Tests on high-strength rectangular concrete-filled steel hollow section stub columns

This study was conducted to evaluate the applicability of concrete-filled steel tube (CFT) columns made from high-performance construction materials. KBC2016, South Korea’s current building code, limits the maximum compressive strength of concrete at 70 MPa and the maximum yield strength of steel at 650 MPa. Similar restrictions to material properties are imposed on major composite structural design parameters in other countries worldwide. With the recent acceleration of the pace of development in the field of material technology, the compressive strength of commercial concrete has been greatly improved and the problem of low tensile strength, known to be the major limitation of concrete, is being successfully addressed by adding fiber reinforcement to concrete. Therefore, the focus of this study was to experimentally determine the strength and ductility enhancement effects, which depend on material composition. To this end, we performed concentric axial loading tests on CFT stub columns made from steel with a yield strength of 800 MPa and steel fiber-reinforced high-strength concrete. By measuring the strain at the yield point of CFT steel during the test, we could determine whether steel yields earlier than ultimate failure load of the member, which is a key design concept of composite structures. The analysis results revealed that the yield point of steel preceded that of concrete on the stress-strain curve by the concurrent action of the strain increase at the maximum strength, attributable to the high compressive strength and steel fiber reinforcement, and the strain increase induced by the confining stress of the steel tube. Additionally, we performed parametric study using ABAQUS to establish the broad applications of CFT using high-performance materials, with the width-to-thickness ratio as the main parameter. Parametric study was undertaken as experimental investigation was not feasible, and we reviewed the criteria for limiting the width-to-thickness ratio as specified in the current building code.

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Compressive stress-strain model of cold-formed circular hollow section stub columns considering local buckling

Thin-Walled Structures ◽

10.1016/j.tws.2017.09.017 ◽

2017 ◽

Vol 120 ◽

pp. 495-505 ◽

Cited By ~ 3

Author(s):

Chang Yang ◽

Hua Zhao ◽

Yuping Sun ◽

Shichun Zhao

Keyword(s):

Compressive Stress ◽

Local Buckling ◽

Stress Strain ◽

Hollow Section ◽

Circular Hollow Section ◽

Strain Model ◽

Stub Columns

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Equivalent substitution criteria of aluminum for steel and its application in automobile structures

Advances in Mechanical Engineering ◽

10.1177/1687814020911228 ◽

2020 ◽

Vol 12 (3) ◽

pp. 168781402091122

Author(s):

Song Li ◽

Jiantao Bai ◽

Xinchen Wang ◽

Limin Song ◽

Kai Luo ◽

...

Keyword(s):

Large Deformation ◽

Small Deformation ◽

High Strength ◽

Steel Tube ◽

Equal Mass ◽

Body Structure ◽

Cross Sectional ◽

Hollow Section ◽

Automobile Body ◽

Triple Cell

Lightweight automobile body structure, made of aluminum, can extend the endurance mileage of electric automobile. However, the mechanisms for the application of aluminum in automobile body structure are not clear until now. The main contribution of this work is to propose a method of equivalent substitution criteria of aluminum for steel. This method researches small deformation and large deformation under bending mode. First, formulations of cross-sectional properties, including open, single-cell, double-cell, three-cell, and four-cell sections, are derived, and equivalent substitution criteria in the case of small deformation, which include equal stiffness design and equal strength design, are initially proposed. Second, in the case of large deformation, the steel circular tube and channel tube are substituted by aluminum tube under equivalent stiffness. The bending resistance of five types of tubes, including rectangular hollow section, rectangular hollow section with double-cell, rectangular hollow section with triple-cell, mild steel, and high-strength steel tube, are, respectively, compared considering crashworthiness under equal mass. Third, the side frame and chassis frame examples verify the effectiveness of the proposed method, which is universal and can also be applied in aerospace structures.

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Compressive strengths of concrete-filled double-skin (circular hollow section outer and square hollow section inner) aluminium tubular sections

Advances in Structural Engineering ◽

10.1177/1369433219842381 ◽

2019 ◽

Vol 22 (11) ◽

pp. 2418-2434 ◽

Cited By ~ 1

Author(s):

Feng Zhou ◽

Ben Young

Keyword(s):

Concrete Strength ◽

Element Model ◽

Numerical Results ◽

Outer Skin ◽

Hollow Section ◽

Composite Columns ◽

Double Skin ◽

Stub Column ◽

Circular Hollow Section ◽

Stub Columns

Experimental and numerical investigations of concrete-filled double-skin aluminium stub column with a circular hollow section as the outer skin and a square hollow section as the inner skin are presented in this article. A test program was carried out to study the influences of aluminium tube geometric dimensions and concrete strength on structural performance and strength of composite columns. A series of composite columns was tested on outer circular hollow section tubes and inner square hollow section tubes; the spaces between them had been filled with concrete of different nominal cylinder strengths of 40, 70 and 100 MPa. The tubes were fabricated by extrusion using 6061T6 heat-treated aluminium alloy having a nominal 0.2% proof stress of 240 MPa. A non-linear finite element model was developed and verified against experimental results. The test and numerical results were compared with the design strengths to evaluate the applicability of the design rules in the American specifications for aluminium and concrete structures. In addition, the proposed design equations, developed by the authors for concrete-filled double-skin aluminium tubular stub columns with circular hollow section as both outer and inner skins, were used to calculate the design strengths and compared with the experimental and numerical results obtained in this study. The proposed design equations also predicted the ultimate strengths of the concrete-filled double-skin aluminium tubular stub columns accurately with circular hollow section as the outer skin and square hollow section as the inner skin.

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