scholarly journals Experimental Study and Mechanism Analysis of Concrete-Filled Square Steel Tubular Columns Reinforced by Rhombic Stirrups Under Axial Compression

2021 ◽  
Vol 8 ◽  
Author(s):  
Zongping Chen ◽  
Fan Ning ◽  
Linlin Mo
Keyword(s):  
Aspect Ratio ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Axial Compression ◽  
Failure Process ◽  
Steel Tube ◽  
Mechanism Analysis ◽  
Steel Ratio ◽  
Load Displacement ◽  
Square Steel Tube

The square steel tube component has a beautiful appearance, simple joint connection, and it is widely available. However, the uneven distribution of effective constraints in the cross-section of a square steel tube hinders its application. A novel concrete-filled square steel tubular column was tested under axial compression. There were 11 specimens [10 concrete-filled square steel tube columns reinforced with rhombic stirrups with 90-degree internal angle (SSSC specimens) and 1 concrete-filled square steel tube column (SC specimen)]. The load-displacement curves, the law of failure process, failure mode, mechanism analysis, energy consumption, ductility, and stiffness degradation were described, we then investigated the influence of stirrup diameter, stirrup side length, stirrup spacing, steel tube thickness, aspect ratio, and steel ratio on the mechanical properties of the specimens. The results show that the failure process of the SSSC specimens was basically the same. The ultimate failure mode of the specimens with an aspect ratio of 4 was local buckling failure. The specimens with an aspect ratio of 5 and 6 failed due to bending failure in the plastic stage. The steel tube bulged out in different degrees in most of the debonding areas. The longitudinal bars also produced outward bending deformation in the larger bulging area of the steel tube. Some of the stirrups were broken in the later stage of loading. The characteristics of load-displacement curve changed with the changing of stirrup spacing. The strength of longitudinal constraint had an obvious influence on the bearing capacity. In a certain range of steel ratio (ρs = 8.97% ∼ 9.05%), the weakening of the lateral restraint of the stirrup cage had a greater adverse effect on the bearing capacity than the weakening of the effective restraint of the corner. In a certain range of steel ratio (ρs = 8.97% ∼ 9.49%), strengthening the effective corner constraint of stirrups improved the stiffness of the specimen, however, the ductility performance was reduced. The opposite was true for strengthening the lateral constraint of the stirrup cage.

scholarly journals Experimental Study of H-Shaped Honeycombed Stub Columns with Rectangular Concrete-Filled Steel Tube Flanges Subjected to Axial Load

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jing Ji ◽  
Maomao Yang ◽  
Zhichao Xu ◽  
Liangqin Jiang ◽  
Huayu Song
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Axial Load ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Design Guidelines ◽  
Correction Function ◽  
Concrete Filled Steel Tube ◽  
Load Displacement ◽  
Stub Columns

The behavior of H-shaped honeycombed stub columns with rectangular concrete-filled steel tube flanges (STHCCs) subjected to axial load was investigated experimentally. A total of 16 specimens were studied, and the main parameters varied in the tests included the confinement effect coefficient of the steel tube (ξ), the concrete cubic compressive strength (fcu), the steel web thickness (t2), and the slenderness ratio of specimens (λs). Failure modes, load-displacement curves, load-strain curves of the steel tube flanges and webs, and force mechanisms were obtained by means of axial compression tests. The parameter influences on the axial compression bearing capacity and ductility were then analyzed. The results showed that rudder slip diagonal lines occur on the steel tube outer surface and the concrete-filled steel tube flanges of all specimens exhibit shear failure. Specimen load-displacement curves can be broadly divided into elastic deformation, elastic-plastic deformation, and load descending and residual deformation stages. The specimen axial compression bearing capacity and ductility increase with increasing ξ, and the axial compression bearing capacity increases gradually with increasing fcu, whereas the ductility decreases. The ductility significantly improves with increasing t2, whereas the axial compression bearing capacity increases slightly. The axial compression bearing capacity decreases gradually with increasing λs, whereas the ductility increases. An analytical expression for the STHCC short column axial compression bearing capacity is established by introducing a correction function ( w ), which has good agreement with experimental results. Finally, several design guidelines are suggested, which can provide a foundation for the popularization and application of this kind of novel composite column in practical engineering projects.

scholarly journals Experimental Study on Ultrahigh Strength Concrete Filled Steel Tube Short Columns under Axial Load

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaojun Zhou ◽  
Tingmin Mou ◽  
Hongyuan Tang ◽  
Bikun Fan
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Steel Tube ◽  
Strength Concrete ◽  
Steel Ratio ◽  
Ultrahigh Strength ◽  
Short Columns ◽  
Confining Effect ◽  
Steel Strength

Based on the project of Modaoxi Bridge, an experimental study on the compressive behavior of ultrahigh strength concrete filled steel tube (UHSCFST) short column was conducted. A total of 9 UHSCFST specimens were tested, and the cube strength (fcu) of the core concrete reached 115.4 MPa. Main parameters were the confining factor (ξ=0.608, 0.919, and 1.015), steel ratio (α=14.67%, 20.02%, and 21.98%), and steel strength (fy = 349 MPa, 352 MPa, and 427 MPa). The axially loading test results showed that the visible damage of steel tube occurred under the ultimate load. The higher the confining effect, the less the damage features. And all specimens basically presented a drum-type failure mode. The confining effect of steel tube effectively changed the brittle failure mode of ultrahigh strength concrete (UHSC) and tremendously improved the load bearing capacity and ductility of specimens. Moreover, the higher the steel ratio and steel strength of the specimens, the stronger the confining effect. Meanwhile the excellent mechanical properties will be obtained. Also it is recommended that the UHSCFST prefers Q345 or above strength steel tube to ensure sufficient ductility, and the steel ratio should be more than 20%. Furthermore, the confining effect of steel tubes can improve the ultimate bearing capacity of the ultrahigh strength CFST short columns.

