scholarly journals Analysis on Flexural Capacity of Square Steel Tube Truss Concrete Beams with Grouted Chords

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Kun Wang ◽  
Zhiyu Zhu ◽  
Huihui Luo ◽  
Ahmed Ahmad Omar
Keyword(s):  
Concrete Beams ◽  
Composite Beams ◽  
Steel Tube ◽  
Parameter Analysis ◽  
Vertical Load ◽  
Flexural Capacity ◽  
Steel Tubes ◽  
Normal Section ◽  
Steel Ratio ◽  
Square Steel Tube

In this research paper, simulations on five specimens of square steel tube truss concrete beams with grouted chords were conducted by finite element analysis (FEA) software ABAQUS. Comparison of failure modes, vertical load-deflection curves, and steel tube strain variation with tests was done. The rationality and validity of the FEA models were also verified. On this basis, parameter analysis was carried out, and the influence of concrete strength, steel ratio of upper and lower chords, and spacing of steel tube truss joints on the vertical load-deflection curves were obtained. From the results of tests and parameter analysis, design formulae of flexural bearing capacity for composite beams were proposed based on the assumption that steel tubes are equivalent to ordinary longitudinal steel bars. Accordingly, the results indicated that the steel tubes of the upper chords in the composite beams cannot get yield for full sections due to the structural requirements; the steel tube of the lower chords will be the first to reach fully yielding and the upper concrete crushed subsequently, showing a failure mode analogous to that of the under-reinforced concrete beam; the steel ratio of lower chords is the primary factor affecting the flexural capacity of the normal section among the parameters; the calculation from the proposed design formulae for the flexural capacity of normal section is in agreement with the tests and simulations. This research could provide reference for the design of this kind of composite beam.

Flexural Capacity Study on Square Tube Filled with Steel Reinforced Concrete Members

2010 ◽  
Vol 163-167 ◽  
pp. 1574-1577 ◽  
Author(s):  
Tong Feng Zhao ◽  
Hong Nan Li ◽  
Jia Huan Yu
Keyword(s):  
Reinforced Concrete ◽  
Steel Tube ◽  
Flexural Capacity ◽  
Steel Reinforced Concrete ◽  
Deformation Curves ◽  
Concrete Members ◽  
Bending Load ◽  
Square Steel Tube ◽  
Abaqus Software

Moment-deformation curves of square steel tube filled with steel reinforced concrete subjected to bending load were simulated by the ABAQUS software. Calculated and experimental curves agreed well with each other. Through studying further the calculated member, the behavior of materials subjected to moment is given. Finally, flexural capacity formula of square steel tube filled with cross steel reinforced concrete is proposed.

Experimental study on the flexural behavior of steel tube slab composite beams and key parameters optimization

2019 ◽  
Vol 22 (11) ◽  
pp. 2476-2489 ◽  
Author(s):  
Pengjiao Jia ◽  
Wen Zhao ◽  
Yongping Guan ◽  
Jiachao Dong ◽  
Qinghe Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Composite Beams ◽  
Steel Tube ◽  
Design Guidelines ◽  
Reinforcement Ratio ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Design Elements ◽  
Steel Bolts

This work presents an experimental study on the flexural behavior of steel tube slab composite beams subjected to pure bending. The main design elements considered in the work are the flange thickness, reinforcement ratio of high strength bolts, spacing between the tubes, and transverse patterns of the tube connections. Based on nine flexural experiments on simply supported steel tube slab specimens, the failure process and crack development in steel tube slab specimens, and their load–deflection curves are investigated. The results of the laboratory tests show that the welding of the bottom flange significantly improves the flexural capacity of the steel tube slab structure. In addition, a lower concrete’s compressive strength improves the ductility of the steel tube slab specimens. Moreover, the flexural capacities predicted from the design guidelines are in good agreement with the experimental test results. Finally, based on the numerical simulations using the ABAQUS software, a numerical model is established to further investigate the effect of the additional parameters on the flexural capacity of steel tube slab structures. The numerical results suggested that the diameter of the steel bolts and the reinforcement ratio have a limited effect on the flexural bearing capacity of the steel tube slab beams, and the ultimate bearing capacity increases linearly along with increase in the diameter of the steel bolts and the reinforcement ratio in a certain range.

