• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.441-452
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• 2023

Buildings that have been long neglected can suffer severe durability reduction due to factors such as rebar rust and concrete quality deterioration resulting from exposure to outside air. Furthermore, the issues associated with these suspended buildings, including safety accidents, social crimes, and environmental pollution, are becoming increasingly serious. This study investigates the current status of these buildings in the Jeju area, identifies the problems, and examines the durability of the structure in a specific location to assess the possibility of future use. Aesthetic surveys(visual and slope inspections) as well as non-destructive tests(compressive strength tests, neutralization tests, and rebar detection tests) were conducted to assess durability. The analysis revealed that the structure maintained satisfactory durability and the building's condition was good in comparison to the years of neglect.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2A
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• pp.339-349
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• 2006

The purpose of this study is to investigate the seismic behavior of circular reinforced concrete bridge piers with confinement steel and to provide the data for developing improved seismic design criteria. Fourteen circular reinforced concrete bridge piers were tested under a constant axial load and a cyclically reversed horizontal load. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. In the companion paper, the proposed numerical method for the seismic performance assessment of circular reinforced concrete bridge piers with confinement steel is verified by comparison with experimental results.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.761-768
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• 2005

Lately outmoded and functionally obsolete buildings constructed in 1960s and 1970s are often remodelled and restored. Even though there are not serious structural defects in the existing buildings, many old buildings have been reconstructed to improve residence quality or to extend residence area of the buildings. The experimental or theoretical research on plane expansion of RC apartments is quite scare. In this research, 12 specimens and 19 RC slabs connected by hinged joints were tested. The new slab was connected to the existing slab by hinge joints injecting dowel bars between two slabs. Main parameters of the slabs are types of the dowel bars (D13 and D19), spacing of the dowel bars (150mm, 300mm, and 450mm), and the locations of the steel bars in the existing slabs. The test results indicated that the shear strength of the RC test slabs having various types of dowel bars was about twice that calculated by the ACI 318-02 code. All slabs failed in concrete spatting and the dowel steel bars did not reach their yield strengths.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.329-336
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• 2010

An experimental study to evaluate bursting behavior in anchorage zone of the standard PSC I girders (span length : 30 m) has been carried out. The arrangement of bursting reinforcement in anchorage zone of the standard PSC I girders is considered to be designed without accurately reflecting the stress flows in the end zone of the PSC I girders caused by presstressing forces of the tendons. Also, due to excessive arrangement of the bursting bars, the workability of the girder is decreased greatly. In this study, three specimens with the same dimensions as the end zone of the standard PSC I girder are prepared and the experiment is carried out by applying PS forces. The bursting reinforcement of each specimen consists of 100 mm, 200 mm, and 300mm spacings, respectively. The experimental results show that the range of the PS forces to cause crack in the anchorage zone of the specimen are more than 1.6 times of the design PS forces. The bursting cracks occur in the vertical direction on the inside of all specimens. After applying 2.7 times of the design PS force, some of the transverse bursting reinforcements only in the specimen reinforced by 300 mm spacing yielded. The experimental results show that the anchorage zone of the standard PSC I girders arranged by 300 mm spacing of the bursting reinforcements which is the maximum spacing allowed in the road bridge design specifications, can be considered safe enough.

• Magazine of the Korea Concrete Institute
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• v.14 no.2
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• pp.52-60
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• 2002

지하철 구조물과 같은 매스 콘크리트 구조물을 시공할 때 온도 측정을 하는 경우는 많으나 이는 내외부 온도차를 적정한 수준으로 유지하여 균열 발생을 제어하기 위한 수단일 뿐 균열폭을 일정한도 내로 제어할 수 있는 조치는 아니다. 매스 콘크리트 구조물에서 균열폭을 제한 값 이하로 하기 위해서는 적절한 양의 철근을 배치하여야 한다. 또한 시공 이음 등을 작은 간격으로 설치하는 것은 구속도를 완화시키고 온도응력이나 균열폭을 저감시켜 균열 제어상 매우 효과적인 수단이 될 수 있다. 그러나 시공 이음, 균열 유발 줄눈 등의 이음간 간격을 좁히면 내하력 수밀성, 내구성 등에 악영향을 미칠 가능성이 높고, 타설 회수가 많아져 동일한 공정이 반복 투입되므로 시공 속도의 저하 및 공사비 상승 등의 단점이 나타날 수 있다.(중략)

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.159-160
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• 2019

Reinforced concrete construction is one of the labor intensive construction projects and its productivity is very low. It is necessary to increase the productivity of rebar construction for improving the productivity of construction work. Therefore, in this study, the rebar drawings of apartment buildings are analyzed to prefabricate wall rebar unit shaped mesh in the factory and installing it on site. If the proposed wall rebar unit is applied to apartment construction working time of wall rebar can be reduced by 50% or more.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.295-297
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• 2013

Reinforcing bar coupling method has a variety of ways including lap-splice method. However, there are problems that need to be improved in terms of constructability, economics analysis. We should be improved about the problems of the existing methods. Accordingly, this study were developed a new type of staggered grip type reinforcing bar coupling. The proposed method show the following effects than existing methods. First, this method can be reduce time through improved workability. Second, increasing safety through the slip removal. Third, improving economic efficiency by reduce the manufacturing costs.

• Tunnel and Underground Space
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• v.20 no.3
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• pp.169-182
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• 2010

H-beam and lattice-girder are the two most commonly used steel supports in domestic tunnels. Reinforced Ribs of Shotcrete(R.R.S.), which is frequently used in Scandinavian countries, is yet to be employed in Korea despite its advantages over H-beam or lattice girder in terms of economy and constructional efficiency. In this study, laboratory tests were conducted to determine the most suitable design of R.R.S in domestic tunnels. Various configuration of steel reinforcements including double layer of steel rebars were tested and compared. Reinforcement with H-beam and lattice girder were also analyzed. Results of this study can be of great use in selecting and designing of tunnel supports when the tunnel is excavated by NATM or Norwegian Method of Tunnelling(NMT).

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.527-530
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• 2002

The purpose of this study is to present an improvement of the form work process. The current slab form work has waste factor by unnecessary process and not complete integration with the finishing process. Therefore the study used value stream analysis methodology for effective improvement of slab form work process. The main contents of the study are as follows; 1) Understanding of non-value adding activities in existing slab form work process 2) Process integration by value stream mapping 3) Effect analysis of time-cost reduction. The study recommends that, as a future research, development of tool and technique for the non-value adding activities are eliminated in building construction.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.359-362
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• 2002

The construction industry from the research about materials calculate automation became accomplished plentifully. Material price calculate with application in the CAD plan is more quicker and accurate than with existing handy work. It gives a many effect in development of the research and estimation program against material calculate production automation with application of the CAD. But material calculate production uses an estimate program from generally a framework construction and the material calculate production work becomes accomplished. A thesis of the material calculate production methodology about a part of materials boundary condition from material calculate production work of framework construction is the actual condition which is insufficient. From the dissertation which it sees standardize the concrete, a concrete form a each part of materials calculate method from framework construction material calculate production. It standardize a part of materials agree with a condition of material calculate methodology which from a each part of materials boundary condition.