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.

Experimental Study on Circular Hybrid SCCC Columns under Axial Compressive Load

2011 ◽  
Vol 368-373 ◽  
pp. 369-372
Author(s):  
Zhu Yan Li ◽  
Yong Jun Liu ◽  
Dong Wang
Keyword(s):  
Bearing Capacity ◽  
Test Specimen ◽  
Compressive Load ◽  
Strain Curve ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Compressive Performance ◽  
Core Concrete

The tests are order to investigate the axial compressive performance of the new circular hybrid Steel-Concrete- CFRP-Concrete column (simply called SCCC column).SCCC column is composed of steel tube, annular concrete, CFRP tube and core concrete. Axial ultimate bearing capacity test was performed on 3 SCCC columns, from which we gains the law of affecting SCCC columns, the load-strain curve and load-displacement curve of SCCC columns, and compare the test results of the test specimen with different annular concrete thicknesses, from which we finds that after the relationship curve of test specimen with small annular concrete thickness reaches yield load, the bearing capacity starts to decline, and then continues to rise till the ultimate load is reached and the test specimen is damaged. The result shows that the smaller the annular concrete thickness is, the greater the axial ultimate bearing capacity of SCCC column is, and also indicates that CFRP tube plays a role of binding and constraining to the core concrete in later period of loading the test specimens.

Bearing Capacity of Concrete Filled Square Steel Tube Short Columns with Inner CFRP Circular Tube under Eccentric Compression

2011 ◽  
Vol 243-249 ◽  
pp. 1272-1278
Author(s):  
Tian Hua Li ◽  
Jun Hai Zhao ◽  
Xue Ying Wei ◽  
Wei Kong ◽  
Xiao Ming Dong
Keyword(s):  
Bearing Capacity ◽  
Circular Tube ◽  
Steel Tube ◽  
Reduction Factor ◽  
Eccentricity Ratio ◽  
Strength Reduction Factor ◽  
The Core ◽  
Short Columns ◽  
Square Steel Tube ◽  
Core Concrete

Based on the unified strength theory, the bearing capacity of the concrete filled square steel tube short columns with inner CFRP circular tube under eccentric compression was analyzed. The restriction effect of the inner CFRP circular tube upon the core concrete, strength reduction factor for eccentricity ratio and the equivalent reduction factor, which considered the ratio of thickness to side effect, were taken into account in the theoretical analysis. The axial bearing capacity formula of the square steel tube short columns filled with inner CFRP circular tube was deduced. By introducing the strength reduction factor for eccentricity ratio, the eccentric bearing capacity formula on the basis of the axial bearing capacity formula was obtained. Parametric studies were carried out to evaluate the effects of intermediate principal stress, different CFRP deployment ratios, eccentricity ratios and the tension-compression ratio on the eccentric bearing capacity of the column. The formula was verified by the comparison of the theoretical results with the experimental data. The results show that inner CFRP circular tube can effectively restrain the core concrete.

scholarly journals A Study on Axial Compression Performance of Concrete-Filled Steel-Tubular Shear Wall with a Multi-Cavity T-Shaped Cross-Section

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4831
Author(s):  
Hao Sun ◽  
Qingyuan Xu ◽  
Pengfei Yan ◽  
Jianguang Yin ◽  
Ping Lou
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Limit State ◽  
Shear Wall ◽  
Steel Tube ◽  
Element Analysis ◽  
Compression Performance ◽  
The Core ◽  
Core Concrete

In order to study the axial compression performance of the T-shaped multi-cavity concrete-filled steel tube shear wall, first, three specimens were designed to perform the axial compression test. Then three-dimensional finite element analysis by the ABAQUS software was used to obtain the axial bearing capacity of the shear wall with different parameters. According to the results of the finite element model, the computational diagram in the limit state was obtained. The diagram was simplified into the core concrete in the non-enhanced area that was not constrained by the steel tube and the core concrete in the enhanced area that was uniformly constrained by the steel tube. Finally, a new practical equation for calculating the axial bearing capacity of a multi-cavity concrete-filled steel tubular shear wall was deduced and proposed based on the theory of ultimate equilibrium. The calculation results of the proposed equation were in good agreement with the finite element results, and the proposed equation can be used in practical engineering design.

