Effects of Hollowness on Strength of Double Skinned Concrete Filled Steel Tubular Columns of Different Geometries under Axial Loading

2011 ◽  
Vol 94-96 ◽  
pp. 1746-1751
Author(s):  
Naseem Baig Muhammad ◽  
Jian Sheng Fan ◽  
Jian Guo Nie
Keyword(s):  
Axial Loading ◽  
High Strength ◽  
External Pressure ◽  
Strength Increase ◽  
Geometric Shapes ◽  
Composite Columns ◽  
Tubular Columns ◽  
Section Modulus ◽  
Conservative Values ◽  
Rc Bridge Columns

Concrete filled tubular columns (CFT) have been used in buildings and bridges since long in history, and research reported in china is since 1970s. It has become popular as structural members due to their excellent structural performance characteristics, which include high strength, stiffness and high ductility. In modern building construction, steel rectangular hollow sections (RHS), square hollow sections (SHS) and circular hollow sections (CHS) are often filled with concrete to form a composite column. Such composite columns are well recognized in view of their high load carrying capacity, fast construction, small cross section, and high fire resistance. Compared to concrete-filled steel tubular (CFT) columns, the DSCFT can reduce its own weight while have a high flexural stiffness. Compared to traditional RC bridge columns and CFT columns it has high bending stiffness, avoids instability under external pressure, is light weight, possesses good damping characteristics due to increase in section modulus. In present study it is found that there is a definite increase in strength. Circular columns had all the properties better than other geometric shapes; strength increase was almost 20 % as compared to square columns. It is expected that if same ratios are maintained at projected scale, there would be a definite increase in strength and behavior of the columns. New concept of hollowness introduced is valid for all geometric shapes in DSCFTs and gives fairly good idea about its limits and effects on strength of columns. The equations given in different design codes give conservative values and hence need to be revised for DSCFTs both for seismic and normal designs.

Mechanical Properties of High Strength Concrete Filled Steel Tubular Columns

2012 ◽  
Vol 472-475 ◽  
pp. 1119-1125 ◽  
Author(s):  
Ke Feng Tan ◽  
Lai Bao Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Strength Increase ◽  
Strength Concrete ◽  
Tubular Columns ◽  
Short Columns ◽  
Core Concrete

This study investigated the mechanical properties of High Strength Concrete filled steel tubular short columns (HSCFSTSC) with length to diameter ratio (L/D) of 3.5.The strength of concrete used to fill the steel tubular columns ranged from 54MPa to 116MPa. The test results showed that using a steel tube as confinement can significantly improve the ductility and compressive strength of core concrete. The magnitude of compressive strength increase of core concrete was directly proportional to the Confinement Index, , and the extent of improvement of the ductility increases as the  increases. For thoroughly improving the ductility of core concrete, the Confinement Index  should be equal or larger than 0.48. The formula used to calculate the load bearing capacity of HSCFSTSC was given out.

Mechanical Behaviors of Slender Steel Tubular Columns Filled with Steel-Reinforced High-Strength Concrete

2015 ◽  
Vol 1089 ◽  
pp. 235-238
Author(s):  
Ping Guan ◽  
Lan Xiang Chen
Keyword(s):  
Yield Stress ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Mechanical Behaviors ◽  
Composite Columns ◽  
Strength Concrete ◽  
Tubular Columns ◽  
Finite Element Software ◽  
Mechanical Models

To study on the mechanical behaviors of the new slender steel-concrete composite columns that are named after steel tubular columns filled with steel-reinforced high-strength concrete(STSRHC), the mechanical models of slender STSRHC are established for the analysis with the finite element software ABAQUS. There are seven influencing factors on the mechanical behaviors of slender STSRHC, they are: slender ratio, eccentricity, the thickness of steel tube, the yield stress of steel tube, the yield stress of inserted steel, the cube strength of high-strength concrete, the shape of inserted steel cross section. The results show the results calculated by software have good agreements with the tested ones; slender ratio, eccentricity and the thickness are the most effective factors on the mechanical properties of slender STSRHC.

Relative Performance of FRP-Concrete-Steel Double Skin Tubular Columns versus Solid and Hollow Concrete-Filled FRP Tubes

2014 ◽  
Vol 501-504 ◽  
pp. 3-7
Author(s):  
Butje Alfonsius Louk Fanggi ◽  
Togay Ozbakkaloglu
Keyword(s):  
High Strength ◽  
Experimental Program ◽  
Composite Columns ◽  
Tubular Columns ◽  
Reinforced Polymer ◽  
Double Skin ◽  
Steel Composite ◽  
Comparison Of The Results ◽  
The University ◽  
Frp 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 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.

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 Failure Analysis on a Collapsed Flat Cover of an Adjustable Ballast Tank Used in Deep-Sea Submersibles

2019 ◽  
Vol 9 (23) ◽  
pp. 5258
Author(s):  
Fang Wang ◽  
Mian Wu ◽  
Genqi Tian ◽  
Zhe Jiang ◽  
Shun Zhang ◽  
...  
Keyword(s):  
Deep Sea ◽  
Material Selection ◽  
High Strength ◽  
External Pressure ◽  
Element Analysis ◽  
Ballast Tank ◽  
Material Inhomogeneity ◽  
Comprehensive Properties ◽  
Ultimate Cause ◽  
Flat Cover

A flat cover of an adjustable ballast tank made of high-strength maraging steel used in deep-sea submersibles collapsed during the loading process of external pressure in the high-pressure chamber. The pressure was high, which was the trigger of the collapse, but still considerably below the design limit of the adjustable ballast tank. The failure may have been caused by material properties that may be defective, the possible stress concentration resulting from design/processing, or inappropriate installation method. The present paper focuses on the visual inspections of the material inhomogeneity, ultimate cause of the collapse of the flat cover in pressure testing, and finite element analysis. Special attention is paid to the toughness characteristics of the material. The present study demonstrates the importance of material selection for engineering components based on the comprehensive properties of the materials.

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