scholarly journals Experimental study on seismic behavior of full scale square concrete filled steel tubular stocky columns

2021 ◽  
Vol 272 ◽  
pp. 02024
Author(s):  
Jin Liu ◽  
Liang Jian ◽  
Du Xiuli
Keyword(s):  
Shear Failure ◽  
Plastic Hinge ◽  
Local Buckling ◽  
Steel Tube ◽  
Calculation Model ◽  
Full Scale ◽  
Cross Sectional ◽  
Short Columns ◽  
Cfst Columns ◽  
Plastic Hinge Length

This study mainly presented a pseudo-static experiment on two full-scale square CFST short columns with the cross-sectional width of 600 mm under combined constant axial load and cyclic lateral load. The seismic performance of the two full-scale CFST columns were investigated. Meanwhile, the plastic hinge length of the specimens was discussed. The test results presented that the specimens suffered bend-shear failure. The local buckling of steel tube occurred at the end of the specimens and the core concrete crushed. The safety redundancy of lateral bearing capacity decreased in full-scale specimen. By the method of physical observation, the plastic hinge length Lp1 was determined mainly according to the range of the local buckling of steel tube. There had a great difference between the prediction of plastic hinge lengths by the existing calculation model and the plastic hinge lengths obtained by the test.

Experimental Study on In-Plane Behavior of CFST Arch with New-Type Dumbbell-Shaped Section

2011 ◽  
Vol 255-260 ◽  
pp. 1198-1203 ◽  
Author(s):  
Ye Sheng
Keyword(s):  
Local Buckling ◽  
High Strength ◽  
Steel Tube ◽  
Calculation Model ◽  
Plastic Behavior ◽  
Loading Process ◽  
New Type ◽  
Set Up ◽  
Ultimate Load Carrying Capacity ◽  
Shaped Section

The weakness of traditional dumbbell-shaped section is that when concrete is filled into the web space, great stress is likely to produce cracks in the weld sealing between steel tube and web plates. In order to avoid this condition, a new-type dumbbell-shaped section is proposed. Experiments on concrete filled steel tubular (CFST) model arches with new-type dumbbell-shaped section have been carried out, concentrated loading at crown and L/4 section respectively. The result indicated that the new-type CFST arch has good elastic-plastic behavior and high strength, no local buckling appeared during the whole loading process, its in-plane mechanic behavior is similar with that of the CFST arch with single-tube. The dual nonlinear finite element calculation model is set up for the model arch, by means of this model the load-deflection curves during the loading process and the ultimate load-carrying capacity is analyzed.

scholarly journals Research on Compression Behavior of Square Thin-Walled CFST Columns with Steel-Bar Stiffeners

2018 ◽  
Vol 8 (9) ◽  
pp. 1602 ◽  
Author(s):  
Zhao Yang ◽  
Chengxiang Xu
Keyword(s):  
Bearing Capacity ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Tubes ◽  
Compression Behavior ◽  
Steel Bar ◽  
Steel Bars ◽  
Thin Walled ◽  
Structural Measure ◽  
Cfst Columns

Local buckling in steel tubes was observed to be capable of reducing the ultimate loads of thin-walled concrete-filled steel-tube (CFST) columns under axial compression. To strengthen the steel tubes, steel bars were proposed in this paper to be used as stiffeners fixed onto the tubes. Static-loading tests were conducted to study the compression behavior of square thin-walled CFST columns with steel bar stiffeners placed inside or outside the tube. The effect and feasibility of steel bar stiffeners were studied through the analysis of failure mode, load–displacement relationship, ultimate load, ductility, and local buckling. Different setting methods of steel bars were compared as well. The results showed that steel-bar stiffeners proposed in this paper can be effective in delaying local buckling as well as increasing the bearing capacity of the columns, but will decrease the ductility of the columns. In order to obtain a higher bearing capacity of columns, steel bars with low stiffness should be placed inside and steel bars with high stiffness should be placed outside of the steel tubes. The study is helpful in providing reference to the popularization and application of this new structural measure to avoid or delay the local buckling of thin-walled CFST columns.

scholarly journals Buckling Analysis and Section Optimum for Square Thin-Wall CFST Columns Sealed by Self-Tapping Screws

