Summary of Performance and the Application of the Concrete Filled Steel Tubular Structures

2013 ◽  
Vol 834-836 ◽  
pp. 693-696
Author(s):  
Jing Gong ◽  
Jia Li ◽  
Yue Tang ◽  
Yuan Miao

Due to the restraint of steel tube concrete of concrete filled steel tubular components,three directions’ compression at the same time, the bearing capacity of concrete is obviously improved.As a result of the existence of steel pipe concrete,can effectively prevent the steel tube of local buckling ,com-plementary advantages and disadvantages of these two kinds of material , the performance of the material is greatly improved. In this paper, the performance and characteristics of the composite material has carried on the detailed instructions,the ultimate bearing capacity of calculation principle has carried on the detailed analysis and research, the application of this new type of material are summarized.

2008 ◽  
Vol 400-402 ◽  
pp. 513-518 ◽  
Author(s):  
Yong Chang Guo ◽  
Pei Yan Huang ◽  
Yang Yang ◽  
Li Juan Li

The improvement of the load carrying capacity of concrete columns under a triaxial compressive stress results from the strain restriction. Under a triaxial stress state, the capacity of the deformation of concrete is greatly decreased with the increase of the side compression. Therefore, confining the deformation in the lateral orientation is an effective way to improve the strength and ductility of concrete columns. This paper carried out an experimental investigation on axially loaded normal strength concrete columns confined by 10 different types of materials, including steel tube, glass fiber confined steel tube (GFRP), PVC tube, carbon fiber confined PVC tube (CFRP), glass fiber confined PVC tube (GFRP), CFRP, GFRP, polyethylene (PE), PE hybrid CFRP and PE hybrid GFRP. The deformation, macroscopical deformation characters, failure mechanism and failure modes are studied in this paper. The ultimate bearing capacity of these 10 types of confined concrete columns and the influences of the confining materials on the ultimate bearing capacity are obtained. The advantages and disadvantages of these 10 types of confining methods are compared.


2011 ◽  
Vol 255-260 ◽  
pp. 1198-1203 ◽  
Author(s):  
Ye Sheng

The weakness of traditional dumbbell-shaped section is that when concrete is filled into the web space, great stress is likely to produce cracks in the weld sealing between steel tube and web plates. In order to avoid this condition, a new-type dumbbell-shaped section is proposed. Experiments on concrete filled steel tubular (CFST) model arches with new-type dumbbell-shaped section have been carried out, concentrated loading at crown and L/4 section respectively. The result indicated that the new-type CFST arch has good elastic-plastic behavior and high strength, no local buckling appeared during the whole loading process, its in-plane mechanic behavior is similar with that of the CFST arch with single-tube. The dual nonlinear finite element calculation model is set up for the model arch, by means of this model the load-deflection curves during the loading process and the ultimate load-carrying capacity is analyzed.


2018 ◽  
Vol 8 (9) ◽  
pp. 1602 ◽  
Author(s):  
Zhao Yang ◽  
Chengxiang Xu

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
He Zhang ◽  
Kai Wu ◽  
Chao Xu ◽  
Lijian Ren ◽  
Feng Chen

Two columns of thin-walled concrete-filled steel tubes (CFSTs), in which tube seams are connected by self-tapping screws, are axial compression tested and FEM simulated; the influence of local buckling on the column compression bearing capacity is discussed. Failure modes of square thin-wall CFST columns are, first, steel tube plate buckling and then the collapse of steel and concrete in some corner edge areas. Interaction between concrete and steel makes the column continue to withstand higher forces after buckling appears. A large deflection analysis for tube elastic buckling reflects that equivalent uniform stress of the steel plate in the buckling area can reach yield stress and that steel can supply enough designing stress. Aiming at failure modes of square thin-walled CFST columns, a B-type section is proposed as an improvement scheme. Comparing the analysis results, the B-type section can address both the problems of corner collapse and steel plate buckling. This new type section can better make full use of the stress of the concrete material and the steel material; this type section can also increase the compression bearing capacity of the column.


Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2716 ◽  
Author(s):  
Shiming Liu ◽  
Xinxin Ding ◽  
Xiaoke Li ◽  
Yongjian Liu ◽  
Shunbo Zhao

This paper studies the effect of high-strength steel fiber reinforced concrete (SFRC) on the axial compression behavior of rectangular-sectional SFRC-filled steel tube columns. The purpose is to improve the integrated bearing capacity of these composite columns. Nine rectangular-sectional SFRC-filled steel tube columns and one normal concrete-filled steel tube column were designed and tested under axial loading to failure. The compressive strength of concrete, the volume fraction of steel fiber, the type of internal longitudinal stiffener and the spacing of circular holes in perfobond rib were considered as the main parameters. The failure modes, axial load-deformation curves, energy dissipation capacity, axial bearing capacity, and ductility index are presented. The results identified that steel fiber delayed the local buckling of steel tube and increased the ductility and energy dissipation capacity of the columns when the volume fraction of steel fiber was not less than 0.8%. The longitudinal internal stiffening ribs and their type changed the failure modes of the local buckling of steel tube, and perfobond ribs increased the ductility and energy dissipation capacity to some degree. The compressive strength of SFRC failed to change the failure modes, but had a significant impact on the energy dissipation capacity, bearing capacity, and ductility. The predictive formulas for the bearing capacity and ductility index of rectangular-sectional SFRC-filled steel tube columns are proposed to be used in engineering practice.


2010 ◽  
Vol 163-167 ◽  
pp. 3580-3585
Author(s):  
Yuan Che ◽  
Qing Li Wang ◽  
Yong Bo Shao ◽  
Hai Tao Mu

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.


2013 ◽  
Vol 838-841 ◽  
pp. 439-443 ◽  
Author(s):  
Zhi Liang Zuo ◽  
Da Xin Liu ◽  
Jian Cai ◽  
Chun Yang ◽  
Qing Jun Chen

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.


2010 ◽  
Vol 163-167 ◽  
pp. 1033-1037
Author(s):  
Qing Jun Chen ◽  
Jian Cai ◽  
Xiao Qin Zhao ◽  
Ping Yang ◽  
Chun Yang

Concrete filled steel tubular (CFST) column-beam joint with the column tube discontinuous in joint zone is a new type of joint. In this paper, the compressive tests on this joint were carried out after the cyclic reversed loading. First the cyclic loading experiment results were introduced briefly, then the compressive tests were presented. The bearing capacity, crack patterns, deformation, strain of the reinforcements of the specimens were studied. These specimens were also compared with the other specimens only under compressive test. The results show that the specimens have good ductility. The concrete of the reinforced concrete (RC) ring beam cracked before the yield of the steel ring bars or the buckling of the steel tube. Although the cyclic loading caused some damage on the ring beam, it had few effects on the axial bearing capacity. The RC ring beam can still confine the joint zone and ensure the capacity of the joint zone was not lower than the CFST column.


2008 ◽  
Vol 400-402 ◽  
pp. 901-910 ◽  
Author(s):  
Fu Jun Liu ◽  
Jian Cai

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.


2014 ◽  
Vol 513-517 ◽  
pp. 4123-4126 ◽  
Author(s):  
Yun Xu

The steel tube-plate joints are widely applied in tall-slender tower of transmission line engineering,but there are few studies at home and abroad. In this paper,experimental study with full-scale model and analysis based on FEM were carried out on the ultimate bearing capacity of typical h-joints , and the results showed that the bending moment was transferred to the chord from the ear-plate of a narrow area, which led to local buckling on the chord wall , so the local strength of chord is one of the most important control factors in the design of this typical joint;thus the bearing capacity can improve by enhancing the strength of steel or increasing the thickness of ear-plate. In view of the phenomenon that stress concentration is easy to emerge at the intersection of the steel tube-plate joints, some improvement measures for the connections are put forward,such as adding outer half-ring stiffening plates , adding outer-ring plates , adding inner-ring plates, and revising ear-plates to smooth the concave angle , etc.


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