• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.573-579
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• 2004

For the fast construction and replacement of bridges in urban area, a prefabricated bridge system can be an excellent alternative. Details of prefabricated slabs for PSC girders were developed and static tests on shear connections were conducted to propose design equations of the shear connection. Stirrups and stud connectors were used as shear connectors and non-shrink mortar was used for the filling material in shear pockets for shear connectors. Stirrups and studs were fabricated to insert embedded nut-type devices in PSC girders. Shear strength of the shear connection considering chemical bond, friction and mechanical connectors was evaluated and empirical equations were suggested. Due to the mechanical connectors, ultimate slip capacity of the shear connection was sufficient for shear load redistribution, and suggested details of the shear connection showed good performance in terms of strength and ductility.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.356-361
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• 1994

From the previous experimental test results, it has shown that shear that shear strength in lightweight concrete beams was about 85% on that in normal concrete beams. It is speculated that shear connectors in composite beams of steel and lightweight concrete associated with the longitudinal shear strength decrease more in strength than those in normal concrete. So this paper, as a study on strength of shear connectors in composite beams of steel and lightweight concrete slabs, has a purpose to compare the strength formula resulted from the push-out test of thirteen solid slab and four deck Plate slab with the established ones, and then to suggest a proper strength formula of the shear connectors. The established strength formula of the shear connectors is prescribed for $P_ps = 0.50A_s . \sqrt{f_C . E_C}$by AISC coed, but from the experimental test results the strength values of the shear connectors in lightweignt concrete slabs shows about 70% on those of the shear connectors in normal concrete slabs by AISC code. Therefore, as a strength formula this paper suggests to multiply the established strength formula by reduction factor$(\varphi=0.7)$.

• Steel and Composite Structures
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• v.27 no.5
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• pp.537-543
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• 2018

Mechanical shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface in composite beams. Steel pipe as a new shear connector is proposed in this research and its performance to achieve composite strength is investigated. Experimental monotonic push-out tests were carried out for this connector. Then, a nonlinear finite element model of the push-out specimens is developed and verified against test results. Further, the finite element model is used to investigate the effects of pipe thickness, length and diameter on the shear strength of the connectors. The ultimate strengths of these connectors are reported and their respective failure modes are discussed. This paper comprises of the push-out tests of ten specimens on this shear connector in both the vertical and horizontal positions in different reinforced concretes. The results of experimental tests are given as load-deformation plots. It is concluded that the use of these connectors is very effective and economical in the medium shear demand range of 150-350 KN. The dominant failure modes observed were either failure of concrete block (crushing and splitting) or shear failure of pipe connector. It is shown that the horizontal pipe is not as effective as vertical pipe shear connector and is not recommended for practical use. It is shown that pipe connectors are more effective in transferring shear forces than channel and stud connectors. Moreover, based on the parametric study, a formula is presented to predict the pipe shear connectors' capacity.

• Smart Structures and Systems
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• v.22 no.3
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• pp.335-340
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• 2018

The behavior of concrete slabs in composite beam with C and L shaped angle shear connectors has been studied in this paper. These two types of angle shear connectors' instalment have been commonly utilized. In this study, the finite element (FE) analysis and soft computing method have been used both to present the shear connectors' push out tests and providing data results used later in soft computing method. The current study has been performed to present the aforementioned shear connectors' behavior based on the variable factors aiming the study of diverse factors' effects on C and L shaped angle in shear connectors. ANFIS (Adaptive Neuro Fuzzy Inference System), has been manipulated in providing the effective parameters in shear strength forecasting by providing input-data comprising: height, length, thickness of shear connectors together with concrete strength and the respective slip of shear connectors. ANFIS has been also used to identify the predominant parameters influencing the shear strength forecast in C and L formed angle shear connectors.

• Steel and Composite Structures
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• v.7 no.5
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• pp.377-390
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• 2007

In the design of concrete filled composite columns, it is assumed that the load transfer between the steel tube and concrete core has to be achieved by the natural bond. However, it is important to investigate the mechanisms of shear transfer due to the possibility of steel-concrete interface separation. This paper deals with the contribution of headed stud bolt shear connectors and angles to improve the shear resistance of the steel-concrete interface using push-out tests. In order to determine the influence of the shear connectors, altogether three specimens of concrete filled composite column were tested: one without mechanical shear connectors, one with four stud bolt shear connectors and one with four angles. The experimental results showed the mechanisms of shear transfer and also the contribution of the angles and stud bolts to the shear resistance and the force transfer capacity.

