• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.37-40
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• 2008

Recently, Construction Business, is changing very quickly, exceedingly needs to slim down the construction expensive by reducing material costs and the term of works. The term of formwork takes 25% of the term of works and costs 15% to 20% of the cost of construction. Hereupon, the purpose of this study is to investigate the Axial Strength of Centrifugall Formed Shell PC Columns that can reduce the term of formwork, the costs of material, the difficulty of throwing away the waste. Shell PC Column is loaded stirrups and manufactured at factory, so it has good points like construction's quality control and part's precision. However, it needs to be tested for checking bonded ability because it is set up at core and coverd with concrete. therefore this study is necessary three type of columns, which are a RC column, different type of two compressive strength core concrete columns and a Shell PC Column. By three columns, this study compare with and analysis three columns's bonded and Compressive Behavior abilities.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.315-319
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• 2007

지하에 설 치된 맨홀의 구조물이 노후되거나, 내부에 수 용된 시설물로 작업 공간이 협소하여 맨홀 구조물을 대개체 할 펼요가 있을 경우, 지금까지는 대부분 현장 콘크리트 타설에 의한 방법을 사용하였다. 이러한 방법은 거푸집 시공, 콘크리트 타설, 콘크리트 양생, 거푸집 철거 등의 공정이 소요되어 공사 기간이 장기화 되고, 도심지에 위치한 맨홀인 경우에는 차량과 보행자의 통행 불편을 초래하기도 하였다. 또한, 통상적으로 사용되고 있는 프리캐스트 맨홀에 비해 시공 품질이 낮아 향후 맨홀의 운용 및 유지관리에 많은 어려움을 겪는 원인이 되기도 하였다. 본 논문에서는 이러한 문제점들을 해결하기 위해, 폴리머 콘크리트를 이용하여 하부, 벽체, 상부로 구성된 다수의 세그먼트를 생산한 후, 현장에서 이들 세그먼트를 조립하여 맨홀을 설치하는 방법을 연구하였다. 가변형 거푸집을 이용한 세그먼트 제작과 조립식 블록에 의한 관구를 사용하여 현장 적용성을 높임은 물론, 프리캐스트로 생산되는 폴리머 콘크리트 맨홀 수준의 시공 품질을 확보할 수 있도록 하였다.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.487-495
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• 2014

Shortening the construction duration of structural frame work is extremely important because the work accounts for a major percentage of all cost and duration in large projects. For this reason, new construction methods to reduce the duration of structural frame work are being continuously studied and developed. A PSRC composite column, which uses steel angles instead of H-beams, has the advantages of flexural strength and ductility. Moreover, with this PSRC technique, conventional work for reinforcing bars in columns in practice can be skipped. However, one limitation exists in which the form work is still required. This research proposes a Form-LPSRC column method that is prefabricated with the column frame that includes permanent forms attached. Feasibility was examined with mock-up specimens and finally, the technique applied to real practice. Compared to the conventional SRC column method, this study demonstrated that the proposed technique has many advantages in construction duration, cost, quality, safety and environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.92-103
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• 2015

Development of new concrete bridge deck system with FRP plank using as a permanent formwork and the main tensile reinforcement recently has been actively conducted. Concurrent use as a reinforcing material and a permanent formwork, it is possible to reduce the construction time and construction costs than the usual concrete slab. In this study, an experiment was carried out for the bond stress between cast-in-place concrete and the type of FRP plank using as a permanent formwork. The interfacial fracture energy that can be one of the most important parameters were evaluated for adhesion performance and bond stress to know the characteristics of the failure mechanism of the adhesion surface. Interfacial fracture energy of normal concrete is 0.24kN/m of GF11 case, in the case of GF21, 0.43kN/m appears, in the case of CF11 and GF31, 0.44kN/m and 0.46kN/m respectively it appeared. In case of RFCON, 0.52kN/m appears from GF12, the CF12 and GF22, 0.51kN/m and 0.36kN/m appeared each case.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.513-516
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• 2008

Recently, a demand for reduction of construction cost by reducing construction period is increasing because of the slump of the construction business, the increasing price of raw-materials and the enforcement of after-sale system. As a method of reducing construction period, many construction companies usually apply a method of reducing curing period. But if they use an existing early strength cement or admixture, they spend a heavy cost on materials and there are many problems, such as a heat of hydration and a loss of workability. The purpose of this research is a reduction of construction cost by reducing construction period as a earlier removal time of form. To check up application of concrete using high early strength binder and admixture, comparative tests were carried out with concrete using an existing early strength cement or admixture such as tests of diurnal variation, setting time and compressive strength.

