Push-out tests and bond strength of rectangular CFST columns

Qu, Xiushu; Chen, Zhihua; Nethercot, D.A.; Gardner, Leroy; Theofanous, Marios

doi:10.12989/scs.2015.19.1.021

Cited by 36 publications

(29 citation statements)

References 20 publications

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“…Therefore, it is necessary to examine the bond strength versus slip curve to determine the development of each mechanism. As shown in literature [18], the common features of all the load-slip curves are an elastic stage and a transitional portion before the bond strength reached the peak point. The differences occur after the first peak point (ultimate bond stress).For the present tests, only TCB9 exhibited an increasing branch after the first peak point (Type3), whereas previous studies [1], have shown that most bond stress-slip curves exhibited this feature.…”

Section: Interface Bond Strength and τ-S Constitutive Modelsmentioning

confidence: 70%

“…Considering all the test results from literature [18], the typical load-slip curve exhibits a number of important features; these are marked in Fig. 1 and listed in Table 1.…”

Section: Interface Bond Strength and τ-S Constitutive Modelsmentioning

confidence: 99%

“…However, some evidence suggests that square CFST columns possess lower bond strengths than circular CFST columns in 2015, a total of 18 CFST specimens were tested to measure the bond strength between rectangular steel tubes and a concrete core by Qu [18]. The experimental study focused not only on the influence of factors such as concrete compressive strength, steel strength, interface length and cross-sectional proportions on the load-carrying capacity, but also assessed the adverse effect of lubrication at the steel-concrete interface.…”

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confidence: 99%

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Research on Interface bond strength and bond-slip constitutive models for rectangular CFST columns

Qu¹,

Liu²

2017

Proceedings of the 2017 Global Conference on Mechanics and Civil Engineering (GCMCE 2017)

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Abstract. More recent studies have suggested that parameters such as cross-section type, cross-sectional dimensions, interface length, concrete compressive strength, slenderness ratio, steel strength, roughness of interface, concrete casting style, and concrete curing conditions potentially have some influence on the value of the bond strength. In this paper, a brief review of previous research and literature that are pertinent to the present study of the interface bond strength and τ-S constitutive models are presented first. According to the previous laboratory testing results, three equations are designed to calculated are average elastic limit bond strength, average ultimate bond strength and average post-peak residual bond strength, respectively. Moreover, a new simplified four-part model has been proposed to describe the τ-S response. IntroductionThe steel-concrete interface bond stress is the force being on the interface between the steel tube and the concrete core. It is the guarantee to assure the concrete and steel tube to work together. In the beam-column joint area, shearing force from the beam translates to the steel tube of the column through the beam-to-column connection. Then, it is gradually translated into the core concrete through the steel-concrete interface bond stress. The value of interface band strength can influence the load transfer to a certain extent and it is the key point for the individual differences of different calculation theories. Parameters such as cross-section type, cross-sectional dimensions, interface length, concrete compressive strength, slenderness ratio, steel strength, roughness of interface, concrete casting style, and concrete curing conditions potentially have some influence on the value of the bond strength [1][2][3][4][5][6]. Previous research on the bond strength versus slip (τ-S) constitutive model is relatively small. Previous Laboratory Testing for Interface Bond StrengthThe earliest research on the interface bond strength of rectangular CFST columns was carried out by Virdi and Dowling in 1975 [1]. A push-out test programme applied to 88 circular CFT columns were conducted to investigate the value and the composition of the bond strength. It was found that the bond strength did not appear to be greatly influenced by the variation in the concrete cube strength. In 1991, push-out tests have been carried out on 36 CFST stub columns by Shakir-Khalil [7]. The tests showed that the push-out load is a variation upon or function of the shape of the steel hollow section, as well as also a variation or function of the type of shear connectors and the way in which the load is applied to the steel section.In 1993, a further experimental study on the interface condition as applied to the interface bond strength was investigated by . Six out of twelve of square CFST columns and six out of twelve circular columns were tested by means of oiling the steel-concrete interface. The results of the tests indicated that oiling the steel-concrete interface resulted in its halving ...

