Study on shear capacity of prestressed composite joints with concrete-encased CFST columns

2021 ◽  
pp. 136943322110005
Author(s):  
Kun Wang ◽  
Zhiyu Zhu ◽  
Yang Yang ◽  
Kai Yan ◽  
Guanpu Xu ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Steel Tube ◽  
Shear Capacity ◽  
Steel Beams ◽  
Element Analysis ◽  
Stress Variation ◽  
Peak Loads ◽  
Steel Bar ◽  
Cfst Columns ◽  
Axial Compressive Ratio

Through assuming reasonable constitutive relation of materials, finite element analysis (FEA) models of joints consisting of prestressed concrete-encased steel beams and concrete-encased concrete filled steel tube (CFST) columns were established by soft ABAQUS, and the simulated results were compared with tested ones. On this basis, the nonlinear analysis on the total loading process was conducted, and the stress variation of concrete, profile steel skeleton, steel bar skeleton, and prestressing tendons were observed at yield, peak, and ultimate loads; the influence of axial compressive ratio, steel tube ratio, stirrup ratio, and prestressing level on lateral load-displacement curves at column top and shear force-shear angle in joint core were investigated, and the shear capacity formulae of joint core were developed. It could be concluded that, the lateral peak loads and shear capacity could be improved with the increase of axial compressive ratio, steel tube ratio, stirrup ratio, and prestressing levels in varying degrees, and the ductility of joints will reduce with the increase of axial compressive ratio. Additionally, the shear capacity calculated by proposed practical formula was a little lower than FEA results, which could keep the joints safety and could be used in engineering design.

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 Seismic Damage Investigation of Spatial Frames with Steel Beams Connected to L-Shaped Concrete-Filled Steel Tubular (CFST) Columns

2018 ◽  
Vol 8 (10) ◽  
pp. 1713 ◽  
Author(s):  
Jicheng Zhang ◽  
Yong Li ◽  
Yu Zheng ◽  
Zhijie Wang
Keyword(s):  
Finite Element ◽  
Frame Structures ◽  
Steel Beams ◽  
Element Analysis ◽  
Testing Specimen ◽  
Tubular Columns ◽  
Finite Element Software ◽  
Fea Model ◽  
Composite Frames ◽  
Cfst Columns

Currently, the frame structures with special-shaped concrete-filled steel tubular columns have been widely used in super high-rise buildings. Those structural members can be used to improve architectural space. To investigate the seismic behavior of spatial composite frames that were constructed by connecting steel beams to L-shaped concrete-filled steel tubular (CFST) columns, a finite element analysis (FEA) model using commercial finite element software ABAQUS was proposed to simulate the behavior of the composite spatial frames under a static axial load on columns and a fully-reversed lateral cyclic load applied to frames in this paper. Several nonlinear factors, including geometry and material properties, were taken into account in this FEA model. Four spatial specimens were designed, and the corresponding experiments were conducted to verify the proposed FEA model. Each testing specimen was two-story structure consisting of eight single span steel beams and four L-shaped CFST columns. The test results showed that the proposed FEA model in this paper could evaluate the behavior of the composite spatial frames accurately. Based on the results of the nonlinear analysis, the stress developing progress of columns is investigated. The load transferring mechanism and failure mechanism are also determined. The results are discussed and conclusions about the behavior of those spatial frame structures are presented.

Preliminary Study on Dynamic Progressive Collapse Analysis of Spatial Composite Frames with Concrete-Filled Steel Tubular Columns

2012 ◽  
Vol 166-169 ◽  
pp. 164-167 ◽  
Author(s):  
Xiao Yan Zhou ◽  
Jing Xuan Wang ◽  
Wen Da Wang
Keyword(s):  
Progressive Collapse ◽  
Nonlinear Dynamic Analysis ◽  
Internal Force ◽  
Nonlinear Material ◽  
Steel Beams ◽  
Element Analysis ◽  
Composite Frame ◽  
Collapse Analysis ◽  
Cfst Columns ◽  
Progressive Collapse Analysis

This paper presented a progressive collapse analysis of spatial composite frame with concrete-filled steel tubular (CFST) columns. A typical finite element analysis (FEA) model of a 12-story building was established by using ABAQUS. The shell elements were used to simulate the slab, and all of the steel beams and CFST columns were simulated by the beam elements incorporating nonlinear material and geometric, respectively. Nonlinear dynamic analysis was carried out for the sudden loss of columns for different scenarios of column removal, and the capacity of progressive collapse resistance of the 3-D composite frame and other components internal force around the removed column were investigated.