Axial impact behaviors of stub concrete-filled square steel tubes

2019 ◽  
Vol 22 (11) ◽  
pp. 2490-2503 ◽  
Author(s):  
YT Zhang ◽  
B Shan ◽  
Y Xiao
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Steel Tube ◽  
Experimental Results ◽  
Parameter Analysis ◽  
Steel Tubes ◽  
Simple Method ◽  
Concrete Filled Steel Tube ◽  
Drop Weight ◽  
The Impact

Existing research on the widely used concrete-filled steel tubes is mainly focused on static or cyclic loading, and the studies on effects of high strain rate are relatively rare. In this article, seven stub concrete-filled steel tubular columns with square section were tested under both static and impact loads, using a large-capacity drop-weight testing machine. The research parameters were variable height of the drop-weight and different load types. The experimental results show that the failure modes of the concrete-filled steel tube columns from the impact tests are similar with those under static load, characterized by the local buckling of the steel tube. The time history curves of impact force and steel strain were investigated. The results indicate that with increasing impact energy, the concrete-filled steel tube stub columns had a stronger impact-resistant behavior. The dynamic analysis software LS-DYNA was employed to simulate the impact behaviors of the concrete-filled steel tube specimens, and the finite element results were reasonable compared with the test results. The parameter analysis on the impact behavior of concrete-filled steel tube columns was performed using the finite element model as well. A simple method was proposed to calculate the impact strength of square concrete-filled steel tube columns and compared favorably with experimental results.

scholarly journals Experimental Studies on the Effect of Properties and Micro-Structure on the Creep of Concrete-Filled Steel Tubes

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1046 ◽  
Author(s):  
Rongling Zhang ◽  
Lina Ma ◽  
Qicai Wang ◽  
Jia Li ◽  
Yu Wang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Steel Tube ◽  
Creep Tests ◽  
Steel Tubes ◽  
Concrete Filled Steel Tube ◽  
Steel Ratio ◽  
Air Content ◽  
Lateral Restraint ◽  
Concrete Filled Steel Tubes ◽  
Core Concrete

To study different lateral restraints, different constituents of expansion agents, the influence of different steel ratios, and concrete creep properties, we carried out experiments with lateral restraint and without lateral restraint conditions separately on 12 specimens with the expansion agent content accounting for 4%, 8%, and 12% respectively. In addition, the creep tests were performed on specimens with different steel ratios of 0.0%, 3.8%, 6.6%, and 9.2%. The test results show that the lateral restraint improves the strength of the system (concrete-filled steel tubes) which resists further load after the concrete ultimate strength is surpassed and reduces the creep. The creep degree of the concrete-filled steel tube with lateral restraint is about 0.09–0.30 times smaller than that of the tube without lateral restraints. The creep degree of the concrete-filled steel tube increases as the steel ratio decreases. Creep tests with different amounts of expansion agent indicate that the creep degree of the concrete structure increases as expansion agent content decreases. To study the internal mechanism of the creep of concrete-filled steel tubes with different lateral restraints and different expansion agent concentrations, a microscopic pore structure test on the steel core concrete was conducted using the RapidAir457 pore structure instrument. Microscopic studies show that the air content and the length of the bubble chord of the laterally restrained core concrete are lower than those without lateral restraint core concrete. The amount of air content and the length of the bubble chord of core concrete specimens increase as the expansion agent content in the core concrete specimens decreases from 12% to 4%. Under the same external loading conditions, as steel ratio increases, the lateral restraint causes a further reduction of creep. The results of this study suggest that the creep of concrete can be reduced by selecting appropriate lateral restraint conditions and an optimal amount of expansion agent in the mix design of concrete for concrete-filled steel tubes.

