Academic literature on the topic 'CFST columns'
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Journal articles on the topic "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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Wang, Xiao Lu, and Xiao Xiong Zha. "Experimental Research on Concrete-Filled GFRP Tubes and GFRP-Steel Composite Tubes under Axial Compressive Load." Advanced Materials Research 163-167 (December 2010): 2052–55. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2052.
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Axial compression experiments of eighteen concrete-filled GFRP tube (CFFT) and concrete-filled GFRP reinforced steel tube (CFFST) specimens in total have been carried out to study their mechanical behaviors. Experimental results show that, GFRP tubes with different filament-wound angles could enhance the strength and ductility of core concrete at different levels. Fibers with hoop directions provide the best confinement and enhance the ultimate strength up to 266% comparing with unconfined concrete columns. Fibers with ±45° winding angles have minor effects on bearing capacity, but greatly improve the ductility of concrete columns. Compared with CFST columns, GFRP reinforced CFST columns with hoop direction fibers increase the bearing capacity of 35.0%, and the fibers along 45° winding angles could enhance by 17.5%. The mechanical behavior and the failure modes of the six experimental group specimens are also discussed in this paper.
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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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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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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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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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Sarir, Payam, Huanjun Jiang, Panagiotis G. Asteris, Antonio Formisano, and Danial Jahed Armaghani. "Iterative Finite Element Analysis of Concrete-Filled Steel Tube Columns Subjected to Axial Compression." Buildings 12, no. 12 (November 25, 2022): 2071. http://dx.doi.org/10.3390/buildings12122071.
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Since laboratory tests are usually costly, simulating methods using computers are always under the spotlight. This study performed a finite element analysis (FEA) using iterative solutions for simulating circular and square concrete-filled steel tube (CFST) columns infilled with high-strength concrete and reinforced with a cross-shaped plate (comprising two plates along the columns that divide the hollow columns into four equal sections) with and without opening. For this reason and for validation purposes, the columns had length of 900 mm, width/diameter of 150 mm and wall thickness of 3 mm. In this study, unlike in some other studies, the cross-shaped plate was assumed to be fixed at the top and the bottom of a column, and the columns were subjected to axial compression pointed in the center. The outcomes revealed that the cross-shaped plate could improve the axial strength of both circular and square CFST columns; however, the structural performance of the square CFST columns changed: local outward buckling was observed after inserting the cross-shaped plate. By inserting an opening on the cross-shaped plate, the bearing capacity of the circular CFST columns was further improved, while the square CFST columns experienced a decline in their ultimate bearing capacity compared with the corresponding models without the opening. The lateral deflection also improved for the circular CFST columns by adding the reinforcement. However, for the square CFST columns, while it initially improved, increasing the thickness of the cross-shaped plate inversely influenced the lateral deflection of the square CFST columns. The results were also compared with some available codes, and a good agreement was achieved with those outcomes.
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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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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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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.
Dissertations / Theses on the topic "CFST columns"
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Abd, El Fattah Ahmed Mohsen. "Behavior of concrete columns under various confinement effects." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/13533.
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Doctor of PhilosophyDepartment of Civil Engineering
Hayder Rasheed
The analysis of concrete columns using unconfined concrete models is a well established practice. On the other hand, prediction of the actual ultimate capacity of confined concrete columns requires specialized nonlinear analysis. Modern codes and standards are introducing the need to perform extreme event analysis. There has been a number of studies that focused on the analysis and testing of concentric columns or cylinders. This case has the highest confinement utilization since the entire section is under confined compression. On the other hand, the augmentation of compressive strength and ductility due to full axial confinement is not applicable to pure bending and combined bending and axial load cases simply because the area of effective confined concrete in compression is reduced. The higher eccentricity causes smaller confined concrete region in compression yielding smaller increase in strength and ductility of concrete. Accordingly, the ultimate confined strength is gradually reduced from the fully confined value fcc (at zero eccentricity) to the unconfined value f’c (at infinite eccentricity) as a function of the compression area to total area ratio. The higher the eccentricity the smaller the confined concrete compression zone. This paradigm is used to implement adaptive eccentric model utilizing the well known Mander Model and Lam and Teng Model. Generalization of the moment of area approach is utilized based on proportional loading, finite layer procedure and the secant stiffness approach, in an iterative incremental numerical model to achieve equilibrium points of P- and M- response up to failure. This numerical analysis is adaptod to asses the confining effect in circular cross sectional columns confined with FRP and conventional lateral steel together; concrete filled steel tube (CFST) circular columns and rectangular columns confined with conventional lateral steel. This model is validated against experimental data found in literature. The comparison shows good correlation. Finally computer software is developed based on the non-linear numerical analysis. The software is equipped with an elegant graphics interface that assimilates input data, detail drawings, capacity diagrams and demand point mapping in a single sheet. Options for preliminary design, section and reinforcement selection are seamlessly integrated as well. The software generates 2D interaction diagrams for circular columns, 3D failure surface for rectangular columns and allows the user to determine the 2D interaction diagrams for any angle between the x-axis and the resultant moment. Improvements to KDOT Bridge Design Manual using this software with reference to AASHTO LRFD are made. This study is limited to stub columns.
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Alam, Md Iftekharul. "Behaviour of FRP strengthened steel tubular members subjected to transverse impact loading." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/105782/1/Md%20Iftekharul_Alam_Thesis.pdf.
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This PhD thesis is devoted to contributing to the existing knowledge of FRP (Fibre Reinforced Polymer) strengthened metallic structural members subjected to dynamic impacts. The outcome of this research will be beneficial to design structures for mitigating damage and failure due to lateral impact forces from transportation accidents, explosive attacks or from flying debris. A new series of laboratory tests results along with computer based structural analyses are presented to understand the effectiveness of FRP strengthening of tubular structural members. FRP strengthening found to be a promising sustainable option for minimising structural damage and human casualty due to impact loads.
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Ahmed, Asmaa Abdeldaim Ibrahim. "Behaviour of reinforced CFFT columns under axial compression loading." Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8759.
