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

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

Performance of composite L-shaped CFST columns with inner I-shaped steel under axial compression

2020 ◽  
Vol 170 ◽  
pp. 106138
Author(s):  
Yifei Xiao ◽  
Xue-Meng Bie ◽  
Xin Song ◽  
Jicheng Zhang ◽  
Guofeng Du
Keyword(s):  
Axial Compression ◽  
Cfst Columns

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 Axial Compression Behavior of Circular Concrete-Filled High-Strength Thin-Walled Steel Tubular Columns with Out-of-Code D/t Ratios

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jun-Xin Li ◽  
Jian-Tao Wang ◽  
Qing Sun ◽  
Yan-Ru Wu ◽  
Shi-Ming Zhou ◽  
...  
Keyword(s):  
Axial Compression ◽  
Full Range ◽  
High Strength ◽  
Displacement Curve ◽  
Fe Model ◽  
Range Analysis ◽  
Cross Sectional ◽  
Compression Behavior ◽  
Thin Walled ◽  
Cfst Columns

This paper systematically investigated the axial compression behavior of circular concrete-filled high-strength thin-walled steel tubular (CFHTST) columns with out-of-code diameter-to-thickness (D/t) ratios. The axial compression test was first conducted to examine the failure mode, load-displacement curves, and composite mechanism effect. The finite element (FE) model was thereafter established to perform full-range analysis on the load versus displacement curve as well as the interaction behavior, where the parametric study was performed to investigate the influences of the material strengths and geometric sizes. Subsequently, the applicability of typical design methods was evaluated, and a revised equation for determining strain εscy corresponding to ultimate strength was established to assess the plastic deformation capacity of CFHTST columns. Finally, a theoretical model for calculating axial bearing capacity was derived based on unified twin-shear strength theory by considering the influence of intermediate principal stress. The research results indicate that a relatively high confine effect can be guaranteed for CFHTST columns under out-of-code D/t ratios, given that the ratio Nu/Nnom between the measured capacity (Nu) and nominal cross-sectional capacity (Nnom) mainly distributes within 1.179∼1.292; the full-range analysis reflects that the axial load-deformation curve can be distinguished by four various loading stages; the scope b = 0.3∼0.55 of intermediate stress coefficient is generally suggested for predicting axial strength of circular CFST columns within an error of ±5%. The abovementioned study can provide the meaningful design reference for the analysis and application of CFHTST columns.

scholarly journals Test on Hysteretic Behaviour of Prestressed Composite Joints with Concrete-Encased CFST Columns

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Kun Wang ◽  
Huihui Luo
Keyword(s):  
Energy Dissipation ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Hysteretic Behaviour ◽  
Axial Compression Ratio ◽  
Flexural Failure ◽  
Composite Joint ◽  
Cfst Columns

Four composite joint specimens consisted of concrete-encased steel beams and concrete-encased concrete-filled steel tube (CFST) columns were tested under lateral cyclic loading, in which three specimens were prestressed and the other was not. In the tests, crack distributions and failure modes of the joint specimens were acquired, and the energy dissipation, rigidity degeneration, ductility, and residential deformation were investigated. Meanwhile, the strain variation of longitudinal rebars and I-steel flanges at beam ends as well as steel tubes in panel zones were analysed. The experimental results showed that a type of mixed mode consisting of shear failure in the panel zone and flexural failure at beam ends was found for three prestressed joint specimens, whilst only flexural failure at beam ends was observed for the non-prestressed one, and all joint specimens showed good hysteretic behaviour. In addition, as can be seen from the skeleton curves, the lateral peak loads of prestressed joint specimens could be enhanced to some extent by increasing the prestressing level, and the axial compression ratio had little effect on lateral loads; meanwhile, the ductility and energy dissipation for prestressed joint specimens also could be reduced by increasing the prestressing level and axial compression ratio.

Investigation of the Axial Bearing Capacity of the Discontinuous-Tube-in-Core Concrete Filled Steel Tubular Column-Slab Joint

2008 ◽  
Vol 400-402 ◽  
pp. 901-910 ◽  
Author(s):  
Fu Jun Liu ◽  
Jian Cai
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Steel Tube ◽  
Working Mechanism ◽  
Engineering Applications ◽  
New Type ◽  
Cfst Columns ◽  
The Cost ◽  
Core Concrete

Based on the principle of restrained concrete, this paper presents a new-type concrete filled steel tubular column-slab joint. This new-type joint is characterized by keeping the concrete floor slab continuous while breaking the steel tube of the column for the joint, thus joining the slab and the concrete filled steel tubular(CFST) columns at the top and the bottom of the slab. The joint has the advantage of transferring loads dependably, constructing conveniently and saving on the cost. Three groups of experiments (21 specimens contained) were performed to test the safety of the joint and investigate its axial bearing capacity. The results show that the joint is dependable and feasible in engineering applications. In addition, this paper studies the working mechanism and mechanical properties of the joint under axial compression, discusses the factors to influence its axial bearing capacity, and finally brings out the formula of the joint’s bearing capacity under axial compression that adapts to engineering applications, which conservatively evaluate the result of the experiments.

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 Behavior of Concrete-Filled Steel Tube Columns Subjected to Axial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Pengfei Li ◽  
Tao Zhang ◽  
Chengzhi Wang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Ultimate Load ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Plastic Behavior ◽  
Numerical Comparison ◽  
Reinforcing Bars ◽  
Concrete Filled Steel Tube ◽  
Cfst Columns

The behavior of concrete-filled steel tube (CFST) columns subjected to axial compression was experimentally investigated in this paper. Two kinds of columns, including CFST columns with foundation and columns without foundation, were tested. Columns of pure concrete and concrete with reinforcing bars as well as two steel tube thicknesses were considered. The experimental results showed that the CFST column with reinforcing bars has a higher bearing capacity, more effective plastic behavior, and greater toughness, and the elastoplastic boundary point occurs when the load is approximately 0.4–0.5 times of the ultimate bearing capacity. The change of rock-socketed depth and the presence of steel tube will affect the ultimate bearing capacity of rock-socketed pile. The bearing capacities of the rock-socketed CFST columns are lower than those of rock-socketed columns without a steel tube under a vertical load; besides, the greater the rock-socketed depth, the greater the bearing capacity of the rock-socketed piles. In addition, a numerical comparison between the ultimate load and the theoretical value calculated from the relevant specifications shows that the ultimate load is generally considerably greater than the theoretical calculation results.

scholarly journals Derivation of the unified equation of axial compression of CFST columns

2020 ◽  
Vol 143 ◽  
pp. 01004
Author(s):  
Ruoyang Zhou ◽  
Xiaoxiong Zha
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Limit Equilibrium ◽  
Concrete Columns ◽  
Steel Tube ◽  
Steel Reinforcement ◽  
Steel Plates ◽  
Steel Tubes ◽  
High Rise ◽  
Cfst Columns

The steel tube concrete columns with steel reinforcement cages, steel plates and steel tubes has been used in super high-rise buildings, which are called concrete-filled steel tubular (CFST) columns with internal stiffeners. Based on the theory of limit equilibrium, the unified equation for the axial bearing capacity of the CFST columns with internal stiffeners is obtained. The derived equation in this study can provide reference for the future engineering applications.

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