• Korean Journal of Construction Engineering and Management
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• v.25 no.3
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• pp.27-36
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• 2024

The effective control of cost overrun is a crucial issue for construction companies to secure profitability. Especially in situations where cost pressures are significant due to factors such as rising raw material prices and increased financial costs due to high-interest rate policies, cost overruns resulting from project failures have a highly detrimental impact on the profitability of construction firms. The objective of this study is to analyze the current status of cost overrun control measures adopted by construction companies using the IPA technique and provide key characteristics and implications. The IPA analysis results showed that practitioners in general contractors exhibit a high level of interest and effort regarding cost overrun while the performance level is relatively low. Nevertheless, the measures considered important to control cost overruns generally show a high tendency for execution as well. Cost overrun control measures that show high importance but low execution are primarily related to collaboration and communication sectors. To effectively control cost overruns, enhancing collaboration and communication with construction supervisors/CM, headquarters, and regulatory authorities emerged as the most urgent need. Through this study, the current status and areas for improvement regarding cost overrun control measures in general contractors can be identified. This can be valuable for deriving directions and enhancements for future cost overrun control strategy development.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.563-571
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• 2021

Recently, due to the increase in high-rise apartment and residential-commercial complex buildings, a number of mega-class mass concrete members with a thickness of 3m or more have been designed. As the construction of mass concrete such as transfer beam and slab is increasing not only in foundation members but also in special structures, research on reducing temperature cracks in mass concrete is being conducted. To review temperature cracks in mass concrete, it is important to review the thermal properties of concrete, but it is difficult to use an adiabatic temperature rise tester in the field, so the semi-adiabatic temperature rise test is mainly used. In this study, to improve the accuracy of the results of concrete heat characteristics gained by the semi-adiabatic temperature rise test, various factors affecting heat loss compensation and methods were reviewed and presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.773-776
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• 2008

The corrosion of steel in concrete is significant in marine environment. Marine bridges are readily deteriorated due to the exposure to marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100cm column specimens with eight of 10cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both 10$^{\circ}$C and 40$^{\circ}$C in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode

• 월간 기계설비
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• s.275
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• pp.48-61
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• 2013

건설공사 분리발주가 공공의 이익이 매우 큰 것으로 분석됐다. 또 분리발주로 인한 공사지연, 하자분쟁 등 효율성 저하는 철저한 공사관리와 발주자 보호장치 활용으로 해결, 일부의 우려는 기우에 불과하다는 분석자료가 나왔다. 대한건설정책연구원(원장 노재화)은 박근혜 정부의 주요 국정과제 중의 하나인 공공공사 분리발주 법제화의 효과를 분석하고 향후 도입방향을 제안한 '공공공사 분리발주 법제화의 효과와 도입방향' 보고서를 발간했다. 홍성호 연구위원이 발표한 이 보고서에 따르면 공공공사의 20% 수준으로 분리발주 적용범위 결정 시 4,693억원의 공공예산 절감과 4,198억원의 부가가치, 2만6,048명의 고용이 증진되는 등 공공의 이익이 매우 큰 것으로 밝혀졌다. 또한 발주자 선택권과 자유계약 원칙을 중요시하는 미국, 일본, 독일 등 선진국도 분리발주의 법제화 또는 적극적인 활용을 통해 공공예산 절감, 부가가치 및 고용창출효과를 거두고 있을 뿐만 아니라 통합발주의 문제점도 해결하고 있다고 밝혔다. 선진국은 또 전기 소방 통신 설비공종 뿐만 아니라 건축 및 토목공종에 해당되는 여러 개의 공종을 분리발주하는 다공종 분리발주 방식을 많이 활용하고 있는 것으로 나타났다. 연구원은 또 일부에서 우려하는 다수의 공종 패키지로 인한 효율성 저하는 통합발주에서도 동일하게 발생하는 현상이며 철저한 공사관리와 발주자 보호장치 활용으로 해결 가능하므로 이같은 우려는 현실성 없는 기우에 불과하다고 밝혔다. 이와 함께 분리발주로 인해 발주자 관리업무는 일부 증가하지만 건축 및 토목공종의 일부만 분리된다면 그 증가폭은 크지 않아 크게 문제되지 않고 있으며 향후 CM용역을 통해 충분히 해소 가능할 뿐만 아니라 오히려 건설산업 발전에 필요한 'Smat 발주자 육성'이 가능하다고 전망했다. 본지는 지면관계 상 연구논문 중 공공공사 분리발주 도입에 따른 효과와 공공공사 분리발주의 도입 방향 부문만 게재한다.

• Magazine of the Korea Concrete Institute
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• v.14 no.6
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• pp.41-48
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• 2002

2001년도 년간 302만 4,000ton의 사용실적을 보이고 전체 콘크리트 말뚝 사용량의 99.5%를 점유하고 있는 PHC 말뚝은 국내에 도입된 1992년이래 약 10년 동안 양적, 질적으로 많은 발전을 거듭하여 왔으며 현재 우리나라의 건축 토목공사용 기초자재로서 없어서는 안될 중요한 위치를 확보하고 있는 것이 사실이다. 1970년대까지 주로 사용되었던 RC 말뚝은 1970년대 후반부터 PC 말뚝으로 대체되었고, 1990년도 초반 생산되기 시작한 PHC 말뚝이 우리나라 콘크리트 말뚝의 주류를 이루어 현재콘크리트 말뚝의 대명사로 자리 매김하며 발전을 거듭하고 있는 것이다. 또한 PHC 말뚝에 사용되는 콘크리트의 압축강도는 800kgf/$\textrm{cm}^2$ 이상이 확보되어야 함으로 콘크리트 공장제품 중에서 보기 드물게 고강도를 요구하고 있으며 고강도화를 위한 제조공정의 품질관리도 높은 수준이 요구되어 우리나라 콘크리트 공장제품의 고강도화와 품질향상에 기여한 정도가 이루 말할 수 없을 정도로 크다고 볼 수 있다.(중략)