scholarly journals Research on the mechanical properties of concrete stub column under axial compression loading with square steel tube self-compacting iron tailing

2020 ◽  
Vol 165 ◽  
pp. 04024
Author(s):  
Yuan Xi Wang ◽  
Xi Kai Du ◽  
Jing Hong Liu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Test Piece ◽  
Substitution Rate ◽  
Steel Tube ◽  
Test Results ◽  
Compression Loading ◽  
Stub Column ◽  
Square Steel Tube ◽  
Stub Columns

In this paper, the influence of steel rate and substitution rate of iron tailing powder on the bearing capacity of the stub columns is mainly investigated through the test of five concrete stub columns under axial compression loading with square steel tube self-compacting iron tailing, and the test bearing capacity is compared with the bearing capacity calculated by each code. The test results show that the bearing capacity of the test piece increases obviously with the increase of the steel content; the bearing capacity of the test piece is less affected by the substitution rate of iron tailing powder; it is suggested to use code GB50936-2014 to design and calculate the bearing capacity of the stub column under axial compression loading.

Finite Element Simulation on Behavior of the High-Strength Concrete Filled High-Strength Square Steel Tube Middle-Long Columns under Axial Compressive Load

2014 ◽  
Vol 578-579 ◽  
pp. 340-345
Author(s):  
Guo Chang Li ◽  
Bo Wen Zhu ◽  
Yu Liu
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Slenderness Ratio ◽  
High Strength ◽  
Steel Tube ◽  
New Combination ◽  
Length Variation ◽  
Compression Process ◽  
Strength Concrete ◽  
Square Steel Tube

In this paper, using ABAQUS, 16 high-strength concrete filled high-strength square steel tube middle-long columns’ axial compression process were simulated. The load-deflection relationships were obtained and the new combination in improving the bearing capacity and plastic deformation has a great advantage. Realization of length variation slenderness ratio by changing the length of column, this paper also study the influence of slenderness ratio, the main parameters of the high-strength concrete filled high-strength square steel tube middle-long column. It is found that both bearing capacity and the plastic capacity are associated with slenderness ratio.

scholarly journals Experimental Study on Axial Compression Behavior of Masonry Columns’ Strengthening with Bamboo Scrimber Bar Mesh Mortar Layer

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Hongyao Liu ◽  
Min Lei ◽  
Bowang Chen
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Process ◽  
Engineering Application ◽  
Compression Tests ◽  
Compression Behavior ◽  
Bamboo Scrimber ◽  
Calculation Results ◽  
Strengthening Method

We propose a new method to strengthen structural masonry. To study on the axial compression behavior of masonry columns’ strengthening with a bamboo scrimber bar mesh mortar layer, axial compression tests of twelve masonry columns have been completed: nine strengthened columns and three unstrengthened columns. The failure process, bearing capacity, and failure mode are carried out. The strengthening method of bamboo scrimber bar mesh mortar layer permits the upgrade of the columns’ bearing capacity. The effects of bamboo bar ratio and mortar strengthening ratio on bearing capacity of the reinforced columns are compared. We propose the method for calculating the axial bearing capacity of such a reinforced column. The calculation results agree well with the experimental results, and the research results are available for engineering application.

Numerical Simulation on the Mechanical Performance of the Wind Generator Latticed Concrete-Filled Steel Tubular Tower

2014 ◽  
Vol 578-579 ◽  
pp. 751-756
Author(s):  
Bin Li ◽  
Qun Hui Zhang ◽  
Chun Yan Gao
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Mechanical Performance ◽  
Great Influence ◽  
Local Buckling ◽  
Ultimate Bearing Capacity ◽  
Thickness Ratio ◽  
Stiffness Ratio

Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.

Investigate on Axial Load Behaviors of T-Shaped CFT Stub Columns with Binding Bars

2014 ◽  
Vol 501-504 ◽  
pp. 510-513
Author(s):  
Xin Zhi Zheng ◽  
Xin Hua Zheng
Keyword(s):  
Experimental Data ◽  
Bearing Capacity ◽  
Ultimate Strength ◽  
Failure Mode ◽  
Axial Compression ◽  
Axial Load ◽  
Constitutive Relationship ◽  
Relationship Of ◽  
Stub Columns

. Abstract. Tests on TCFT-WB, including 11 specimens with binding bars and 5 without binding bars under axial compression were carried out. The effects of parameters on the behavior of specimens such as failure mode, bearing capacity and ductility are analyzed to provide experimental data for the following research. The formula to calculate ultimate strength of TCFT-WB columns under axial compression are deduced from the constitutive relationship of TCFT-WB. The calculated results are compared with those calculated by FEM analyses, showing the proposed formula can give reasonable predictions on the ultimate strength of TCFT-WB stub columns under axial compression.

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.

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.

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

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