Behavior of CFRP-confined reactive powder concrete-filled steel tubes under axial compression

2020 ◽  
pp. 136943322097478
Author(s):  
Song Li ◽  
Chu-Jie Jiao
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Local Buckling ◽  
Steel Tube ◽  
Experimental Results ◽  
Reactive Powder Concrete ◽  
Test Results ◽  
Steel Tubes ◽  
Reactive Powder ◽  
Concrete Filled Steel Tubes

Reactive powder concrete-filled steel tubes (RPCFSTs) have become an important research target in recent years. In engineering applications, RPCFSTs can provide superior vertical components for high-rise and tower buildings, thereby enabling developers to provide more floor space. However, this type of composite structure is prone to inelastic outward local buckling. The use of carbon fiber reinforced polymer (CFRP) wrapping to suppress such local buckling has shown great potential in limited test results. This paper presents experimental results concerning the axial compression of CFRP-confined reactive powder concrete-filled circular steel tubes (CF-RPCFSTs). We included 18 specimens in our experimental investigation, varying the number of CFRP layers, steel tube thickness, and RPC strength. According to our test results, CF-RPCFSTs exhibit compression shear failure and drum-shaped failure. The CFRP wrap can effectively enhance bearing capacity and postpone local buckling of the steel tube. In addition, three-layer CFRP-confined RPC-filled thin-wall steel tubes are suitable for engineering. We also propose a model to calculate the bearing capacity of CF-RPCFSTs. Compared to the existing model of CFRP-confined concrete-filled steel tubes, the results obtained using the proposed model are in good agreement with our experimental results.

scholarly journals Bearing Capacities of Different-Diameter Concrete-Filled Steel Tubes under Axial Compression

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Wenjing Wang ◽  
Zhenyun Tang ◽  
Zhenbao Li ◽  
Hua Ma
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Peak Load ◽  
Steel Tube ◽  
Specimen Size ◽  
Small Scale ◽  
Strengthening Effect ◽  
Steel Tubes ◽  
Specimen Diameter ◽  
Concrete Filled Steel Tubes

The bearing capacities of concrete-filled steel tubes are normally derived through experiments with small-scale specimens, but it is uncertain whether such derivations are appropriate for the much larger components used in practical engineering. This study therefore investigates the effect of different diameters (219, 426, 630, and 820 mm) on the axial compression of short concrete columns in steel (Q235) tubes. It is found that the peak nominal stress decreases with increasing specimen size and that the axial bearing capacity is determined by three separate components: the cylinder compressive strength of the concrete, the improvement in strength due to the confining effect of the steel tube, and the longitudinal strength of the steel tube. At peak load, increases in the specimen diameter reduce the hoop stresses in the steel tube, thereby reducing the strengthening effect of confinement. Vertical stress in the steel tube is increased with diameter; therefore, the axial bearing capacity of the steel tube is directly related to the specimen size. Size effect coefficients for these three aspects of bearing capacity are defined and used to develop a size-dependent model for predicting the axial bearing capacity of large, concrete-filled steel tubes. The model is then validated against experimental data.

scholarly journals Comparative Study on the Axial Compression and Bearing Capacity of Reactive Powder Concrete-Filled Circular Steel Tube

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Mingyang Chen ◽  
Xiaomeng Hou
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Limit Equilibrium ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Loading Mode ◽  
Circular Steel Tube ◽  
Reactive Powder

