Compressive behavior of concrete-filled steel tubular columns with internal high-strength steel spiral confinement

2020 ◽  
pp. 136943322098165
Author(s):  
J.G. Teng ◽  
J.J. Wang ◽  
Guan Lin ◽  
J. Zhang ◽  
P. Feng
Keyword(s):  
Axial Compression ◽  
High Strength Steel ◽  
Axial Load ◽  
Axial Strain ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Experimental Program ◽  
Cfst Columns

Concrete-filled steel tubular (CFST) columns have been extensively studied and widely used in practice. Existing research has shown that non-circular CFST columns is much less ductile than their circular counterparts, particularly when thin/high strength steel (HSS) tubes and high-strength concrete are used. To address this problem, a new form of CFST columns has recently been proposed by the first author. The new column consists of a steel tube filled with concrete that is confined with HSS spiral reinforcement typically with a yield stress exceeding 1000 MPa. These columns, referred to as confined concrete-filled steel tubular (CCFST) columns, also maintain the ease for connection to CFST or steel beams. This paper presents the results of a series of concentric axial compression tests on such columns of square cross-section to demonstrate their advantages. The experimental program included 13 CCFST columns, four CFST columns without internal spiral confinement, two hollow steel tube (HST) columns, and 11 circular HSS spiral-confined concrete columns. Three different compressive strengths and three HSS spiral pitches were examined in the experimental program. The CFST columns, HST columns, and HSS spiral-confined concrete columns were all tested under axial compression to gain a good understanding of the confinement mechanism in a CCFST column. The test results show that the new columns possess much greater ductility than those without internal spiral confinement, although the use of HSS spirals increases the steel volume by only a small percentage. It is also shown that the axial load-axial strain curve of a CCFST column can be conservatively predicted by summing the axial load-axial strain curves of the hollow steel tube without local buckling, the HSS spiral-confined concrete core, and the sandwiched concrete between the two.

Experimental Study on Axial Compression Performance of Full-Scale Square Columns of Reinforced Concrete Confined by High-Strength Reinforcement Hoops

2012 ◽  
Vol 446-449 ◽  
pp. 981-988
Author(s):  
Zhen Bao Li ◽  
Wen Jing Wang ◽  
Wei Jing Zhang ◽  
Yun Da Shao ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Bearing Capacity ◽  
Axial Compression ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Full Scale ◽  
Compression Performance ◽  
Deformation Ability

Axial compression experiments of four full-scale reinforced concrete columns of two groups were carried out. One group of three columns used high-strength steel with the yield strength of 1000MPa as reinforcement hoops, and the second group used the ordinary-strength steel with yield strength of 400MPa. The axial compressive performances between these two groups were assessed. Compared to the specimen using the ordinary-strength steel, the axial compressive bearing capacity of using the high strength steel dose not increase significantly, while the deformation ability increases greatly. The results also indicate that the stress redistributions of the hoops and the concrete sections are obvious, and long-lasting when specimens achieve the ultimate bearing capacity after the yield of the rebar and local damage of concrete materials, at this time the strain of the specimens developes a lot, especially stress - strain curves of speciments with high-strength hoop all show a wide and flat top.

scholarly journals Investigation of the effect of impact load on concrete-filled steel tube columns under fire

2020 ◽  
Vol 14 (54) ◽  
pp. 317-324
Author(s):  
Ali Golsoorat Pahlaviani ◽  
Ali Mohammad Rousta ◽  
Peyman Beiranvand
Keyword(s):  
Impact Load ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Lateral Impact ◽  
Concrete Filled Steel Tube ◽  
Axial Strength ◽  
High Rise ◽  
Working Space ◽  
Cfst Columns

Concrete-filled steel tube (CFST) columns are increasingly used in the construction of high-rise buildings which require high strength and large working space especially at lower stories. As compared to reinforced concrete columns, existence of the exterior steel tube not only bears a portion of axial load but also most importantly provides confinement to the infill concrete.with the confinement provided by the steel tube, axial strength of the infill concrete can be largely enhanced.this paper presents the investigation effect of impact load on concrete-filled steel tube columns under fire by numerical simulations using ABAQUS software.the results indicate that the CFST sections with larger confinement factor ξ=1.23 behaved in a very ductile manner under lateral impact. And the sections with smaller confinement factor ξ=0.44  generally behaved in a brittle mechanism.

