Behaviour and design of eccentrically loaded CFST columns with high strength materials and slender sections

2022 ◽  
Vol 188 ◽  
pp. 107004
Author(s):  
Tan-Trac Nguyen ◽  
Huu-Tai Thai ◽  
Dongxu Li ◽  
Jia Wang ◽  
Brian Uy ◽  
...  
Keyword(s):  
High Strength ◽  
Cfst Columns

scholarly journals Axial Compression Behavior of Circular Concrete-Filled High-Strength Thin-Walled Steel Tubular Columns with Out-of-Code D/t Ratios

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jun-Xin Li ◽  
Jian-Tao Wang ◽  
Qing Sun ◽  
Yan-Ru Wu ◽  
Shi-Ming Zhou ◽  
...  
Keyword(s):  
Axial Compression ◽  
Full Range ◽  
High Strength ◽  
Displacement Curve ◽  
Fe Model ◽  
Range Analysis ◽  
Cross Sectional ◽  
Compression Behavior ◽  
Thin Walled ◽  
Cfst Columns

This paper systematically investigated the axial compression behavior of circular concrete-filled high-strength thin-walled steel tubular (CFHTST) columns with out-of-code diameter-to-thickness (D/t) ratios. The axial compression test was first conducted to examine the failure mode, load-displacement curves, and composite mechanism effect. The finite element (FE) model was thereafter established to perform full-range analysis on the load versus displacement curve as well as the interaction behavior, where the parametric study was performed to investigate the influences of the material strengths and geometric sizes. Subsequently, the applicability of typical design methods was evaluated, and a revised equation for determining strain εscy corresponding to ultimate strength was established to assess the plastic deformation capacity of CFHTST columns. Finally, a theoretical model for calculating axial bearing capacity was derived based on unified twin-shear strength theory by considering the influence of intermediate principal stress. The research results indicate that a relatively high confine effect can be guaranteed for CFHTST columns under out-of-code D/t ratios, given that the ratio Nu/Nnom between the measured capacity (Nu) and nominal cross-sectional capacity (Nnom) mainly distributes within 1.179∼1.292; the full-range analysis reflects that the axial load-deformation curve can be distinguished by four various loading stages; the scope b = 0.3∼0.55 of intermediate stress coefficient is generally suggested for predicting axial strength of circular CFST columns within an error of ±5%. The abovementioned study can provide the meaningful design reference for the analysis and application of CFHTST columns.

scholarly journals Investigation of the effect of impact load on concrete-filled steel tube columns under fire

2020 ◽  
Vol 14 (54) ◽  
pp. 317-324
Author(s):  
Ali Golsoorat Pahlaviani ◽  
Ali Mohammad Rousta ◽  
Peyman Beiranvand
Keyword(s):  
Impact Load ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Lateral Impact ◽  
Concrete Filled Steel Tube ◽  
Axial Strength ◽  
High Rise ◽  
Working Space ◽  
Cfst Columns

Concrete-filled steel tube (CFST) columns are increasingly used in the construction of high-rise buildings which require high strength and large working space especially at lower stories. As compared to reinforced concrete columns, existence of the exterior steel tube not only bears a portion of axial load but also most importantly provides confinement to the infill concrete.with the confinement provided by the steel tube, axial strength of the infill concrete can be largely enhanced.this paper presents the investigation effect of impact load on concrete-filled steel tube columns under fire by numerical simulations using ABAQUS software.the results indicate that the CFST sections with larger confinement factor ξ=1.23 behaved in a very ductile manner under lateral impact. And the sections with smaller confinement factor ξ=0.44  generally behaved in a brittle mechanism.