Reactive powder concrete (RPC) was confined by the circular steel tube to obtain the required ductility. The axial compression test results of 139 columns from different scholars were collated and compared to study the axial compression and bearing capacity of a reactive powder concrete-filled circular steel tube, of which the confining coefficient is 0.057–2.312 and the RPC strength is 76.6–178.2 MPa. Load-displacement curves have been categorized into four stages: (1) elastic; (2) elastic-plastic; (3) descending; and (4) strengthening. The failure mode can be divided into three types according to the different confining coefficients as (1) wall buckling; (2) diagonal shear; and (3) drum-shaped. The confining coefficient, core RPC strength, steel fiber volume, steel tube D/t ratio, and loading mode on the ultimate bearing capacity were analyzed. The results showed the confining coefficient to be the main factor affecting ultimate bearing capacity. The equation for determining ultimate bearing capacity was established based on the limit equilibrium theory, with the lateral confining coefficient of RPC (k) determined to be 2.86, less than that of normal concrete at 4.1. Based on the experimental analysis results and China’s “Design and Construction Code for Concrete-Filled Steel Tube Structure” (CECS 28-2012), the design proposal for an RPC-filled steel tube was recommended.

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.

Research on Hysteretic Behavior of the Concrete Filled Square CFRP-Steel Tubular (S-CFRP-CFST) Beam-Columns (I): Experimental Study

2010 ◽  
Vol 163-167 ◽  
pp. 3580-3585
Author(s):  
Yuan Che ◽  
Qing Li Wang ◽  
Yong Bo Shao ◽  
Hai Tao Mu
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Local Buckling ◽  
Steel Tube ◽  
Hysteretic Behavior ◽  
Strengthening Effect ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Beam Columns ◽  
Hysteretic Performance

Overall 12 specimens were experimentally investigated in this paper to study the hysteretic behaviors of the concrete-filled square CFRP-steel tubular (S-CFRP-CFST) beam-columns. The test results indicated that CFRP can provide transverse confinement effect and longitudinal strengthening effect for the concrete filled square steel tubular (S-CFST) beam-columns effectively and the local buckling of the steel tube is deferred. The hysteretic load-deflection curves and the hysteretic moment-curvature curves at the mid-span of all the specimens are generally plump, and it shows these specimens have good hysteretic performance. In the later loading period, the load bearing capacity drops.

Experimental Study of Post-Fire Bearing Capacity of the Circular Steel Tubes with Different Fire-Resistant Coating

2010 ◽  
Vol 163-167 ◽  
pp. 749-753
Author(s):  
Yao Ji ◽  
Xin Tang Wang ◽  
Ming Zhou ◽  
Wan Zhen Wang
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Fire Test ◽  
Steel Tube ◽  
Test Results ◽  
Fire Response ◽  
Steel Tubes ◽  
Protective Material ◽  
Tubular Columns ◽  
Maximum Value

In order to look into the causes of fire response and post-fire bearing capacity of the steel tubular columns protected with different materials, the fire test was conducted for a set of circular steel tubes protected with different materials such as gypsum fireproof panel, bamboo plywood and the ordinary lumber core plywood, and the steel tube without any protective material. The fire response temperature of surface of steel tubes is measured and the axial compressive bearing capacity of the specimens after fire are tested and analyzed. The test results show that gypsum fireproof panel has the best fire protection characteristics, the ordinary lumber core plywood and bamboo plywood can also retard rising of the surface temperature of the steel tubes during the initial 35min although they are combustible materials. It is found that the post-fire bearing capacity of the steel tubes protected with different materials varies evidently, and the maximum value of response temperature has the greatest effect.

Experiment on T-Shaped CFT Stub Columns with Binding Bars Subjected to Axial Compression

2013 ◽  
Vol 838-841 ◽  
pp. 439-443 ◽  
Author(s):  
Zhi Liang Zuo ◽  
Da Xin Liu ◽  
Jian Cai ◽  
Chun Yang ◽  
Qing Jun Chen
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Failure Modes ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Plates ◽  
Buckling Modes ◽  
Cft Column ◽  
Stub Columns ◽  
Strength And Ductility

To improve the mechanical behavior of T-shaped concrete-filled steel tubular (T-CFT) column, the method that setting binding bars along the height of steel tube is proposed. Five T-CFT stub columns with binding bars and another two without binding bars subjected to axial compression were tested. The influences of the spacing and diameter of binding bars on the failure modes, maximum strength, and ductility of T-CFT stub columns are investigated. The experimental results demonstrate that by setting binding bars or decreasing the spacing of binding bars, the buckling modes of the steel plates are changed, the local buckling of the steel plates is postponed, and the confinement effects on the core concrete can be improved significantly. By setting binding bars, the bearing capacity and ductility of the columns are enhanced by 1.17 and 3.38 times at most, respectively. By increasing the diameter of binding bars, the ductility of the columns is improved, but the bearing capacity and buckling strength cannot be improved when the diameter is large enough.