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Section: Interface Bond Strength and τ-S Constitutive Modelsmentioning

confidence: 70%

“…Considering all the test results from literature [18], the typical load-slip curve exhibits a number of important features; these are marked in Fig. 1 and listed in Table 1.…”

Section: Interface Bond Strength and τ-S Constitutive Modelsmentioning

confidence: 99%

mentioning

confidence: 99%

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Research on Interface bond strength and bond-slip constitutive models for rectangular CFST columns

Qu¹,

Liu²

2017

Proceedings of the 2017 Global Conference on Mechanics and Civil Engineering (GCMCE 2017)

Self Cite

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“…At this point, the ultimate bond load (P u ) corresponding to the loadslip (P-S) curve could be considered as the ultimate bond force at the entire interface. erefore, the average bond strength was calculated using the following formula [14,26]:…”

Section: Average Bond Strengthmentioning

confidence: 99%

“…However, the interfacial bond strength increased with the increase of the slenderness ratio. e results of the study by Lihong and Shaohuai [12,13] and Qu et al [14] show that the strength of the core concrete clearly influences the interfacial bond strength, and the interfacial bond strength increases with the increase of the core concrete strength. In addition, the relation between the bond strength and concrete strength was deduced.…”

Section: Introductionmentioning

confidence: 99%

Study on the Bond‐Slip Performance of CFSSTs Based on Push‐Out Tests

Wang

Chen

Zhong

et al. 2018

Advances in Materials Science and Engineering

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To study the interfacial bond-slip performance of concrete-filled square steel tubes (CFSSTs), taking the core concrete strength, slenderness ratio, and width-to-thickness ratio as the influencing factors; 9 specimens were designed with 3 factors and 3 levels for the orthogonal test method. In addition, different from the above 9 specimens, one specimen without rust removal was designed for the purpose of comparison. Based on the bond stress distribution and deformation coordination relationships between the specimens during the push-out tests, a theoretical formula for calculating the relative slip of a CFSST was deduced. e results show that with the increase of load, the relative slip at the loading ends was earlier than that at the free ends of the specimens; the interfacial bond failure and relative slip gradually developed from the two ends towards the centre of the specimens; the increase of the bond stress in the middle part was faster than that at the ends of the specimens. e order of these factors from main to secondary is the presence of rust in the inner wall of the square steel tube, the slenderness ratio, the core concrete strength, and the width-to-thickness ratio.

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Innovative shear transfer system for Concrete Filled Steel Tubes (CFST) in columns

Soltanalipour¹,

Ferrer²,

Albareda³

et al. 2021

ce papers

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The common failure mode of composite steel‐concrete structural elements, such as composite columns, generally occurs due to the relative slipping or separation of the steel sheet and the concrete. This leads to materials overspending and low resistance. In the case of beam‐to‐column joints, the most common solution used in composite construction is introducing a perpendicular gusset plate, which is complex in terms of execution. On the other hand, there is no efficient solution for shear transferring along the whole length of the column to prevent slip under bending. The UPC patent improves very significantly the shear transferring between steel and concrete, enough to achieve the permanent connection in many cases, by means of generating a series of many crown‐shaped breakages produced by punching in the profiling stage, not only in the joints but also in the whole length. When the concrete sets, the said breakages embedded therein have the function of resisting shearing forces generated between both materials. It has been successfully applied to composite slabs and, in terms of composite columns, it is also a disruptive innovation to solve the current shear transfer limitation. Besides, this innovative system is easy to be massively produced avoiding the complexities of the conventional beam‐to‐column joints and reducing the construction costs, especially in high‐rise buildings. The aim of this paper is to present this new technology for connecting steel sheet and concrete in CFST columns.

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Push-out tests and bond strength of rectangular CFST columns

Cited by 36 publications

References 20 publications

Research on Interface bond strength and bond-slip constitutive models for rectangular CFST columns

Research on Interface bond strength and bond-slip constitutive models for rectangular CFST columns

Study on the Bond‐Slip Performance of CFSSTs Based on Push‐Out Tests

Innovative shear transfer system for Concrete Filled Steel Tubes (CFST) in columns

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