Impact Factors Study on Strength of Steel Tube Confined Concrete Columns under Axial Compression

2013 ◽  
Vol 639-640 ◽  
pp. 1069-1072
Author(s):  
Hao Xiong Feng ◽  
Wei Jian Yi
Keyword(s):  
Axial Compression ◽  
Theoretical Basis ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Impact Factors ◽  
Working Mechanism

This paper describes principle and working mechanism of the steel tube confined concrete, to analyze impact factors of steel tube confined concrete strength. By the studies, presents several solutions to improve the strength of steel tube confined concrete, fully execute the behavior of steel tube and filled-in-concrete, strengthen the interactions between steel tube and filled-in-concrete to provide theoretical basis for the design and use of steel tube confined concrete.

scholarly journals Influence of steel tube thickness and concrete strength on the axial capacity of stub CFST columns

2018 ◽  
Author(s):  
Carmen Ibáñez Usach ◽  
David Hernández-Figueirido ◽  
Ana Piquer Vicent
Keyword(s):  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Steel Tube ◽  
Experimental Program ◽  
Ultimate Capacity ◽  
Strength Concrete ◽  
Axial Capacity ◽  
Thin Walled ◽  
Cfst Columns

In order to study the mechanical response of concrete-filled steel tubular (CFST) columns, several experimental and theoretical studies have been conducted in the last years. However, the influence of thin-walled steel tubes on the axial capacity of these composite columns is not completely stablished, especially when it is combined with high-strength concrete as infill. In this paper, the results of an experimental campaign on 9 concrete-filled steel tubular stub columns subjected to concentric load are presented. Different cross-section shapes are considered in this campaign, i.e. circular, square and rectangular. The influence of the steel tube wall thickness is analysed by including in the tests specimens with thin-walled tubes, whose behaviour needs to be studied in depth given the issues arising when working under compression. The experimental program is designed so the analysis of the results permits to drawn consistent conclusions. For each series, the steel tube thickness is the only geometric parameter modified in order to properly study its effect. Besides, two different concrete strengths were considered for the concrete infill, i.e. normal and high- strength concrete, to observe their effect on the ultimate capacity of the columns. During the tests, the specimens are subjected to axial load and the evolution of the axial displacement with the load is registered. The ultimate capacity of each specimen is obtained and an analysis of the steel tube thickness and concrete strength influence is accomplished. Finally, the study of the dependency of the failure mode on these parameters is carried out.

scholarly journals Prediction of axial strength in circular steel tube confined concrete columns using artificial intelligence

2021 ◽  
Vol 15 (2) ◽  
pp. 113-126
Author(s):  
Ngoc-Tri Ngo ◽  
Thi-Phuong-Trang Pham ◽  
Le Hoang An ◽  
Quang-Trung Nguyen ◽  
Thi-Thao-Nguyen Nguyen ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
High Strength Concrete ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Support Vector ◽  
Axial Strength ◽  
Strength Concrete ◽  
Circular Steel Tube

In recent years, together with the boom of the industrial revolution 4.0, terms such as artificial intelligence (AI) are gradually gaining popularity engineering domain. This study proposed a number of AI models for predicting the axial strength in circular steel tube confined concrete (STCC) columns. Particularly, artificial neural networks (ANNs), support vector regression (SVR), linear regression (LR), and M5P were applied in this study. This study applied 136 samples of short and intermediate STCC columns infilled with normal strength concrete, high strength concrete, or ultimate high strength concrete to evaluate the AI models. Compressive strengths of concrete cylinders was ranged from 23.20 Mpa to 188.10 Mpa. The AI models were assessed by statistical indexes including MAPE, MAE, RMSE, and R. The analytical results revealed that the M5P the most effective AI model comparing to others. Comparing with the other models, predicted data obtained by the M5P model show the highest agreement with the actual data in predicting the axial strength of STCC columns. Particularly, the MAPE and R of M5P models were 10.62% and 0.977 respectively. Similarly, the RMSE by the M5P model was 330.38 kN which is the lowest value among 419.39 kN by the LR model, 337.84 kN by the ANNs model, and 857.11 kN by the SVR model. Therefore, the M5P model can be considered as a useful tool to accurately predict the compressive capacity of the STCC columns. Keywords: artificial intelligence; circular steel tube confined concrete columns; axial strength; support vector regression.