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
He Zhang ◽  
Kai Wu ◽  
Chao Xu ◽  
Lijian Ren ◽  
Feng Chen
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Steel Plate ◽  
Local Buckling ◽  
Steel Tube ◽  
Thin Wall ◽  
Type Section ◽  
Plate Buckling ◽  
Thin Walled ◽  
Cfst Columns

Two columns of thin-walled concrete-filled steel tubes (CFSTs), in which tube seams are connected by self-tapping screws, are axial compression tested and FEM simulated; the influence of local buckling on the column compression bearing capacity is discussed. Failure modes of square thin-wall CFST columns are, first, steel tube plate buckling and then the collapse of steel and concrete in some corner edge areas. Interaction between concrete and steel makes the column continue to withstand higher forces after buckling appears. A large deflection analysis for tube elastic buckling reflects that equivalent uniform stress of the steel plate in the buckling area can reach yield stress and that steel can supply enough designing stress. Aiming at failure modes of square thin-walled CFST columns, a B-type section is proposed as an improvement scheme. Comparing the analysis results, the B-type section can address both the problems of corner collapse and steel plate buckling. This new type section can better make full use of the stress of the concrete material and the steel material; this type section can also increase the compression bearing capacity of the column.

Numerical analysis of concentrically loaded hexagonal concrete-filled steel tubular short columns incorporating concrete confinement

2021 ◽  
pp. 136943322110297
Author(s):  
Mizan Ahmed ◽  
Qing Quan Liang
Keyword(s):  
Computational Modeling ◽  
Constitutive Relations ◽  
Concrete Strength ◽  
Steel Tube ◽  
Design Equation ◽  
Design Standards ◽  
Short Columns ◽  
Concrete Confinement ◽  
Current Design ◽  
Cfst Columns

Hexagonal concrete-filled steel tubular (HCFST) columns have been used to carry large loads in tall composite buildings. Their behavior and strength are different from those of circular and square concrete-filled steel tubular (CFST) columns due to the confinement effect. This article describes a computational modeling method of nonlinear fiber analysis recognizing the concrete confinement for the response simulation of HCFST short columns subjected to axial compression. New constitutive relations of confinement for quantifying the confining stresses on the concrete confined by the hexagonal steel tube and the residual concrete strength are developed by means of analyzing existing test data. The computational modeling program written is verified by existing experimental data and then employed to ascertain the behavior of HCFST columns with important parameters. The current design standards for CFST circular columns are used to determine the strengths of HCFST columns to evaluate their applicability to the design of HCFST columns. Proposed is a new simple design equation for computing the axial capacities of HCFST columns. The computational model and the design equation proposed are shown to be accurate, and effective simulation and design tools for HCSFT stub columns that are loaded concentrically in comparisons with the current design codes.

scholarly journals Performance of a Multi-Storey Complex Building with CFST Columns.

2020 ◽  
Vol 9 (7) ◽  
pp. 195-201
Keyword(s):  
Agricultural Land ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Steel Tube ◽  
Seismic Zone ◽  
Cross Sectional ◽  
Seismic Zones ◽  
Complex Building ◽  
Cfst Columns ◽  
Vertical Development

Due to rapid on-going horizontal development and restricted vertical development of buildings has resulted in congestion of cities and shrinkage of agricultural land, particularly in high seismic zones. For vertical development, there is a need for the construction of buildings as high as possible. The restriction to the vertical development is due to the reason that high rise structures are more vulnerable to lateral loads acting on the building resulting from the seismic events. With a background in view, the current work studies the seismic responses of a multi-storey complex building with concrete-filled steel tube columns (CFST). In present work, CFST columns of different sizes were used for the study of a Ground+12 storey building with plan dimensions 35m x 30m, situated in seismic Zone-V and medium soil type as per IS 1893-2016 classification. The Response spectrum analysis was carried out for different building models as per IS 1893:2016 provisions. E-TABS software was used for three-dimensional modelling and analysis of buildings. Several response parameters like fundamental time period, maximum storey displacement, maximum storey drift, storey shear and overturning moment are considered in this study to evaluate the performance of the building. It was concluded that CFST columns perform well for high seismic zones even at smaller cross-sectional dimensions.

