Experimental Research on Concrete-Filled GFRP Tubes and GFRP-Steel Composite Tubes under Axial Compressive Load

2010 ◽  
Vol 163-167 ◽  
pp. 2052-2055
Author(s):  
Xiao Lu Wang ◽  
Xiao Xiong Zha
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Compressive Load ◽  
Concrete Columns ◽  
Steel Tube ◽  
Filament Wound ◽  
Reinforced Steel ◽  
Steel Composite ◽  
Cfst Columns ◽  
Experimental Group

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.

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.

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.

scholarly journals Derivation of the unified equation of axial compression of CFST columns

2020 ◽  
Vol 143 ◽  
pp. 01004
Author(s):  
Ruoyang Zhou ◽  
Xiaoxiong Zha
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Limit Equilibrium ◽  
Concrete Columns ◽  
Steel Tube ◽  
Steel Reinforcement ◽  
Steel Plates ◽  
Steel Tubes ◽  
High Rise ◽  
Cfst Columns

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

Experimental Research on Eccentric Compressive Performance of Steel Tube-Reinforced Concrete Column

2010 ◽  
Vol 163-167 ◽  
pp. 184-190
Author(s):  
Quan Quan Guo ◽  
Yu Xi Zhao ◽  
Kun Shang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Compressive Load ◽  
Concrete Columns ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Concrete Column ◽  
Reinforced Concrete Column ◽  
Reinforced Concrete Columns

Eccentric loading experiment of 13 steel tube-reinforced concrete columns and a reinforced concrete column is implemented. The whole process from the start load on the steel tube-reinforced concrete column until damage has been researched. Change of ultimate bearing capacity with eccentricity, longitudinal reinforcement ratio, position coefficient has been studied, and deflection curve and load-vertical displacement curve under eccentric compressive load were obtained. Failure characteristics of steel tube-reinforced concrete were divided into two different type, small eccentric damage and big eccentric damage. With the same conditions, when steel tube ratio of steel tube-reinforced concrete was 2%, its ultimate bearing capacity was nearly double of reinforced concrete columns.

Eccentric compression behaviour of rectangular concrete-filled steel tube columns with self-compacting lower expansion concrete

2022 ◽  
pp. 136943322110542
Author(s):  
XiuShu Qu ◽  
Yuxiang Deng ◽  
GuoJun Sun ◽  
Qingwen Liu ◽  
Qi Liu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Numerical Models ◽  
Experimental Studies ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Compression Behaviour ◽  
Eccentric Compression ◽  
Cfst Columns

The use of a self-compacting lower expansion concrete in a concrete-filled steel tube (CFST) structure not only promotes the quality of concrete pouring but also improves the bond behaviour between the steel and the concrete. In combination with the actual stress state of the columns in the engineering structure, it is necessary to study the eccentric compression behaviour of the column. In this study, experimental studies involving both uniaxial and biaxial bending tests of rectangular self-compacting lower expansion CFST columns were carried out. The variation laws of the load–displacement curves, the lateral deflection curves and the stress–strain curves during the loading phase were analysed. Furthermore, the failure modes and the mechanical properties of the specimens under eccentric compression loads were investigated. Subsequently, the numerical models of CFST columns with self-compacting lower expansion concrete were considered and established. In order to verify the rationality of the finite element modelling, the numerical calculation results were compared with test results. Then, a parametric analysis of the compression and the bending bearing capacities of each column was carried out by changing the eccentricity of the load, and the N–M curves or N-Mx-My surfaces describing the ultimate bearing capacity of the column were obtained. Finally, by the parametric finite element analysis of the rectangular CFST columns regarding to the bearing capacity under the same eccentricity, a conclusion was obtained: when the expansion agent content γ of a specimen increased from 0% to 10%, the bearing capacity of the columns increases significantly, but when continue increasing the expansive agent content, the expansion agent content has little effect on the compression–bending bearing capacity.

scholarly journals Axial Behaviour of Slender RC Circular Columns Strengthened with Circular CFST Jackets

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yiyan Lu ◽  
Tao Zhu ◽  
Shan Li ◽  
Weijie Li ◽  
Na Li
Keyword(s):  
Bearing Capacity ◽  
Ductile Failure ◽  
Steel Tube ◽  
Experimental Results ◽  
Strengthening Effect ◽  
Load Bearing Capacity ◽  
Rc Columns ◽  
Load Bearing ◽  
Cfst Columns ◽  
Material Utilization

This paper investigates the axial behavior of slender reinforced concrete (RC) columns strengthened with concrete filled steel tube (CFST) jacketing technique. It is realized by pouring self-compacting concrete (SCC) into the gap between inner original slender RC columns and outer steel tubes. Nine specimens were prepared and tested to failure under axial compression: a control specimen without strengthening and eight specimens with heights ranging between 1240 and 2140 mm strengthened with CFST jacketing. Experimental variables included four different length-to-diameter (L/D) ratios, three different diameter-to-thickness (D/t) ratios, and three different SCC strengths. The experimental results showed that the outer steel tube provided confinement to the SCC and original slender RC columns and thus effectively improved the behavior of slender RC columns. The failure mode of slender RC columns was changed from brittle failure (concrete peel-off) into ductile failure (global bending) after strengthening. And, the load-bearing capacity, material utilization, and ductility of slender RC columns were significantly enhanced. The strengthening effect of CFST jacketing decreased with the increase of L/D ratio and D/t ratio but showed little variation with higher SCC strength. An existing expression of load-bearing capacity for traditional CFST columns was extended to propose a formula for the load-bearing capacity of CFST jacketed columns, and the predictions showed good agreement with the experimental results.

