Journal articles: 'Concrete-filled steel tubular (CFST) columns'

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Cui, Ying, Meimei Song, Zhan Qu, Shanshan Sun, and Junhai Zhao. "Research on Damage Assessment of Concrete-Filled Steel Tubular Column Subjected to Near-Field Blast Loading." Shock and Vibration 2020 (November 23, 2020): 1–19. http://dx.doi.org/10.1155/2020/8883711.

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Concrete-filled steel tubular (CFST) columns are widely used in engineering structures, and they have many different cross section types. Among these, normal solid sections and concrete-filled double-skin steel tubular sections are often used. Although many studies have been conducted on CFST columns with these two section types, no studies have been conducted on their damage assessment under blast loading. In this study, experimental analysis and a numerical simulation method were integrated to evaluate the responses and assess the damage of two concrete-filled steel tubular (CFST) columns with different cross sections subjected to near-field blast loading. The results showed that for a scaled distance of 0.14 m/kg1/3, plastic bending deformation occurred on the surfaces of the two CFST columns facing the explosive. The antiexplosion performance of the normal solid-section (NSS) CFST column was better than that of the concrete-filled double-skin steel tubular (CFDST) column. The explosion centre was set at the same height as the middle of column, and the distributions of the peak pressure values of the two columns were similar: the peak pressures at the middle points of the columns were the greatest, and the peak pressures at the bottom were higher than those at the top. With the analysis of the duration of the positive pressure, the damage at the middle was the most severe when subjected to blast loading. Using pressure-impulse damage theory and the validated numerical simulations, two pressure-impulse damage evaluation curves for NSS and CFDST columns were established separately by analysing the experimental and simulation data. Finally, based on the two pressure-impulse damage evaluation curves, the two pressure-impulse damage criteria for these two different fixed-end CFST columns were defined based on the deflection of the surfaces facing the explosives. Furthermore, the mathematical formulae for the two different column types were established to generate pressure-impulse diagrams. With the established formulae, the damage of the CFST columns with these two cross section types can be evaluated. Damage to other similar CFST columns with different cross section types due to near-field blast loading can also be evaluated by this method.

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Ci, Junchang, Mizan Ahmed, Viet-Linh Tran, Hong Jia, and Shicai Chen. "Axial compressive behavior of circular concrete-filled double steel tubular short columns." Advances in Structural Engineering 25, no. 2 (October 19, 2021): 259–76. http://dx.doi.org/10.1177/13694332211046345.

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This article investigates the axial compressive performance of concrete-filled double steel tubular (CFDST) short columns composed of circular section loaded concentrically. An experimental program comprised of compression tests on short columns is carried out to examine their structural performance. Axial compression tests on conventional concrete-filled steel tubular (CFST) columns and double-skin concrete-filled steel tubular (DCFST) columns are also performed for comparison purposes. The test parameters include the diameter-to-thickness of the outer and inner steel tubes, concrete strength, and diameter ratio. The test results exhibit that CFDST short columns composed of the circular section have improved structural performance compared to its CFST and DCFST counterparts. A theoretical model is also presented to simulate the test ultimate strengths and load-axial strain relationships of CFDST columns. The existing design models proposed including the codified design specifications are evaluated against the collected test data for predicting the axial compressive strengths of circular CFDST columns. It is seen that the existing codified design models cannot yield their ultimate axial compressive strengths accurately. A practical artificial neural network (ANN) model is proposed to estimate the ultimate load of such columns loaded concentrically.

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Boukhalkhal, Said Hicham, Abd Nacer Touati Ihaddoudène, Luis Filipe Da Costa Neves, and Wafa Madi. "Dynamic behavior of concrete filled steel tubular columns." International Journal of Structural Integrity 10, no. 2 (April 8, 2019): 244–64. http://dx.doi.org/10.1108/ijsi-07-2018-0040.

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Purpose The purpose of this paper is to investigate the static and dynamic inelastic response of rigid and semi-rigid connections of steel structures with concrete-filled steel tube (CFST) columns built in high seismic areas, and to compare it with those with open section columns. Design/methodology/approach CFST columns are frequently used in moment resistant steel frames located in seismic areas due to their inherent advantages, including their ductility, energy absorption capacity as well as their high bearing capacity. The smart combination of steel and concrete makes it possible to benefit from the advantages of both components to the maximum. This research work presents the nonlinear dynamic response of moment resistant steel frames with CFST columns, with rigid or semi-rigid connections, built in high seismic areas, according to the Algerian seismic code RPA 99/2003, European EC8 and American FEMA 356 to show the nonlinear characteristics of this type of structures, and their advantages over steel frames with open section columns. Findings The paper presents the advantages of using CFST columns with rigid and semi-rigid connections on the seismic response of portal steel frames. A high performance level in terms of ductility, plastic hinges distribution and their order of appearance has been obtained. It also shows the low effect of seismic loading on the structural elements with CFST columns compared to structures with open section columns. Originality/value The investigation of the numerical results has shown the possibility of their use in the seismic areas for their adequate performance, and also with respect to the design limits specified in the seismic guidelines. In addition, this study represents a first step to develop seismic performance factors for steel structures with CFST columns in Algeria, where the Algerian code do not include a comprehensive specification for the composite steel structures.

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Bhatia, Sakshi, and Aditya Kumar Tiwary. "Concrete Filled Double Skinned Tubular Columns Subjected to Different Loading Conditions." IOP Conference Series: Earth and Environmental Science 889, no. 1 (November 1, 2021): 012050. http://dx.doi.org/10.1088/1755-1315/889/1/012050.

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Abstract The meteoric growth in light weight structures have opened on doors to many revolutionary concepts and innovations. Studies have manifested that the lowered weight of the structures somehow help to fight the material cost with a better seismic performance. The hollow core structures aimed reducing the structural weight with an improved structural performance as well. The Concrete filled double steel tubes (CFDST) can be taken as amalgamation of Hollow core columns and CFST i.e. single skinned columns. The co-relation of CFST and Hollow core columns gave birth to Concrete filled double skinned tubular columns (CFDST) which can possess the advantages of both the concepts. A sedulous review of concrete filled double skinned columns is being conveyed through this article. The behavior of confined concrete as well as the confining inner and outer steel in the CFDST model and its overall structural behavior is being succinctly reviewed in this article and a simultaneous comparison of CFDST columns to solid concrete/conventional columns is also being carried out where required.

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Yin, Fu Xin, Ji Tao Zhang, and Ping Bo Xu. "Summary of Research on Concrete Filled Steel Tubular (CFST) Columns." Advanced Materials Research 594-597 (November 2012): 891–95. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.891.

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Base on the achievement and research on the concrete filled steel tube (CFST), with 4 aspects: research on fundamental structural behavior, dynamic property, bonding theory of interface and research on the concrete filled square steel tube, summarize the findings about CFST and introduce the 4 stages of development of study of CFST. Point out that the research on the bond theory of interface between steel tube and core concrete and the concrete filled square steel tube are needed the further study and research.

