scholarly journals Axial Compression Behaviors of the Steel Tube Confined Reinforced Concrete Columns with Binding Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hao Hu ◽  
Zhengliang Li ◽  
Xi Tu ◽  
Junfeng Tang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Modes ◽  
Tube Wall ◽  
Concrete Strength ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Axial Deformation ◽  
Section Dimension

An experimental study on the steel tube confined reinforced concrete (STCRC) column with binding bars under axial compression is conducted. The bearing capacity and failure modes are obtained. It can be known that the axial deformation of concrete occurred under compression. The core concrete is wrapped and constrained by the steel tube wall, and the steel tube wall is constrained by binding bars locally, so the local buckling shape of the wall between the binding bars is like wave shape. The 3D finite element model is also developed to analyze the behavior of this type of column under axial compression. Good agreement is shown between the test and predicted results in terms of the load-deformation curves and ultimate strength. The parametric studies indicate that the spacing of binding bars, diameter of longitudinal bars, concrete strength, thickness of the steel tube wall, and section dimension of the column generate different influence on the mechanical properties and bearing capacity. The diameter of longitudinal bars, concrete strength, and section dimension of the column have a great effect on the ultimate bearing capacity. The numerical results also show that the spacing of binding bars has little effect on the ultimate bearing capacity. The larger thickness of the steel tube wall leads to adverse effect on the specimen performance. Finally, the theoretical calculation is carried out, and the result is good.

Experimental Studies on Axially Loaded Concrete Columns Confined by Different Materials

2008 ◽  
Vol 400-402 ◽  
pp. 513-518 ◽  
Author(s):  
Yong Chang Guo ◽  
Pei Yan Huang ◽  
Yang Yang ◽  
Li Juan Li
Keyword(s):  
Bearing Capacity ◽  
Glass Fiber ◽  
Failure Modes ◽  
Experimental Studies ◽  
Concrete Columns ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Advantages And Disadvantages ◽  
Axially Loaded ◽  
Normal Strength

The improvement of the load carrying capacity of concrete columns under a triaxial compressive stress results from the strain restriction. Under a triaxial stress state, the capacity of the deformation of concrete is greatly decreased with the increase of the side compression. Therefore, confining the deformation in the lateral orientation is an effective way to improve the strength and ductility of concrete columns. This paper carried out an experimental investigation on axially loaded normal strength concrete columns confined by 10 different types of materials, including steel tube, glass fiber confined steel tube (GFRP), PVC tube, carbon fiber confined PVC tube (CFRP), glass fiber confined PVC tube (GFRP), CFRP, GFRP, polyethylene (PE), PE hybrid CFRP and PE hybrid GFRP. The deformation, macroscopical deformation characters, failure mechanism and failure modes are studied in this paper. The ultimate bearing capacity of these 10 types of confined concrete columns and the influences of the confining materials on the ultimate bearing capacity are obtained. The advantages and disadvantages of these 10 types of confining methods are compared.

Ultimate Bearing Capacity Analysis of Axially Compressive Circular Steel Tube Columns Filled with Bar-Reinforced Concrete

2011 ◽  
Vol 94-96 ◽  
pp. 1205-1210
Author(s):  
Zhao Liu ◽  
Jun Hai Zhao
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Strength Theory ◽  
Principal Stresses ◽  
Unified Strength Theory ◽  
Short Columns ◽  
Circular Steel Tube ◽  
Circular Bar

The mechanical behavior and ultimate bearing capacity of the circular bar-reinforced concrete filled steel tube (BRCFST) short columns under axial compression are analyzed in this paper based on the unified strength theory. Considering the restriction effect of steel tube and hoop bar on concrete, the calculation formula of bearing capacity of the column is deduced. Parametric studies are carried out to evaluate the effects of intermediate principal stresses, diameter-thickness ratio of steel tube and the stirrup ratio on the bearing capacity of the column. A good agreement is reached by comparing the results calculated by the formula with the test results. It is concluded that the unified strength theory is applicable in the theoretical analyses of the BRCFST columns.

