• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.133-143
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• 2018

Concrete filled steel tube (PCFT) piles, which compose PHC piles inside thin steel pipes, were developed to increase the flexural strength of the pile with respect to the horizontal load. In order to compare the flexural strength of PCFT pile with that of steel pipe pile, several flexural tests were performed on the PCFT and steel pipe piles with the same diameter and the P-M curves for both piles were constructed by the limit state design method. Four test piles were also installed and lateral pile load tests were performed to compare the lateral load capacities and lateral behaviors of the hybrid composite piles using PCFT piles and the existing piles such as HCP and steel pipe piles. The flexural test results showed that the flexural strength of PCFT piles was 18.7% higher than that of steel pipe piles with thickness of 12mm and the same diameter, and the mid-span deflection of piles was 50% lower than that of steel pipe piles at the same bending moment. From the P-M curves, it can be seen that the flexural strength of PCFT piles subjected to the vertical load is greater than that of steel pipe piles, but the flexural strength of PCFT piles subjected to the pullout load is lower than that of steel pipe piles. In addition, field pile load tests showed that the PCFT hybrid composite pile has 60.5% greater lateral load capacity than the HCP and 35.8% greater lateral load capacity than the steel pipe pile when the length of the upper pile in hybrid composite piles was the same.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.561-566
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• 2001

Load at steel beam column joints transfered by beam depend on bond strength between concrete and steel tube. But it is different to transmit a load efficiently in the established concrete filled steel tubular column. Therefore, shear-connector is demanded for transfering loads efficiently. An ascent of bond stress and a transmission of load after debonding are expected by a reinforcement of shear-connector

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.567-572
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• 2001

A transmission of load that is transmitted by beam in steel beam-column joint depends on bond strength between concrete and steel tube. But it is different to transmit a load efficiently in the established concrete filled steel tubular column. Therefore, shear-connector is demanded for a reinforcement about a transmission of load. An ascent of bond stress and a transmission of load after debonding are expected by a reinforcement of shear-connector.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.587-596
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• 1997

This study is concerning the structural behavior of reinforced concrete filled tubular column to steel H-beam connections with outer diaphram by simplified connection type. The important parameters of this study are the cross-section shape of tubular column and the spacing of hoop (60mm, 30mm, 20mm) and the concrete filled or not. The experimental results are summarized for the strength and displacement of each specimen.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.222-227
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• 2001

Full scale construction tests of CFT(concrete filled steel tube) column to solve construction problem and to confirm quality were performed in apartment site. To improve construction efficiency, the tests has been accomplished two stages after the tests for material mixing design had been completed. In the first stage, the experimental variables were the placing methods, existence of guiding pipe, placing velocity and drop height and the height of specimen were $3.6{\cal}m$. In the second stage, Filling steel tube of 9.6m height with concrete was performed by two ways, that is, the pump-up method and the dropping method. The filled condition of the concrete and concrete strength distribution according to the column height were checked and the quality of the CFT column was confirmed.

• 건축구조
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• v.20 no.2
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• pp.29-34
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• 2013

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.681-687
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• 2006

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.523-532
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• 2010

Concrete-filled square steel tube (CFT) columns have inherently high fire resistance and load-bearing capacity. Nevertheless, it is sometimes necessary to improve their fire resistance using external fire protection. This paper presents the experimental results of the temperature distribution of CFT columns with fire protection. A fire load test was carried out by exposing small-scale specimens to heat in an electric furnace that was especially built for testing loaded columns. The temperature distribution of CFT columns under constant axial loads was determined, as were its significant parameters, such as the types of fire protection and thickness, the thickness of the square CFT, and the fire duration times. The results of this study showed the temperature distribution of each specimen of the electric furnace and the temperature distribution properties of concrete and steel. In addition, the axial displacement and local buckling behavior of CFT columns based on temperature changes was observed.

• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.83-90
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• 2007

Buildings become high and large. CFT(Concrete Filled steel Tube) columns have been developed to manage effectively that loads which columns support and cross sections of columns are increased. Because CFT column is the composite structure made of two different materials, many researches have been performed to look into mechanical behaviors. This study is an analytic study about bond stress on interface between concrete core and steel tube in circular and rectangular CFT columns. ABAQUS/Standard Version 5.8 is used to analyze bond stress by bond form and position of shear-connector, and improved analystic method about mechanical characters on interface is suggested.

• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.403-411
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• 2007

CFT (Concrete filled steel tube) column has become popular for building construction due to not only its composite effect but also economic effect. However, the conventional CFT column also has its own disadvantages having plastic buckling at the end of column followed by the reduction of strength by yielding of steel tube. An experiment on TR-CFT (Transversely reinforced CFT) column are conducted for making up for conventional CFT column's disadvantages. The experiment parameters are strength of concrete, the layer numbers of carbon fiber sheet. In this study, hysteretic curve, initial stiffness, strength, plastic deformation capacity, and dissipated energy are compared and analyzed between CFT and TR-CFT columns.