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Abstract : The construction industry is expressing great demand for innovative and durable structural members such as bridge decks and piers, piling, and poles. Many steel-reinforced concrete structures subjected to de-icing salts and marine environments require extensive and expensive maintenance. Fiber-reinforced polymers (FRPs) have recently gained wide acceptance as a viable construction material for repair, rehabilitation, or new construction of the aging infrastructures particularly those exposed to harsh environment conditions. The promising concept of concrete-filled FRP tube (CFFT) system, that may be further reinforced with steel or FRP bars, has raised great interest amongst researchers in the last decade. The CFFT technique has been used successfully in different concrete structure elements such as pier column and girder for bridges and also as fender piles in marine structures. The FRP tube acts as a stay-in-place structural formwork, a noncorrosive reinforcement for the concrete for flexure and shear, provides confinement to the concrete in compression, and the contained concrete is protected from intrusion of moisture with corrosive agents that could otherwise deteriorate the concrete core. Using FRP bars instead of conventional steel bars in the CFFT columns can provide a step forward to develop a promising totally corrosion-free new structural system. Nonetheless, the axial behaviour of FRP bars as longitudinal reinforcement in compression members has yet to be explored, especially for the CFFT columns. To date, most of the experimental investigations performed on FRP confined concrete columns have considered short, unreinforced, small-scale concrete cylinders, tested under concentric, monotonic, and axial load. The slenderness ratio, internal longitudinal reinforcement type (steel or FRP bars), and axial cyclic loading effects on the behaviour of FRP confined concrete long columns, however, have received only limited research attention. To address such knowledge gaps, this study aimed at investigating the behaviour of the CFFT long columns internally reinforced with steel or FRP bars tested under monotonic and cyclic axial loading. A total of ten reinforced concrete (RC) and CFFT columns were constructed and tested until failure. All columns had 1900-mm in height and 213-mm in diameter. The investigated parameters were: i) the effect of internal reinforcement type (steel, glass FRP (GFRP), or carbon FRP (CFRP)) and amount, ii) GFRP tube thicknesses, and iii) nature of loading (i.e. monotonic and cyclic). The effect of the different parameters on the axial behaviour of the tested columns is presented and discussed. The research work presented in this dissertation has resulted in one paper submitted to the Elsevier Journal of Engineering Structures (manuscript ID: ENGSTRUCT-D-15-01381) and one accepted conference paper submitted to the 5 th International Structural Specialty Conference (CSCE 2016), London, Ontario, June 1st - 4th, 2016. The experimental test results showed that the CFFT columns reinforced with GFRP bars exhibited similar responses compared to their counterparts reinforced with steel bars with no significant difference in terms of ultimate axial strength and strain capacities. The GFRP tubes provided significant confinement of the tested specimens attributing to shift the mode of failure from axially dominated material failure to flexural-dominated instability failure. The results also indicated that the plastic strains of the FRP-reinforced CFFT columns was linearly proportional to the envelop unloading strains (εun,env). The relationship depended little on level of confinement, but strongly on the longitudinal reinforcement amount and type, particularly when εun,env > 0.0035. On the other hand, an analytical investigation was conducted to examine the validity of the available design provisions for predicting the ultimate load capacity of tested columns. The results of the analysis were compared with the experimental values. It was found that the ACI 440.R1 (2015), CSA S806 (2012), and CSA S6-06 (2010) design provisions provided higher conservative results for the GFRP-reinforced control specimens than that of steel-reinforced specimen. This might be due to neglecting the contribution of the compressive resistance of the GFRP bars to the axial carrying capacity. Furthermore, for FRP-reinforced CFFT columns, the ACI 440.2R (2008), CSA S806 (2012), and CSA S6-06 (2010) provisions results over the experimental results were an average of 1.68±0.31, 1.57±0.18, and 1.72±0.35 with a COV of 18.4%, 11.3%, and 20.5%, respectively. By considering the confinement codes limits, the CSA S806 (2012) showed better correlation for the ultimate carrying capacity based on the average than the CSA S6-06 (2010) and ACI 440.2R (2008), particularly for specimens cast with tube Type B.Résumé : L'industrie de la construction exprime une grande demande pour les structures innovantes et durables tels que les tabliers de ponts et les quais, les pieux et les poteaux. Plusieurs structures en béton armé sont soumises à des sels de déglaçage et à des environnements marins qui exigent un entretien coûteux. Les polymères renforcés de fibres (PRF) ont récemment été reconnus en tant que matériau de construction viable pour la réparation, la réhabilitation ou la construction de nouvelles infrastructures vieillissantes en particulier celles exposées à des conditions d'environnement sévères. Le concept prometteur du système de tube rempli de béton PRF (CFFT), qui peut être encore renforcé avec de l'acier ou des barres en PRF, a amorcé un grand intérêt parmi les chercheurs durant la dernière décennie. La technique CFFT a été utilisée avec succès dans les différents éléments de structure en béton tels que les colonnes et les poutres de ponts et aussi comme des pieux pour les structures marines. Le tube en PRF agit comme un coffrage structural sur place, un renforcement non corrosif pour le béton en flexion et au cisaillement en utilisant l'orientation des fibres multidirectionnelle, fournit un confinement au béton en compression, et le béton est protégé de toute intrusion d'humidité des agents corrosifs qui, autrement, pourraient détériorer le noyau de béton (ACI 440. R-07 (2007)). L’utilisation des barres de PRF au lieu de barres d'acier conventionnelles dans les colonnes CFFT peut fournir un pas en avant pour développer un nouveau système structurel. Néanmoins, le comportement axial des barres en PRF comme armatures longitudinales dans les membrures en compression n'a pas encore été exploré, en particulier pour les colonnes CFFT. À ce jour, la plupart des études expérimentales effectuées sur les colonnes en béton confinés de PRF, ont considéré des cylindres en béton, courts, à petite échelle non armés, et testés sous un charge concentrique, monotone, et axiale. Le rapport d'élancement, le renfort longitudinal interne (acier ou barres en PRF), et les effets du chargement axial cyclique sur le comportement des colonnes élancées de béton confinés et en PRF, ont connu une recherche limitée. Pour combler ce manque de connaissance, cette étude vise à étudier le comportement des colonnes élancées CFFT armé en acier ou en barres de PRF testées sous charges axiales monotones et cycliques. Un total de dix colonnes en béton armé (RC) et CFFT été fabriquées et testées jusqu'à la rupture. Toutes les colonnes ont 1900 mm de hauteur et 213 mm de diamètre. Les paramètres étudiés sont les suivants: i) l'effet de type de renforcement interne et la quantité de renforcement, ii) les épaisseurs de tubes PRV, et iii) le type de chargement (monotone et cyclique). L'effet des variables considérées sur le comportement axial des colonnes testées dans le travail expérimental est