Analysis of Uniaxial Dynamic Performance of Concrete-Filled Square Steel Tube Composite Column

2011 ◽  
Vol 94-96 ◽  
pp. 220-224 ◽  
Author(s):  
Xi Guang Cui ◽  
Hai Dong Xu
Keyword(s):  
Strain Rate ◽  
Bearing Capacity ◽  
Dynamic Performance ◽  
Concrete Strength ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Element Analysis ◽  
Compression Performance ◽  
Calculation Results ◽  
Square Steel Tube

Considering the strain rate then puts forward the modified uniaxial dynamic constitutive model related to strain rate in concrete-filled square steel tube and the modified calculation results match well with the experimental results. Based on the above conclusion, uniaxial compression performance finite element analysis with different strain rate among 10-5/s–10-3/s is completed, the results showed that strain rate can obviously change the dynamic performance of the concrete-filled square steel tube. Through the analysis of the influencing factors of the core concrete compressive strength, it is showed that with the increasing of the strain rate and the improving of concrete strength, the ultimate bearing capacity of concrete-filled square steel tube is higher and the ductility is reduced. With the increasing of stirrup ratio, ultimate bearing capacity is greater and the ductility is enhanced. With the sectional dimensions increasing, the ultimate bearing capacity is greater and the ductility is enhanced.

On the Stability Capacity of Steel Tube Filled with Steel-Reinforced Concrete Column Subject to Axial Compression

2012 ◽  
Vol 490-495 ◽  
pp. 3177-3181
Author(s):  
Xiao Liu ◽  
Lei Zhao
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Energy Method ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Least Square ◽  
Stability Coefficient ◽  
Steel Reinforced Concrete ◽  
Axial Stability

Steel tube filled with steel-reinforced concrete (STSRC) is a new kind of heavy load column, which made by inserting steel skeletons into the steel tube, then injecting the concrete to the tube. In order to study the combined column’s stability subject to axial compression, we use energy method and numerical methods analysis derives the formula of stability coefficient in which slenderness ratio as the main parameters. Using the 1/1000 column length as the initial deflection of the STSRC columns by FORTUNE calculation program, stability coefficient is produced through comparison and analysis between calculated results from quantile regression and that from ordinary least square regression respectively. According to the computer results and energy method, the formula for calculating the axial stability bearing capacity of STSRC was established. A good agreement between the calculation results and testing results illustrates, which is feasible to using the calculating formula to calculate the bearing capacity of STSRC

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong Ding ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

scholarly journals Experimental Study and Damage Model on the Seismic Behavior of Reinforced Concrete L-Shaped Columns under Combined Torsion

2020 ◽  
Vol 10 (19) ◽  
pp. 7008
Author(s):  
Deyi Xu ◽  
Yang Yang ◽  
Zongping Chen
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Combined Loading ◽  
Equivalent Viscous Damping ◽  
Axial Compression Ratio

Due to the advantage of saving indoor space, a special-shaped column frame attracted more attention of the engineers and researchers. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) L-shaped columns under compression-flexure-shear-torsion combined loadings to investigate the effect in the ratio of torsion to moment (T/M) and axial compression ratio (n) on their seismic performance. The results showed that the failure modes of L-shaped specimens included bending failure, bending-torsion failure, and torsion-shear failure with the hysteretic curves exhibiting S shape. With the increase of T/M ratio, cracks on the flange developed more fully, and the height of plastic hinge decreased and torsion bearing capacity improved. Besides, as the T/M ratio increased the twist ductility increased, while displacement ductility decreased. On the other hand, with a higher axial compression ratio, torsion bearing capacity and bending stiffness were both increased. Moreover, the equivalent viscous damping coefficient of bending and torsion were 0.08~0.28 and 0.13~0.23, respectively. The average inter-story drift ratio met the requirements of the Chinese standard. Finally, two modified models were proposed to predict the progression of damage for the L-shaped column under combined loading including torsion.