Study on shear capacity of connections with external stiffening rings between square steel tubular columns and steel beams

2020 ◽  
pp. 136943322095683
Author(s):  
Bin Rong ◽  
Lei Wang ◽  
Ruoyu Zhang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
Compression Ratio ◽  
Shear Behavior ◽  
Steel Tube ◽  
Shear Capacity ◽  
Steel Beams ◽  
Tubular Columns ◽  
Axial Compression Ratio ◽  
Panel Zone

This paper studied the shear behavior of the connections with external stiffening rings between square steel tubular columns and steel beams by experimental, numerical and analytical methods. Two connections with external stiffening rings were tested under low cyclic loading to investigate the effect of axial compression ratio on the shear behavior and capacity of the connection. The test result showed that the change of the axial compression ratio had little effect on the shear capacity of the connection while the ductility of the connection was decreasing with the increase of the axial compression ratio. Seven nonlinear finite element models were designed to investigate the seismic behavior of the connection under cyclic test. Parametric studies are carried out to study the influence of the following parameters on the shearing capacity and deformation in panel zone: the width and the height of the steel tube in panel zone and the thickness of the external stiffening rings. Finally, based on the model considering the post-buckling strength of the web of the steel tube in panel zone, a calculation formula was fitted by the results of the finite element simulation.

scholarly journals Experimental Study of Self-Compacted Concrete-Filled Steel Tube (CFST) Truss Girders

2019 ◽  
Vol 12 (2) ◽  
pp. 98-104
Author(s):  
Marwa M. Thejeel ◽  
Muhaned A. Shallal
Keyword(s):  
Experimental Study ◽  
Flexural Strength ◽  
Failure Modes ◽  
Steel Tube ◽  
Design Equation ◽  
Self Compacting Concrete ◽  
Concrete Filled Steel Tube ◽  
Peak Loads ◽  
Steel Bar ◽  
The World

Concrete filled steel tube one of the most important modern innovations in the world. This paper studies the performance of steel tube truss girders filled with self-compacting concrete. Four CFST truss girders specimens tested. The first novelty in this research was using square tubes to made truss girder; the main parameters were bottom chord concrete compressive grade and reinforce steel bar is embedded in the bottom chord (second novelty). One bar with a nominal diameter 16 mm was used to reinforce the concrete in the bottom chord while keeping the concrete in the top chord without reinforced. This paper shows the load-displacement curves at the mid-span, deflections along the span, peak loads, flexural strength, and failure modes of the tested specimens. The design equation was used to predict the flexural strength of CFST truss specimens. Results show that the flexural strength increased with increasing the concrete grade from 29.23MPa to 48.41MPa by about 4.5% and increased by about 10.27% when using reinforce steel bar embedded the concrete in the bottom chord.

scholarly journals Cyclic Testing of Bolt-Weld Joints Reinforced by Sleeves Connecting Circular CFST Columns to Steel Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yonghong Bu ◽  
Qi Yang ◽  
Yihong Wang ◽  
Dongfang Zhang
Keyword(s):  
Failure Modes ◽  
Hysteresis Loops ◽  
Steel Tube ◽  
Steel Beams ◽  
Equivalent Viscous Damping ◽  
Concrete Filled Steel Tube ◽  
Weld Joints ◽  
Joint Construction ◽  
Strength And Stiffness ◽  
Cfst Columns