Behaviour and design of high strength CFST columns with slender sections

2021 ◽  
Vol 182 ◽  
pp. 106645
Author(s):  
Tan-Trac Nguyen ◽  
Huu-Tai Thai ◽  
Tuan Ngo ◽  
Brian Uy ◽  
Dongxu Li
Keyword(s):  
High Strength ◽  
Cfst Columns

scholarly journals Influence of steel tube thickness and concrete strength on the axial capacity of stub CFST columns

2018 ◽  
Author(s):  
Carmen Ibáñez Usach ◽  
David Hernández-Figueirido ◽  
Ana Piquer Vicent
Keyword(s):  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Steel Tube ◽  
Experimental Program ◽  
Ultimate Capacity ◽  
Strength Concrete ◽  
Axial Capacity ◽  
Thin Walled ◽  
Cfst Columns

In order to study the mechanical response of concrete-filled steel tubular (CFST) columns, several experimental and theoretical studies have been conducted in the last years. However, the influence of thin-walled steel tubes on the axial capacity of these composite columns is not completely stablished, especially when it is combined with high-strength concrete as infill. In this paper, the results of an experimental campaign on 9 concrete-filled steel tubular stub columns subjected to concentric load are presented. Different cross-section shapes are considered in this campaign, i.e. circular, square and rectangular. The influence of the steel tube wall thickness is analysed by including in the tests specimens with thin-walled tubes, whose behaviour needs to be studied in depth given the issues arising when working under compression. The experimental program is designed so the analysis of the results permits to drawn consistent conclusions. For each series, the steel tube thickness is the only geometric parameter modified in order to properly study its effect. Besides, two different concrete strengths were considered for the concrete infill, i.e. normal and high- strength concrete, to observe their effect on the ultimate capacity of the columns. During the tests, the specimens are subjected to axial load and the evolution of the axial displacement with the load is registered. The ultimate capacity of each specimen is obtained and an analysis of the steel tube thickness and concrete strength influence is accomplished. Finally, the study of the dependency of the failure mode on these parameters is carried out.

scholarly journals Seismic Behavior of Steel-Fiber-Reinforced High-Strength Concrete Shear Wall with CFST Columns: Experimental Investigation

Fibers ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 75
Author(s):  
Ke Shi ◽  
Mengyue Zhang ◽  
Pengfei Li ◽  
Ru Xue ◽  
Peibo You ◽  
...  
Keyword(s):  
Seismic Behavior ◽  
Steel Fiber ◽  
Shear Walls ◽  
High Strength ◽  
Shear Wall ◽  
Fiber Reinforced ◽  
Composite Shear Wall ◽  
Energy Dissipation Capacity ◽  
Cfst Columns ◽  
Composite Shear

To improve the seismic behavior of shear walls, a new composite shear wall composed of a steel-fiber-reinforced high-strength concrete (SFRHC) web and two square concrete-filled steel tube (CFST) columns, namely a steel-fiber-reinforced concrete shear wall with CFST columns, is proposed in this paper. Therefore, the main purpose of this paper is to present an experimental investigation of the seismic behavior of the SFRHC shear wall with CFST columns. Pseudo-static tests were carried out on seven composite shear walls, and the seismic performance of the shear walls was studied and quantified in terms of the aspects of energy consumption, ductility and stiffness degradation. Furthermore, the experimental results indicated that adding steel fiber can effectively restrain the crack propagation of composite shear walls and further help to improve the ductility and energy dissipation capacity of composite shear walls and delay the degradation of their lateral stiffness and force. Moreover, the seismic behavior of the SFRHC shear wall with CFST columns was obviously superior to that of the conventionally reinforced shear wall, in terms of load-bearing capacity, ductility, stiffness and energy dissipation capacity, because of the confinement effect of the CFST columns on the web. Finally, the preliminary study demonstrated that the composite shear wall has good potential to be used in regions with high seismic risk.

scholarly journals Use of the Gene-Expression Programming Equation and FEM for the High-Strength CFST Columns