présenté et discuté. Le travail de recherche présenté dans cette analyse a fait l’objet d’un article scientifique soumis à Elsevier Journal of Engineering Structures (manuscrit ID: ENGSTRUCT-D-15-01381) et un article lors d’une conférence acceptée soumis à la 5ième International Structural Specialty Conference (CSCE 2016), London, Ontario, Juin 1er - 4ième, 2016. Les résultats des essais expérimentaux ont montré que les colonnes CFFT renforcées de barres en PRFV présentaient des réponses similaires par rapport à leurs homologues renforcées avec des barres d'acier sans différence significative en termes de capacité ultime de résistance axiale et de déformation. Les tubes en PRFV fournissent un confinement significatif des échantillons testés attribuant à changer le mode de rupture, c’est-à-dire d’une rupture des matériaux axialement à une rupture d’instabilité en flexion. En outre, l'augmentation de l'épaisseur du tube en PRFV de 2,9 à 6,4 mm améliore les rapports de résistance et de déformation de 25 % et 12 %, respectivement. Les résultats indiquent également que les déformations plastiques des colonnes renforcées de PRF sont linéairement proportionnelles aux enveloppes de tension de déchargement (εde,env). La relation dépend un peu du niveau de confinement, mais fortement de la quantité et du type de renfort longitudinal, en particulier lorsque εde,env > 0,0035. D'autre part, une investigation a été menée pour examiner la validité des dispositions de conception disponibles pour prédire la capacité de la charge ultime des colonnes testées. Les résultats de l'analyse ont été comparés avec les valeurs expérimentales. Il a été constaté que les prévisions de l'ACI 440.R1 (2015), CSA S806 (2012), et CSA S6-06 (2010) ont fourni des résultats conservateurs plus élevés pour les échantillons de contrôle en PRFV que celui de l'échantillon d'acier. Cela peut être dû à la négligence de la contribution de la résistance à la compression des barres de PRFV à la capacité de charge axiale. En outre, pour les colonnes de CFFT renforcées de PRF, les prévisions de l'ACI 440.2R (2008), du CSA S806 (2012), et du CSA S6-06 (2010) étaient de 1,68 ± 0,31, 1,57 ± 0,18 et 1,72 ± 0,35 avec un COV de 18,4 %, 11,3%, et 20,5%, respectivement. En considérant les limites des codes de confinement, le code CSA S806 (2012) a révélé les meilleures prévisions pour la capacité de charge ultime basée sur la moyenne que celui du code CSA S6-06 (2010) et de l’ACI 440.2R (2008), en particulier pour les échantillons réalisés avec des tubes de Type B.
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Pons, Aliaga David. "ESTUDIO NUMÉRICO DE LA CAPACIDAD PORTANTE DE COLUMNAS MIXTAS CON DOBLE TUBO RELLENAS DE HORMIGON." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/62209.
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[EN] Concrete-filled steel tubular columns composed of double-tube sections are a recent development. This type of sections are the result of applying a technique used in the construction of immersed tunnels, by forming a sandwich composite section made up of steel-concrete-steel.
Apart from the own advantages of concrete-filled steel tubular (CFST) columns, double-tube columns present other additional advantages which make them of great interest for designers and engineers, such as: reduced weight, higher ductility, improved energy absorption and, above all, an enhanced fire resistance. In turn, the improvements in the manufacturing technique of high strength concrete makes their use in double-tube columns create the suitable synergy for the design of slender structural members.
Nevertheless, the fast evolution and development of composite construction has led to a situation where the current design guidance cannot provide updated analytical expressions and recommendations. Give this situation, and due to the innovative nature of this configuration, as well as the complexity of experimental testing, few experimental and analytical works can be found on this typology of columns.
This makes the numerical investigation of concrete-filled double-tube columns interesting from the scientific point of view.
The mechanical behaviour of concrete-filled double-tube columns is studied in this thesis through a realistic three-dimensional finite element model. The values adopted for the variables of the model are the result of a comprehensive sensitivity analysis. The accuracy of the numerical model is verified against experimental tests and, once the numerical model is validated, an extensive parametric study is developed, with the aim of studying the influence of the main factors which affect the mechanical response of this columns and being able to provide design recommendations. With this information, a comparative study is carried out with the results of the application of the current calculation method for composite columns in Eurocode 4-Part 1.1, in order to evaluate the validity of the method for double-tube columns subjected to axial compression and combined compression and uniaxial bending, infilled with ultra-high strength concrete.
The scope of this thesis is limited to slender circular double-tube columns filled with normal and ultra-high strength concrete subjected to monotonic concentric or eccentric axial load of uniform bending moment.[ES] Las columnas tubulares de acero rellenas de hormigón compuestas de una sección de doble tubo son de reciente creación. Son el resultado de aplicar la técnica utilizada en la construcción de túneles sumergidos, de construir una sección compuesta tipo sándwich, a base de acero-hormigón-acero. Además de las ventajas propias de las columnas tubulares de acero rellenas de hormigón (CFST), las columnas de doble tubo poseen otras ventajas adicionales que las hace muy interesantes para proyectistas e ingenieros como son, por ejemplo: menor peso, mayor ductilidad, mayor absorción de energía, y sobretodo, mejor resistencia a fuego. Por otra parte, la mejora de la técnica de fabricación de hormigones de altas resistencias hace que su utilización en columnas de doble tubo produzca una sinergia idónea para diseñar elementos estructurales esbeltos. Sin embargo, la rápida evolución y desarrollo de la construcción mixta hace que las normas actuales no tengan las expresiones analíticas ni las recomendaciones de diseño actualizadas. Debido a ello y por la relativa solución innovadora de esta configuración, así como la complejidad de realizar ensayos experimentales, existen pocos trabajos experimentales y estudios analíticos acerca de esta tipología de columnas. Es por esto que el estudio numérico de columnas de doble tubo rellenas de hormigón sea, desde el punto de vista científico, interesante. El comportamiento mecánico de columnas de doble tubo rellenas de hormigón se estudia en esta tesis a través de un modelo realista tridimensional de elementos finitos. Los valores adoptados de las variables del modelo son el resultado de un amplio análisis de sensibilidad. La precisión del modelo numérico se verifica con ensayos experimentales y, una vez se dispone de un modelo validado, se desarrolla un extenso estudio paramétrico con el fin de evaluar la influencia de los principales factores que afectan la respuesta mecánica de las mismas y poder establecer recomendaciones de diseño. Con esa información, se realiza una comparativa con los resultados de aplicar el método de cálculo de columnas mixtas del Eurocódigo 4 - Parte 1.1, con el propósito de evaluar la validez del método en columnas de doble tubo comprimidas y flexo-comprimidas rellenas de hormigón de ultra alta resistencia. El alcance de esta tesis queda limitado a columnas circulares esbeltas de doble tubo rellenas de hormigón de resistencia normal y ultra alta resistencia sometidas a carga monotónica centrada y excéntrica de momento uniforme.
