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.

scholarly journals Mechanism Study on the Axial Compressive Performance of Short Square CFST Columns with Different Stiffeners

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bing Xu ◽  
Fahong Wu ◽  
Guizhong Xu
Keyword(s):  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Mechanism Study ◽  
Compression Performance ◽  
Compressive Performance ◽  
Combined Action ◽  
Cfst Columns ◽  
Distribution Of Stress ◽  
Core Concrete

In order to limit the disengaging of short square concrete-filled steel tube (CFST) columns and strengthen the combined action of steel tubes and concrete, a reinforcing method of stiffener is put forward in this paper. The axial compression performance and mechanism are studied through experiments, which indicate that (1) the buckling model of stiffening members changes into double wave, (2) stiffeners enforce the constraint in core concrete, (3) stiffeners can effectively improve the ultimate bearing capacity, (4) the stiffeners increase the stress in the middle of the steel tube and improve the distribution of stress for the core concrete, and (5) the direct ribs have more influence on the bearing capacity while ribs with holes have more impact on the deformation of the tube. At the end of the article, a formula for calculating the ultimate bearing capacity is presented, which can bring out a more accurate bearing capacity value.

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.

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.

scholarly journals Axial Compression Performance of Square Thin Walled Concrete-Filled Steel Tube Stub Columns with Reinforcement Stiffener under Constant High-Temperature

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1098 ◽  
Author(s):  
Xuetao Lyu ◽  
Yang Xu ◽  
Qian Xu ◽  
Yang Yu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Bearing Capacity ◽  
Numerical Models ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Concrete Filled Steel Tube ◽  
Finite Element Software ◽  
Thin Walled

This study investigated the axial compressive performance of six thin-walled concrete-filled steel tube (CFST) square column specimens with steel bar stiffeners and two non-stiffened specimens at constant temperatures of 20 °C, 100 °C, 200 °C, 400 °C, 600 °C and 800 °C. The mechanical properties of the specimens at different temperatures were analyzed in terms of the ultimate bearing capacity, failure mode, and load–displacement curve. The experiment results show that at high temperature, even though the mechanical properties of the specimens declined, leading to a decrease of the ultimate bearing capacity, the ductility and deformation capacity of the specimens improved inversely. Based on finite element software ABAQUS, numerical models were developed to calculate both temperature and mechanical fields, the results of which were in good agreement with experimental results. Then, the stress mechanism of eight specimens was analyzed using established numerical models. The analysis results show that with the increase of temperature, the longitudinal stress gradient of the concrete in the specimen column increases while the stress value decreases. The lateral restraint of the stiffeners is capable of restraining the steel outer buckling and enhancing the restraint effect on the concrete.

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.

scholarly journals Axial Compressive Performance of a Composite Concrete-Filled GFRP Tube Square Column

2021 ◽  
Vol 11 (15) ◽  
pp. 6757
Author(s):  
Jiancheng Lu ◽  
Yujun Qi ◽  
Yifei Li ◽  
Xuxu Wang
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Peak Load ◽  
Strain Curve ◽  
Displacement Curve ◽  
Composite Column ◽  
Composite Columns ◽  
Compressive Performance ◽  
New Type ◽  
The Impact

A composite concrete-filled glass fiber reinforced polymer (GFRP) tube square column is a new type of composite column, where GFRP is externally wrapped over several GFRP square tubes to form a multicavity GFRP tube, and then concrete is poured inside. External GFRP wrapping methods can be divided into two types: entirely wrapped and strip-type wrapped methods. The former is superior to the latter in terms of performance under stress. However, difficulties are introduced in the construction process of the former, and substantial materials are required to wrap the entire structure. To examine the axial compressive performance for this new type of composite column and the impact of the wrapping method, we designed and fabricated one type of entirely wrapped composite column and two types of strip-type wrapped composite columns with clear spacings of 85 mm and 40 mm, respectively, and performed static axial compression tests. Through tests and numerical simulations, we obtained the failure mode, load–displacement curve, and load–strain curve of the specimen, and analyzed the impact of the externally wrapped GFRP on the mechanical behavior of the composite column. The results show that the composite column reached the peak load before the fracture of the GFRP tube fiber occurred, and the bearing capacity declined sharply to approximately 75% of the peak load after the fiber fractured, then entered a platform section, thereby displaying ductile failure. As the wrapped layers of GFRP strips increased, the load capacity of the specimen exhibited a linear growth tendency. Compared with the performance of the entirely wrapped method, the load capacity of the specimens in the W5040 group declined 9.8% on average, and the peak efficiency of the GFRP strips increased by 50%, thereby indicating that the use of appropriate GFRP layers and strip distance intervals can ensure the appropriate bearing capacity of composite columns and full utilization of GFRP material properties.

