axial Strain ◽  
The Self ◽  
Confined Concrete ◽  
Concrete Column ◽  
Health State ◽  
Damage Scenarios ◽  
Double Skin ◽  
Steel Composite ◽  
Sensing Performance

Fiber-reinforced polymer (FRP) composites have been widely employed to design advanced structural columns such as the hybrid FRP–concrete–steel double-skin tubular column (hybrid DSTC) with potential benefits. To date, the safety and self-monitoring of the hybrid DSTCs are still a challenge to overcome due to the complex damage scenarios. This paper investigates the self-sensing performance of a newly developed smart double-skin tubular confined concrete column (smart BFST-DSTC) made of basalt FRP–steel composite with built-in optical fiber Bragg grating sensors (OFBGs). The design of the smart BFST-DSTC and sensing principle are firstly addressed, followed by an experimental investigation on the basic mechanical properties and strain-based sensing performance of ten scaled specimens under axial compression. The outcomes reveal the enhancement of the proposed column in terms of load-carrying capacity, confinement ratio, and axial stress-axial strain behavior, as well as failure and damage modes when compared with the hybrid DSTC. The self-sensing investigation demonstrates that the measurement range satisfies the requirement to monitor and evaluate the hoop strains of the FRP jackets and the health state of the inner tube. The smart BFST-DSTC can replace the hybrid DSTC with the ability to provide early failure warning and life cycle health monitoring.

Experimental Study on Concrete-Filled Steel Tubular with External Octagon Steel Tube and Inner Circle PVC-U Pipe under Axial Compression

2011 ◽  
Vol 368-373 ◽  
pp. 511-514
Author(s):  
Wei Bin Yuan ◽  
Shi Long Ma
Keyword(s):  
Experimental Study ◽  
Numerical Analysis ◽  
Axial Load ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Cross Sectional Size ◽  
Double Skin ◽  
Core Concrete

An investigation of the octagon-shaped concrete-filled double skin steel tubular columns which used PVC-U pipe to replace the steel tube as inner tube was carried out. In order to study the performances and mechanisms of the components when suffered axial load, ultimate axial bearing capacities of 9 components were tested. The cross-sectional size of the outer steel tube and inner PVC-U pipe and length of the specimen was concerned by the nominal steel ratio and the hollow ratio and slenderness ratio, respectively. The external steel tube and core concrete appeared three and four types of destruction phenomenons, respectively, but the inner PVC-U pipe did not destroy. Finally, experimental results and numerical analysis results were comparied.

Compressive Behavior of Large-Scale Hybrid FRP-Concrete-Steel Double-Skin Tubular Columns

2011 ◽  
Vol 243-249 ◽  
pp. 1138-1144 ◽  
Author(s):  
Pan Xie ◽  
T Yu ◽  
Y.L. Wong ◽  
J.G. Teng
Keyword(s):  
Large Scale ◽  
Experimental Studies ◽  
Steel Tube ◽  
Small Scale ◽  
Structural Members ◽  
Compression Tests ◽  
Tubular Columns ◽  
Compressive Response ◽  
Double Skin ◽  
Frp Tube

Hybrid FRP-concrete-steel double-skin tubular columns (DSTCs) are a new form of hybrid structural members. A hybrid DTSC consists of an inner steel tube, an outer FRP tube and a concrete infill between them. Hybrid DSTCs possess many important advantages over conventional structural members, including their excellent corrosion resistance as well as excellent ductility and seismic resistance. A large amount of research has been conducted on hybrid DSTCs, but the existing experimental studies have been limited to the testing of small-scale columns. This paper presents preliminary results from the first series of large-scale axial compression tests on hybrid DSTCs, which forms part of a larger experimental study currently under way at The Hong Kong Polytechnic University. These test results confirm the excellent axial compressive response of hybrid DSTCs as initially expected.

Effect of Inner Steel Tube Cross-Sectional Shape on Compressive Behavior of Square FRP-Concrete-Steel Double-Skin Tubular Columns

2015 ◽  
Vol 752-753 ◽  
pp. 578-583 ◽  
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkloglu
Keyword(s):  
Steel Tube ◽  
Experimental Program ◽  
Steel Tubes ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Column System ◽  
Double Skin ◽  
Concrete Filling ◽  
Sectional Shape ◽  
The University

