• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.63-75
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• 2015

In this study, Composite beam flexural capacity was investigated experimentally using angle as a shear connector. The main experimental parameters are the size and the spacing of the angle and the overall behavior of before and after composite. Also, the composite beam bending performance when it used with hollow PC slab and the general RC slab was compared. When determining that it synthetically, the flexural capacity of the composite beam with angle shear connector estimated 25% to 55% more strength than the nominal strength. Effects of strength parameters of composite beam by angles shear connector are size and spacing of the angle. As expected, the larger and the narrower spacing of the angles, the more strength the composite beam have. In addition, the performance of the composite beam with a hollow slab was well demonstrated by the test.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.587-598
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• 2004

In this study, an experiment was conducted on the Slim Floor system, using a hollow core PC slab, which could reduce the over-all depth of a composite beam. The Slim Floor system is a method used in steel frame multi-story building construction, in which the structural depth of each floor is minimized after incorporating the steel floor beams within the depth of the concrete floor slab. This experimental study focused on the flexural behavior of the partially connected Slim Floor system with asymmetric steel beams encased in hollow core PC slabs. Ten full-scale specimens were constructed and tested in this study, with different steel beam heights, hollow core PC slabs, slab widths, and PC slab bearings. Observations made in line with the experiments indicated that the degree of shear connection without additional shear connection was 0.48-0.98 times more than that of the full shear connection, due to inherent mechanical and chemical bond stress.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.6
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• pp.63-68
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• 2007

The purpose of this study was to develop a new connection method between steel beams and PC columns known as SL connectors. Composite moment frames consisting of PC columns (or composite columns) and steel beams make the best use of advantages of both concrete and steel materials. However, the connection between two members of different materials can be complex and/or increase the fabrication costs significantly. The concept of SL connectors is based on using wedges and the emphasis is on a self-locking (SL) feature. SL connectors are easy to install and provide better seismic performance compared to conventional connections. To evaluate the seismic performance of the steel beam-to-PC column joints with SL connectors, cyclic load tests were conducted. Test result showed that steel beam-to-concrete column joint with SL connectors was able to provide sufficient performance for use in seismic resistant moment frames.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.34-42
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• 2012

Green frame technology intended to facilitate the remodeling of apartment housing complexes in Korea and extend their service life has been developed. Green frame design is a Rahmen structure using composite precast concrete members and, unlike a bearing-wall structure, lifting and installing structural members accounts for major steps of structural construction. Therefore, if green frame structure construction is to be scheduled appropriately, systematic lifting plan needs to be developed in advance. Development of lifting plan also requires unit lifting process of composite PC members (columns and beams) that consist of green frame to be analyzed first. Therefore, this study attempts to analyze the lifting process of composite PC members used in green frame structure. To that end, lifting procedure and time of composite PC column and beam are estimated and applied to a project case to analyze the lifting cycle of reference floor. Outcomes produced herein will be used as key data for development of lifting plan in subsequent green frame structure construction.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.493-504
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• 2008

This paper deals with the experimental analysis of the flexural behaviour of encased composite beams with hollow core slabs and channels. The shear force between steel beams and hollow core slabs are transferred by channels. Three full-scale specimens were constructed and tested with different steel beam heights, which were compared with those of previous studies. Based on observation of the experiments, the encased composite beams exhibited full shear connection behaviour without any other shear connectors due to their inherent mechanical and chemical bond stress. Experimental results show a behaviour similar to steel-concrete composite beams with classical connectors: elastic and yield domains, great ductility, flexural failure mode (plastic hinge), low relative movement at steel-concrete interface and all specimens failed in a very ductile manner. Consequently, this study enables the validation of the proposed connection device under static loading and shows that it meets modern structural requirements.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.399-409
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• 2015

Recently, the use of composite construction method using precast (PC) and cast-in-place (CIP) concrete is increased in modular construction. For PC members, pre-tensioning is used to improve efficiency of the structural performance. However, current design codes do not clearly define shear strength of prestressed PC-CIP composite members. In this study, 22 specimens were tested to evaluate shear strength of prestressed composite members with vertical shear reinforcement. The test variables were the area ratio of high-strength (60 MPa) to low-strength concrete (24 MPa), prestressing force of strands, shear span-to-depth ratio(a/d), and vertical shear reinforcement ratio. The test results showed the prestressing force did not completely restrain diagonal cracking of non-prestressed concrete in the web. Thus, the effect of prestress force was not insignificant in the effect for monolithic beams. The vertical shear strength and horizontal shear strength of the composite beams were compared with the strength predictions of KCI design method.

• Journal of Korean Society of Steel Construction
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• v.16 no.6 s.73
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• pp.747-757
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• 2004

With steel and concrete composite beams, the incomplete interaction between the steel and the concrete slab leads to an appreciable increase in beam deflections. Moreover, encased composite beams using a deep deck plate or hollow-core PC slabs are critical to deflection due to their inherent geometry. In this paper, by using the calculation tools that were developed for a previous study on the deflection of encased composite beams considering the slip effects and load-slip curve, the shear bond stress and additional deflection induced due to interface slip of the encased composite beam are presented. It was found that the slip effects significantly contribute to the encased composite beam deflections and result in stiffness reduction of up to 30% compared to that of full shear interaction beams. The predicted results were compared with the measurement of 18 specimens tested in this study, and comparisons show a high degree of accuracy, within 6%.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.189-199
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• 2014

Currently, in the precast concrete construction, Precast Concrete (PC) and Cast-In-Place (CIP) concrete with different concrete strengths are frequently used. However, current design codes do not specifically provide shear design methods for PC-CIP hybrid members using dual concrete strengths. In the present study, simply supported composite beams with shear reinforcement were tested. The test variables were the area ratio of the two concretes, spacing of shear reinforcement, and shear span-to-depth ratio. The shear strengths of the test specimens were evaluated by current design codes on the basis of the test results. The results showed that the shear strength of the composite beams was affected by the concrete strength of the compressive zone and also proportional to the flexural rigidity of un-cracked sections. Furthermore, the contribution of shear reinforcements varied according to the concrete strength of the compressive zone.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.20 no.2
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• pp.39-45
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• 2016

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.533-543
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• 2014

Currently, composite construction of prestressed Precast Concrete (PC) and Cast-In-Place (CIP) concrete with different concrete strengths are frequently used in the modular construction. However, current design codes do not clearly define shear design methods for such composite beams. In this present study, simply supported prestressed PC-CIP composite beams without vertical shear reinforcement or only with horizontal shear reinforcement were tested to evaluate the effect of prestressing on the shear strength and the shear design method for such composite members. The test variables were the area ratio of PC and CIP concretes, prestressing force, shear span-to-depth ratio, and shear reinforcement ratio. The results showed that the shear strength was increased by the increase of prestressing force and prestressed PC area, and the decrease of shear span-to-depth ratio.