• 한국건설관리학회논문집
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• 제23권1호
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• pp.16-27
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• 2022

본 연구에서는 공정거래에 관련된 법·제도와 건설산업에서 발생하는 불공정거래의 사례를 분석하여, 건설산업의 공정성 평가요인을 건설산업의 주요 참여자별(원도급자와 하도급자)와 건설공사의 주요단계별(입찰·계약·시공단계)로 분류하여 도출하였다. 그 후, 종합 및 전문건설사업자 238명을 대상으로 설문조사를 수행하여, 그 평가요인의 중요도를 분석하고 공정성 지수를 개발하였다. 원도급자보다 하도급자가 건설산업의 공정성 수준을 낮게 인식하고 있었으며, 원도급자와 하도급자 모두 시공과정에서의 공정성이 가장 낮게 인식하는 것으로 분석되었다. 원도급자는 입찰단계와 계약단계, 하도급자는 계약단계의 공정성 수준을 가장 높게 인식하고 있었다. 제안된 건설산업의 공정성 지수를 사용한다면, 건설공사 참여자별 및 공사단계별로 공정성 향상이 필요한 요인을 도출할 수 있으며, 이를 기반으로 공정성 향상방안의 수립에 기여할 수 있을 것이다.

• Journal of Construction Engineering and Project Management
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• 제3권3호
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• pp.10-16
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.287-293
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• Structural Engineering and Mechanics
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• 제42권4호
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• pp.489-505
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• 2012

In this study, it is aim to perform the construction stage analysis of suspension bridges using time dependent material properties. Fatih Sultan Mehmet Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element models of the bridge are modelled using SAP2000 program considering project drawing. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength variations and geometric variations are included in the analysis. Because of the fact that the bridge has steel structural system, only prestressing steel relaxation is considered as time dependent material properties. The structural behaviour of the bridge at different construction stages has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. As analyses result, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given with detail. It is seen that construction stage analysis has remarkable effect on the structural behaviour of the bridge.

• Korean Journal of Hydrosciences
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• 제5권
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• pp.17-31
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• 1994

Because of the Keumkangsan-Dam and the Peace-Dam constructed in recent years, it is expected that the peak flood discharge and the peak flood stage at the Hwachun-Dam site have been changed. In this study, two methods were used to simulate and compare the effects of the upstream dam construction on the change of the discharge and the stage. One is the storage function method widely used for the hydrological routing in the country. The other is the DWOPER(Dynamic Wave Operational Model) package conducted on four different scenarios: (1) before the construction of the Keumkangsan-Dam and the Peace-Dam; (2) the exclusion of the Keumkangsan-Dam watershed (before the construction of the Peace-Dam); (3) the exclusion of the Keumkangsan-Dam watershed (after the construction of the Peace-Dam) ; (4) the exclusion of the Peace-Dam watershed. The results of the four test cases from the two methods show that the peak flood discharge and the peak flood stage at the Hwachun-Dam site are reduced due to the construction of the Peace-Dam. From these findings, it is suggested that the operational criteria for the optimal dam-operation of the Hwachun-Dam need to be modified.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.213-214
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• 2023

Positioning information of workers is important for safety management at construction sites. Among the various indoor positioning technologies, geomagnetic fields-based technology is more economical and has less error than other technologies. However, there is a problem that the installation and dismantling of materials such as formwork at construction sites can cause degradation in positioning performance. Therefore, in this study, the distortion of the geomagnetic field near euro-form was quantitatively measured and the application method of geomagnetic field-based indoor positioning technology on formwork stage was presented. The results showed that the distortion occurred within 10cm of the wall and column form, but positioning accuracy could be affected up to 60cm from the form due to the characteristic of geomagnetic field-collecting technology. Therefore, applying this technology to the formwork stage requires complementary measures, such as using other positioning techniques up to 60 cm near the formwork, or excluding distorted area when positioning. It is expected that this study can contribute to the efficient safety management of workers by suggesting ways to prevent an increase in positioning error when applying geomagnetic field sequence-based indoor positioning technology during the formwork stage.