Recently, a new type of composite system was proposed in the form of fibre reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs). The performance of this column system, which consists of an outer tube made of FRP and an inner tube made of steel, has been experimentally investigated in a number of studies. However, apart from a single study reported on square DSTCs, all of the existing studies have been concerned with DSTCs with circular external tubes. This paper reports on part of an ongoing experimental program at the University of Adelaide that was aimed at addressing this research gap. The effect of cross-sectional shape of inner steel tube on compressive behaviour of square DSTCs was investigated through the test of 16 hollow and concrete-filled DSTCs. The result of the experimental study indicate that concrete in hollow DSTCs with circular inner steel tubes develop significantly larger ultimate axial stresses and strains than concrete in companion hollow DSTCs with square inner steel tubes. On the other hand, the results also indicate that the presence of a concrete-filling inside inner steel tubes results in a significant improvement in the behavior of DSTCs with square inner steel tubes.

scholarly journals Axial Compression Behaviour of Hybrid Double-Skin Tubular Columns Filled with Rubcrete

2019 ◽  
Vol 3 (2) ◽  
pp. 62 ◽  
Author(s):  
Osama Youssf ◽  
Reza Hassanli ◽  
Julie E. Mills ◽  
Yan Zhuge
Keyword(s):  
Wall Thickness ◽  
Steel Tube ◽  
Hoop Strain ◽  
Conventional Concrete ◽  
Tubular Columns ◽  
Rubber Particles ◽  
Fibre Reinforced Polymer ◽  
Double Skin ◽  
Adverse Influence ◽  
Frp Tube

Double-skin tubular columns (DSTCs) have become a competitive candidate for column members due to their important advantages compared with conventional reinforced concrete columns, including their better weight-to-strength ratio and ease of construction. Using Rubcrete in hybrid DSTCs is of great interest due to the potential of this system to overcome the Rubcrete material deficiencies and to add more ductility, toughness, seismic resistance, confinement effectiveness, and environmentally-friendly features to that structural system compared to conventional concrete. In this paper, hybrid DSTCs made out of Rubcrete, sandwiched between a fibre reinforced polymer (FRP) tube and a steel tube, were tested. The examined variables were concrete sand or stone replacement ratio (0% and 20%), FRP wall thickness (1- and 2-layers), steel wall thickness (3.2 mm and 4.5 mm), void ratio (50% and 76%), and void shape (circular or square). The axial and lateral stress–strain responses were monitored, measured, and compared. According to this investigation, using Rubcrete in hybrid DSTCs can enhance the axial and hoop strain capacities, especially with fine rubber particles. It was also observed that the adverse influence of using rubber on column ultimate capacity was much lower in DSTC specimens, compared with that of unconfined Rubcrete columns. Therefore, using Rubcrete with fine rubber particles is recommended in DSTC structural columns.

Influence of Inner Steel Tube Properties on Compressive Behavior of FRP-HSC-Steel Double-Skin Tubular Columns

2013 ◽  
Vol 438-439 ◽  
pp. 701-705
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu
Keyword(s):  
Axial Stress ◽  
High Strength ◽  
Steel Tube ◽  
Experimental Program ◽  
Stress And Strain ◽  
Steel Tubes ◽  
Composite Columns ◽  
Tubular Columns ◽  
Double Skin ◽  
The University

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.

scholarly journals Axial Behavior of Concrete-Filled Double-Skin Tubular Stub Columns Incorporating PVC Pipes

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1434
Author(s):  
Muhammmad Faisal Javed ◽  
Haris Rafiq ◽  
Mohsin Ali Khan ◽  
Fahid Aslam ◽  
Muhammad Ali Musarat ◽  
...  
Keyword(s):  
Steel Tube ◽  
Tube Material ◽  
Steel Tubes ◽  
Tubular Columns ◽  
Axial Capacity ◽  
Double Skin ◽  
Axial Behavior ◽  
Pvc Pipe ◽  
The Cost ◽  
Stub Columns

This experimental study presents concrete-filled double-skin tubular columns and demonstrates their expected advantages. These columns consist of an outer steel tube, an inner steel tube, and concrete sandwiched between two tubes. The influence of the outer-to-inner tube dimension ratio, outer tube to thickness ratio, and type of inner tube material (steel, PVC pipe) on the ultimate axial capacity of concrete-filled double-skin tubular columns is studied. It is found that the yield strength of the inner tube does not significantly affect the ultimate axial capacity of concrete-filled double-skin tubular composites. With the replacement of the inner tube of steel with a PVC pipe, on average, less than 10% strength is reduced, irrespective of size and dimensions of the steel tube. Hence, the cost of a project can be reduced by replacing inner steel tubes with a PVC pipes. Finally, the experimental results are compared with the existing design methods presented in AISC 360-16 (2016), GB51367 (2019), and EC4 (2004). It is found from the comparison that GB51367 (2019) gives better results, followed by AISC (2016) and EC4 (2004).

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