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Sangeetha, P., and R. Senthil. "Experimental Behaviour of Steel Tubular Columns for Varying in Filled Concrete." Archives of Civil Engineering 63, no. 4 (December 1, 2017): 149–60. http://dx.doi.org/10.1515/ace-2017-0046.

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AbstractThis paper investigates the behaviour of axially-loaded tubular columns filled with M20 grade concrete and partially replaced concrete. The parameters varying in the study are slenderness ratio (13.27, 16.58 & 19.9), and normal M20 grade concrete, partially replaced quarry dust and concrete debris. The effects of the various concrete mixes and composite action between the steel tube and the concrete core are studied and a graph visualizing the differences between the load carrying capacity and the axial deflection is plotted. Some of the performance indices like the Ductility Index (DI), Concrete Contribution Ratio (CCR), Confinement Index (θ) and Strength Index (SI) are also evaluated and compared amongst the CFST columns. From the results it has been noted that an increase in the L/D ratio decrease the behaviour of the composite columns irrespective of the in filled materials. The composite action was achieved in the CFST columns filled with partially replaced quarry dust and concrete debris when compared with hollow steel columns. The load carrying capacity of the CFST column increases by 32 % compared with the hollow tubular columns.

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Liao, Fei Yu, and Yong Jin Li. "Experimental Behaviour of Concrete Filled Steel Tubes (CFST) with Initial Concrete Imperfection Subjected to Eccentric Compression." Applied Mechanics and Materials 174-177 (May 2012): 35–38. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.35.

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Gap between steel tube and concrete core could be recognized as a type of initial concrete imperfection in concrete-filled steel tubular (CFST) members. This paper is an attempt to study the effect of gap on the behaviour of concrete-filled steel tubular (CFST) columns subjected to eccentric compression. A total 14 specimens were tested and the main parameters were the gap type (circumferential gap and spherical-cap) and gap ratio. The influence of gap on the failure mode and ultimate strength of CFST columns were experimentally examined.

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Simon, Ms Sandra Mariam, and Ms Anju Thulasi. "Non Linear Analysis on CFDST columns with and without GFRP Wrapping." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 612–16. http://dx.doi.org/10.22214/ijraset.2022.45379.

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Abstract: Concrete Filled Double Skin Steel Tube (CFDST) columns are modified form of Concrete Filled Steel Tubular (CFST) columns, developed by several researchers. CFDST column composed of two concentric steel tubes in which concrete is packed in between them. It is available in various geometrical shapes. CFDST have many advantages such as high strength, high bending stiffness, good seismic and fire performance. But it is found that CFDST columns have some disadvantages including ageing of structures, corrosion of steel tubes etc. which reduces the strength of the column. So, to prevent these drawbacks and to strengthen the structure, Glass Fiber Reinforced Polymer (GFRP) can be used as an external cover. The present study aims to do nonlinear static analysis of CFDST columns having different hollow ratio wrapped with and without GFRP under axial compression using ANSYS finite element analysis software.

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Anupama, P. N., Mathew Anu, and Kavya K. Kumar. "Numerical Analysis of Through-Beam Connection between CFST Column and RC Beam." Applied Mechanics and Materials 857 (November 2016): 159–64. http://dx.doi.org/10.4028/www.scientific.net/amm.857.159.

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The concrete filled steel tubular (CFST) columns consist of steel tube in-filled with concrete. The connections are the most important components of a CFST column and reinforced concrete beam structural system, since it combines the beams and the columns. In this paper, a through-beam ring connection for strengthening the joint between CFST column and RC beam is modeled using the finite element software package ANSYS and analysed the axial compressive behavior of the connection system. The numerical model is validated with the results available in the literature to confirm the structural efficiency of the ring beam connection system.

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A, Arunraj, Ashwin Kumar J, and Ajith J. "Behaviour of Basalt Fiber Reinforced Concrete Filled Mild Steel Tube." International Journal of Engineering & Technology 7, no. 4.2 (September 22, 2018): 15. http://dx.doi.org/10.14419/ijet.v7i4.2.19994.

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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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Xiang, Kai, Guo Hui Wang, and Yan Chong Pan. "Review of Fire Performance Experiment of Concrete-Filled Steel Tubular Columns." Applied Mechanics and Materials 638-640 (September 2014): 1397–401. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1397.

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This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

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Manigandan, R., and Manoj Kumar. "Effect of Debonding on Axial Response of Concrete Filled Steel Tubular Columns." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 95–104. http://dx.doi.org/10.38208/acp.v1.479.

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The axial strength and ductility of concrete filled steel tubes is significantly improved due to two major factors namely, firstly due to confining effect provided by steel tube, and secondly due to the synergistic interaction between steel tube and concrete core. Sometimes, the contact between concrete core and steel tube is vanished and debonding between concrete core and steel tube (normal referred as gap) occurs owing to various reasons such as improper compaction, shrinkage in concrete, lack of curing of encased concrete, and due to non-uniform distribution of load at column top. Due to occurrence of gap, the composite action between concrete core and steel tube no longer remains effective the concrete core becomes unconfined in the initial phase of loading, consequently, the axial load carrying capacity of the concrete filled steel tubular (CFST) column decreases. The aim of this paper is to numerically investigate the effect of the gap between concrete core and steel tube on the axial load-deformation response and to Comparisons the predicted column strengths according to the Eurocode-4. In the present study, the gap between square section concrete core and encasing steel tube is considered on all the four sides with the magnitude of gap as 1 mm and 2 mm. Moreover, in order to investigate the effect of the gap on different size of square section CFST columns, keeping the length of column and steel tube thickness as constant 540 mm and 3.8 mm respectively, the side length of square section CFST column has been varied between 140 mm to 200 mm at an interval of 20 mm. The nonlinear finite element analysis of the CFST columns has been performed using the Abaqus where the C3D8R element has been used to discretize the concrete core as well as steel tube and the Drucker-Prager model has been used to simulate plastic behaviour of concrete. It has been observed that the presence of gaps between concrete core and steel tube significantly reduces the axial strength square CFST column.

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Wang, Qing Li, Yuan Che, Yong Bo Shao, and Jun Wu. "Experimental Study on Hysteretic Behavior of the Concrete Filled Circular CFRP-Steel Tubular (C-CFRP-CFST) Beam-Columns." Advanced Materials Research 243-249 (May 2011): 5512–16. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5512.

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Overall 12 specimens were experimentally investigated in this paper to study the hysteretic behaviors of the concrete-filled circular CFRP-steel tubular (C-CFRP-CFST) beam-columns. The test results indicated that CFRP can provide transverse confinement effect and longitudinal strengthening effect for the concrete filled circular steel tubular (C-CFST) beam-columns effectively and the local buckling of the steel tube is deferred. With the increase of the strengthening factor of the longitudinal CFRP, the damage scale reduces.

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Phan, Hao Dinh. "Numerical analysis of seismic behavior of square concrete filled steel tubular columns." Journal of Science and Technology in Civil Engineering (STCE) - NUCE 15, no. 2 (April 27, 2021): 127–40. http://dx.doi.org/10.31814/stce.nuce2021-15(2)-11.