[CAT] Les columnes tubulars d'acer emplenades de formigó compostes d'una secció de doble tub són de recent creació. Són el resultat d'aplicar la tècnica utilitzada en la construcció de túnels submergits, de construir una secció composta tipus sandvitx, a base d'acer-formigó-acer. A més dels avantatges propis de les columnes tubulars d'acer emplenades de formigó (CFST), les columnes de doble tub posseeixen altres avantatges addicionals que les fa molt interessants per a enginyers com són, per exemple: menor pes, major ductilitat, major absorció d'energia, i sobretot, millor resistència a foc. D'altra banda, la millora de la tècnica de fabricació de formigons d'altes resistències fa que la seva utilització en columnes de doble tub produïsca una sinergia idònia per dissenyar elements estructurals verticals esvelts. No obstant això, la ràpida evolució i desenvolupament de la construcció mixta fa que les normes actuals no tinguin les expressions analítiques ni les recomanacions de disseny actualitzades. Per aquest motiu i per la relativa solució innovadora d'aquesta configuració, així com la complexitat de realitzar assajos experimentals, existeixen pocs treballs experimentals i estudis analítics sobre aquesta tipologia de columnes. És per això que l'estudi numèric de columnes de doble tub farcides de formigó siga, des del punt de vista científic, interessant. El comportament mecànic de columnes de doble tub emplenades de formigó s'estudia en aquesta tesi mitjançant un model realista tridimensional d'elements finits. Els valors adoptats per a les variables del model són el resultat d'una extensa anàlisi de sensibilitat. La precisió del model numèric es verifica amb assajos experimentals i, una vegada es disposa d'un model validat, es desenvolupa un extens estudi paramètric amb la finalitat d'avaluar la influència dels principals factors que afecten la resposta mecànica de les columnes i poder establir recomanacions de disseny. Amb aquesta informació, es realitza una comparativa amb els resultats d'aplicar el mètode de càlcul de columnes mixtes del Eurocódigo 4-Part 1.1, amb el propòsit d'avaluar la validesa del mètode en columnes de doble tub comprimides i flexo-comprimides emplenades de formigó d'ultra alta resistència. L'abast d'aquesta tesi queda limitat a columnes circulars esveltes de doble tub emplenades de formigó normal i d'ultra alta resistència sotmeses a càrrega monotònica centrada i excèntrica amb moment uniforme.
Pons Aliaga, D. (2016). ESTUDIO NUMÉRICO DE LA CAPACIDAD PORTANTE DE COLUMNAS MIXTAS CON DOBLE TUBO RELLENAS DE HORMIGON [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62209
TESIS
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Perea, Tiziano. "Analytical and experimental study on slender concrete-filled steel tube columns and beam-columns." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37303.
Full textAbstract:
The use of composite steel-concrete columns and beam-columns in many structural systems is increasing globally due to the intrinsic synergy when these materials are designed and detailed together properly. However, limited test data are available to justify the structural system response factors and comprehensive design equations in current design specifications. This research, through the testing of 18 full-scale, slender concrete-filled steel tube (CFT) beam-columns, attempts to address the latter need. The circular and rectangular CFT specimens tested for this research are by far the longest and the most slender full-scale CFT members tested worldwide. These CFT specimens were subjected to a complex load protocol that includes pure compression, uniaxial and biaxial bending combined with compression, pure torsion, and torsion combined with compression. In addition, data from the hydrostatic pressure on the steel tubes due to the fresh concrete at casting was evaluated. The single most important contribution of this research is the clarification of the interaction between strength and stability in slender composite concrete-filled columns and beam-columns. Parallel to the experimental study, advanced computational analyses were carried out to calibrate material and element models that characterize the salient features of the observed CFT response, such as steel local buckling and residual stresses, concrete confinement, stability effects, strength, and stiffness degradation, among others. Based on the observed behavior, simplified guidelines for the computation of the strength and stiffness parameters for CFT columns and beam-columns are proposed for design purposes.
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Zhao, H., R. Wang, Dennis Lam, C.-C. Hou, and R. Zhang. "Behaviours of circular CFDST with stainless steel external tube: Slender columns and beams." Elsevier, 2020. http://hdl.handle.net/10454/18141.
Full textAbstract:
NoIn this work, experimental and numerical investigations were performed on the behaviours of circular concrete filled double steel tubular (CFDST) slender columns and beams, in which the external tube employed stainless steel tube. Eighteen specimens, 12 slender columns and 6 beams, were tested to obtain the failure patterns, load versus deflection relationships and strain developments of stainless steel tube. A finite element (FE) model was developed and verified by experimental results. The validated FE model was then employed to investigate the effects of key parameters, including hollow ratio, eccentric ratio and material strength, on the load-carrying capacity. The load distribution among the components and contact stress between steel tube and sandwiched concrete were also analyzed. Finally, the design methods for CFDST, hollow CFST and solid CFST members with carbon steel external tube respectively suggested by Han et al. (2018), Chinese GB 50936-2014 (2014) and AISC 360-16 (2016) were employed to evaluate their applicability for the circular CFDST slender columns and beams with stainless steel outer tube.
The authors gratefully acknowledge the Shanxi Province Outstanding Youth Fund (No. 201701D211006) and the National Natural Science Foundation (No. 51838008).
The full-text of this article will be released for public view at the end of the publisher embargo on 9th Nov 2021.
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Valenzuela, Quintana Rodrigo Alejandro. "Aplicación de Columnas Compuestas CFT al Diseño Sísmico de Edificios en Chile." Tesis, Universidad de Chile, 2007. http://repositorio.uchile.cl/handle/2250/104673.