Experimental Research on the Confinement Effect for the Composite Concrete-Filled Square Steel Tubular Short Columns

2010 ◽  
Vol 163-167 ◽  
pp. 2118-2123
Author(s):  
Bin Li ◽  
Chun Yan Gao
Keyword(s):  
Bearing Capacity ◽  
Concrete Strength ◽  
Steel Tube ◽  
Compression Tests ◽  
Steel Ratio ◽  
The Core ◽  
Short Columns ◽  
Core Concrete ◽  
Inclined Cracks ◽  
Section Form

Through the axial compression tests of two ordinary concrete-filled square steel tubular(CFSST) short columns and six composite CFSST short columns, the influence laws of section types, confinement coefficient, steel ratio and concrete strength on the mechanical behavior of the CFSST short columns were studied. The results show that in CFSST columns, the change of steel tube’s section form can improve effectively the cooperative work ability between the steel tube and core concrete, enhance the restraint effect of the steel tube on the core concrete, delay or inhibit the development of inclined cracks in the core concrete, increase the ductility and improve significantly the ultimate bearing capacity when the steel ratio or confinement coefficient is close to each other. With the increment of the confinement coefficient and steel ratio, the bearing capacity and ductility improve.

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 Numerical simulation of complex tubular joints of Beijing New Airport Terminal C type column

2019 ◽  
Vol 138 ◽  
pp. 01001
Author(s):  
A Zhang ◽  
G Shangguan ◽  
Yanxia Zhang ◽  
Dinan Shao
Keyword(s):  
Numerical Simulation ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Simulation Analysis ◽  
Economic Benefits ◽  
Tubular Joints ◽  
Airport Terminal ◽  
Stiffening Ribs ◽  
Final Optimization

The numerical simulation analysis of the two groups of fullscale complex tubular joints of the Beijing New Airport Terminal C type steel column under space static loading tests has been conducted by adopting software ABAQUS. The results obtained from the numerical simulation analysis consistent with those from the tests which enriched the research findings. Based on the research, mechanical performance of the joints has been carried out, the failure modes and ultimate bearing capacity of the joints with no stiffening ribs, three stiffening ribs and five stiffening ribs has been obtained. The numerical simulation results showed that, the bearing capacity of the joints without stiffening ribs were relatively low, the plastic failure of the main pipe was the major form of the destruction and the safety performance were too poor to meet the actual needs of the project. The bearing capacity of the joints significantly improved with the stiffening ribs set inside and the destruction changed to the connection of the main tubular and the branch, which means that the stress of the joints has been obviously improved by the setting of the stiffening ribs and was able to meet the needs of Beijing New Airport Terminal C type column. Through the comparative analysis of the stiffening ribs setting, it can be found that the bearing capacity of the joints were similar between the three and five stiffening ribs, considering the construction difficulty and economic benefits, three stiffening ribs has been selected as the final optimization result.

Study on the Axial Ultimate Bearing Capacity of Concrete-Filled Square Steel Tubular Stub Columns

2013 ◽  
Vol 690-693 ◽  
pp. 742-746
Author(s):  
Peng Wu ◽  
Jian Feng Xu ◽  
Jun Hai Zhao ◽  
Qian Zhu ◽  
Su Wang
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Strength Theory ◽  
Constraint Effect ◽  
Unified Strength Theory ◽  
Square Steel Tube ◽  
Core Concrete ◽  
Stub Columns

Based on unified strength theory, the mechanical behavior of core-concrete of concrete-filled square steel tubular stub columns was analyzed. Through controlling the constraint effect between square steel tube and core-concrete by width-thickness ratio, the ultimate bearing capacity formula for concrete-filled square steel tubular stub columns under axial compression was proposed, and the influencing factors of which was also discussed. The rationality of proposed formula was proved from the comparison of the analytical results obtained in this paper and experimental data.