2021 ◽  
Vol 11 (21) ◽  
pp. 10468
Author(s):  
Huanjun Jiang ◽  
Ahmed Salih Mohammed ◽  
Reza Andasht Kazeroon ◽  
Payam Sarir
Keyword(s):  
Gene Expression ◽  
Bearing Capacity ◽  
High Strength Concrete ◽  
Gene Expression Programming ◽  
High Strength ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Quick Method ◽  
Strength Concrete ◽  
Cfst Columns

The ultimate strength of composite columns is a significant factor for engineers and, therefore, finding a trustworthy and quick method to predict it with a good accuracy is very important. In the previous studies, the gene expression programming (GEP), as a new methodology, was trained and tested for a number of concrete-filled steel tube (CFST) samples and a GEP-based equation was proposed to estimate the ultimate bearing capacity of the CFST columns. In this study, however, the equation is considered to be validated for its results, and to ensure it is clearly capable of predicting the ultimate bearing capacity of the columns with high-strength concrete. Therefore, 32 samples with high-strength concrete were considered and they were modelled using the finite element method (FEM). The ultimate bearing capacity was obtained by FEM, and was compared with the results achieved from the GEP equation, and both were compared to the respective experimental results. It was evident from the results that the majority of values obtained from GEP were closer to the real experimental data than those obtained from FEM. This demonstrates the accuracy of the predictive equation obtained from GEP for these types of CFST column.

scholarly journals A numerical model with varying passive confinement for circular and elliptical concrete-filled steel tubular columns

2018 ◽  
Author(s):  
Andrés Lapuebla-Ferri ◽  
Cesar Lacuesta ◽  
Manuel L. Romero ◽  
José M. Adam
Keyword(s):  
Numerical Model ◽  
Concrete Strength ◽  
High Strength ◽  
Experimental Tests ◽  
Concrete Core ◽  
Tubular Columns ◽  
Volumetric Deformation ◽  
Cfst Columns ◽  
Plastic Components ◽  
Strength And Ductility

In this work, a non-linear 3D numerical model to study concrete-filled tubular (CFST) columns is presented. The numerical model is capable to consider the passive confinement that occurs in the concrete core of CFST columns, under which an increase in the strength and ductility of the element is expected. Passive confinement is governed by the volumetric deformation of the concrete core and by the increment of concrete strength, so it was necessary to define both aspects in the constitutive model. In the volumetric deformation, the elastic and plastic components were included, the latter by using the Drucker-Prager model. Different values for the angle of dilatancy were defined for normal and high strength concrete. The model was validated by using experimental tests performed on stub columns and eccentrically loaded columns. In addition, different section geometries were tested. According to the results, the model was able to describe the non-uniform confinement that appears in the concrete core of CFST columns. 

scholarly journals Behaviour of Basalt Fiber Reinforced Concrete Filled Mild Steel Tube

2018 ◽  
Vol 7 (4.2) ◽  
pp. 15
Author(s):  
Arunraj A ◽  
Ashwin Kumar J ◽  
Ajith J
Keyword(s):  
Reinforced Concrete ◽  
Testing Machine ◽  
Basalt Fiber ◽  
High Strength ◽  
Steel Tube ◽  
Absorption Capacity ◽  
Fiber Reinforced Concrete ◽  
Uniaxial Compression Test ◽  
Fiber Reinforced ◽  
Cfst Columns

The present study is an attempt to understand the behavior of concrete filled steel tubular column under uniaxial load. A concrete-filled steel tubular (CFST) column is formed by filling a steel tube with concrete. It is well known that concrete- filled steel tubular (CFST) columns are currently being used in the construction of buildings, due to their excellent static and earthquake-resistant properties, such as high strength, high ductility, large energy absorption capacity, bending stiffness etc. The external strengthening of using basalt fiber reinforced concrete material is emerging as a new trend in enhancing the structural performance concrete filled steel tubular members to counteract the drawbacks of the past rehabilitation work. In this project we are going to study about strength of the steel and concrete by doing compression strength, flexural strength, push out and uniaxial compression test. The tests are carried out with the help of universal testing machine. The readings are recorded and graphs are plotted.  

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