Experimental Investigation of Stiffened Square CFST Columns under Axial Load

2014 ◽  
Vol 919-921 ◽  
pp. 1794-1800
Author(s):  
Xin Zhi Zheng ◽  
Xin Hua Zheng
Keyword(s):  
Experimental Investigation ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Axial Load ◽  
Local Buckling ◽  
Test Results ◽  
Tubular Columns ◽  
Economical Benefit ◽  
Steel Consumption ◽  
Cfst Columns

Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

scholarly journals Simplified 2D Finite Element Model for Calculation of the Bearing Capacity of Eccentrically Compressed Concrete-Filled Steel Tubular Columns

2021 ◽  
Vol 11 (24) ◽  
pp. 11645
Author(s):  
Anton Chepurnenko ◽  
Batyr Yazyev ◽  
Besarion Meskhi ◽  
Alexey Beskopylny ◽  
Kazbek Khashkhozhev ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Longitudinal Force ◽  
Effective Area ◽  
Element Analysis ◽  
Tubular Columns ◽  
Cfst Columns

Concrete-filled steel tubular (CFST) columns are widely used in construction due to effective resistance to compression and bending joint action. However, currently, there is no generally accepted effective calculation method considering both nonlinearities of the materials and lateral compression. The article proposes the finite element analysis method of concrete-filled steel tubular columns in a physically nonlinear formulation by reducing a three-dimensional problem to a two-dimensional one based on the hypothesis of plane sections. The equations of Geniev’s concrete theory of plasticity are used as relations establishing the relationship between stresses and strains. The technique was tested by comparing the solution with the calculation in a three-dimensional formulation in the LIRA-SAPR software package and with the experimental data of A.L. Krishan and A.I. Sagadatov. It has been established that the effective area of operation of circular-section columns are small eccentricities of the longitudinal force. The proposed approach can be applied to analyzing the stress–strain state and bearing capacity of pipe-concrete columns of arbitrary cross-sections. There are no restrictions on the composition of concrete, and the shell material can be steel and fiberglass.

scholarly journals Experimental and Numerical Analysis of Large-Scale Circular Concrete-Filled Steel Tubular Columns with Various Constructural Measures under High Axial Load Ratios

2018 ◽  
Vol 8 (10) ◽  
pp. 1894 ◽  
Author(s):  
Lidong Zhao ◽  
Wanlin Cao ◽  
Huazhen Guo ◽  
Yang Zhao ◽  
Yu Song ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Axial Load ◽  
Large Scale ◽  
Steel Tube ◽  
Test Results ◽  
Welded Steel ◽  
Axial Forces ◽  
Circular Steel Tube ◽  
Cfst Columns

To investigate the effect of constructional measures (including horizontal and vertical stiffeners, rebar cages, embedded steel tubes, and cavity welded steel plates) under high axial load ratios on the seismic performance of concrete-filled steel tubular (CFST) columns, quasi-static tests for six large-scale CFST columns with various constructional measures are performed. All specimens are subjected to identical axial forces. The failure mode, hysteresis characteristics, bearing capacity, stiffness degradation, ductility, and energy dissipation of specimens are analyzed. The study shows that the horizontal stiffener delays the occurrence and severity of column base buckling, the vertical stiffener improves the bending resistance capacity and initial stiffness of the member, the rebar cage improves the ductility, and the embedded circular steel tube significantly improves the member’s bearing capacity, ductility, and energy dissipation. When an internal circular steel tube and cavity welded steel plate are applied in tandem, the section steel ratio increases by 4.42% and the bearing capacity improves by 42.72%. A finite element model is created to verify test results, and simulation results match the test results well.

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.