Full textAbstract:
Ingeniero CivilUna columna CFT (“Concrete Filled Tube”) corresponde a un elemento compuesto conformado por un perfil tubular de acero en cuyo interior se coloca hormigón con el fin de aumentar su resistencia y rigidez. El presente proyecto de título trata acerca de la aplicabilidad de columnas compuestas CFT al diseño sísmico de edificios en Chile. Junto con esto se realiza la comparación entre el diseño al utilizar columnas de perfiles doble T y el diseño utilizando columnas compuestas CFT. Para analizar la aplicabilidad del uso de columnas compuestas se realiza el diseño de tres edificios cuyas dimensiones generales en planta son dimensiones observadas en edificios chilenos, diferenciándose sólo en la cantidad de pisos. En el diseño de estos edificios se utilizan paralelamente columnas doble T de acero y columnas compuestas CFT, para así poder comparar los resultados de ambos diseños. En el diseño de los edificios se utiliza la normativa vigente. Luego de haber realizado el diseño de los edificios, se analiza el comportamiento de una de las estructuras diseñadas en base a columnas compuestas CFT mediante dos tipos de análisis: Pushover y Análisis Tiempo-Historia. El modelo involucrado en estos análisis incorpora la no linealidad proveniente de la fluencia del acero tanto de vigas como columnas, así como también la producida por las deformaciones del hormigón en el interior de las columnas CFT. Los resultados obtenidos de estos análisis se comparan con los resultados esperados de acuerdo a la normativa utilizada con el fin de apreciar si los parámetros de diseño empleados son los correctos o deberían ser éstos modificados para obtener resultados consistentes con la filosofía de diseño de la norma chilena para el diseño sísmico de edificios. Los resultados obtenidos en este trabajo de titulación indican que los edificios prototipo con columnas CFT diseñados de acuerdo a la normativa chilena resultan con una sobre resistencia muy alta, lo cual, si bien asegura un buen comportamiento sísmico para un sismo de nivel de diseño, no permite visualizar las ventajas, desde un punto de vista económico, de utilizar este tipo de elementos en estructuras sismorresistentes. En este trabajo de titulación queda en evidencia que el criterio de deformaciones admisibles impuesto por la norma NCh433.Of 96 es demasiado restrictivo para las estructuras analizadas, la relajación de este criterio podría resultar ventajosa económicamente para las estructuras controladas por el corte basal mínimo.
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Carrasco, Navarrete Sebastián Andrés. "Recomendaciones de Diseño de Columnas Compuestas de Acero-Hormigón Sometidas a Esfuerzos Básicos." Tesis, Universidad de Chile, 2010. http://www.repositorio.uchile.cl/handle/2250/103984.
Full textAbstract:
A medida que el hombre ha ido creando nuevas estructuras como grandes edificios. Estos se realizan sin importar que no cumplan con los límites de resistencia impuestos por los materiales tradicionales como son el hormigón armado o las estructuras hechas de perfiles de acero. En éstas estructuras, las columnas forman parte esencial de ellas, ya que a través de éstas se transmiten a la base las acciones a las cuales queda sometida la estructura.
Es por esto que para grandes esfuerzos en elementos como columnas, hace un tiempo en países como U.S.A. y Japón, entre otros, se han utilizado desde hace más de veinte años columnas compuestas. Las cuales se encuentran formadas por hormigón armado y además perfiles de acero. Las columnas compuestas pueden ser clasificadas en tres tipos: secciones de acero embebido en hormigón armado (steel reinforced concrete, SRC), secciones circulares de acero rellenas de hormigón armado (concrete filled tuve, CFT) y secciones rectangulares de acero rellenas de hormigón armado (rectangular concrete filled tuve, RCFT). Esta sinergia existente entre ambos materiales entrega distintas ventajas: (1) en columnas CFT o RCFT, el acero incrementa la resistencia y ductilidad del hormigón por su efecto de confinamiento, el hormigón inhibe el pandeo local del perfil de acero y a la vez hace innecesaria la utilización de moldajes; (2) en columnas SRC el hormigón previene el pandeo local del perfil de acero y a la vez sirve como protector del fuego.
Ahora, en base a las normativas existentes y las distintas investigaciones desarrolladas en distintos tipos de columnas compuestas. El objetivo principal de la presente memoria de título fue formular recomendaciones de diseño de columnas compuestas de acero y hormigón, sometidas a esfuerzos de tracción, compresión, flexión y corte. Para que puedan ser utilizadas en Chile como recomendaciones de diseño para el ingeniero que desee información más ordenada acerca del diseño de este tipo de columna.
El resultado final de diseño propuesto para cada uno de los distintos tipos de columnas sometidas a cada uno de los distintos esfuerzos, fue que las normativas americanas se destacan en sus resultados en comparación con códigos europeos. Y a la vez para aquellos tipos de ensayos en los cuales no se encontró datos experimentales para poder llevar a cabo la comparación, se sugiere al lector diseñar, según el criterio que posea, entre alguna de las dos normas americanas.
En base a los resultados obtenidos en la presente memoria de título. Se recomienda llevar a cabo estudios experimentales, de tal forma de obtener en base a datos reales el comportamiento de las columnas compuestas sometidas principalmente a esfuerzos de corte y de flexión pura. Los cuales no se encontraron datos experimentales de algunas columnas para poder llevar a cabo la comparación de cual método sería el apropiado.
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Ding, Jun. "Behaviour of restraint concrete filled tubular (CFT) columns and their joints in fire." Thesis, University of Manchester, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507960.
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Jamaluddin, Norwati. "Behaviour of elliptical concrete-filled steel tube (CFT) columns under axial compression load." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/11322/.
Full textAbstract:
This thesis describes a research of the behaviour of the elliptical CFT columns under axial loading. The most substantial part of this research is experimental works conducted on twenty-seven specimens including the hollow stub columns as references. Parameters such as slenderness ratio, uni-axial compressive strength of concrete infill and the aspect ratio were considered to investigate their influence on the behaviour on these columns. The results presented are the first member buckling tests on elliptical CFT columns. Keys results from the tests have been presented and discussed. Parallel with the experimental works, numerical analyses were carried out and verified with the experimental results. Parametric studies were performed following the validation of the numerical models. As there is no design guidance seems to be available in any standard, thus this research provides a review of the existing design standards of Eurocode 4 (EC4) and American Specifications (AISC). The design expressions from these current design provisions for circular, square and rectangular concrete- filled tubes design strengths were used to predict the capacities of elliptical eFT columns. The influences of concrete enhancement, steel reduction due to biaxial effects and column slenderness were all incorporated in design rules of EC4. Based on the experimental, numerical findings the evaluations were made on the design rules of the codes. This investigation was aimed at providing reliable design guidelines for practising engineers to employ the elliptical concrete-infill columns in the construction industry.