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This paper presents a numerical analysis of the seismic behavior of square concrete filled steel tubular (CFST) columns. Finite element analysis (FEA) models in ABAQUS software were used to simulate a series of columns subjected to axial compression and cyclic lateral loading. The CFST columns were simulated using nonlinear tri-dimensional (3-D) finite elements for the infilled concrete, and nonlinear two-dimensional (2-D) finite elements for the steel tube. The feasibility of the FEA model has been validated by published experimental results. The validated FEA model was further extended to conduct parametric studies with various parameters including axial load level (n), width-to-thickness ratio of steel tube (B/t), and concrete strength. The numerical analysis results reveal that with the same B/t and constitute materials, the higher the axial compression, the lower the shear strength and deformation capacity were. The thicker steel wall (B/t = 21) resulted in higher strength and larger deformation capacity of the column. Increasing concrete strength helped to significantly develop the column’s shear strength in all cases. Meanwhile, it just led to an increase in deformation capacity in some cases depending on n and B/t. This study also reveals that the square CFST columns with B/t of 21 satisfy the seismic performance demand in high seismic zones (ultimate interstory drift ratio (IDRu) not less than 3% radian) under the two axial load levels, 0.35 and 0.45, but the columns with B/t of 28 satisfy the above demand under just one axial load level of 0.35. Keywords: square concrete filled steel tubular (CFST) columns; finite element analysis (FEA) model; width-to-thickness ratio (B/t); high axial load level; seismic behavior.

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Xu, YouWu, Jian Yao, Feng Hu, Ying Zhou, and Shuai Jiang. "Seismic Behavior of Elliptical Concrete-Filled Steel Tubular Columns under Combined Axial Compression and Cyclic Lateral Loading." Advances in Materials Science and Engineering 2021 (December 31, 2021): 1–14. http://dx.doi.org/10.1155/2021/5892788.

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Elliptical concrete-filled steel tubular (CFST) column is a new form of CFST columns, consisting of an outer elliptical tube filled with concrete. Although the study on mechanical performance of the elliptical CFST members is receiving more and more attention, they have been limited to static behavior. Against this background, an experimental study on elliptical CFST columns was carried out under combined axial compression and cyclic lateral loading. The failure modes, hysteretic curves, skeleton curves, load carrying capacity, deformability, stiffness degradation, and energy dissipation ability was obtained and discussed. The test results indicated that the elliptical CFST columns possess excellent seismic performance and ductility. Valuable experimental data were provided for the formulation of the theoretical hysteresis model of the elliptical CFST columns.

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PATEL, VIPULKUMAR ISHVARBHAI, QING QUAN LIANG, and MUHAMMAD N. S. HADI. "NUMERICAL ANALYSIS OF CIRCULAR CONCRETE-FILLED STEEL TUBULAR SLENDER BEAM-COLUMNS WITH PRELOAD EFFECTS." International Journal of Structural Stability and Dynamics 13, no. 03 (April 2013): 1250065. http://dx.doi.org/10.1142/s0219455412500654.

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This paper presents a new numerical model for the nonlinear analysis of circular concrete-filled steel tubular (CFST) slender beam-columns with preload effects, in which the initial geometric imperfections, deflections caused by preloads, concrete confinement and second order effects are incorporated. Computational algorithms are developed to solve the nonlinear equilibrium equations. Comparative studies are undertaken to validate the accuracy of computational algorithms developed. Also included is a parametric study for examining the effects of the preloads, column slenderness, diameter-to-thickness ratio, loading eccentricity, steel yield stress and concrete confinement on the behavior of circular CFST slender beam-columns under eccentric loadings. The numerical model is demonstrated to be capable of predicting accurately the behavior of circular CFST slender beam-columns with preloads. The preloads on the steel tubes can affect significantly the behavior of CFST slender beam-columns and must be taken into account in the design.

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Abraham, Er Nimmy, Er Gopika Moorthy, and Er Prashanth Krishnan. "Seismic Analysis of Concrete Filled Steel Tubular Column and H Steel Beam of Normal and Reduced Beam Sections." International Journal of Engineering Research in Mechanical and Civil Engineering (IJERMCE) 9, no. 6 (June 24, 2022): 37–40. http://dx.doi.org/10.36647/ijermce/09.06.a007.

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A beam-column junction is a structural member that is subjected to transverse bending and axial compression at the same time. H Steel beams are beams that are composed of an H-steel core within a precast concrete beam. Advantage of H steel beam is its high bearing capacity compared to RC columns. Concrete Filled Steel Tubular (CFST) structure consists of hollow steel tube filled with plain or reinforced concrete. They are lighter than RC columns and are safer and dependable in seismic regions. The study is to find the seismic analysis of developed joints between H steel beam and CFST column under cyclic loading and to compare the behavior of those joints of CFST tubes with normal and Reduced Beam Section beams (RBS). The result aims to show a significant seismic behavior in RBS section than the normal beam section in terms of load- displacement hysteresis curve.

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Cakiroglu, Celal, Kamrul Islam, Gebrail Bekdaş, and Muntasir Billah. "CO2 Emission and Cost Optimization of Concrete-Filled Steel Tubular (CFST) Columns Using Metaheuristic Algorithms." Sustainability 13, no. 14 (July 20, 2021): 8092. http://dx.doi.org/10.3390/su13148092.

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Concrete-filled steel tubular columns have garnered wide interest among researchers due to their favorable structural characteristics. To attain the best possible performance from concrete-filled steel tubular columns while reducing the cost, the use of optimization algorithms is indispensable. In this regard, metaheuristic algorithms are finding increasing application in structural engineering due to their high efficiency. Various equations that predict the ultimate axial load-carrying capacity (Nu) of concrete-filled steel tubular columns are available in design codes as well as in the research literature. However, most of these equations are only applicable within certain parameter ranges. To overcome this limitation, the present study adopts a recently developed set of equations for the prediction of Nu that have broader ranges of applicability. Furthermore, a newly developed metaheuristic algorithm, called the social spider algorithm, is introduced and applied in optimizing the cross-section of circular concrete-filled steel tubular columns. The improvement of the structural dimensioning under the Nu constraint is demonstrated. The objective underlying the optimization presented here is to minimize the CO2 emission and cost associated with the fabrication of concrete-filled steel tubular stub columns. In this context, the relationships between the cross-sectional dimensioning of circular concrete-filled steel tubular columns and the associated CO2 emissions and cost are characterized and visualized.

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Li, Biao, Faxing Ding, Yujie Yu, Jingke Zhang, Qiong Huang, Chenjie Gong, and Haibo Wang. "Research on Confinement Effect of the Outer Steel Tube in Notched Square CFST Columns." Materials 15, no. 15 (July 25, 2022): 5161. http://dx.doi.org/10.3390/ma15155161.