Research on Behavior of Rectangular CFST Stub Columns with Binding Bars under Axial Compression

2013 ◽  
Vol 351-352 ◽  
pp. 790-797
Author(s):  
Hong Liang Liu ◽  
Jian Cai
Keyword(s):  
Poisson Ratio ◽  
Local Buckling ◽  
Steel Tube ◽  
Constitutive Relationship ◽  
Fe Model ◽  
Longitudinal Stress ◽  
Concrete Confinement ◽  
Central Regions ◽  
Cfst Columns ◽  
Core Concrete

The constitutive model of core concrete was proposed, which was suitable for finite element (FE) analysis of rectangular concrete-filled steel tubular (CFST) columns with binding bars. Based on the ABAQUS FE platform, the USDFLD subroutine was compiled, which could consider the changing of Poisson ratio of many materials in loading process. A FE model was developed and used to simulate the rectangular CFST columns with binding bars. The mechanical behavior were analyzed for stress versus strain relationship curves, confined effect among steel tube, core concrete and binding bars, longitudinal stress distributions of core concrete. The results show that the FE results simulated by using constitutive relationship of core concrete of this paper are in good agreement with test results. The local buckling of steel tube is delayed which can make the yield of steel tube occur before ultimate strength of specimens, the concrete confinement of the corner regions and central regions is improved, the longitudinal stress of concrete is increased and the capacity and ductility of specimens are improved, by setting binding bars and decreasing the binding bars spacing.

scholarly journals Tests of Inclined Concrete-Filled Steel Tubular Stub Columns under Vertical Cyclic Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chayanon Hansapinyo ◽  
Chinnapat Buachart ◽  
Preeda Chaimahawan
Keyword(s):  
Cyclic Loading ◽  
Local Buckling ◽  
Steel Tube ◽  
Cyclic Behavior ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Steel Column ◽  
Inclination Angles ◽  
Inclined Angle ◽  
Stub Columns

This paper presents an experimental study on the cyclic behavior of fifteen concrete-filled steel tubular columns subjected to vertical cyclic loading. All test samples’ cross-sectional area is 75 × 75 mm2square, and they are 500 mm long. The main variables in the test are the thickness of the steel tube (1.8 and 3.0 mm with the width-to-thickness ratios (b/t) of 41.7 and 25), the strength of the infilled concrete (no-fill, 23 MPa, and 42 MPa), and the inclined angle (0, 4, and 9 degrees). The results show that all samples failed due to local buckling in compression followed by tearing of the steel tube in tension. The inclination angles of 4 and 9 degrees decreased the vertical compressive capacity of the 1.8 mm vertical hollowed steel column by 34 and 39 percent, respectively. However, the infilled concrete and thicker tube (3.0 mm) could substantially reduce the adverse effect of the inclination angle. The compressive ductility of the hollowed column with the thinner tube was significantly enhanced by the infilled concrete as well.

scholarly journals Axial behaviour of concrete filled steel tube stub columns: a review

2018 ◽  
Author(s):  
Soner Güler ◽  
Fuat Korkut ◽  
Namik Yaltay ◽  
Demet Yavuz
Keyword(s):  
Cross Section ◽  
Axial Load ◽  
Load Capacity ◽  
Local Buckling ◽  
Bending Moment ◽  
Steel Tube ◽  
High Rise ◽  
Axial Load Capacity ◽  
The Cross ◽  
Cfst Columns

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.

Study on shear performance of the connection with external stiffening ring between square steel tubular column and unequal-depth steel beams

2020 ◽  
pp. 136943322098166
Author(s):  
Shuhao Yin ◽  
Bin Rong ◽  
Lei Wang ◽  
Yiliang Sun ◽  
Wuchen Zhang ◽  
...  
Keyword(s):  
Failure Modes ◽  
Plastic Hinge ◽  
Steel Tube ◽  
Nonlinear Finite Element ◽  
Steel Beams ◽  
Finite Element Models ◽  
Test Results ◽  
Panel Zone ◽  
Load Paths ◽  
Shear Performance

This paper studies the shear performance of the connection with the external stiffening ring between the square steel tubular column and unequal-depth steel beams. Two specimens of interior column connections were tested under low cyclic loading. The deformation characteristics and failure modes exhibited by the test phenomena can be summarized as: (1) two specimens all exhibited shear deformation in steel tube web of the panel zone and (2) weld fracture in the panel zone and plastic hinge failure at beam end were observed. Besides, load-displacement behaviors and strain distributions have been also discussed. The nonlinear finite element models were developed to verify the test results. Comparative analyses of the bearing capacity, failure mode, and load-paths between the equal-depth and unequal-depth beam models have been carried out.

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