Research on Hysteretic Behavior of the Concrete Filled Square CFRP-Steel Tubular (S-CFRP-CFST) Beam-Columns (I): Experimental Study

2010 ◽  
Vol 163-167 ◽  
pp. 3580-3585
Author(s):  
Yuan Che ◽  
Qing Li Wang ◽  
Yong Bo Shao ◽  
Hai Tao Mu
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Local Buckling ◽  
Steel Tube ◽  
Hysteretic Behavior ◽  
Strengthening Effect ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Beam Columns ◽  
Hysteretic Performance

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

Overview of Research Progress for Concrete-Filled Steel Tubular Columns after Exposure to Fire

2014 ◽  
Vol 638-640 ◽  
pp. 197-201
Author(s):  
Yan Chong Pan ◽  
Guo Hui Wang ◽  
Kai Xiang
Keyword(s):  
Mechanical Properties ◽  
Residual Strength ◽  
Fire Safety ◽  
Axial Load ◽  
Research Progress ◽  
Building Structures ◽  
Fire Exposure ◽  
Tubular Columns ◽  
Cfst Columns ◽  
Exposure Process

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

Experimental Study of Post-Fire Bearing Capacity of the Circular Steel Tubes with Different Fire-Resistant Coating

2010 ◽  
Vol 163-167 ◽  
pp. 749-753
Author(s):  
Yao Ji ◽  
Xin Tang Wang ◽  
Ming Zhou ◽  
Wan Zhen Wang
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Fire Test ◽  
Steel Tube ◽  
Test Results ◽  
Fire Response ◽  
Steel Tubes ◽  
Protective Material ◽  
Tubular Columns ◽  
Maximum Value

In order to look into the causes of fire response and post-fire bearing capacity of the steel tubular columns protected with different materials, the fire test was conducted for a set of circular steel tubes protected with different materials such as gypsum fireproof panel, bamboo plywood and the ordinary lumber core plywood, and the steel tube without any protective material. The fire response temperature of surface of steel tubes is measured and the axial compressive bearing capacity of the specimens after fire are tested and analyzed. The test results show that gypsum fireproof panel has the best fire protection characteristics, the ordinary lumber core plywood and bamboo plywood can also retard rising of the surface temperature of the steel tubes during the initial 35min although they are combustible materials. It is found that the post-fire bearing capacity of the steel tubes protected with different materials varies evidently, and the maximum value of response temperature has the greatest effect.

Dynamic Stability of Slender Concrete-Filled Steel Tubular Columns with General Supports

2019 ◽  
Vol 19 (04) ◽  
pp. 1950045
Author(s):  
Youqin Huang ◽  
Jiyang Fu ◽  
Di Wu ◽  
Airong Liu ◽  
Wei Gao ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Dynamic Stability ◽  
Cross Sections ◽  
Dynamic Instability ◽  
Static Stability ◽  
Constant Component ◽  
Cross Sectional ◽  
Tubular Columns ◽  
New Findings ◽  
Cfst Columns

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

Axial Strength of Concrete-Filled Square Steel Tubular Columns Reinforced by Inner Circular Steel Tube

2010 ◽  
Vol 163-167 ◽  
pp. 4542-4545 ◽  
Author(s):  
Xin Zhong Li ◽  
Xue Ying Wei ◽  
Jun Hai Zhao
Keyword(s):  
Experimental Investigation ◽  
Steel Tube ◽  
Experimental Results ◽  
Test Results ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Axial Strength ◽  
Tubular Columns ◽  
Circular Steel Tube ◽  
Good Agreement

This paper presents the theoretical and experimental results of concrete-filled steel tube columns subjected to axially compression. A total of 6 specimens with outer square sections reinforced by inner cicular steel tube were constructed for experimental investigation. The ultimate strengths of the columns from tests were obtained. The theoretical strengths of the columns were also investigated based on unified strength theory, and compared with the test results. Good agreement can be observed from the comparison.

scholarly journals Experimental Study of the Seismic Performance of L-Shaped Columns with 500 MPa Steel Bars

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Tiecheng Wang ◽  
Xiao Liu ◽  
Hailong Zhao
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Axial Compression ◽  
Seismic Performance ◽  
Axial Load ◽  
Test Results ◽  
Characteristic Value ◽  
Steel Bars ◽  
Curvature Ductility

Based on tests on six L-shaped RC columns with 500 MPa steel bars, the effect of axial compression ratios and stirrup spacing on failure mode, bearing capacity, displacement, and curvature ductility of the specimens is investigated. Test results show that specimens with lower axial load and large stirrup characteristic value (larger than about 0.35) are better at ductility and seismic performance, while specimens under high axial load or with a small stirrup characteristic value (less than about 0.35) are poorer at ductility; L-shaped columns with 500 MPa steel bars show better bearing capacity and ductility in comparison with specimens with HRB400 steel bars.

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