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The outer steel tube in a concrete-filled steel tubular (CFST) column confines the core concrete and improves the compressive strength of the core concrete. When there is a notch damage in the tube, the confinement effect may be affected. The confinement effects of the notched steel tube in rectangular CFST columns were systematically investigated by using numerical approaches. Refined three-dimensional finite element models with advanced concrete constitutive relations were established. With the verified finite element modeling method, full-sized square CFST columns with horizontal, vertical, or diagonal notches at different locations of the steel tube were simulated. Stress distributions and deformation modes of the steel tube and core concrete were analyzed. Columns with a horizontal notch at the plate center location displayed a higher axial strength reduction than those with vertical notches. A parametric study was performed to investigate the influences of concrete strengths, steel strengths, steel ratios, notch length to column width ratios, and notch angles on the compressive strengths of the rectangular CFST columns. A practical design formula was proposed based on the obtained results. The proposed formula could effectively predict the influences of different notches on the confinement effect in the notched CFST columns.

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Achuthan, Preetha, Ganapathy Ganesh Prabhu, George Gabriel Vimal Arokiaraj, Panneerselvam Arul Sivanantham, and Subramanian Suthagar. "Axial Compression Performance of Concrete-Filled Steel Tubular Columns with Different D/t Ratios." Advances in Materials Science and Engineering 2022 (July 12, 2022): 1–13. http://dx.doi.org/10.1155/2022/9170525.

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The impacts of three diameter/thickness (D/t) ratios (21.22, 25.46, and 31.83) and concrete strengths (40 N/mm2, 50 N/mm2, and 60 N/mm2) on the strength capabilities of concrete-filled steel tubular (CFST) columns are investigated in this study. The central composite design (CCD) of the response surface methodology (RSM) was used to design the trials in order to complete the tests in a cost-effective manner. 13 (9 distinct tests) columns were evaluated according to the CCD experimental design, and the failure mode of the specimens, load–deformation behavior, and ultimate strength capacity were investigated. Concrete strength improves, resulting in a decrease in steel tube confinement on the core. Because the steel tube longitudinal compressive stress (fsl) increases as the D/t ratio lowers, the confinement is reduced by inhibiting the circumferential tensile stress (fsc). The Reynolds stress model’s, analysis of variance (ANOVA), Pareto chart, and contour plot demonstrated that the column D/t ratio, rather than the in-filled concrete strength, has a considerable impact on the CFST column’s strength capability. The proposed design models in different international codes and literature were evaluated for their effectiveness in predicting the strength capacities of CFST columns subjected to axial compression load. Using regression analysis, a simple design model was suggested to predict the axial strength capacities of CFST short columns, taking into account material strength and column shape. In comparison to other existing and suggested design models, the proposed design model of the present study delivers a more accurate and stable forecast.

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Huang, Youqin, Jiyang Fu, Di Wu, Airong Liu, Wei Gao, and Yonglin Pi. "Dynamic Stability of Slender Concrete-Filled Steel Tubular Columns with General Supports." International Journal of Structural Stability and Dynamics 19, no. 04 (April 2019): 1950045. http://dx.doi.org/10.1142/s0219455419500457.

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The static stability of slender concrete-filled steel tubular (CFST) columns has been explored thoroughly while few researches have been carried out on the dynamic stability of CFST columns even if all applied loadings are naturally time-dependent. This paper presents an analytical procedure for evaluating the dynamic stability of CFST columns of various composite cross-sections under general boundary conditions. This paper is featured by the following facts: (1) proportional damping is considered in derivation of the governing equations on the lateral parametric vibration of the CFST columns subject to axial excitation; (2) Bolotin’s method is used to determine the boundaries of the regions of dynamic instability for the CFST columns with general supports; (3) the relationship of static and dynamic stability, and the effects of boundary conditions and cross-sectional forms are uncovered. New findings of this investigation are (1) larger amplitude or constant component of excitation make it easier for the dynamic instabilities of the CFST columns to occur, while increasing the constant component of excitation reduces the critical value of frequency ratio for the dynamic instability to occur; (2) the dynamic stability analysis can determine the critical loads for both the static and dynamic instability of CFST columns, and the critical instability load decreases with increasing disturbance on the static load; (3) under the same consumptions of steel and concrete, the square columns have better performance of dynamic stability than the circular columns, but there is no definite conclusion on the effect of hollow size on the dynamic stability of double-skin columns.

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Liu, Lin Lin, Yong Qing Tu, and Ying Hua Ye. "The Constitutive Relationship of Concrete Core in Circular Concrete-Filled Steel Tubular Columns." Advanced Materials Research 163-167 (December 2010): 2063–67. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2063.

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Considering the confining mechanism in circular concrete-filled steel tubular (CFST) columns, a volume-based method for dividing the effectively and ineffectively confined area of concrete core and calculating the value of effectively confined coefficient is presented. The constitutive relationship of concrete core is developed by means of modifying the expressions of effective lateral pressure and the descending stage in Mander’s confined concrete model. Numerical simulation of several circular CFST columns under axial load is carried out in ABAQUS. The comparisons between calculated results and experimental results demonstrate that the suggested concrete constitutive relationship is appropriate for the nonlinear analysis of circular CFST columns.

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Zhang, Fengjie, Junwu Xia, Guo Li, Zhen Guo, Hongfei Chang, and Kejin Wang. "Degradation of Axial Ultimate Load-Bearing Capacity of Circular Thin-Walled Concrete-Filled Steel Tubular Stub Columns after Corrosion." Materials 13, no. 3 (February 10, 2020): 795. http://dx.doi.org/10.3390/ma13030795.

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This work aimed to investigate the effects of steel tube corrosion on the axial ultimate load-bearing capacity (AULC) of circular thin-walled concrete-filled steel tubular (CFST) members. Circular thin-walled CFST stub column specimens were made of steel tubes with various wall-thicknesses. These CFST column specimens were subjected to an accelerated corrosion test, where the steel tubes were corroded to different degrees of corrosion. Then, these CFST specimens with corroded steel tubes experienced an axial static loading test. Results show that the failure patterns of circular thin-walled CFST stub columns with corroded steel tubes are different from those of the counterpart CFST columns with ordinary wall-thickness steel tubes, which is a typical failure mode of shear bulging with slight local outward buckling. The ultimate strength and plastic deformation capacity of the CFST specimens decreased with the increasing degree of steel corrosion. The failure modes of the specimens still belonged to ductile failure because of the confinement of outer steel tube. The degree of steel tube corrosion, diameter-to-thickness ratio, and confinement coefficient had substantial influences on the AULC and the ultimate compressive strength of circular thin-walled CFST stub columns. A simple AULC prediction model for corroded circular thin-walled CFST stub columns was presented through the regression of the experimental data and parameter analysis.

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He, Ran, Xing Ping Shu, and Bo Wang Chen. "Test on Eccentricaly Loaded Four-Tube Concrete-Filled Steel Tubular (CFST) Laced Columns of No Yield Point." Applied Mechanics and Materials 204-208 (October 2012): 4658–63. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.4658.