• Steel and Composite Structures
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• v.46 no.2
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• pp.175-193
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• 2023

Stainless steel-concrete composite beam has become an attractive structural form for offshore bridges and iconic high-rise buildings, owing to the superior corrosion resistance and excellent ductility of stainless steel material. In a composite beam, stainless steel shear connectors play an important role by establishing the interconnection between stainless steel beam and concrete slab. To enable the best use of high strength stainless steel shear connectors in composite beams, high strength concrete is recommended. To date, the application of stainless steel shear connectors in composite beams is still very limited due to the lack of research and proper design recommendations. In this paper, a total of seven pushout specimens were tested to investigate the load-slip behaviour of stainless steel shear connectors. A thorough discussion has been made on the differences between stainless steel bolted connectors and welded studs, in terms of the failure modes, load-slip behaviour and ultimate shear resistance. In parallel with the experimental programme, a finite element model was developed in ABAQUS to simulate the behaviour of stainless steel shear connectors, with which the effects of shear connector strength, concrete strength and embedded connector height to diameter ratio (h/d) were evaluated. The obtained experimental and numerical results were analysed and compared with existing codes of practice, including AS/NZS 2327, EN 1994-1-1 and ANSI/AISC 360-16. The comparison results indicated that the current codes need to be improved for the design of high strength stainless steel shear connectors. On this basis, modified design approaches were proposed to predict the shear capacity of stainless steel bolted connectors and welded studs in the composite beams.

• Steel and Composite Structures
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• v.20 no.6
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• pp.1275-1303
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• 2016

Steel plates and carbon-fiber-reinforced polymer (CFRP) laminates or plates bonded to concrete substrates have been widely used for concrete strengthening. However, this technique cause plate debonding, which makes the strengthening system inefficient. The main objective of this study is to enhance the bond strength of externally bonded steel plates and CFRP laminates to the concrete surface by proposing new embedded adhesive and steel connectors. The effects of these new embedded connectors were investigated through the tests on 36 prism specimens. Parameters such as interfacial shear stress, fracture energy and the maximum strains in plates were also determined in this study and compared with the maximum value of debonding stresses using a relevant failure criterion by means of pullout test. The study indicates that the interfacial bond strength between the externally bonded plates and concrete can be increased remarkably by using these connectors. The investigation verifies that steel connectors increase the shear bond strength by 48% compared to 38% for the adhesive connectors. Thus, steel connectors are more effective than adhesive connectors in increasing shear bond strength. Results also show that the use of double connectors significantly increases interfacial shear stress and decrease debonding failure. Finally, a new proposed formula is modified to predict the maximum bond strength of steel plates and CFRP laminates adhesively glued to concrete in the presence of the embedded connectors.

• Steel and Composite Structures
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• v.29 no.2
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• pp.257-272
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• 2018

The research of shear connectors composed from mechanical couplers with rebar anchors, embedded in concrete, and steel bolts, as a mean of shear transfer in composite connections is presented in the paper. Specific issues related to this type of connections are local concrete pressure in the connector vicinity as well as the shear flow along the connector axis. The experimental research included 18 specimens, arranged in 5 series. Nonlinear numerical analyses using Abaqus software was conducted on corresponding FE models. Different failure modes were analysed, with emphasis on concrete edge failure and bolt shear failure. The influence of key parameters on the behaviour of shear connector was examined: (1) concrete compression strength, (2) bolt tensile strength and diameter and (3) concrete edge distance. It is concluded that bolted shear connectors with mechanical couplers have sufficient capacity to be used as shear connectors in composite structures and that their behaviour is similar to the behaviour of post installed anchors as well as other types of connectors anchored without the head.

• Steel and Composite Structures
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• v.2 no.1
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• pp.51-66
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• 2002

Perforated shear connectors currently used in composite steel and concrete structures are described and evaluated. Modifications of the perforated connector suitable for common use injavascript:confirm_mark('abe', '1'); civil and bridge engineering are proposed. The connectors were tested in laboratories of CTU Prague for shear load capacity. Push tests of connectors with 32 mm openings and with 60 mm openings, both in normal and lightweight concrete of different strength characteristics and with different transverse reinforcement, were carried out. The experimental study also dealt with the connector height and parallel arrangement of two connectors and their influence on shear resistance. While extensive tests with static loading were carried out, fatigue tests under repeated loading are still in progress. After statistical evaluation of the experimental results and comparisons with other available data the authors developed reasonable shear resistance formulas for all proposed arrangements.

• Steel and Composite Structures
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• v.17 no.6
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• pp.967-980
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• 2014

In regions of high shear forces in composite bridges, headed stud shear connectors need to be arranged with a small spacing in order to satisfy the design requirement of resisting the high interface shear force present at this location. Despite this, studies related to groups of headed studs are somewhat rare. This paper presents an investigation of the static behaviour of grouped stud shear connectors in high-strength concrete. Descriptions are given of five push-out test specimens with different arrangements of the studs that were fabricated and tested, and the failure modes, load-slip response, ultimate load capacities and related slip values that were obtained are reported. It is found that the load-slip equation given by some researchers based on a single stud shear connector in normal strength concrete do not apply to grouped stud shear connectors in high-strength concrete, and an algebraic load-slip expression is proposed based on the test results. Comparisons between the test results and the formulae provided by some national codes show that the equations for the ultimate capacity provided in these codes are conservative when used for connectors in high-strength concrete. A reduction coefficient is proposed to take into account the effect of the studs being in a group.