Book chapters on the topic "CFST columns"
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Geng, Yue, Gianluca Ranzi, Yu-yin Wang, Raymond Ian Gilbert, and Sumei Zhang. "State-of-the-art review on the time-dependent behaviour of composite steel-concrete columns." In Time-dependent behaviour and design of composite steel-concrete structures, 83–109. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/sed018.ch5.
Full textAbstract:
<p>This chapter presents a state-of-the-art review of the time-dependent behaviour of composite columns. The first part of the chapter outlines the available typologies and advantages of composite columns. This is followed by an overview of the time-dependent response of concrete (specific to composite columns) and an introduction to concrete confinement. The main part of the chapter is devoted to the state-of-the-art review on how concrete time effects influence the long-term and ultimate behaviour of concrete-filled steel tube (CFST) columns, and on the combined effects produced by sustained loading and chloride corrosion on CFST columns. The review then deals with the long-term behaviour of concrete-filled double skin tube (CFDST) and encased composite columns. The final parts of the chapter provide a review of the time-dependent differential axial shortening (DAS) in vertical components of multi-storey buildings and on the long-term response of arch bridges.</p>
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Kothari, Shashank, Deepak K. Singh, and Pankaj Chamoli. "Comparative Analysis of CFST Columns and RC Columns Under Uniaxial Compressive Loads." In Springer Proceedings in Energy, 135–44. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6879-1_15.
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Azna, P. A., and Ranjan Abraham. "Structural Performance of Multi-sectional CFST Columns with Double Corrugated Plate." In Lecture Notes in Civil Engineering, 189–203. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-55115-5_19.
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Thripthi, A. Ranjith, A. Tanvi Rai, and Sahana Suresh. "Comparative Study on Behaviour of CFST and CES Columns Using ABAQUS Software." In Lecture Notes in Civil Engineering, 333–47. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6828-2_26.
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Narang, Aishwarya, Ravi Kumar, and Amit Kumar Dhiman. "Prediction of fire-resistance rate of CFST columns using gene expression programming." In Application of Soft Computing Techniques in Mechanical Engineering, 187–98. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003257691-14.
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Reddy, S. Vijaya Bhaskar, and S. Sivasankar. "Axial Behaviour of Corroded CFST Columns Wrapped with GFRP Sheets—An Experimental Investigation." In Lecture Notes in Civil Engineering, 15–28. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4079-0_2.
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Tiwary, Aditya Kumar, and Ashok Kumar Gupta. "Axial Loading Behaviour of Concrete Filled Steel Tube (CFST) Columns: A Parametric Study." In Lecture Notes in Civil Engineering, 873–83. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6557-8_71.
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Xue, Junqing, Yifei Zhang, Bruno Briseghella, and Baochun Chen. "Experimental Research on Effects of Debonding on Circular CFST Columns with Different Slenderness Ratios." In Structural Integrity, 369–77. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-29227-0_38.
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Nguyen, Tran-Trung, and Phu-Cuong Nguyen. "K-Fold Cross-Validation Technique for Predicting Ultimate Compressive Strength of Circular CFST Columns." In Lecture Notes in Civil Engineering, 867–74. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3303-5_79.
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Phan, Hao D., and Ker-Chun Lin. "Seismic Performance of Concrete Filled Steel Tubular (CFST) Columns with Variously Axial Compressive Loads." In Lecture Notes in Mechanical Engineering, 915–25. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-3239-6_71.
Full textConference papers on the topic "CFST columns"
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Sulthana, U. Mashudha, and S. Arul Jayachandran. "Investigations on global buckling behaviour of concrete-filled double-skinned steel tubular columns." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7144.
Full textAbstract:
Concrete-Filled Double-skinned Steel Tubular columns (CFDST) are proved to possess exceptional structural resistance in case of fire and multi-hazard situations. This superior quality of CFDST makes it preferable in long column applications. However, studies on the long column behaviour of CFDST is very few, and their results are not in line with the behaviour of CFST long columns. Whereas, several researches on stub column CFDST shows that, the axial compression behaviour of CFDST is similar to CFST. In this paper, selected results (4 numbers of circular CFDST specimens) from a large test data is presented. Axial compression behaviour of long column CFDST specimens is studied, with non-dimensional slenderness λ around 1.0, and hollowness ratio as the governing parameter for study. Test results namely, axial load carrying capacity, axial deformation and lateral deflection are presented in this paper. Numerical models are also developed and validated with the experimental results, to carry out more parametric studies. Further, the experimental axial capacity values are compared with modified capacity equations from EC4 and AISC. Results show that extended EC4 and AISC equations gives conservative predictions for CFDST column even in the long column range. Moreover, the initial imperfections in the specimen and their corresponding boundary conditions for load application, are found to be governing parameters in long column buckling study.
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Güler, Soner, Fuat Korkut, Namik Yaltay, and Demet Yavuz. "Axial behaviour of concrete filled steel tube stub columns: a review." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7602.
Full textAbstract:
Concrete-filled steel tubular (CFST) columns are widely used in construction of high-rise buildings and peers of bridges to increase the lateral stiffness of the buildings, the axial load capacity, ductility, toughness, and resistance of corrosion of the columns. The CFST columns have much superior characteristics compared with traditionally reinforced concrete columns. The position of the concrete and steel tube in the cross-section of the CFST column is the most appropriate solution in terms of the strength and ductility. The steel tube, which is placed outside of the cross-section of the column, withstand the bending moment effectively. The concrete that is placed into the steel tube delay the local buckling of the steel tube and increase the axial load capacity of the column due to continually lateral confining. This paper presents a review on experimental results of the axial behavior of CFST columns performed by various researchers.
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Han, Lin-Han, and Kan Zhou. "Fire performance of concrete-encased CFST columns and beam-column joints." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.6927.