Dynamic Behavior of Concrete Filled Double Steel Tube under Impact with Simply Supported

2014 ◽  
Vol 1065-1069 ◽  
pp. 1341-1344
Author(s):  
Gao Lei ◽  
Rui Wang
Keyword(s):  
Bearing Capacity ◽  
Dynamic Behavior ◽  
Power Transmission ◽  
Steel Tube ◽  
Transmission Tower ◽  
Good Resistance ◽  
Impact Performance ◽  
Simply Supported ◽  
High Rise ◽  
Core Concrete

Concrete filled double skins steel tube is a new components which is based on concrete filled steel tubular and use inner steel tube instead of core concrete. The components have many advantages such as little weight, good resistance for earthquake, good stiffness for resist bending and good performance for resist fire, and has been used in bridge pier, high-rise buildings, power transmission tower and so on. While these structures may inevitably suffer impact which comes from vehicles, ships, aircraft, etc. the structures which is impacted have taken much attention. This article will analysis dynamic behavior of concrete filled double steel tube under impact with simply supported, and propose formula of dynamic bearing capacity, laid the foundation for the analysis of impact performance of CFDST.

scholarly journals Experimental Investigation of Connection Details on the Cyclic Performance of All-steel Tubular Buckling Restrained Braces

2020 ◽  
Author(s):  
Seayf Allah Hemati ◽  
Ali Kheyroddin ◽  
Mohammad Ali Barkhordari Bafghi
Keyword(s):  
Compressive Load ◽  
Tensile Load ◽  
Variable Cross Section ◽  
Steel Tube ◽  
Transitional Region ◽  
Variable Cross ◽  
Load Bearing ◽  
The Core ◽  
Buckling Restrained Braces ◽  
Geometrical Defects

To eliminate the geometrical defects and to reduce the damage caused by out-off-plane rotation of the end portion of the conven-tional buckling restrained braces, as well as introducing a new way to facilitate the construction and installation process, the exper-imental behavior of 5 proposed specimens as new type of all-steel tubular buckling restrained braces (AST-BRB) under cyclic axial loads was studied.The proposed specimens consist of a steel tube as a load bearing member (core), which is placed inside a larger tube as a buckling restraining member (pod). At the two ends of the core member, different end details and connection (compared to the common BRBs) are provided as the elastic transitional region. The performance of the specimens were evaluated based on indices, such as damage mode, repeatable behavior, adjusted strength factors, load-bearing capacity, and cumulative inelastic displacement.The evaluation of the results indicated that, the specimens, which welded variable cross-section steel lids at both ends of the core, have superior seismic performance. The superior specimens, for all cycles with larger displacements of the yielding displacement, exhibited a stable hysteresis behavior in bearing of cyclic loads. The bearing pressure was about 1.07 times greater than the tensile load. The cumulative inelastic axial displacements of these specimens is at least 209 times of their yield displacement. Meanwhile, they can tolerate at least 140 % compressive load and 10 % greater tension loads relative to the nominal capacity of the core individual.

Experimental Research on Full-Scale Reinforced Concrete Columns with Strong Confinement under Concentric Compression

2012 ◽  
Vol 166-169 ◽  
pp. 836-842
Author(s):  
Wei Jing Zhang ◽  
Bing Zhang ◽  
Zhen Bao Li ◽  
Jinjin Wang ◽  
Wen Jing Wang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Columns ◽  
Full Scale ◽  
Tensile Yield Strength ◽  
Reinforced Concrete Columns ◽  
The Core ◽  
Deformation Ability ◽  
Strong Confinement ◽  
Core Concrete

To investigate the axial compressive behavior of reinforced concrete columns with strong confinement, a total of five full-scale reinforced concrete columns with stirrup characteristic values in the range 0.22~0.47 and section dimension 600mm×600mm were tested under concentric compression loading. The test results indicated that all specimens failed in a similar way. The longitudinal bars buckled in compression; the peripheral stirrups bowed out and several stirrups fractured; the cover concrete in the mid-height section of specimens spalled seriously; however, the core concrete of specimens was not crushed. The axial compressive bearing capacity and deformation ability of reinforced concrete columns could be improved by strong confinement. When specimens reached the ultimate bearing capacity, the longitudinal reinforcement yielded and provided axial bearing capacity for specimens; the transverse reinforcement reached tensile yield strength and provided effective confinement for the core concrete.

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