Double-tube concrete columns with a high-strength internal steel tube: Concept and behaviour under axial compression

2018 ◽  
Vol 21 (10) ◽  
pp. 1585-1594 ◽  
Author(s):  
Jin-Guang Teng ◽  
Zihao Wang ◽  
Tao Yu ◽  
Yang Zhao ◽  
Li-Juan Li
Keyword(s):  
Experimental Study ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Steel Tube ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Polymer Tube

This article presents a new form of fibre-reinforced polymer-concrete-steel hybrid columns and demonstrates some of its expected advantages using results from an experimental study. These columns consist of a concrete-filled fibre-reinforced polymer tube that is internally reinforced with a high-strength steel tube and are referred to as hybrid double-tube concrete columns. The three components in hybrid double-tube concrete columns (i.e. the external fibre-reinforced polymer tube, the concrete infill and the internal high-strength steel tube) are combined in an optimal manner to deliver excellent short- and long-term performance. The experimental study included axial compression tests on eight hybrid double-tube concrete columns with a glass fibre–reinforced polymer external tube covering different glass fibre–reinforced polymer tube thicknesses and diameters as well as different high-strength steel tube diameters. The experimental results show that in hybrid double-tube concrete columns, the concrete is well confined by both the fibre-reinforced polymer tube and the high-strength steel tube, and the buckling of the high-strength steel tube is suppressed so that its high material strength can be effectively utilized, leading to excellent column performance. Due to the high yield stress of high-strength steel, the hoop stress developed to confine the core concrete is much higher than can be derived from a normal-strength steel tube, giving the use of high-strength steel in double-tube concrete columns an additional advantage.

scholarly journals Axial load behaviour of steel tube columns in-filled with various high performance concretes

2021 ◽  
Author(s):  
Katie Chu
Keyword(s):  
Axial Load ◽  
High Performance ◽  
Failure Modes ◽  
Lightweight Concrete ◽  
High Strength ◽  
Crumb Rubber ◽  
Steel Tube ◽  
Axial Strength ◽  
Coarse Aggregates ◽  
Cfst Columns

This research concentrates on the axial load behaviour of circular, square and rectangular concrete filled steel tube (CFST) columns incorporating high-performance self-consolidating concretes such as ultra-high strength concrete (UHSC), engineered cementitious composite (ECC), lightweight concrete (LWC), and crumb rubber concrete (CRC). Seventy-four CFST specimens with varying slenderness, shape, concrete type and presence of internal bar reinforcements are tested experimentally under axial compression loading. The effect of these variables on axial load-deformation response, strain characteristics, failure modes, concrete confinement and axial strength are evaluated through experimental results. Performance of existing analytical/code based models for axial strength and concrete confined strength is evaluated. Concretes without coarse aggregates including UHSC proved less effective at enhancing axial strength of filled tube columns through confinement. In contrast, confinement in filled steel tube columns was found most effective with the use of concretes with coarse aggregates such as LWC and CRC.

Research on Bearing Capacity of Short Concrete Filled Double Skin Steel Tubes Columns under Axial Compression

2010 ◽  
Vol 168-170 ◽  
pp. 2154-2157
Author(s):  
Jing Yu Chen ◽  
Ying Hai
Keyword(s):  
Axial Compression ◽  
Ultimate Load ◽  
Concrete Columns ◽  
Steel Tube ◽  
Confined Concrete ◽  
Load Estimation ◽  
Test Results ◽  
Steel Tubes ◽  
Double Skin ◽  
Structural Engineers

The use of steel tube confined concrete columns has been the interests of many structural engineers. For investigation of the axially loading capacity of short concrete filled double skin tubes (CFDST) columns, axial compression loading experiments were carried on 9 short CFDST column samples. According to experimental results and with numerical analysis, an ultimate load estimation equation of CFDST column with one correction parameter is presented, the linear relation between the parameter and the inner-to-outer diameters ratio Di/Do is given out. The ultimate load estimation equation is validated by the test results of short CFDST column samples.

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