scholarly journals A Simple Formula for Prediction of Compressive Strength of Square CFT Columns

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Muhammad Aun Bashir
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Composite Structures ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Experimental Results ◽  
Simple Equation ◽  
Material Strength ◽  
Concrete Filled Steel Tube ◽  
Short Columns

Concrete filled steel tube structures are becoming very popular in the modern civil engineering projects. Studying composite structures is useful, since it is an innovative and contemporary way to build structures. This type of structure has the ability to use respective strength of both steel and concrete due to confinement. Prefabrication of steel tube section is beneficial, and allows rapid installation into main structure. It also reduces the assembly cost and construction time. This paper will present the simple equation to predict the compressive strength of square concrete filled steel tube by using Finite Element Analysis (FEA)based software ABAQUs. In this study, 3D non-linear finite element models of short square composite columns were prepared using ABAQUS. The results were compared with published experimental tests of a concrete filled steel tube short columns. After getting the good agreement with the experimental results, a simple equation for the prediction of compressive strength is presented by considering the width to thickness ratio of steel tube. Results are validated with experimental results. The equation can predict the compressive strength only for the given material strengths and in future, the simple equation can be improved by considering different parameters e.g. material strength, slenderness ratio and end conditions.

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.

Axial impact behaviors of stub concrete-filled square steel tubes

2019 ◽  
Vol 22 (11) ◽  
pp. 2490-2503 ◽  
Author(s):  
YT Zhang ◽  
B Shan ◽  
Y Xiao
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Steel Tube ◽  
Experimental Results ◽  
Parameter Analysis ◽  
Steel Tubes ◽  
Simple Method ◽  
Concrete Filled Steel Tube ◽  
Drop Weight ◽  
The Impact

Existing research on the widely used concrete-filled steel tubes is mainly focused on static or cyclic loading, and the studies on effects of high strain rate are relatively rare. In this article, seven stub concrete-filled steel tubular columns with square section were tested under both static and impact loads, using a large-capacity drop-weight testing machine. The research parameters were variable height of the drop-weight and different load types. The experimental results show that the failure modes of the concrete-filled steel tube columns from the impact tests are similar with those under static load, characterized by the local buckling of the steel tube. The time history curves of impact force and steel strain were investigated. The results indicate that with increasing impact energy, the concrete-filled steel tube stub columns had a stronger impact-resistant behavior. The dynamic analysis software LS-DYNA was employed to simulate the impact behaviors of the concrete-filled steel tube specimens, and the finite element results were reasonable compared with the test results. The parameter analysis on the impact behavior of concrete-filled steel tube columns was performed using the finite element model as well. A simple method was proposed to calculate the impact strength of square concrete-filled steel tube columns and compared favorably with experimental results.

Nonlinear Finite Element Analysis of Stiffened T-Shaped Thin-Walled Concrete-Filled Steel Tube Composite Columns

2012 ◽  
Vol 193-194 ◽  
pp. 1461-1464
Author(s):  
Bai Shou Li ◽  
Ai Hua Jin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Element Analysis ◽  
Concrete Filled Steel Tube ◽  
Composite Columns ◽  
Short Columns ◽  
Thin Walled

Based on the characteristics of the special-shaped concrete-filled steel tubes and consideration of material nonlinearity of constitutive relation, stimulation of 6 T-shaped thin-walled ribbed and un-ribbed concrete-filled steel tube short columns is implemented, as well as comparable analysis of stress, strain, displacement and bearing capacity, through the finite element analysis software ANSYS. The result indicates that the rib can effectively improve the ductility, delaying the buckling occurs, which enhances the core concrete confinement effect, so as the stimulated ultimate bearing capacity which is greater than nominal ultimate bearing capacity.

The Practice of Concrete Filled Steel Tube Piers to Bridges: A Review

2013 ◽  
Vol 405-408 ◽  
pp. 1602-1605 ◽  
Author(s):  
Zhi Jing Ou
Keyword(s):  
Structural Design ◽  
Slenderness Ratio ◽  
Research Direction ◽  
Steel Tube ◽  
Future Research ◽  
Material Strength ◽  
Concrete Filled Steel Tube ◽  
Construction Methods ◽  
High Pier ◽  
Available Information

Due to the small section dimension, high compressive strength, large stiffness, and excellent deformation capacity, the use of concrete filled steel tube (CFST) piers is attractive, especially to high-pier and super-high-pier bridges located in mountains. This paper reviews available information concerning the application and development of CFST piers. Three bridge examples are then introduced, while the structural design and the construction methods of CFST column piers are described in detail. Furthermore, main parameters of CFST piers, such as slenderness ratio and material strength are concluded. Finally the future research direction of CFST column piers is viewed.

scholarly journals Confined Expansion and Bond Property of Micro-Expansive Concrete- Filled Steel Tube Columns