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In order to study the characteristics about deformation and stress of four-tube concrete-filled steel tubular(CFST) laced columns of no yield point, a test with the parameter of eccentricity on two our-tube concrete-filled steel tubular(CFST) laced columns of no yield point has been finished by means of 500t press. The results of the test shows that the larger the eccentricity, the more obvious the global deformation of laced columns tends to become, and the four-tube CFST laced columns of no yield point under eccentric compression were subjected to overall bending failure and ductile failure with obvious premonition; In the meanwhile, confinement effect of main tubes away from the loading point of laced columns under eccentric compression was inapparent , while confinement effect of the two main tubes close to the loading point begain to play and increase before it was to fail, which made the characteristics about deformation and stress of the the two main tubes close to the loading point similar to the single CFST column under axial compression.

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Bukovská, Pavla, Marcela Karmazínová, and Michal Štrba. "Benefit of Ultra-High Strength Infill in Concrete-Filled Steel Tubular Columns." Key Engineering Materials 898 (August 27, 2021): 93–99. http://dx.doi.org/10.4028/www.scientific.net/kem.898.93.

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Concrete filled steel tubes (CFST) represent a composite building member suitable especially for the construction of columns of a skeleton frame. Filling the steel tube with concrete allows the use of suitable properties of both materials and their interaction. This is very beneficial in a fire exposure, where a circular column has slightly better fire resistance than a square column. In case of an assessment of columns at the ultimate limit state (ULS), a buckling resistance decides. In previous research, it was found that increasing the strength of concrete increases buckling resistance only to a certain extent. The main aim of the article is to show through a theoretical study what benefit the use of ultra-high strength concrete has for buckling resistance of CFST.

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Zhou, Ruoyang, and Xiaoxiong Zha. "Derivation of the unified equation of axial compression of CFST columns." E3S Web of Conferences 143 (2020): 01004. http://dx.doi.org/10.1051/e3sconf/202014301004.

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The steel tube concrete columns with steel reinforcement cages, steel plates and steel tubes has been used in super high-rise buildings, which are called concrete-filled steel tubular (CFST) columns with internal stiffeners. Based on the theory of limit equilibrium, the unified equation for the axial bearing capacity of the CFST columns with internal stiffeners is obtained. The derived equation in this study can provide reference for the future engineering applications.

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Liu, Yanhua, Shiyu Tong, and Qingxin Ren. "Study on Rubberized Concrete-Filled Steel Tubular Stub Columns Under Axial Compression." Science of Advanced Materials 12, no. 9 (September 1, 2020): 1371–80. http://dx.doi.org/10.1166/sam.2020.3821.

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In order to study the behavior of rubberized concrete-filled steel tubular (RuCFST) stub columns, an innovative composite member with steel tube and concrete filled with rubber particles was made. Twenty-four RuCFST stub columns were tested, in which six conventional CFST stub columns were prepared for comparison. The effects of changing rubber particle size (in the range of 1–2 mm and 2–5 mm) and rubber replacement ratio (0%, 10%, 20% replacement of sand) were made to discover the characteristics of the columns. The tested RuCFST stub columns displayed a local buckling similar to the conventional CFST stub columns. The tested results are compared with the predicted results of finite element analysis and the existing codes of CFST. Generally, the agreement between the predictions and results are reasonable.

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Liu, Yang-bing, Ping-ping Cui, and Fang Chen. "On Factors behind the Reasonable Failure Mode of Concrete-Filled Circular Steel Tubular Composite Frame." Advances in Materials Science and Engineering 2021 (December 22, 2021): 1–10. http://dx.doi.org/10.1155/2021/3027640.

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As the most basic structure, the concrete-filled steel tubular (CFST) frame has been widely used in various structures and systems. Compared with conventional reinforced concrete structures and steel structures, CFST structures in strong earthquake showcase more complicated strength and deformation behavior because there are many factors underlying the failure mode. Furthermore, according to the specifications at home and abroad, the corresponding design method to achieve reasonable failure modes for CFST structures has not been clarified. Based on a destructive test on steel beam-CFST plane frames under constant axial load and lateral load, the fiber mode method and solid element model method are adopted to simulate the failure process of the test frames. Based on finite element model simulations and tests, the fiber model method is proposed to carry out the pushover analysis on the CFST frame structures. The factors behind the reasonable failure mode of steel beam-concrete-filled circular steel tubular (CFCST) frame structures are analyzed. Furthermore, the law and influencing factors behind the ratio of flexural capacity of column to beam, the ratio of line stiffness of beam to column, and the ratio of axial compression on the deformation, bearing capacity, and failure modes of the structure are discussed. Some suggestions on the design of reasonable failure mode of steel beam-concrete-filled circular steel tubular (CFCST) frame structures are proposed.

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Hui, Cun, Wan Lin Cao, and Hong Ying Dong. "Nonlinear FEM Simulation of Bottom Strengthened Concrete Filled Circular Steel Tubular Columns." Applied Mechanics and Materials 256-259 (December 2012): 620–23. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.620.

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The structural measures about puting the additional energy dissipation plat at the bottom of the CFST columns where bears more stress, was proposed to improve the seismic energy dissipation performance of concrete filled circular steel tubular (CFST) columns. Selecting the axial compression ratio and height of the energy dissipation plate as parameters, finite element anylsis of 8 circular CFST columns with different structural measure were performed. On the basis of finite element anylasis results, this paper, which obtained load-displacement curves of each finite element model, analyzed and compared the bearing capacity of each model. The results show that: comparing to the ordinary circular CFST columns, the columns with energy dissipation plat show much better performence about bearing capacity and seismic capacity, the height of the energy dissipation has a great effect on bearing capacity but the bearing capacity is inversely proportional to the axial compression ratio.

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30

Ahmed, Ahmed Dalaf, and Esra Mete Güneyisi. "Structural performance of frames with concrete-filled steel tubular columns and steel beams: Finite element approach." Advanced Composites Letters 28 (January 1, 2019): 2633366X1989459. http://dx.doi.org/10.1177/2633366x19894593.

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Composite columns such as concrete-filled steel tube (CFST) were adopted in many building constructions in recent years because of carrying high loading with the ability to resist buckling and small cross-sectional area. The high behavior of the CFST columns is due to the interaction between steel and concrete which called the composite action. This type of composite column without main and tie reinforcements embedded in concrete gives high axial compression strength to resist the external loadings with the economic sectional area. The work presented in this article includes simulation models that tested by other researchers and a parametric study on the performance of frames that connected steel beam by composed columns of circular CFST that subjected to lateral loading. A finite element (FE) approach is adopted to simulate the models by ANSYS software. All models consider the linear and nonlinear material analysis of the concrete and steel. The validity of the developed model was examined by comparing with the experimental data founded in the literature. Different parameters such as the ratio of the axial load, the slenderness ratio of CFST column, the linear stiffness ratio of the beam–column, the steel yield strength of the beam, the steel yield strength of the tube, and concrete strength on the performance of the composite frames were also studied and the load-deformation performance was obtained over the different cases of the study. Analysis results by FE modeling were in good agreement with the experimental results.

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31

Xia, Song, and Ai Min Qin. "Nonlinear Analysis of Eccentrically Loaded Concrete Filled Circular Steel Tubular Columns." Advanced Materials Research 163-167 (December 2010): 392–97. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.392.