• Land and Housing Review
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• v.2 no.4
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• pp.509-516
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• 2011

Compared with the traditional RC system, precast stairs can save construction time, reduce the cost of concrete casting, etc. This paper focuses on an investigation of improved continuous longitudinal joint details for PC stair systems. The performance of the precast concrete stair connections subjected to displacement control cyclic loading is compared with that of the monolithic connection. The developed connection is composed of U-rods and clamp joint metals. This paper proposes precast stair connection with improved structural performance and experimentally evaluates the structural performance of the proposed joints in terms of maximum load, displacement ductiliy, strain, crack and failure modes.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.531-534
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• 2001

At the beginning of construction, the estimation for the construction duration is very important to effectively control and use labors, builder's equipment, permanent and temporary materials, supplies and utilities, and money. In spite of the importance of the estimation for the construction duration, there is no estimation standard of optimal construction duration in korea. The purpose of this study is to suggest the estimation standard of optimal construction duration that is reasonable and systematical through developing the method for estimating, the construction duration. it is expected to be helpful for estimating, planning and scheduling. The analysis is executed the existing estimation standards and consulting the results of the interviews with the on-site engineers and the concrete compressive stress tests.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.605-615
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• 2021

Recently, to shorten construction periods and reduce labor costs, the need for a corrugated beam form in the RC structure is being emphasized. The purpose of this study is to evaluate the deformation performance of SY Beam, a newly developed corrugated beam form work, during concrete casting. The standard cross-sectional shape of SY Beam was determined by modeling the deck structure of various thicknesses using the MIDAS GEN program. As a result, the cross-sectional dimensions of the SY Beam were determined to be 400mm and 450mm in width and height, respectively. A total of three SY Beam specimens were fabricated using steel plate thicknesses of 0.8, 1.0, and 1.2mm. The load conditions applied during casting concrete at the actual site are reflected. The vertical and horizontal displacements of the SY beam were measured during concrete casting. As a result, the vertical displacement showed a tendency to decrease as the thickness increased. Considering both vertical and horizontal displacement, the case with steel plate thickness of 1.2mm is the safest and most immediately applicable to the field. In the future, to secure manufacturability, constructability, and economics, the optimum steel plate thickness should be derived, and additional analysis and experimental studies for 1.05, 1.1, and 1.15mm are required.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.344-346
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• 2022

본 논문에서 거푸집의 가장취약 부분인 접합부위에 로드센서를 부착하여 실시간 콘크리트 측압을 측정 할 수 있으며, 관리자는 모니터링을 통하여 확인 할 수 있도록 하며 LORA의 저전력 장거리 통신망을 사용하는 디바이스를 개발하여 로드센서에 측정한 값을 데이터변경, 웹 기반의 클라우드 서비스로 발송하여 PC 및 Mobile로 확인 할 수 있는 시스템을 구축하였다. 여러가지 센서로부터 데이터를 수신하여 모바일로 송신해 주는 무선송수신기의 개발을 원하고 있으며, 하중센서, 경사도센서, 풍향센서 등 다중 데이터값을 수신할 수 있어야 한다. 이렇게 구성된 센서와 데이터의 수신을 통해서 콘크리트 타설시 발생하는 측압을 측정하고 공사기간 동안 별도의 전원 공급 없이 작동이 유지될 수 있는 시스템을 구축하였다. 수요자가 Application과 호환이 이루어져야 하며 또한 MEMS센서를 이용하여 상태를 모니터링 하고 임계값을 지정하여 이상 신호 발생시 위험상황에 대해서 인공지능기법을 이용하여 관리자에게 알림을 주어 효과적으로 사용할 수 있는 시스템을 개발하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.179-187
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• 2021

In the past five years, form construction, which accounts for approximately 25% of the total construction period, has continued to occur without a significant decrease in the number of deaths, with the largest proportion of collapse accidents. Accordingly, this study analyzed the difference in perception between the manager and worker by a questionnaire survey on the degree of risk and safety management level regarding a mold collapse accident. The survey was conducted in three groups: safety manager, field worker, and field manager. The results of the survey were analyzed by an independent sample T-Test using the SPSS program. As a result, there was almost no difference in recognition between managers, but a significant difference in recognition between managers and workers. In addition, there was a difference in management perception between the administrator and worker, which clearly shows the difference in the position between the administrator who manages and supervises hazardous disaster factors and the worker who works directly in the field. Such differences in perception can be a factor that cannot be mitigated. Based on this study, more developed research can narrow the perception gap between managers and workers and be used as a basic material for disaster research.