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.45-53
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• 2022

The purpose of this study is to present a model for analyzing construction errors of reinforced concrete pile foundations using drones. First, a drone is used to obtain an aerial image of the construction site, and an orthomosaic image is generated based on those images. Then, the circular pile foundation is automatically recognized from the orthomosaic image by using the Hough transform circle detection method. Finally, the distance is calculated based on the the center point of the reinforced concrete pile foundation in the overlapped data. As a case study, the proposed concrete concrete pile foundation construction quality control model was applied to the real construction site in Incheon to evaluate the proposed model.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.60-69
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• 2020

This research is a preliminary study to find out the module of 20 students in a classroom. This research investigated the widths of passages in the 30 classrooms of 5 elementary schools in Namyangju City, Korea. The conclusions were as follows: First, the area of unit for 1 student was 650 (W) × 950 (D). Second, the desk placements for most classrooms were one-way types (87%), and group-study types constituted 13%. Third, the width between the blackboard and the very front desk was 2.17 m. The width of passage between the very back seat and the backside lockers was 1.32 m. The width of passage between the sidewall and the nearby desk was 0.8 m. The width of passage between the window and the nearby desk was 0.8 m. The average widths of 2 vertical passages between the desks were respectively 0.67 m and 0.68 m. Fourth, the area of the teacher was 2.1-2.25 m × 2.16 m = 4.5-4.8 ㎡.

• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.47-59
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• 2022

A series of experiments were performed to investigate the design and application of a rubble-ground modification method with grout injection. A small-sized injection machine was designed, and the grouts with various mix proportions were injected into 25 mm aggregate using the designed small-sized injection machine. With the compressive strength of the grout ranging from 20 to 80 MPa, the uniaxial compressive strength of the grout-filling bodies with clean gravels was higher than 1/6th of the strength of grouts themselves. However, this fraction may reduce depending on the interface conditions. The erosion resistance of the hardened grout was evaluated, and it was determined that the grout with a strength greater than 15 MPa did not require erosion consideration. Moreover, a full-scale injection test was performed for 25 cm-sized rubbles in cages with a diameter greater than 1 m and a height of 1.2 m to evaluate the filling characteristics of the grout. Results from this test indicated that the grout flowability sensitively influenced the filling characteristics.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.24-33
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• 2024

Recently, as smart construction has become more active, construction companys are evaluating their smart construction capabilities in order to transform into smart construction companies. However, the revitalization of smart construction doesn't only apply to construction companies, the level of utilization of all participants, including owners, designers, construction project managers, and construction company, must be improved. Therefore, this study aims to present a model that evaluate the building information modeling (BIM) utilization level for measuring the BIM utilization level of construction management companies in executing construction project management. In this study, an AHP questionnaire survey targeting BIM practitioners to calculate the weight of each BIM utilization item and score it to construct evaluation model and evaluate it by applying it to construction management companies are conducted. As a result of the evaluation using model, there were differences between companies in the number of BIM users, and in the qualitative evaluation, it is mainly used for interference review, constructability review, and design change management. Therefore, in order to revitalize BIM, it is believed that it is necessary to strengthen BIM utilization ability through separate training for construction manager (CMr) and to present clear utilization standards and scope of work for BIM utilization in performing construction management tasks. Consequently, evaluating more construction management companies using the model presented in this study will result in the transition of CM companies to smart construction and revitalization of BIM adoption.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.575-585
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• 2013

This research was performed to evaluate the recycling feasibility as a construction material of dredged harbor soil mixed with clay and glass frit. Concentration of heavy metals of the dredged soil from D harbor was severly high, showing Zn of 526.0~13,150.1 mg/kg. The dredged soil was maily composed of 48.30 wt% $SiO_2$, 16.60 wt% $Al_2O_3$, 10.10 wt% CaO, 7.75 wt% $Fe_2O_3$. The clay and the glass frit contained 70.82 wt% $SiO_2$ and $Al_2O_3$ 18.78 wt%, and 71.75 wt% $SiO_2$, 13.99 wt% CaO, 8.51 wt% $Na_2O$, respectively. After adding 10~40 wt% to the clay and sintering them at $1,000^{\circ}C$ or $1,100^{\circ}C$, the compressive strength of the sintered specimens showed $132.6{\sim}178.5kgf/cm^2$ or $581.2{\sim}793.7kgf/cm^2$, respectively. In case of SC46 with the addition 40 wt% of the dredged soil to the clay, the compressive strength ($793.7kgf/cm^2$) of specimen sintered at $1,100^{\circ}C$ was over 5 times higher than that at $1,000^{\circ}C$. The specimen mixed with 40 wt% of dredged soil, 60 wt% of clay and 1 wt% of glass frit satisfied the 1st grade standard for clay brick by KS L 4201. The results of all specimens by Korean Standard Leaching Test also satisfied the standard criteria.