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.

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.

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 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.

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).

Dynamics of a Large Scale Hydraulic Capsule Pipeline System

1999 ◽  
Vol 124 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Hongliu Du ◽  
Satish S. Nair
Keyword(s):  
Large Scale ◽  
Control Method ◽  
Experimental Studies ◽  
Small Scale ◽  
Pipeline System ◽  
Centrifugal Pumps ◽  
Long Distance ◽  
Column Separation ◽  
In Series ◽  
Hydraulic Capsule Pipeline

The dynamics of a booster station, which is critical for the control of a novel, long distance, hydraulic capsule pipeline, is simulated mathematically for design studies and control of the hydraulic transients caused by the valve actuators in the system. Several modifications to the pump bypass station configuration of the booster station have been studied. With the objective of eliminating column separation and reducing flow reversals, a configuration with several centrifugal pumps connected in series, and a carefully sized air chamber is found to be a viable design. A valve control method is designed to eliminate column separation and the design results in acceptable flow reversal levels in the main pipe. The simulation results match with trends in limited experimental studies performed on a small scale experimental capsule pipeline system.

Reflections on Mechanisms Affecting the Behavior of FRP-Concrete-Steel Double-Skin Tubular Columns

2016 ◽  
Vol 705 ◽  
pp. 323-331 ◽  
Author(s):  
Togay Ozbakkaloglu
Keyword(s):  
Complex System ◽  
Detailed Examination ◽  
Steel Tube ◽  
Experimental Program ◽  
System Behavior ◽  
Compressive Behavior ◽  
Tubular Columns ◽  
Double Skin ◽  
Concrete Filling ◽  
The University

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.

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.

INVESTIGATION INTO THE INFLUENCE OF IMPREGNATION ON PINE TIMBER COMBUSTION USING A CONE CALORIMETER AND LARGE SCALE TESTS

2011 ◽  
Vol 3 (3) ◽  
pp. 91-104 ◽  
Author(s):  
Jerzy Gałaj ◽  
Zbignev Karpovič ◽  
Waldemar Jaskółowski
Keyword(s):  
Cone Calorimeter ◽  
Large Scale ◽  
Experimental Studies ◽  
Fire Retardant ◽  
Full Scale ◽  
Lower Amount ◽  
Small Scale ◽  
Fire Retardants ◽  
Co Concentration ◽  
Piloted Ignition

Fire safety is one of the main requirements with respect to the regulations on the buildings involved into the category of human hazards. Human safety measures are applied equally to inhabitants, users, customers, spectators, etc., as well as to fire brigades taking part in the activities connected with rescue actions. Methods for emission research were applied to estimate thermo-kinetic parameters related to smoke and toxic gases. The methods fall into two types: full scale methods reflect fire conditions and small laboratory scale methods having a significantly lower degree of reflection. This paper presents the results of studies on the influence of BAK-1 and Flamasepas-2 fire retardants produced in Lithuania and applied for timber on the selected parameters of the fire environment. Experimental studies were conducted using a cone calorimeter (small scale) in the closed compartment equipped with measuring devices (full scale). The undertaken studies have demonstrated that considering some parameters, such as heat release rate (HRR), a positive effect of the lower amount of the released heat can be obtained. Unfortunately, in case of the major part of the studied parameters, including time to ignition, CO concentration and extinction parameter reflecting smokiness, worse results (shorter time, higher CO values and higher extinction coefficient) have been observed for the treated timber rather than for the non-impregnated one. The obtained results have showed combustion with piloted ignition. In case of no piloted ignition, the results were slightly different. For all studied specimens treated with fire retardants, no ignition was observed and tests were terminated following 15 minutes. CO concentration and extinction parameter (smokiness) were higher for non-impregnated timber. Full scale experiments have confirmed the above provided information; moreover, it has been found that the application of fire retardant has no significant impact on temperatures in the compartment.

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