This study examined the design of joints reinforced by sleeves for connecting circular concrete-filled steel tube columns to steel beams. Six half-scale specimens, including four bolt-weld joints reinforced by sleeves and two bolt and stiffened end-plate joints, were designed and tested under cyclic loading to evaluate the seismic behavior of these joints. The joint construction and beam-column stiffness ratio were taken as the main parameters in the tests. The seismic behaviors, including the failure modes, hysteretic curves, ductility, strength and stiffness degradation, and energy dissipation, were investigated. The experimental results showed that no obvious bolt loosening, fracture, or widespread weld cracking appeared in the joints reinforced by sleeves. Furthermore, the joint strength and stiffness were markedly increased by the sleeves in the joint core area. Overall, most specimens exhibited full hysteresis loops and excellent ductilities, the equivalent viscous damping coefficients were 0.263∼0.532, and the ductility coefficients were 1.77∼3.42. The interstory drift ratios satisfied the requirements specified by technical regulations. The connections of these types exhibit favorable energy dissipations and can be effectively utilized for building construction in earthquake-prone areas. This research should contribute to the future engineering applications of concrete-filled steel tube to composite structure.

scholarly journals Numerical analysis of seismic behavior of square concrete filled steel tubular columns

2021 ◽  
Vol 15 (2) ◽  
pp. 127-140
Author(s):  
Hao Dinh Phan
Keyword(s):  
Numerical Analysis ◽  
Axial Load ◽  
Seismic Behavior ◽  
Concrete Strength ◽  
Steel Tube ◽  
Load Level ◽  
Deformation Capacity ◽  
Element Analysis ◽  
Fea Model ◽  
Cfst Columns

This paper presents a numerical analysis of the seismic behavior of square concrete filled steel tubular (CFST) columns. Finite element analysis (FEA) models in ABAQUS software were used to simulate a series of columns subjected to axial compression and cyclic lateral loading. The CFST columns were simulated using nonlinear tri-dimensional (3-D) finite elements for the infilled concrete, and nonlinear two-dimensional (2-D) finite elements for the steel tube. The feasibility of the FEA model has been validated by published experimental results. The validated FEA model was further extended to conduct parametric studies with various parameters including axial load level (n), width-to-thickness ratio of steel tube (B/t), and concrete strength. The numerical analysis results reveal that with the same B/t and constitute materials, the higher the axial compression, the lower the shear strength and deformation capacity were. The thicker steel wall (B/t = 21) resulted in higher strength and larger deformation capacity of the column. Increasing concrete strength helped to significantly develop the column’s shear strength in all cases. Meanwhile, it just led to an increase in deformation capacity in some cases depending on n and B/t. This study also reveals that the square CFST columns with B/t of 21 satisfy the seismic performance demand in high seismic zones (ultimate interstory drift ratio (IDRu) not less than 3% radian) under the two axial load levels, 0.35 and 0.45, but the columns with B/t of 28 satisfy the above demand under just one axial load level of 0.35. Keywords: square concrete filled steel tubular (CFST) columns; finite element analysis (FEA) model; width-to-thickness ratio (B/t); high axial load level; seismic behavior.

Finite Element Analysis of Prestressed Concrete-Filled Square Steel Tube Truss

2013 ◽  
Vol 838-841 ◽  
pp. 510-513
Author(s):  
Chun Li Zhou ◽  
Ru Yang ◽  
Xue Ying Tang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Design Strength ◽  
Load Bearing ◽  
Square Steel Tube

Prestressed concrete-filled square steel tube truss is the kind of truss whose upper chords and lower chords are respectively concrete-filled square steel tube and prestressed square steel tube. Four truss models as square steel tube truss, concrete-filled square steel tube truss, prestressed square steel tube truss and prestressed concrete-filled square steel tube truss were analysed by ANSYS, each of those truss models’ span has three variations. The result shows that the bar sections’ strength of square steel tube truss and concrete-filled square steel tube truss are far from reaching their design strength when the allowable values of deflection has reachedl//400. Unlike the cases described above, when the bar sections’ strength of prestressed square steel tube truss and prestressed concrete-filled square steel tube truss has reached their design strength, their load-bearing capacity is 1 or 1.5 times higher than those cases above and their deflection has not reached the allowable values.

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