scholarly journals Axial Compressive Behaviour of Square Through-Beam Joints between CFST Columns and RC Beams with Multi-Layers of Steel Meshes

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2482
Author(s):  
Weining Duan ◽  
Jian Cai ◽  
Xu-Lin Tang ◽  
Qing-Jun Chen ◽  
Chun Yang ◽  
...  
Keyword(s):  
Axial Compression ◽  
Mechanical Performance ◽  
Concrete Strength ◽  
Volume Ratio ◽  
Design Criterion ◽  
Design Methods ◽  
Rc Beams ◽  
Compressive Behaviour ◽  
Joint Area ◽  
Cfst Columns

The axial compressive behaviour of an innovative type of square concrete filled steel tube (CFST) column to reinforced concrete (RC) beam joint was experimentally investigated in this paper. The innovative joint was designed such that (i) the steel tubes of the CFST columns were completely interrupted in the joint region, (ii) the longitudinal reinforcements from the RC beams could easily pass through the joint area and (iii) a reinforcement cage, including a series of reinforcement meshes and radial stirrups, was arranged in the joint area to strengthen the mechanical performance of the joint. A two-stage experimental study was conducted to investigate the behaviour of the innovative joint under axial compression loads, where the first stage of the tests included three full-scale innovative joint specimens subjected to axial compression to assess the feasibility of the joint detailing and propose measures to further improve its axial compressive behaviour, and the second stage of the tests involved 14 innovative joint specimens with the improved detailing to study the effect of the geometric size of the joint, concrete strength and volume ratio of the steel meshes on the bearing strengths of the joints. It was generally found from the experiments that (i) the innovative joint is capable of achieving the design criterion of the ‘strong joint-weak member’ with appropriate designs, and (ii) by decreasing the height factor and increasing the volume ratio of the steel meshes, the axial compressive strengths of the joints significantly increased, while the increase of the length factor is advantageous but limited to the resistances of the joint specimens. Because of the lack of existing design methods for the innovative joints, new design expressions were proposed to calculate the axial compression resistances of the innovative joints subjected to bearing loads, with the local compression effect, the confinement effect provided by the multi-layers of steel meshes and the height effect of concrete considered. It was found that the proposed design methods were capable of providing accurate and safe resistance predictions for the innovative joints.

scholarly journals Seismic Behavior of Elliptical Concrete-Filled Steel Tubular Columns under Combined Axial Compression and Cyclic Lateral Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
YouWu Xu ◽  
Jian Yao ◽  
Feng Hu ◽  
Ying Zhou ◽  
Shuai Jiang
Keyword(s):  
Axial Compression ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Lateral Loading ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Static Behavior ◽  
Tubular Columns ◽  
Load Carrying ◽  
Cfst Columns

Elliptical concrete-filled steel tubular (CFST) column is a new form of CFST columns, consisting of an outer elliptical tube filled with concrete. Although the study on mechanical performance of the elliptical CFST members is receiving more and more attention, they have been limited to static behavior. Against this background, an experimental study on elliptical CFST columns was carried out under combined axial compression and cyclic lateral loading. The failure modes, hysteretic curves, skeleton curves, load carrying capacity, deformability, stiffness degradation, and energy dissipation ability was obtained and discussed. The test results indicated that the elliptical CFST columns possess excellent seismic performance and ductility. Valuable experimental data were provided for the formulation of the theoretical hysteresis model of the elliptical CFST columns.

scholarly journals Experimental Study on Axial Compression Behavior and Bearing Capacity Analysis of High Titanium Slag CFST Columns

2019 ◽  
Vol 9 (10) ◽  
pp. 2021 ◽  
Author(s):  
Chunli Zhou ◽  
Wei Chen ◽  
Xiaolong Ruan ◽  
Xueying Tang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Concrete Strength ◽  
Diameter Ratio ◽  
Tube Steel ◽  
Titanium Slag ◽  
Compression Behavior ◽  
Strength Grade ◽  
Short Columns ◽  
Cfst Columns

In order to study the axial compression behavior of concrete-filled steel tubular (CFST) columns filled with high titanium slag, a total of 32 specimens, including normal CFST columns, half-high titanium slag CFST columns, and full-high titanium slag CFST columns, were used as experimental samples in this study. The axial compression behaviors of high titanium slag CFST columns and normal CFST columns with various parameters such as length–diameter ratio, strength grade of concrete, strength grade of steel tube, steel content ratio, etc., were evaluated and compared through axial compression testing under monotonic static loading. The results showed that the axial compressive behaviors of high titanium slag CFST columns with various length–diameter ratios were not significantly different from those of normal CFST columns, both of which showed good axial compression performance. In addition, the length–diameter ratio limit between short and medium long column was from 3.5 to 4.4. The length–diameter ratio was the main factor influencing the shape of load–deformation curve of CFST columns. The casing hoop coefficient also had a great influence on the bearing capacity of short columns, while the influence on that of middle and long columns was not obvious. In the end, the bearing capacities of all specimens were calculated by bearing capacity formulas in European EC4, American AISC360-10, and Chinese GB50936-2014 standards. The calculated values were in good agreement with the test results.

