• Structural Engineering and Mechanics
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• v.7 no.4
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• pp.413-432
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• 1999

A macro-element model is developed to account for shear deformation and bond slip of reinforcement bars in the beam-column joint region of reinforced concrete structures. The joint region is idealized by two springs in series, one representing shear deformation and the other representing bond slip. The softened truss model theory is adopted to establish the shear force-shear deformation relationship and to determine the shear capacity of the joint. A detailed model for the bond slip of the reinforcing bars at the beam-column interface is presented. The proposed macro-element model of the joint is validated using available experimental data on beam-column connections representing exterior joints in ductile and nonductile frames.

• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.98-107
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• 2012

Reinforcing bars (rebar) comprise an integral part of a concrete structure, and play a major role in the safety and durability of the building. However, the actual placement or installation of rebar is not planned and controlled by the detailer. Recently, 4D simulations, using 3D model and scheduling software, have been used to improve the efficiency of the construction phrase. However, 4D simulators have not been introduced at the detailed level of work, such as rebar placement. Therefore, this paper suggests a BIM-based simulator for rebar placement to determine the sequence with which rebar is placed into the form. The system using Autodesk Revit API automatically generates rebar placement plans for a building structure, and labels the placement sequence of each individual bar or set of bars with ascending numbers. The placement sequence is then visualized using Autodesk Revit Structure 2012. This paper provides a short description of a field assessment and limits.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.63-66
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• 2000

This paper describes the need for a ductile Fiber Reinforced Plastic(FRP) reinforcement for concrete structures. Using the material hybrid and geometric hybrid, it is demonstrated that the pseudo-ductility characteristic can be generated in FRP rebar. Ductile hybrid FRP bars were successfully fabricated at 4mm and l0mm nominal diameters using an hand lay up method. Tensile specimens from these bars were tested and compared with behavior of FRP rebar and steel bar

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.48-52
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• 2002

This paper describes the need for a ductile Fiber Reinforced Plastic(FRP) reinforcement for Concrete Structures. Using the material hybrid and geometric hybrid, it is demonstrated that the pseudo-ductility Characteristic can be generated in FRP rebar. Ductile hybrid FRP bars were successfully fabricated at Ø3mm and Ø10mm nominal diameters using the braidtrusion process. Tensile and bending specimens from these bars were tested and compared with behavior of stress-strain of steel bar and GFRP rebar

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.45-50
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• 1990

The purpose of this study was to find, through field and questionaire survey, the problems in arrngement of reinforcing bars in wall-slab type apartment buildings. The survey was done in 88 construction sites over the country. The findings from the survey were as followed : (1) reinforcement details were unnecessarily complex in some structural members and could be simplified without sacrificing the safety of the structures; (2) It was found in many cases that drawings of reiforcement failed to show the location of the laps, bent-up positions, and the development length; and (3) it was often found that the workers did not understand the importance of tloerence limits and anchorage in the steel bar arrangement.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.257-260
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• 2006

This paper reports results of a study conducted to assess the effect of degree of corrosion of reinforcing steel bar on their mechanical properties. Reinforcing steel bars, 13mm in diameter, that were corroded by electrically accelerated corrosion method in concrete specimens were removed and tested in tension. Results indicated that the level of reinforcement corrosion influenced yield point, the tensile strength and elongation of steel bars.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.57-62
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• 2000

This paper describes the need for a ductile Fiber Reinforced Plastic(FRP) reinforcement for concrete structures. Using the material hybrid and geometric hybrid. it is demonstrated that the pseudo-ductility characteristic can be generated in FRP rebar. Ductile hybrid FRP bars were successfully fabricated at 4mm and 10mm nominal diameters using an hand lay up method. Tensile specimens from these bars were tested and compared with behavior of FRP rebar and steel bar

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.109-113
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• 2003

In this experiment, we distribute the bending angle to 60$^{\circ}$, 90$^{\circ}$, 120$^{\circ}$, and we separate it in to two groups. One is straightening right after bending and the other is straightening after one week. The bars we will use are HD13 and HD16. The number of tests will be 60 times. In the case of HD16, the increase of bending angle decreased yield strength and maximum strength. And compared with thinner bars, HD16 showed bigger differences in yield strength and maximum strength when the 'being bent' duration got longer. So it shows that when we bend and after straighten a bar, stress change takes place on the surface of the bar. At the beginning it shows it's ductility after that it deforms while transforming it's character to destroying. And also, if we straighten a bar after bending, it doesn't get straighten like the original form. So it makes torsion and this torsion makes moments in different areas.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.319-322
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• 2005

Experimental results on splice strength of concrete and hybrid fiber reinforced cementitious composite are reported. Two series of tests, with six specimens each, were carried out. The research parameters were: bar diameter(D16, D22), lap splice length(50, 75, 100$\%$). The current experimental results demonstrated clearly that the use of hybrid fibers in cementitious matrixes increases significantly the splice strength of reinforcing bars in tension. Also, the presence of fibers increased the number of cracks formed around the spliced bars, delayed the growth of the splitting cracks, and consequently, improved the ductility of bond failure.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.193-203
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• 1999

The corrosion of steel reinforcements in concrete is of great concern in recent years. This study is focused on the corrosion behavior of steel bars induced by internal chlorides in concrete at early ages. The main objective of this study is to determine the chloride thresholds causing depassivation and active corrosion of steel reinforcement in concrete. To examine the threshold concentration of chloride ion, the half-cell potential, chemical composition of expressed pore solutions of concrete and the rate of corosion area of the specimens were measured. Major variables include the added amount of chlorides in concrete, types of binders, and water-to-binder ration. From the present comprehensive experimental results, the factors influencing chloride-induced corrosion are investigated, and the chloride thresholds causing active corrosion of steel bars are proposed. The present study will enable to specify the realistic chloride limit in concrete which can be used in the future technical specification.