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Concrete-encased CFST (concrete filled steel tube) structure is a type of composite structure featuring an inner CFST component and an outer reinforced concrete (RC) component. They are gaining popularity in high-rise buildings and large-span buildings in China nowadays. To date, the behaviour of concrete-encased CFST structures at ambient temperature has been investigated, but their fire performance has seldom been addressed, including the performance in fire and after exposure to fire. This paper summarizes the fire test results of concrete-encased CFST columns and beam-column joints. The cruciform beam-column joint was composed of one continuous concrete-encased CFST column and two cantilevered reinforced concrete (RC) beams. These specimens were subjected to a combined effect of load and full-range fire. The test procedure included four phases, i.e. a loading phase at ambient temperature, a standard fire exposure phase with constant load applied, a sequential cooling phase and a postfire loading phase. The main findings are presented and analysed. Two types of failure were identified, i.e. the failure during fire exposure and the failure during postfire loading. Global buckling failure was observed for all the column specimens. The column specimens with common load ratios achieved high fire ratings without additional fire protection. The concrete-encased CFST columns also retained high postfire residual strength. As for the joint members, beam failure was observed in all cases. The measured temperature-time history and deformation-time history are also presented and discussed. For both the column and joint specimens, the deformation over the cooling phase was significantly greater than that in the standard fire exposure phase.
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Tao, Zhong, Utsab Katwal, Kamrul Hassan, and Wen-Da Wang. "Simplified numerical modelling of rectangular concrete-filled steel columns, beams and beam-columns." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.6949.
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Because of its computational efficiency, simplified numerical modelling is the preferred method to simulate structural frames for routine design. As for concrete-filled steel tubular (CFST) columns, fibre beam element (FBE) modelling is often used in the simplified simulation. However, the accuracy of FBE modelling is greatly affected by the accuracy of the input material models, which should directly account for the interaction between the steel tube and core concrete. In this paper, simple yet accurate material models of steel and concrete are proposed for rectangular CFST columns by utilising a large amount of numerical data generated from detailed three-dimensional finite element modelling of stub columns. The material models are then incorporated into the simplified FBE simulation of rectangular CFST columns, beams and beam-columns. The accuracy of the simplified FBE simulation is verified by a wide range of experimental results on rectangular CFST stub columns, slender columns, beams and beam-columns.
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"An Experimental Investigation on Concrete Filled Steel Tube Columns Under Axial Compression." In Recent Advancements in Geotechnical Engineering. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901618-9.
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Abstract. This paper presents an experimental investigation on the behaviour of concrete filled steel tube columns under axial compression. The steel columns were filled with self-compacting and self-curing concrete instead of normal conventional concrete. A test program consisting of square column, circular column and rectangular column was firstly conducted. The behaviour of three concrete filled steel tubular sections (CFSTs) under axial load is presented. The effect of steel tube dimensions, shapes and confinement of concrete are also examined. Measured column strengths are compared with the values predicted by Euro code 4 and American codes. Euro code 4, gives good estimation of self-compaction concrete. However, lower values as measured during the experiments were predicted by the American Concrete Institute (ACI) equation. Also, the effect of thickness of steel tubes, concrete cube strength and steel percentage is also studied. In addition to CFST column the steel tube also acts as confinement for concrete.
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Alam, Md Iftekharul, Sabrina Fawzia, and Chamila Batuwitage. "CFRP strengthened CFST columns under vehicular impact." In International Conference on Performance-based and Life-cycle Structural Engineering. School of Civil Engineering, The University of Queensland, 2015. http://dx.doi.org/10.14264/uql.2016.1117.
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Ibáñez, Carmen, Luke Bisby, David Rush, Manuel L. Romero, and Antonio Hospitaler. "Analysis of concrete-filled steel tubular columns after fire exposure." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7193.
Full textAbstract:
Concrete filled steel tubular (CFST) columns have a high probability to resist high temperatures compared to steel structures, whose evaluation after a fire is limited by the resulting deformation. A better understanding of the behaviour of CFST columns after a fire, affected by the maximum temperature achieved by the concrete infill, is required to properly estimate their residual strength and stiffness in order to adopt a reasonable strategy with minimum post-fire repair. In this paper, a fiber beam model for the simulation of the post-fire response of slender concrete-filled steel tubular (CFST) columns is presented. First, the model is validated against experimental results and subsequently it is employed to analyse the post-fire response of circular CFST columns. The variation of the residual strength with the load level for realistic fire resistance times is numerically studied. Actually, in a building, the columns support load even while a fire is being extinguished, so it is important to take into account this loading condition when predicting the post-fire behaviour. Therefore, in this research, the complete analysis comprises three stages: heating, cooling and post-fire under sustained load conditions. The model considers realistic features typical from the fire response of CFST columns, such as the existence of a gap conductance at the steel-concrete interface or the sliding and separation between the steel tube and the concrete.
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Bumstead, J., J. Korat, and M. T. Stephens. "Repair Strategies for Earthquake-Damaged CFST Bridge Columns." In Structures Congress 2019. Reston, VA: American Society of Civil Engineers, 2019. http://dx.doi.org/10.1061/9780784482230.016.
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Lapuebla-Ferri, Andrés, Cesar Lacuesta, Manuel L. Romero, and José M. Adam. "A numerical model with varying passive confinement for circular and elliptical concrete-filled steel tubular columns." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.7246.
Full textAbstract:
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.
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Yan, Qiaoling, Baochun Chen, and Tingmin Mu. "Experimental Study on Eccentrically Loaded CFST Composite Strut Columns." In 10th International Conference on Advances in Steel Concrete Composite and Hybrid Structures. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-2615-7_140.
Full textReports on the topic "CFST columns"
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Song, Qian-Yi, Lin-Hai Han, Kan Zhou, and Yuan Feng. TEMPERATURE DISTRIBUTION OF CFST COLUMNS PROTECTED BY INTUMESCENT FIRE COATING. The Hong Kong Institute of Steel Construction, December 2018. http://dx.doi.org/10.18057/icass2018.p.164.
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Pedro F., Rodrigues, Vellasco Pedro C. G. da S., Lima Luciano R. O. de, Silva André T. da, Rodrigues Monique C., and Sarmanho Arlene M. C. EXPERIMENTAL EVALUATION OF COMPOSITE TUBULAR COLUMNS CFDST (STAINLESS STEEL–CONCRETE–CARBON STEEL). The Hong Kong Institute of Steel Construction, December 2019. http://dx.doi.org/10.18057/icass2018.p.025.
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Lai, Zhichao, and Amit H. Varma. ON THE ANALYSIS AND BEHAVIOR OF HIGH-STRENGTH CIRCULAR CFT COLUMNS. The Hong Kong Institute of Steel Construction, December 2018. http://dx.doi.org/10.18057/icass2018.p.071.