Buckling Analysis Method and Application of a Square Steel Tube Member with Initial Geometric Imperfection under Axial Compressive Load and Bending Moment

2013 ◽  
Vol 351-352 ◽  
pp. 237-240 ◽  
Author(s):  
Peng Niu ◽  
Xiao Chu Wang ◽  
Chun Fu Jin ◽  
Yong Qi Zhang
Keyword(s):  
Finite Element Method ◽  
Bearing Capacity ◽  
Compressive Load ◽  
Bending Moment ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Geometric Imperfection ◽  
Axial Compressive Load ◽  
Initial Geometric Imperfection ◽  
Square Steel Tube

Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, considering the initial imperfection, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for a square steel tube member are derived. Using the elastic-plastic finite element method and the theory of nonlinear buckling, the impact by initial geometric imperfections on the square steel tube member under the axial compressive load and the bending moment are analyzed and the numerical solutions of ultimate bearing capacity are obtained. By compared with the values of the finite element method (FEM), it shows that the analytical method in this paper is valid. The results of the example show that the presence of initial imperfections reduces the ultimate bearing capacity of the steel member to a great extent. It is also found that the influence of the initial geometric imperfection on the ultimate bearing capacity of member is smaller when the M increases.

Research on Axial Behavior of Thin-Walled T-Shaped Steel Stub Columns Filled with Recycled Demolished Concrete Lump

2013 ◽  
Vol 690-693 ◽  
pp. 881-885 ◽  
Author(s):  
Ai Hua Jin ◽  
Bai Shou Li
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Thin Wall ◽  
Structural Members ◽  
Short Columns ◽  
Element Simulation

An axial compression test has been done on 12 short columns, ribbed and spiral stirrup short column filled with recycled demolished concrete lump to study the axial compression variable characteristics and ultimate bearing capacity of thin-wall T-shaped steel tube column filled with recycled demolished concrete lump. The load displacement curve has been analyzed, ultimate bearing capacity of standard formula has been compared and the reliability of finite element numerical simulation and been discussed. The result shown that the form of steel tube embedded with structural members has more effectively increased the tensility, delayed bending occurrence, enhanced the effect of restraint of core concrete and increased the ultimate bearing capacity than that the form of plain section form. The ultimate bearing capacity of ribbed form has been increased by 16.76% than non-ribbed form，and the ultimate bearing capacity of spiral stirrup form has been increased by 11.98 % than non-spiral stirrup form. The finite element simulation and the test result was identical properly.

scholarly journals Prediction and Analysis of Ultimate Bearing Capacity of Square CFST Long Column under Eccentric Compression after Acid Rain Corrosion

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2568
Author(s):  
Xuetao Lyu ◽  
Liqiang Zhang ◽  
Tong Zhang ◽  
Ben Li ◽  
Huan Li ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Bearing Capacity ◽  
Acid Rain ◽  
Slenderness Ratio ◽  
Compressive Load ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Steel Ratio ◽  
Eccentric Compression ◽  
Section Size

This paper adopts the method of steel tube wall thickness and strength reduction to simulate corrosion damage. The numerical model of the square concrete-filled steel tube long column (SCFST-LC) under eccentric compression after acid rain corrosion is established in the finite element software, ABAQUS. The reliability and accuracy of the model are verified by comparing it with published relevant experimental results. The failure mode, load-deformation curve, and ultimate compressive load were analysed. Following that, the impacts of section size, yield strength of the steel tube, axial compressive strength of concrete, steel ratio, slenderness ratio, and load eccentricity on its ultimate compressive load are comprehensively investigated. The results demonstrate that the ultimate compressive load of the SCFST-LC decreases significantly with the increase in corrosion rate. The corrosion rate increases from 10 to 40%, and the ultimate bearing capacity decreases by 37.6%. Its ultimate bearing capacity can be enhanced due to the increase in section size, material strength, and steel ratio. In contrast, the ascending slenderness ratio and load eccentricity has harmful effects on the ultimate compressive load of the specimens. Finally, a simplified formula for the axial compressive load of the SCFST-LC under eccentric compression after acid rain corrosion is proposed. The calculation accuracy is high and the deviation of the results is basically within 15%, which is in good agreement with the numerical simulation results.

Study on Buckling of Two Kinds of Thin-Walled Steel Members with Imperfection

2015 ◽  
Vol 744-746 ◽  
pp. 309-314
Author(s):  
Peng Niu ◽  
Hai Tao Wang ◽  
Chun Fu Jin ◽  
Ying Guo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Compressive Load ◽  
Bending Moment ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Axial Compressive Load ◽  
Steel Members ◽  
Square Steel Tube

Based on Ježek method of computing the elastic-plastic buckling of the members under the axial compressive load and the bending moment, considering the initial imperfection, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for an H-shaped member and a square steel tube member are derived. Using the elastic-plastic finite element method and the theory of nonlinear buckling, the impact by initial geometric imperfections on the H-shaped steel member and the square steel tube member under the axial compressive load and the bending moment are analyzed and the numerical solutions of ultimate bearing capacity are obtained. By compared with the values of the finite element method (FEM), it shows that the analytical method in this paper is valid. The results of the example show that the presence of initial imperfections reduces the ultimate bearing capacity of the two kinds of steel members to a great extent. It is also found that the influence of the initial geometric imperfection on the ultimate bearing capacity of members is smaller when the bending moment increases.

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