scholarly journals Analysis of Concrete-Filled Square Steel Tube Short Columns under Eccentric Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Qifeng Shan ◽  
Jingming Cai ◽  
Xiaopeng Li ◽  
Jiawei Tan
Keyword(s):  
Contact Stress ◽  
Structural Engineering ◽  
Constitutive Models ◽  
Steel Tube ◽  
Confinement Effect ◽  
Stress Strain ◽  
Short Columns ◽  
Concentric Loading ◽  
Square Steel Tube ◽  
Strain Model

The concrete-filled square steel tube (CFSST) columns have been widely applied in structural engineering. Although many constitutive models have been proposed to describe CFSST short columns under concentric loading, the applicability of the existing concentric model in the analysis of CFSST short columns under eccentric loading has not been properly verified. In this paper, the eccentric behaviors of CFSST short columns were investigated with the software of ABAQUS/standard. It was found that the contact stress between steel tube and inner concrete was seriously affected by eccentric ratios, indicating that the confinement effect of steel tube on inner concrete was different under concentric and eccentric loading. In this paper, a new stress-strain model of inner concrete which considered the influence of eccentricity was developed and verified with existing experimental results. It was found that the proposed stress-strain model was more accurate in simulating the eccentric behaviors of CFSST short columns.

scholarly journals Experimental Study on CFRP-Confined Circularized Concrete-Filled Square Steel Tube Short Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yuchuan Wen ◽  
Zhongjun Hu ◽  
Anningjing Li ◽  
Quanheng Li ◽  
Xuepeng Li ◽  
...  
Keyword(s):  
Concrete Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Stress Strain ◽  
Short Columns ◽  
Reinforced Polymer ◽  
Square Steel Tube ◽  
Strain Model

This study investigates the suitability of the circularization technique for strengthening square concrete-filled square steel tube (CFSST) short columns. A total of 16 specimens were tested under axial compression. The main parameters under investigation were concrete strength, the thickness of arc cement mortar layer components (CAM), and the layers of carbon fiber-reinforced polymer (CFRP) sheets. Test results indicated that the failure mode of CFRP-confined circularized CFSST (C-C-CFSST) columns was similar to that of CFRP-confined concrete columns. The CFRP-confined circularized strengthening method can increase confinement efficacy and reduce the stress concentration at the corners of CFSST columns. Three existing CFRP-confined concrete stress-strain models were evaluated using the test results. The predictions of the Lam and Teng stress-strain model agree well with the test data.

Finite Element Analysis on Concrete-Filled Square Steel Tube Short Columns with Inner CFRP Profiles under Axial Compression

2014 ◽  
Vol 578-579 ◽  
pp. 335-339 ◽  
Author(s):  
Guo Chang Li ◽  
Bing Zhou ◽  
Jiang Hua Pan
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Axial Compression ◽  
Constitutive Models ◽  
Element Model ◽  
Steel Tube ◽  
Element Analysis ◽  
Short Columns ◽  
Square Steel Tube

The new composite structure concrete-filled square steel tube (CFST) column with inner CFRP profiles is proposed. A finite element model is presented to investigate the mechanical behavior of CFST short columns with internal CFRP profiles subjected to axial compression using ABAQUS based on reasonable constitutive models of materials. In a addition, the content of CFRP profiles and width thickness ratio of steel tube’ effect are considered on mechanical properties of the column. Based on the model, the whole stage of axial compression of the short columns, failure mode and the stress mechanism of the ultimate bearing capacity state are calculated and analyzed.

Comprehensive stress-strain model of square steel tube stub columns under compression

2017 ◽  
Vol 131 ◽  
pp. 503-512 ◽  
Author(s):  
Hua Zhao ◽  
Yuping Sun ◽  
Takashi Takeuchi ◽  
Shichun Zhao
Keyword(s):  
Steel Tube ◽  
Stress Strain ◽  
Square Steel Tube ◽  
Strain Model ◽  
Stub Columns

scholarly journals Finite element analysis of mechanical behavior of concrete-filled square steel tube short columns with inner I-shaped CFRP profiles subjected to bi-axial eccentric load

2018 ◽  
Author(s):  
Guochang Li ◽  
Zhichang Zhan ◽  
Zhijian Yang ◽  
Yu Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compressive Strength ◽  
Steel Tube ◽  
Concrete Compressive Strength ◽  
Eccentric Load ◽  
Element Analysis ◽  
Composite Columns ◽  
Short Columns ◽  
Square Steel Tube