2011 ◽  
Vol 5 (1) ◽  
pp. 173-178 ◽  
Author(s):  
Xu Kai-Cheng ◽  
Chen Meng-Cheng ◽  
Yuan Fang
Keyword(s):  
Bond Strength ◽  
Composite Structures ◽  
Steel Tube ◽  
Concrete Core ◽  
Conventional Concrete ◽  
Obvious Effect ◽  
Concrete Filled Steel Tube ◽  
Swelling Agent ◽  
Short Columns ◽  
Core Concrete

The shrinkage/expansion behavior and bond carrying capacities were investigated through 4 micro-expensive concrete-filled steel tube(MCFST) and 3 conventional concrete-filled steel tube(CFST) short columns. The results show that the temperature field in MCFST is similar to that of ordinary concrete members. Concrete core has obvious effect on shrinkage-compensating with the addition of swelling agent. Pre-stress is produced in the core concrete when it is confined by the steel tube. Both water cement ratio and expansive agent have obvious influence on expansive behaviors of MCFST. The tests also indicate that the pre-stress in core concrete can improve bond strength of core concrete and steel tube of MCFST columns and proposed a new method to improve the interface bond strength of composite structures.

Three Types of Stress-Strain Relationship’s Comparison of Circular Tubed Reinforced Concrete in FEA

2012 ◽  
Vol 204-208 ◽  
pp. 930-933
Author(s):  
Xiao Hu ◽  
Zhen Lin Chen
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Uniaxial Stress ◽  
Steel Tube ◽  
Finite Element Analyses ◽  
Stress Strain ◽  
Concrete Filled Steel Tube ◽  
Bearing Analysis

The paper introduces 3 types of uniaxial stress-strain relationships of concrete filled steel tube by Pan Youguang, Susantha and Saenz, and performs finite element analyses of the axial strengths of 18 CTRC columns, studies the characters of three models, and comprises between the axial strengths from FEA and existed experiments. Results show these 3 types of model are all suitable for bearing analysis, but Pan’s model is more accurate.

scholarly journals Artificial Neural Network-Based Method for Seismic Analysis of Concrete-Filled Steel Tube Arch Bridges

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhen Liu ◽  
Shibo Zhang
Keyword(s):  
Neural Network ◽  
Finite Element Method ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Seismic Analysis ◽  
Steel Tube ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cfst Arch Bridge ◽  
Artificial Neural

Seismic analysis of concrete-filled steel tube (CFST) arch bridge based on finite element method is a time-consuming work. Especially when uncertainty of material and structural parameters are involved, the computational requirements may exceed the computational power of high performance computers. In this paper, a seismic analysis method of CFST arch bridge based on artificial neural network is presented. The ANN is trained by these seismic damage and corresponding sample parameters based on finite element analysis. In order to obtain more efficient training samples, a uniform design method is used to select sample parameters. By comparing the damage probabilities under different seismic intensities, it is found that the damage probabilities of the neural network method and the finite element method are basically the same. The method based on ANN can save a lot of computing time.

scholarly journals Evaluation of Damage Indices for Rectangular Concrete-filled Steel Tube Structures

2019 ◽  
Vol 19 (4) ◽  
pp. 170-184
Author(s):  
Minsheng Guan ◽  
Siying Lin ◽  
Hongbiao Du ◽  
Jie Cui ◽  
Taizhou Yan
Keyword(s):  
Comprehensive Evaluation ◽  
Selection Process ◽  
Slenderness Ratio ◽  
Damage Index ◽  
Steel Tube ◽  
Stiffness Ratio ◽  
Concrete Filled Steel Tube ◽  
Damage Indices ◽  
Drift Ratio ◽  
Secant Stiffness

Abstract The paper aims to select a simple and effective damage index for estimating the extent of damage of rectangular concrete-filled steel tube (RCFT) structures subjected to ground motions. Two experimental databases of cyclic tests conducted on RCFT columns and frames are compiled. Test results from the database are then used to evaluate six different damage indices, including the ductility ratio (μ), drift ratio, initial-to-secant stiffness ratio (DKJ), modified initial-to-secant stiffness ratio (Dms), energy coefficient (E), and the combined damage index (DPA) as a benchmark indicator. Selection criteria including correlation, efficiency, and proficiency are utilized in the selection process. The optimal alternative for DPA is identified on the basis of a comprehensive evaluation. The evaluations indicate that Dms previously proposed by some of the authors is the most appropriate substitution of DPA, followed by the drift ratio. For the case of the slenderness ratio less than or equal to 30, the same grades of relation between the investigated damage indices and the benchmark are observed. However, in the case of the slenderness ratio larger than 30, the drift ratio tends to be the optimal alternative. In most cases, μ is proved to be an inadequate replacement of DPA.

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