Influence of Axial Compression Ratio on Seismic Behavior of Reactive Powder Concrete (RPC) Beam-Column Joints

2014 ◽  
Vol 597 ◽  
pp. 312-315 ◽  
Author(s):  
Yan Zhong Ju ◽  
Chun Yu Li ◽  
De Hong Wang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Seismic Behavior ◽  
Ultimate Bearing Capacity ◽  
Reactive Powder Concrete ◽  
Element Analysis ◽  
Axial Compression Ratio ◽  
Reactive Powder ◽  
Axial Compressive Ratio

To explore the influence of axial compressive ratio on seismic behavior of reactive powder concrete(RPC) beam-column joints,this paper carry out RPC beam-column joints nonlinear finite element analysis,using software ABAQUS.The effect of different axial compression ratio on the ductility,energy dissipation capacity and bearing capacity are studied,based on hysteretic curves and skeleton curves of the components.The results show that,with the increase of axial compression ratio,skeleton curves of the components tend to be steep when the vertical load of beam ends exceed the peak point.The ultimate bearing capacity of the components are improved with the increasing of axial compression ratio which is less then 0.6,while the ultimate bearing capacity show a opposite trend when the axial compressive ratio exceed 0.6.

Properties of Recycled Aggregate Concrete Filled Steel Tubes

2014 ◽  
Vol 1065-1069 ◽  
pp. 1323-1326
Author(s):  
Yi Jie Huang ◽  
Huang Sheng Sun
Keyword(s):  
Mechanical Behavior ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Structural Elements ◽  
Steel Tubes ◽  
Aggregate Concrete ◽  
Flexural Performance ◽  
Concrete Filled Steel Tubes

A review on the properties of recycled aggregate concrete filled steel tubes (RACSFT) was presented, followed by the short overview on the related researches. The uniaxial mechanical behavior, flexural performance, creep performance as well as eccentric loaded behavior of RACSFT specimens were discussed. It was found that the differences between the element made of recycled aggregate concrete (RAC) and that of natural aggregate concrete (NAC) could not be ignored. The performance of the RACFST is inferior to that of natural concrete filled steel tube (CFST). But, the RACSFT can be applied into structural elements safely. Based on the test results, it was also concluded that the RACSFT is an effective method to improve the application of RAC.

Experimental Study of Behavior of Ceramsite Concrete Filled Steel Tubes after Exposure to Fire

2011 ◽  
Vol 71-78 ◽  
pp. 3721-3724 ◽  
Author(s):  
Ming Zhou ◽  
Xin Tang Wang ◽  
Jian Min Wang ◽  
Zhi Guo Xie
Keyword(s):  
Experimental Study ◽  
Bearing Capacity ◽  
Fire Behavior ◽  
Test Results ◽  
Fire Response ◽  
Fire Load ◽  
Steel Tubes ◽  
Maximum Value ◽  
Concrete Filled Steel Tubes ◽  
Strength And Ductility

The post-fire behavior of a set of ceramsite concrete filled steel tubes (note as CCST) after exposure to fire are experimentally studied. Effect of the maximum value of fire response temperatures of the tubes and their geometric parameters on the strength and ductility of the specimens were especially discussed. The test results show that the specimens of CCST have higher post-fire bearing capacity and better ductility, there was no obvious descent segment in post-fire load-displacement curves of the most specimens subjected to fire load. It was concluded that the maximum response temperature of specimens has great effect on the post-fire bearing capacity of concrete-filled steel tubes subjected to fire load.

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