The concrete-filed square steel tube with inner I-shaped CFRP profiles short columns under bi-axial eccentric load were investigated by the finite element analysis software ABAQUS. The working mechanism of the composite columns which is under bi-axial eccentric load are investigated by using the stress distribution diagram of steel tube concrete and the I-shaped CFRP profiles. In this paper, the main parameters; eccentric ratio, steel ratio, steel yield strength, concrete compressive strength and CFRP distribution rate of the specimens were investigated to know the mechanical behavior of them. The interaction between the steel tube and the concrete interface at different characteristic points of the composite columns were analyzed. The results showed that the ultimate bearing capacity of the concrete-filed square steel tube with inner I-shaped CFRP profiles short columns under bi-axial eccentric load decrease with the increase of eccentric ratio, the ultimate bearing capacity of the composite columns increase with the increase of steel ratio, steel yield strength, concrete compressive strength and CFRP distribution rate. The contact pressure between the steel tube and the concrete decreased from the corner zone to the flat zone, and the contact pressure decreased from the mid-height cross section to other sections.

Study on Stress-Strain Relationship of FRP-Confined Concrete Filled Steel Tubes

2010 ◽  
Vol 163-167 ◽  
pp. 3826-3829
Author(s):  
Feng Yu ◽  
Ping Wu
Keyword(s):  
Main Parameter ◽  
Steel Tube ◽  
Confined Concrete ◽  
Stress Strain ◽  
Steel Tubes ◽  
Concrete Filled Steel Tube ◽  
Strain Relationship ◽  
Relationship Of ◽  
Concrete Filled Steel Tubes ◽  
Strain Model

FRP-confined concrete filled steel tube may fully use the character of FRP-confined concrete and concrete filled steel tube. Based on the analysis of existing experimental data, the formula of ultimate bearing capacity of FRP-confined concrete filled steel tube is proposed. The mechanical behavior of FRP-confined concrete filled steel tube is mainly related to the equivalent confinement effect coefficient before the rupture of FRP. Based on the static equilibrium condition, the equivalent conversion section is adopted; taking as main parameter, the simplified stress-strain model of FRP-confined concrete filled steel tube is established. The predictions of the model agree well with test data.

Bearing Capacity of Concrete Filled Square Steel Tube Short Columns with Inner CFRP Circular Tube under Eccentric Compression

2011 ◽  
Vol 243-249 ◽  
pp. 1272-1278
Author(s):  
Tian Hua Li ◽  
Jun Hai Zhao ◽  
Xue Ying Wei ◽  
Wei Kong ◽  
Xiao Ming Dong
Keyword(s):  
Bearing Capacity ◽  
Circular Tube ◽  
Steel Tube ◽  
Reduction Factor ◽  
Eccentricity Ratio ◽  
Strength Reduction Factor ◽  
The Core ◽  
Short Columns ◽  
Square Steel Tube ◽  
Core Concrete

Based on the unified strength theory, the bearing capacity of the concrete filled square steel tube short columns with inner CFRP circular tube under eccentric compression was analyzed. The restriction effect of the inner CFRP circular tube upon the core concrete, strength reduction factor for eccentricity ratio and the equivalent reduction factor, which considered the ratio of thickness to side effect, were taken into account in the theoretical analysis. The axial bearing capacity formula of the square steel tube short columns filled with inner CFRP circular tube was deduced. By introducing the strength reduction factor for eccentricity ratio, the eccentric bearing capacity formula on the basis of the axial bearing capacity formula was obtained. Parametric studies were carried out to evaluate the effects of intermediate principal stress, different CFRP deployment ratios, eccentricity ratios and the tension-compression ratio on the eccentric bearing capacity of the column. The formula was verified by the comparison of the theoretical results with the experimental data. The results show that inner CFRP circular tube can effectively restrain the core concrete.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong Ding ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

Analysis on Bearing Capacity of Solid Multibarrel Tube-Confined Concrete Short Columns (CHS Inner and SHS Outer) under Axial Compressive Load

2011 ◽  
Vol 255-260 ◽  
pp. 151-156 ◽  
Author(s):  
Zhao Qiang Zhang ◽  
Yong Yao
Keyword(s):  
Ultimate Load ◽  
Concrete Strength ◽  
Compressive Load ◽  
Steel Tube ◽  
Confined Concrete ◽  
Unified Strength Theory ◽  
Short Columns ◽  
Circular Steel Tube ◽  
Reduction Coefficient ◽  
Square Steel Tube

By introducing the reduction coefficient of concrete strength and the equivalent restriction reduction coefficient,the non-uniform confinement force of square steel tube to its core concrete is turned to that of equivalent circular steel tube. Then the ultimate load calculation formula for the solid multibarrel tube-confined concrete short columns (CHS inner and SHS outer) is derived based on the Unified Strength Theory(UST),in which the double restriction effect and the decrease of longitudinal stress because of the hoop tensile tension are considered. The influence of intermediate principal stress on the ultimate load is studied and the failure mechanism is discussed. The applicability of the formulas is testified and the results show that the formulas have significance in exerting material potential.

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