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Based on the appropriate numerical constitutive model of concrete filled steel tubes, layered method was applied and fiber model method based on partial sinusoidal shape for concrete filled circular steel tubular (CFST) columns under both concentric and eccentric loading was proposed. Utilizing the relationship between the curvature of the worst section and sinusoidal amplitude, a FORTRAN program was developed and the behavior of CFST columns under concentric loading, eccentric loading of equal end-moment and unequal end-moment were analyzed, showing that the analysis results are in good agreement with the experiment results from references and the fiber model method can reflect the load capacity and deformation of the columns reasonably. Thus the reliability of the present method was validated and this work is the basic for the further researches on the practical expressions of load bearing capacity for the CFST columns under both compression and bending.

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32

Ci, Junchang, Mizan Ahmed, Hong Jia, Shicai Chen, Daxing Zhou, and Liqun Hou. "Experimental and numerical investigations of square concrete-filled double steel tubular stub columns." Advances in Structural Engineering 24, no. 11 (March 22, 2021): 2441–56. http://dx.doi.org/10.1177/13694332211004111.

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In this paper, the structural behavior of concrete-filled double steel tubular (CFDST) stub columns composed of square hollow sections is investigated experimentally and numerically. The experimental program comprises compression tests on short columns loaded concentrically. The test parameters mainly focused on the influences of the width-to-thickness ratios of steel tubes and concrete strength on the axial behavior of CFDST stub columns. Finite element (FE) models are also developed to investigate the influences of a wide range of structural parameters on their axial performance. It is observed that square CFDST columns have improved strength and ductility compared to their CFST and DCFST counterparts. Finally, a calculation formula is proposed to predict their ultimate compressive strengths under the axial compression load.

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Che, Yuan, Qing Li Wang, Yong Bo Shao, and Hai Tao Mu. "Research on Hysteretic Behavior of the Concrete Filled Square CFRP-Steel Tubular (S-CFRP-CFST) Beam-Columns (I): Experimental Study." Advanced Materials Research 163-167 (December 2010): 3580–85. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.3580.

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Overall 12 specimens were experimentally investigated in this paper to study the hysteretic behaviors of the concrete-filled square CFRP-steel tubular (S-CFRP-CFST) beam-columns. The test results indicated that CFRP can provide transverse confinement effect and longitudinal strengthening effect for the concrete filled square steel tubular (S-CFST) beam-columns effectively and the local buckling of the steel tube is deferred. The hysteretic load-deflection curves and the hysteretic moment-curvature curves at the mid-span of all the specimens are generally plump, and it shows these specimens have good hysteretic performance. In the later loading period, the load bearing capacity drops.

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Jayaganesh, S., J. Raja Murugadoss, G. Ganesh Prabhu, and J. Jegan. "Effects of Concentrical Partial (Local) Compression on the Structural Behavior of Concrete Filled Steel Tubular Column." Advances in Materials Science and Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/491038.

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The objective of this present paper is to investigate the structural behavior of square and circular Concrete Filled Steel Tubular (CFST) stub columns subjected to axial partial/local compression. The experimental parameters were local compression area and section type. Among the twelve specimens, six specimens were tested under full compression and the remaining six specimens were tested under local compression. The experimental observation indicated that the failure pattern of the CFST column with partial compression is fairly different from the CFST column subjected to full compression. The confinement provided by the circular section is quite different than the confinement provided by the square section, when the CFST column is subjected to axially local compression. It was found that the elastic modulus (stiffness) and the ultimate bearing capacity of the CFST column decreased with the increase in local compression ratio. The circular and square CFST columns subjected to partial/local compression achieved an ultimate strength of 4.45% and 14.15%, respectively, less than that of the columns subjected to full compression. From the above observation, it can be inferred that the structural performance of the CFST column is significantly influenced by the local area compression ratio and this effect should be taken into account in design models.

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35

Hui, Cun, and Wan Lin Cao. "FEM Analysis of Concrete Filled Square Steel Tubular Columns with Energy Dissipation Plate." Applied Mechanics and Materials 256-259 (December 2012): 666–69. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.666.

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In order to improve the seismic energy dissipation performance of concrete filled square steel tubular (CFST) columns, the structural measure about puting the additional energy dissipation plat at the bottom of the CFST columns where bears more stress, was proposed. Finite element anylsis of 10 CFST columns with different structural measure were performed under the same axial compression, selecting the thickness and height of the energy dissipation plate as parameters. On the basis of finite element anylasis, this paper, which obtained load-displacement curves of each finite element model, analyzed and compared the bearing capacity of each model. The results show that: comparing to the ordinary CFST columns, the columns with energy dissipation plat show better about bearing capacity and seismic performance, the height of the energy dissipation has a significant effect on bearing capacity but the thickness has less impact.

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36

Pan, Yan Chong, Guo Hui Wang, and Kai Xiang. "Overview of Research Progress for Concrete-Filled Steel Tubular Columns after Exposure to Fire." Applied Mechanics and Materials 638-640 (September 2014): 197–201. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.197.

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Fire safety is one of the most important performances index to evaluate building structures. The property of building members after exposure to fire involved with the safety of buildings after fire, and it will be necessary to estimate the post-fire residual strength of the structure in order to decide the appropriate strategy for repair. This paper summarizes the research progress of concrete-filled steel tubular (CFST) columns. Basic mechanical properties of conventional CFST columns after exposure to fire, CFST columns after the whole fire exposure process under sustained axial load, and CFST columns with special forms after exposure to fire are discussed.

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Zhou, Chunli, Wei Chen, Xiaolong Ruan, and Xueying Tang. "Experimental Study on Axial Compression Behavior and Bearing Capacity Analysis of High Titanium Slag CFST Columns." Applied Sciences 9, no. 10 (May 16, 2019): 2021. http://dx.doi.org/10.3390/app9102021.

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In order to study the axial compression behavior of concrete-filled steel tubular (CFST) columns filled with high titanium slag, a total of 32 specimens, including normal CFST columns, half-high titanium slag CFST columns, and full-high titanium slag CFST columns, were used as experimental samples in this study. The axial compression behaviors of high titanium slag CFST columns and normal CFST columns with various parameters such as length–diameter ratio, strength grade of concrete, strength grade of steel tube, steel content ratio, etc., were evaluated and compared through axial compression testing under monotonic static loading. The results showed that the axial compressive behaviors of high titanium slag CFST columns with various length–diameter ratios were not significantly different from those of normal CFST columns, both of which showed good axial compression performance. In addition, the length–diameter ratio limit between short and medium long column was from 3.5 to 4.4. The length–diameter ratio was the main factor influencing the shape of load–deformation curve of CFST columns. The casing hoop coefficient also had a great influence on the bearing capacity of short columns, while the influence on that of middle and long columns was not obvious. In the end, the bearing capacities of all specimens were calculated by bearing capacity formulas in European EC4, American AISC360-10, and Chinese GB50936-2014 standards. The calculated values were in good agreement with the test results.