• Computers and Concrete
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• 제14권5호
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• pp.599-612
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• 2014

This paper presents the effects of the construction stages using time dependent material properties on the structural behaviour of concrete arch dams. For this purpose, a double curvature Type-5 arch dam suggested in "Arch Dams" symposium in England in 1968 is selected as a numerical example. Finite element models of Type-5 arch dam are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the construction stage analysis using P-Delta plus large displacement criterion. In addition, the time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. In the construction stage analyses, a total of 64 construction stages are included. Each stage has generally $6000m^3$ concrete volume. Total duration is taken into account as 1280 days. Maximum total step and maximum iteration for each step are selected as 200 and 50, respectively. The structural behaviour of the arch dam at different construction stages has been examined. Two different finite element analyses cases are performed. In the first case, construction stages using time dependent material properties are considered. In the second case, only linear static analysis (not considered construction stages) is taken into account. Variation of the displacements and stresses are obtained from the both analyses. It is highlighted that construction stage analysis using time dependent material strength variations and geometric variations has an important effect on the structural behaviour of arch dams. The maximum longitudinal, transverse and vertical displacements obtained from construction stages and static analyses are 1.35 mm and 0 mm; -8.44 and 6.68 mm; -4.00 and -9.90 mm, respectively. In addition, vertical displacements increase from the base to crest of the dam for both analyses. The maximum S11, S22 and S33 stresses are obtained as 1.60MPa and 2.84MPa; 1.39MPa and 2.43MPa; 0.60MPa and 0.50MPa, respectively. The differences between maximum longitudinal, transverse, and vertical stresses obtained from construction stage and static analyses are 78%, 75%, and %17, respectively. On the other hand, there is averagely 12% difference between minimum stresses for all three directions.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.849-860
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• 2021

Recently, it is easy to find cases of 3D printing product, equipment, and materials in the architecture field. However, there is a lack of distribution environment where 3D printing products can be traded on an online platform or to access on-demand services in the architecture field. Therefore, in this study, a distribution platform development plan was proposed in consideration of the maturity level of the 3D printing distribution market in the domestic architecture field. For this purpose, the research was carried out as follows. First, by analyzing the case of the 3D printing distribution platform, the development stage of the distribution platform was set as three stages from the perspective of market maturity, platform development level, and sales/purchase experience level of suppliers and consumers. Second, the market maturity of the current domestic architecture field was evaluated as the first stage, and a distribution platform that could be implemented in the first stage was presented as a pilot. Third, we presented the first stage pilot, collected practical opinions on future construction plans through in-depth interviews, and presented detailed implementation plans for each stage necessary to achieve the second and third stage market maturity goals. Based on the roadmap derived from this study, it is expected that the domestic distribution platform market will grow step by step in the future and be utilized for business model development.

• 한국건축시공학회지
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• 제5권4호
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• pp.99-106
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• 2005

With labor shortage and high-wage, the construction cost is rising and the construction-business is dull, demanding the construction environment of Korea to raise profitability through major cost savings and rationalization of construction management. Therefore, in this study, to improve many problems found in calculating rebar quantity for capital expenditure programming which is considered the beginning stage of rebar work. and to improve problems such as no grasping of rebar loss due to lack of systematic management in order/purchase stage and construction management stage, a rebar information-management-system was found and preyed. The relation database was designed for the rebar information management system by analyzing work process of a rebar manufacturing plant, as the rebar information that is necessary in a rebar manufacturing plant if similar to that of a purchasing department of general construction company. The Proposed rebar information management system was implemented in two large rebar production plants. The implementation of the proposed system showed that the system increased work efficiency, reduced the management manpower, and improved the project-integrated management

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1170-1175
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• 2009

When managers estimate exact construction cost at early stage and design phase, they can reduce construction cost in a more efficient way than to predict at construction stage. But, the current of public construction cost estimation and management is concentrated almost after detailed design phase. Therefore, construction cost management in design development phase to generally use approximate estimating is not correct. Also, the existing construction cost used the method that estimated by gross floor area-based cost estimates at design development phase. So, it is difficult to show the specific amount of materials and basis about the estimated cost of the construction. This study derived problems and limits of construction management at design development phase in case of public office building project through review of literature and current survey, and suggested estimating process model process of structural construction cost go improve these matters.