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 Behavior of Rectangular-Sectional Steel Tubular Columns Filled with High-Strength Steel Fiber Reinforced Concrete Under Axial Compression

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2716 ◽  
Author(s):  
Shiming Liu ◽  
Xinxin Ding ◽  
Xiaoke Li ◽  
Yongjian Liu ◽  
Shunbo Zhao
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Local Buckling ◽  
Steel Tube ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Energy Dissipation Capacity

This paper studies the effect of high-strength steel fiber reinforced concrete (SFRC) on the axial compression behavior of rectangular-sectional SFRC-filled steel tube columns. The purpose is to improve the integrated bearing capacity of these composite columns. Nine rectangular-sectional SFRC-filled steel tube columns and one normal concrete-filled steel tube column were designed and tested under axial loading to failure. The compressive strength of concrete, the volume fraction of steel fiber, the type of internal longitudinal stiffener and the spacing of circular holes in perfobond rib were considered as the main parameters. The failure modes, axial load-deformation curves, energy dissipation capacity, axial bearing capacity, and ductility index are presented. The results identified that steel fiber delayed the local buckling of steel tube and increased the ductility and energy dissipation capacity of the columns when the volume fraction of steel fiber was not less than 0.8%. The longitudinal internal stiffening ribs and their type changed the failure modes of the local buckling of steel tube, and perfobond ribs increased the ductility and energy dissipation capacity to some degree. The compressive strength of SFRC failed to change the failure modes, but had a significant impact on the energy dissipation capacity, bearing capacity, and ductility. The predictive formulas for the bearing capacity and ductility index of rectangular-sectional SFRC-filled steel tube columns are proposed to be used in engineering practice.

Research on Concrete-Filled Rectangular Steel Tube Stiffeners and Axial Compression Bearing Capacity

2014 ◽  
Vol 1065-1069 ◽  
pp. 1092-1096 ◽  
Author(s):  
Gao Cheng ◽  
Yong Jian Liu ◽  
Lei Jiang
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Compressive Load ◽  
Steel Tube ◽  
Simple Construction ◽  
The Core ◽  
Steel Bar ◽  
Stiffening Ribs ◽  
Reinforcement Measures ◽  
Core Concrete

Concrete-filled rectangular steel tube four sides restraint effect on the core concrete was weaker than the corner, which made the effect not significant. The paper studied a new kind of stiffening rib –PBL stiffener to strengthen restraint effect of concrete-filled rectangular steel tube , and evaluated its advantages compared with other stiffening ribs. 9 PBL stiffened concrete-filled rectangular steel tube columns under axial compressive load were tested. It also collected the test with other stiffened rids, such as straight ribs, binding bars, knee brace, steel reinforcement cage, steel bar stiffeners, saw tooth shaped stiffeners, stitching straight stiffeners and no rib concrete filled rectangular steel tube to compare. It evaluated increasing coefficient of bearing capacity by stiffening ribs. The results showed that: the PBL stiffeners and binding bar of concrete-filled rectangular steel tube bearing capacity was greater than other reinforcement measures by more than 20%; PBL stiffener could be a new prominent type of stiffener because of its excellent mechanical performance and simple construction.

Effect of Concrete-Filled in Chord Tubes on Mechanical Behavior of RHS Steel Tube Trusses

2010 ◽  
Vol 163-167 ◽  
pp. 2171-2175 ◽  
Author(s):  
Jun Ping Liu ◽  
Yong Jian Liu ◽  
Jian Yang
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Steel Tube ◽  
Structural Stiffness ◽  
Static Behavior ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Compression Load ◽  
Hollow Section ◽  
Joint Deformation

Based on the experimental results, this paper presents the effects of concrete-filled in chord on the static behavior of rectangular hollow section (RHS) steel tubular trusses, including failure modes, load bearing capacity and structural stiffness. Failure of RHS trusses occurs at joints wether concrete-filled in chord or not, concrete-filled in chord changed the failure mode. Load bearing capacity and stiffness of joints subjected to compression load increased significantly, while it is limited to the tension joints. Concrete-filled in the compression chord tube can increase its stiffness significantly, while tension chord tube, it is not that obvious. Finally, based on the results discussed, failure modes and their formulas of calculating the load bearing capacity are discussed. Meanwhile, two methods, that is, amplified factor method and stiffness discounting method, which calculate the structural displacement when considering the joint deformation effects are presented.

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