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Wang, J. F., and Lin Hai Han. "Seismic Behaviour of Semi-Rigid Joints to Concrete Filled Steel Tubular Columns." Key Engineering Materials 400-402 (October 2008): 693–99. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.693.

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This paper discussed the results of experiments on bolted moment connection joints of square or circular concrete filled steel tubular (CFST) columns and H-shaped steel beam using high-strength blind bolts under cyclic loading. The objective of this work was to study the seismic performance of the blind bolted flush endplate connections to CFST columns. The test parameters varied were the column section type and the thickness of the endplate. The feasibility of the proposed beam-column connection is successfully verified by the experiments. The test results showed that under cyclic loading the tested specimens displayed large rotation ductility capacities and could satisfy the request of the structural seismic design. When subjected to cyclic loading, most of failure modes of the tested joints are similar to those under monotonic loading. Moreover, the energy dissipation of the type joints is influenced by the column section type and the thickness of the endplate.

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39

Zhang, Ni, Chenyang Zheng, and Qingwei Sun. "Creep behavior of reinforced concrete-filled steel tubular columns under axial compression." PLOS ONE 16, no. 9 (September 20, 2021): e0255603. http://dx.doi.org/10.1371/journal.pone.0255603.

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The reinforced concrete-filled steel tube (RCFST) column solves several of the problems of the concrete-filled steel tube (CFST) column in practical engineering applications. Moreover, RCFST has a simple joint structure, high bearing capacity, good ductility, and superior fire resistance. From a structural safety perspective, designers prioritize the creep performance of CFST members in structural design. Therefore, the creep behavior of RCFST columns should be thoroughly investigated in practical engineering design. To study the influence of the creep behavior of RCFST columns under axial compression, this work analyzed the mechanical behavior of composite columns based on their mechanical characteristics under axial compression and established a creep formula suitable for RCFST columns under axial compression. A creep analysis program was also developed to obtain the creep strain–time curve, and its correctness was verified by existing tests. On this basis, the effects of the main design parameters, such as the stress level, steel ratio, and reinforcement ratio, on the creep behavior were determined and analyzed. The creep of the tested composite columns increased rapidly in the early stages (28 days) of load action; the growth rate was relatively low after 28 days and tended to stabilize after approximately six months. The stress level had the greatest influence on the creep of RCFST columns under axial compression, followed by the steel ratio. The influence of the reinforcement ratio on the creep behavior was less. The results of this study can provide a reference for engineering practice.

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Niu, Cao, Yong Gang Lu, and Jun Lin Tao. "Numerical Simulation Research for CFST Columns under Blast Load." Advanced Materials Research 838-841 (November 2013): 644–47. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.644.

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The impact of blast load is always taken into consideration in significant pillar bearing component and protective construction. The LS-DYNA software was employed to simulate three typical concrete filled steel tubular (CFST) columns under blast load. The JHC model was used for concrete material and the MAT_PLASTIC_KINEMATIC model which accounted for the strain rate used for steel. Three section concrete-filled steel tube columns are analyzed in different proportion of distance and get the damage form of pillars and displacement of key points. The results show: In proportion to the same distance, the antiknock ability of circular cross section is better than the other two sections. Although in filled concrete damage is serious, but the steel tube columns improve the ductility of the columns. With the increase of proportion of distance, pillar deformation gradually decrease.

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41

Liu, Jing Bo, and Xue Li. "Realization of Strong Column-Weak Beam Failure Mode for Concrete-Filled Square Steel Tubular Frame Structure." Advanced Materials Research 446-449 (January 2012): 424–28. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.424.

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Strong column-weak beam failure mode is considered to be a preferable mode for its large capability to absorb earthquake energy and prevent collapse. However, for composite frames composed of steel-concrete composite beams and concrete-filled steel tubular (CFST) columns, strong column-weak beam design methods are not given in Chinese codes. The column-to-beam strength ratio is one of the most important factors that influence the failure mode of frame structures. Moreover, large axial compression ratio of columns may cut down the actual bending capacity of columns, and thus has an adverse effect upon the realization of strong column-weak beam failure mode. In order to investigate the influence of column-to-beam strength ratio and axial compression ratio on the failure mode of concrete-filled square steel tubular frame structures, pushover analysis of a five-story three-bay composite frames with various column-to-beam strength ratios and axial compression ratios are carried out. Based on the analysis results, suggestions about the reasonable value of column-to-beam strength ratio with different axial compression ratios of columns are given to ensure the realization of strong column-weak beam failure mode for concrete-filled square steel tubular frame structures.

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Li, Wei Wei, and Hui Feng Zhang. "Slenderness Sensitivity Analysis of Thin-Walled Square Steel Tubular Columns Filled with Demolished Concrete Lumps." Advanced Materials Research 1163 (April 2021): 158–73. http://dx.doi.org/10.4028/www.scientific.net/amr.1163.158.

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The demolished concrete lumps (DCLs) have been demonstrated to replacement partial coarse aggregates when casting concrete. However, few studies had focused on the sensitivity of factors affecting mechanical behavior of slender square steel slender columns filled with DCLs and fresh concrete (FC) under axial compression. This research was carried out on the basis of Bo Wu's study. The Orthogonal design method was adopted in this experiment. The experimental studied involved 12 Concrete-Filled Steel Tube (CFST) columns. Each columns diameter was 159mm, the length of specimens was 2000, 2200 and 2400 mm. The Diameter-to-thickness (D/t) ratio was 79, 53 and 40. The replacement ratio of FC by DCLs was 0, 20, 40 and 60%. Test results indicated that the slenderness ratio was the most sensitive factor on the bearing capacity of slender columns under axial compression, followed by D/t ratio, and the DCLs replacement ratio was smallest factor. The ultimate bearing capacity decreased slightly with increasing DCL replacement ratio. The DCLs had slightly affect on the mechanical performances of slender CFST columns. the code CECS 28:2012 was used to calculate the bearing capacity of slender CFST columns filled with DCLs under axial compression.

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43

Yang, Yuanlong, Xinchen Han, Bo Nan, and Xin Tang. "Research on Carrying Capacity of T-Shaped Stiffened Concrete-Filled Steel Tubular Columns Subjected to Eccentrically Compressive Load." Advances in Civil Engineering 2021 (February 19, 2021): 1–20. http://dx.doi.org/10.1155/2021/8867185.

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In this paper, in order to further study the mechanical behavior of T-shaped stiffened concrete-filled steel tubular (CFST) columns, numerical programs of eccentrically compressive T-shaped stiffened CFST columns were developed to calculate moment M-ϕ curvature curves of cross section and column. The calculated curves with the numerical programs agree well with the experimental results. A parametric analysis was carried out to calculate M-N correlation curves of cross section and column to investigate influence of concrete strength fck, steel yielding strength fy, steel tube thickness t, slenderness ratio λ, and loading angle θ. On the basis of parametric analysis, simplified resistance models of T-shaped CFST section and column were proposed and verified by the numerical analysis results. The simplified resistance models are reliable to predict the mechanical behavior for engineering application.