Experimental and Numerical Studies on Flexural Behavior of Casing Joint of Square Steel Tube

2010 ◽  
Vol 163-167 ◽  
pp. 417-420
Author(s):  
Min Ding ◽  
Zhen Hua Hou ◽  
Xiu Gen Jiang ◽  
Yu Zhi He ◽  
Guang Kui Zhang ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Failure Modes ◽  
Shear Failure ◽  
Tube Wall ◽  
Edge Length ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Tube Wall Thickness ◽  
Square Steel Tube

The tests on thirteen specimens of casing joints of square steel tube were conducted to investigate the flexural behavior of the joints. And numerical simulation studies on that were carried out by ANSYS/LS-DYNA. On this basis, effects of tube wall thickness, tube edge length, and inserting depth on failure mode, ultimate flexural capacity and deformation of the joints were discussed. The results show that there are two types of failure modes, i.e., inside tube yield failure and outside tube shear failure. Ultimate flexural capacity and rigidity of the joints increased with the inserting depth increasing. The ultimate flexural capacity is proportional to tube shear strength, tube wall thickness, inserting depth, and tube edge length.

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 Bond Properties of RAC-Filled Square Steel Tubes after High Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Wanjie Zou ◽  
Jiongfeng Liang ◽  
Guangwu Zhang ◽  
Haifeng Yang
Keyword(s):  
Coarse Aggregate ◽  
Concrete Strength ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Bond Properties ◽  
Steel Tubes ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Square Steel Tube

This paper presents the results of an experimental study to investigate the influence of high temperatures on the bond properties between the recycled coarse aggregate (RCA) concrete and square steel tubes. A total of 27 pushout recycled aggregate concrete- (RAC-) filled square steel tube specimens are cast and heated under five different temperatures (20°C, 200°C, 400°C, 600°C, and 800°C) for testing. The main parameters considered in the test are temperature, exposure time of heating, RCA replacement ratio, interface length-to-width ratio, and concrete strength. The experimental results indicate that the bond strength for recycled coarse aggregate concrete and square steel tube increases with increasing temperatures.

scholarly journals Degradation of Axial Ultimate Load-Bearing Capacity of Circular Thin-Walled Concrete-Filled Steel Tubular Stub Columns after Corrosion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 795 ◽  
Author(s):  
Fengjie Zhang ◽  
Junwu Xia ◽  
Guo Li ◽  
Zhen Guo ◽  
Hongfei Chang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Ultimate Load ◽  
Steel Tube ◽  
Parameter Analysis ◽  
Loading Test ◽  
Steel Tubes ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Thin Walled ◽  
Stub Columns

This work aimed to investigate the effects of steel tube corrosion on the axial ultimate load-bearing capacity (AULC) of circular thin-walled concrete-filled steel tubular (CFST) members. Circular thin-walled CFST stub column specimens were made of steel tubes with various wall-thicknesses. These CFST column specimens were subjected to an accelerated corrosion test, where the steel tubes were corroded to different degrees of corrosion. Then, these CFST specimens with corroded steel tubes experienced an axial static loading test. Results show that the failure patterns of circular thin-walled CFST stub columns with corroded steel tubes are different from those of the counterpart CFST columns with ordinary wall-thickness steel tubes, which is a typical failure mode of shear bulging with slight local outward buckling. The ultimate strength and plastic deformation capacity of the CFST specimens decreased with the increasing degree of steel corrosion. The failure modes of the specimens still belonged to ductile failure because of the confinement of outer steel tube. The degree of steel tube corrosion, diameter-to-thickness ratio, and confinement coefficient had substantial influences on the AULC and the ultimate compressive strength of circular thin-walled CFST stub columns. A simple AULC prediction model for corroded circular thin-walled CFST stub columns was presented through the regression of the experimental data and parameter analysis.

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