Seismic Behaviors of Concrete-Filled T-Shaped Steel Tube Columns

2008 ◽  
Vol 400-402 ◽  
pp. 677-683 ◽  
Author(s):  
Yu Yin Wang ◽  
Yuan Long Yang ◽  
Su Mei Zhang ◽  
Jie Peng Liu
Keyword(s):  
Numerical Analysis ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Concrete Strength ◽  
Steel Tube ◽  
Compression Stress ◽  
Analysis Program ◽  
Energy Dissipation Capacity ◽  
Seismic Behaviors

Concrete-filled special-shaped (L-shaped, T-shaped, and cross-shaped, and etc.) steel tube column is a type of member in which concrete is poured into special-shaped steel tube so that steel and concrete support loads together. It improves the seismic behaviors of reinforced concrete special-shaped columns due to the better confining effects provided by the steel tube. A test research on the seismic behaviors of one concrete-filled T-shaped steel tube column with pseudo static method is presented and the load-displacement curve and skeleton curve are provided. Series of steel bar stiffeners were welded onto the steel tube in order to postpone the buckling of steel tube and to enhance confining effects. A numerical analysis program was developed using a fiber-based method. The constitutive model of concrete employed the modified Mander model, and that of steel employed a bi-linear model considering the Bausinger effect. The numerical analysis program was verified by the test results and parametric analysis was carried out, in which the influences of the ratio of axial compression stress to strength, steel tube thickness and concrete strength were mainly discussed. The following conclusions are obtained: with the increase of the ratio of axial compression stress to strength, the bearing capacity of member increases and the energy dissipation capacity improve, while the ductility deteriorates. With the increase of steel tube thickness, the initial rigidity, bearing capacity, ductility and energy dissipation capacity improves simultaneously. With the increase of concrete strength, the bearing capacity increases, the energy dissipation capacity improves, while the ductility deteriorates.

Experiment on T-Shaped CFT Stub Columns with Binding Bars Subjected to Axial Compression

2013 ◽  
Vol 838-841 ◽  
pp. 439-443 ◽  
Author(s):  
Zhi Liang Zuo ◽  
Da Xin Liu ◽  
Jian Cai ◽  
Chun Yang ◽  
Qing Jun Chen
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Modes ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Plates ◽  
Buckling Modes ◽  
Cft Column ◽  
Stub Columns ◽  
Strength And Ductility

To improve the mechanical behavior of T-shaped concrete-filled steel tubular (T-CFT) column, the method that setting binding bars along the height of steel tube is proposed. Five T-CFT stub columns with binding bars and another two without binding bars subjected to axial compression were tested. The influences of the spacing and diameter of binding bars on the failure modes, maximum strength, and ductility of T-CFT stub columns are investigated. The experimental results demonstrate that by setting binding bars or decreasing the spacing of binding bars, the buckling modes of the steel plates are changed, the local buckling of the steel plates is postponed, and the confinement effects on the core concrete can be improved significantly. By setting binding bars, the bearing capacity and ductility of the columns are enhanced by 1.17 and 3.38 times at most, respectively. By increasing the diameter of binding bars, the ductility of the columns is improved, but the bearing capacity and buckling strength cannot be improved when the diameter is large enough.

Behaviour of Concrete Filled Steel Tube Reinforced Concrete (CFSTRC) Stub Columns: Experiments

2012 ◽  
Vol 166-169 ◽  
pp. 859-862 ◽  
Author(s):  
Yong Jin Li ◽  
Qing Xin Ren ◽  
Fei Yu Liao
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Axial Compression ◽  
Theoretical Study ◽  
Concrete Strength ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Stub Columns

Concrete filled steel tube (CFST) reinforced concrete (CFSTRC) columns subjected to axial compression were experimentally investigated in this paper. A total of ten specimens were tested. The main parameters varied in the experiments were steel tube ratio and concrete strength. It was found that, under axial compression, the column ultimate strength increases with the increasing of steel tube ratio and concrete strength. The work in this paper provides a basis for the further theoretical study on the behavior of CFSTRC columns.

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