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Liu, Yanhua, Qingxin Ren, and Yuqing Li. "Compression Behavior of CFST Stub Columns with Holes." Advances in Civil Engineering 2020 (December 12, 2020): 1–16. http://dx.doi.org/10.1155/2020/8863480.

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Holes are always opened in the steel tubes during the inspection and revision of initial concrete imperfections in concrete filled steel tubular (CFST) columns. The structural performance of such composite columns with holes may have obvious differences in comparison with normal CFST members. This paper intends to investigate the influences of sectional type, holes location, holes size, and holes depth on CFST stub columns. The typical failure modes, load-deformation responses, the ultimate strength, and ductility were discussed in detail. A total of twenty-eight specimens, twenty CFST columns with holes, four intact CFST specimens, and four reference hollow steel tubes subjected to axial compressive loading, were tested. The experimental results were compared with predictions of Eurocode 4 and finite element analysis. An empirical equation for predicting the ultimate strength of CFST stub columns with holes was proposed.

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45

Zhou, Xiao Yan, Jing Xuan Wang, and Wen Da Wang. "Preliminary Study on Dynamic Progressive Collapse Analysis of Spatial Composite Frames with Concrete-Filled Steel Tubular Columns." Applied Mechanics and Materials 166-169 (May 2012): 164–67. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.164.

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This paper presented a progressive collapse analysis of spatial composite frame with concrete-filled steel tubular (CFST) columns. A typical finite element analysis (FEA) model of a 12-story building was established by using ABAQUS. The shell elements were used to simulate the slab, and all of the steel beams and CFST columns were simulated by the beam elements incorporating nonlinear material and geometric, respectively. Nonlinear dynamic analysis was carried out for the sudden loss of columns for different scenarios of column removal, and the capacity of progressive collapse resistance of the 3-D composite frame and other components internal force around the removed column were investigated.

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46

Merwad, Abdullah M., Alaa A. El-Sisi, Suzan A. A. Mustafa, and Hossam El-Din M. Sallam. "Lateral Impact Response of Rubberized-Fibrous Concrete-Filled Steel Tubular Columns: Experiment and Numerical Study." Buildings 12, no. 10 (September 29, 2022): 1566. http://dx.doi.org/10.3390/buildings12101566.

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This paper presents an experimental and numerical study on the lateral impact behavior of rubberized-fibrous concrete-filled steel tubular (CFST) columns. Four types of concrete were utilized in the experimental program in the infilled columns: normal concrete (NC), rubberized concrete (RuC), steel fiber concrete (SFC), and hybrid RuC-SFC. Twelve specimens were tested using drop-weight impact with fixed-sliding boundary conditions. Three different transverse impact energies were produced by applying two masses of the hammers dropped from two different heights. A high-speed camera was implemented to measure the mid-span deflection against time. A 3-D finite element model was presented and verified against the tested specimens and some other experimental work from the literature. Load-displacement curves, the impact force time history, impact energy absorption, and failure modes of the CFST columns under the lateral impact were fully analyzed. The present results showed that at, certain impact energies, the steel tubular suffered only from the plastic deformation, beyond which it started cracking depending on the type of filled concrete. The steel tubular filled with hybrid RuC-SFC showed the highest resistance to crack formation, followed by that filled with SFC, while those filled with NC showed the lowest resistance to crack formation. There is an agreement between the numerical and the experimental results.

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Qu, Hui, Lin Hai Han, and Zhong Tao. "Seismic Performance of Reinforced Concrete Beam to Concrete-Filled Steel Tubular Columns Joints." Key Engineering Materials 400-402 (October 2008): 685–91. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.685.

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In this paper, eight reinforced concrete (RC) beam to concrete-filled steel tubular (CFST) column joints enclosed by rebars were tested under reversal horizontal displacement with constant axial load in order to study their seismic behavior. The test parameters are axial load level and the section type of CFST column. In this study, the failure model, hysteretic characteristic, ductility and energy dissipation were investigated. The results indicated that the anti-earthquake abilities of all joints satisfied with the demand on the code.

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48

Ren, Qing Xin, Ya Qing Mo, Lian Guang Jia, and Hong Liu. "Experimental Investigation on Rectangular Inclined Concrete-Filled Steel Tubular Stub Columns." Applied Mechanics and Materials 71-78 (July 2011): 826–29. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.826.

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In recent 10 years, inclined concrete-filled steel tubular (CFST) columns are applied for some real engineering projects in China. And so a total of 10 specimens were experimented to study the behaviors of the rectangular inclined CFST stub columns. The main parameters were the inclined angle (0 degree and 9 degree), the inclined orientation (major axis and minor axis) and with or without infilling concrete. Comparisons with predicted sectional strengths were made using the existing codes. The results clearly show that all the codes were conservative and available for predicting the capacities of the specimens.

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YU, MIN, XIAOXIONG ZHA, JIANQIAO YE, and YI Li. "FIRE RESPONSES AND RESISTANCE OF CONCRETE-FILLED STEEL TUBULAR FRAME STRUCTURES." International Journal of Structural Stability and Dynamics 10, no. 02 (June 2010): 253–71. http://dx.doi.org/10.1142/s0219455410003452.

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This paper presents the results of dynamic responses and fire resistance of concrete-filled steel tubular (CFST) frame structures in fire conditions by using the nonlinear finite element method. Both strength and stability criteria are considered in the collapse analysis. The frame structures are constructed with circular CFST columns and steel beams of I-sections. In order to validate the finite element solutions, the numerical results are compared with those from a fire resistance test on CFST columns. The finite element model is then adopted to simulate the behavior of frame structures in fire. The structural responses of the frames, including the critical temperature and fire-resisting limit time, are obtained for the ISO-834 standard fire. Parametric studies are carried out to show their influence on the load capacity of the frame structures in fire. Suggestions and recommendations are presented for possible adoption in future construction and design of similar structures.

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50

Cakiroglu, Celal, Kamrul Islam, and Gebrail Bekdaş. "Optimization of Concrete-Filled Steel Tubular (CFST) Columns Using Meta-Heuristic Algorithms." International Journal of Digital Innovation in the Built Environment 10, no. 2 (July 2021): 63–74. http://dx.doi.org/10.4018/ijdibe.2021070105.

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Concrete-filled steel tubular (CFST) columns are an extensively studied area due to the favorable structural characteristics of these members. In order obtain the best possible performance from these structures while reducing the cost the use of optimization algorithms is indispensable. For this reason, meta-heuristic algorithms are finding increasing application in engineering due to their high efficiency. Various equations that predict the axial ultimate load-carrying capacity (Nu) of CFST columns are available in design codes as well as the research literature. However, most of these equations are only applicable within certain parameter ranges. A recently developed set of equations that have better parameter ranges of applicability was applied in this study. Furthermore, a newly developed meta-heuristic algorithm called social spider algorithm is applied to the cross-section optimization of circular CFST columns. The improvement of the structural dimensioning under Nu constraint was demonstrated.

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Journal articles on the topic 'Concrete-filled steel tubular (CFST) columns'

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