Comparative study on square and rectangular UHPFRC-Filled steel tubular (CFST) columns under axial compression

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2054-2068
Author(s):  
Yekai Yang ◽  
Chengqing Wu ◽  
Zhongxian Liu ◽  
Yuan Qin ◽  
Weiqiang Wang
Keyword(s):  
Comparative Study ◽  
Axial Compression ◽  
Cfst Columns

scholarly journals Finite Element Analysis on Behavior of Reinforced Hollow High Strength Concrete Filled Square Steel Tube Short Columns under Axial Compression

2021 ◽  
Vol 2101 (1) ◽  
pp. 012059
Author(s):  
Z J Yang ◽  
X Li ◽  
G C Li ◽  
S C Peng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Strength Concrete ◽  
Mechanical Performance ◽  
Concrete Strength ◽  
High Strength ◽  
Steel Tube ◽  
Element Analysis ◽  
Steel Strength ◽  
Square Steel Tube

Abstract Hollow concrete-filled steel tubular (CFST) member is mainly adopted in power transmission and transformation structures, but when it is used in the superstructure with complex stress, the hollow CFST member has a low bearing capacity and is prone to brittle failure. To improve the mechanical performance of hollow CFST members, a new type of reinforced hollow high strength concrete-filled square steel tube (RHCFSST) was proposed, and its axial compression performance was researched. 18 finite element analysis (FEA) models of axially loaded RHCFSST stub columns were established through FEA software ABAQUS. The whole stress process of composite columns was studied, and parametric studies were carried out to analyze the mechanical performance of the member. Parameters of the steel strength, steel ratio, deformed bar and sandwich concrete strength were varied. Based on the simulation results, the stress process of members can be divided into four stages: elastic stage, elastoplastic stage, descending stage and gentle stage. With the increase of steel strength, steel ratio, the strength of sandwich concrete and the addition of deformed bars, the ultimate bearing capacity of members also increases. Additionally, the increment of those parameters will improve the ductility of the member, except for the sandwich concrete strength.

scholarly journals Comparative Study of CFRP-Confined CFST Stub Columns under Axial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ying Guo ◽  
Yufen Zhang
Keyword(s):  
Comparative Study ◽  
Bearing Capacity ◽  
Limit Equilibrium ◽  
Concrete Strength ◽  
Confinement Effect ◽  
Unified Theory ◽  
Enhancement Ratio ◽  
Composite Columns ◽  
Cfst Columns ◽  
Stub Columns

This paper presented a comparative study of concrete-filled steel tubular (CFST) stub columns with three different confinement types from carbon fiber reinforced polymer (CFRP): outer circular CFRP, inner circular CFRP, and outer square CFRP. The compressive mechanism and physical properties of the composite column were analyzed firstly aiming at investigating the confinement effect of CFRP. Ultimate axial bearing capacity of these three CFRP-confined CFST columns was calculated based on Unified Theory of CFST and elastoplastic limit equilibrium theory, respectively. Meanwhile, the corresponding tests are adopted to validate the feasibility of the two calculation models. Through data analysis, the study confirmed the ultimate strength calculation results of the limit equilibrium method were found to be more reliable and approximate to the test results than those of Unified Theory of CFST. Then axial bearing capacity of the pure CFST column was predicted to evaluate the bearing capacity enhancement ratio of the three types of composite columns. It was demonstrated that the averaged enhancement ratio is 16.4 percent, showing that CFRP-confined CFST columns had a broad engineering applicability. Through a comparative analysis, this study also confirmed that outer circular CFRP had the best confinement effect and outer square CFRP did better than inner circular CFRP. The confinement effect of CFRP increased with the decrease of concrete strength, and it was proportional with relative proportions of CFRP and steel under the same concrete strength.

Behavior of FRP Ring-Confined CFST columns under axial compression

2021 ◽  
Vol 257 ◽  
pp. 113166
Author(s):  
Jun-Jie Zeng ◽  
Yu-Wen Zheng ◽  
Feng Liu ◽  
Yong-Chang Guo ◽  
Chao Hou
Keyword(s):  
Axial Compression ◽  
Cfst Columns
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