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CHEN, Yiyi, Kang WANG, Nannan YAN, and Xianzhong ZHAO. STUDY ON THE VERTICAL LOADING TRANSFERRING MECHANISM OF JOINT WITH LARGE DIMENSION CFT COLUMN AND STEEL BEAM. The Hong Kong Institute of Steel Construction, December 2018. http://dx.doi.org/10.18057/icass2018.p.062.
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CALCULATION METHOD OF ULTIMATE LOAD BEARING CAPACITY OF CONCRETE FILLED STEEL TUBULAR LATTICE COLUMNS. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.095.
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To investigate the influence of eccentricity ratio and slenderness ratio on the mechanical properties of eccentric compressed concrete filled steel tubular (CFST) lattice column, the ultimate bearing capacity tests of 20 K shape arrangement lacing strip of four-tube CFST columns were conducted. Based on the stress-strain relationship of CFST and the influence of shear deformation, the equilibrium equation of the mid-section is established and a numerical method for the ultimate bearing capacity of CFST lattice column is proposed. The slenderness reduction coefficient calculation model and equivalent slenderness ratio formula of CFST lattice column are established. Combined with the numerical results and the slenderness ratio reduction coefficient calculation model, the formula of slenderness ratio reduction coefficient is put forward. The comparison between theoretical analysis and experimental results shows that the calculation method of elastic-plastic ultimate bearing capacity of CFST lattice column proposed in this paper is quite accurate. The research outcomes can provide a reference for the application of CFST lattice column and revision of current specifications.
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AXIAL COMPRESSION BEHAVIOR OF SQUARE THIN-WALLED CFST COLUMN TO RC BEAM JOINTS. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.288.
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To investigate the influence of eccentricity ratio and slenderness ratio on the mechanical properties of eccentric compressed concrete filled steel tubular (CFST) lattice column, the ultimate bearing capacity tests of 20 K shape arrangement lacing strip of four-tube CFST columns were conducted. Based on the stress-strain relationship of CFST and the influence of shear deformation, the equilibrium equation of the mid-section is established and a numerical method for the ultimate bearing capacity of CFST lattice column is proposed. The slenderness reduction coefficient calculation model and equivalent slenderness ratio formula of CFST lattice column are established. Combined with the numerical results and the slenderness ratio reduction coefficient calculation model, the formula of slenderness ratio reduction coefficient is put forward. The comparison between theoretical analysis and experimental results shows that the calculation method of elastic-plastic ultimate bearing capacity of CFST lattice column proposed in this paper is quite accurate. The research outcomes can provide a reference for the application of CFST lattice column and revision of current specifications.
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FINITE ELEMENT SIMULATION FOR ULTRA-HIGH-PERFORMANCE CONCRETE-FILLED DOUBLE-SKIN TUBES EXPOSED TO FIRE. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.263.
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Ultra-high-performance concrete (UHPC) or ultra-high-strength concrete (UHSC) are alternatively used to reduce construction materials, thereby achieving more sustainable constructions. Moreover, engaging the advantages of concrete cores and outer steel tubes in concrete-filled steel tubes (CFST) or ductile concrete-filled double-skin tubes (CFDST) is of great interest for the better performance of such members under fire. Nevertheless, current design provisions do not provide design models for UHPC-filled double-skin tubes under fire, and existing finite-element (FE) methodologies available in the literature may not accurately simulate the behaviour of CFDST exposed to fire. Therefore, this paper develops a comprehensive FE protocol implementing the scripting technique to model CFDST members for heat transfer and coupled (simultaneously or sequentially) thermal-stress analyses. Various modelling parameters incorporated in the proposed FE routine include the cross-sectional geometry (circular, elliptical, hexagonal, octagonal, and rectangular), the size (width, diameter, and wall thickness), interactions, meshing, thermal- and mechanical-material properties, and boundary conditions. The detailed algorithm for heat transfer analysis is presented and elaborated via a flow chart. Validations, verifications, and robustness of the developed FE models are established based on extensive comparison studies with existing fire tests available in the literature. As a result, and to recognize the value of the current FE methodology, an extensive parametric study is conducted for different affecting parameters (e.g., nominal steel ratio, hollowness ratio, concrete cylindrical strength, yield strength of metal tubes, and width-to-thickness ratio). Extensive FE results are used for optimizing the fire design of such members. Consequently, a simplified and accurate analytical model that can provide the axial load capacity of CFDST columns under different fire ratings is presented
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EFFICIENCY OF DIFFERENT CONNECTIONS ON THE BEHAVIOUR OF COLD-FORMED SINGLE-ANGLE STEEL MEMBERS CONNECTED THROUGH ONE LEGUNDER AXIAL LOADING. The Hong Kong Institute of Steel Construction, September 2022. http://dx.doi.org/10.18057/ijasc.2022.18.3.10.
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A detailed experimental program was performed using 36 cold-formed steel (CFS) single-angle column members attached by one leg was investigated subjected to axial compression loads. The key purpose of this research is to investigate the effect of slenderness ratio and different connection types on the load-carrying capacity of CFS angle sections under axial compression. The parameters investigated via the test program includes (a) angle sections with and without lipped profile, (b) sectional thicknesses (2 mm and 3mm), (c) slenderness ratios (λ = 20, 50, 80) from short to slender columns, and (d) type of connections i.e. two-bolt, three-bolt and welded connections. Results shown that the angle sections had a significant reduction in the load-carrying capacity when the slenderness ratio was increased from 20 to 80. Moreover, the mode of failure for short columns was changed from local buckling mode to combined local and flexural buckling for intermediate columns (λ = 50) and torsional-flexural buckling mode for long columns (λ = 80). Also, a detailed analytical study was carried out comparing the predictability of existing equations from different standards for angle sections under axial compression.
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BEHAVIOR OF CFST-COLUMN TO STEEL-BEAM JOINTS IN THE SCENARIO OF COLUMN LOSS. The Hong Kong Institute of Steel Construction, March 2019. http://dx.doi.org/10.18057/ijasc.2019.15.1.7.
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SEISMIC OPTIMIZATION ANALYSIS OF VERTICAL STIFFENER CONNECTION TO L-CFST COLUMN. The Hong Kong Institute of Steel Construction, March 2019. http://dx.doi.org/10.18057/ijasc.2019.15.1.13.
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