• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.101-102
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• 2019

The use of high fluidity concrete has been added in recent construction work. In this study, we analyzed segregation resistance due to admixture substitution of the system high fluidity concrete that was hardened. The research results show that the resistance to segregation at the time of admixture replacement is improved. The best results were shown with a ternary system mixed like FA and BS.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.159-160
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• 2016

본 논문에서는 최근 건설기계용으로 연구되고 있는 E-TCS의 Power Electronics System에 대한 Topology와 제어방법을 제안한다. 디젤엔진과 같이 사용되는 E-TCS는 압축기와 터빈 그리고 요구되는 회전속도로 고속회전 및 발전이 가능한 모터와 이를 제어하는 인버터로 구성된다. 기존의 E-TCS를 위한 Power Electronics System의 경우 배터리의 전압강압으로 인버터의 전류량이 증가하여 Power Electronics System 및 모터의 Volume이 커지는 단점이 있으며, 특허가 존재하여 사용이 어렵다. 본 논문에서는 이와 같은 단점을 개선한 E-TCS를 위한 새로운 Topology 구성 및 제어방식을 제안한다.

• Structural Engineering and Mechanics
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• 제71권5호
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• pp.563-576
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• 2019

According to The Concrete Centre, in the UK shear walls have become an inseparable part of almost every reinforced concrete frame building. Recently, the construction industry has questioned the need for shear walls in low to mid-rise RC frame buildings. This study tried to address the issue in two stages: The first stage, the feasibility of removing shear walls in an existing design for a residential building where ETABS and CONCEPT software were used to investigate the structural performance and cost-effectiveness respectively. The second stage, the same structure was examined in various locations in the UK to investigate regional effects. This study demonstrated that the building without shear wall could provide adequate serviceability and strength within the safe range defined by Eurocodes. As a result, construction time, overall cost and required concrete volume are reduced which in turn enhance the sustainability of concrete construction.

• Structural Engineering and Mechanics
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• 제72권4호
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• pp.503-512
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• 2019

The construction of segmental precast concrete bridge is an increase due to its superior performance and economic advantages. This type of bridge is appropriate for spans within 30 to 150 m (100 to 500 ft), known as mega-projects and the design optimization would lead to considerable economic benefits. A box-girder cross section superstructure of balanced cantilever construction method is assessed here. The depth of cross section, (variable along the span linearly), bottom flange thickness, and the count of strands are considered as design variables. The optimum design is characterized by geometry, serviceability, ductility, and ultimate limit states specified by AASHTO. Genetic algorithm (GA) is applied in two fronts: as to the saving in construction cost 8% and as to concrete volume 6%. The sensitivity analysis is run by considering different parameters like span/depth ratio, relation between superstructure cost, span length and concrete compressive strength.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.67-70
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• 2011

The effect of column shortening is a major consideration in design and construction of tall buildings, especially in concrete and composite structural systems. To avoid unexpected demage in structural and nonstructural elements, differential shortening between vertical members resulting from differing stress levels, loading histories, volume-to-surface ratios and other factors in a high-rise building must be properly considered in the design process. This paper represents analyzed and measured shortening results of RC cores and columns at the 72 story Haeundae I'Park. It shows that WACS program based on ACI and PCA material model is effective for the prediction of column shortening.

• 한국수소및신에너지학회논문집
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• 제34권3호
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• pp.246-255
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• 2023

Due to lack of hydrogen charging stations and hydrogen supply compared to the supply of hydrogen vehicles, social phenomena such as 2-hour queues and restrictions on charging capacity are occurring, which negatively affects the spread of hydrogen vehicles. In order to resolve these problems, it is essential to have a strategic operation of the hydrogen charging stations. To establish operational strategies, it is necessary to derive customer demand patterns and characteristics through the analysis of sales data. This study derived the demand patterns and characteristics of customers visiting hydrogen charging stations through data analysis from various perspectives, such as charging volume, charging speed, number of visits, and correlation with external factors, based on the hydrogen sales data of off-site hydrogen charging stations located in domestic residential areas.

• 지질공학
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• 제11권1호
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• pp.101-113
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• 2001

절취암의 물량산정과 사석의 절취 효율성을 판단하기 위한 목적으로 욕망산 인근지역의 지반조사를 실시하였다. 조사지역은 경상분지 동남부의 지질구조를 지배하는 양산단층대의 말단에 위치하여 안산암질암, 유문암질암 등의 화산암류와 이를 관입하고 있는 화강암으로 구성되어 있으며, 북북동-남남서 방향의 우수향 주향이동단층에 의해 규제되고 있다. 단층들은 분포된 절리의 간격과 빈도수 그리고 절리면 압축강도에 직접적인 영향을 끼치고 있다. 절리빈도는 단층면 인접지역에서 최대치를 나타내고 단층에서 멀어짐에 따라 감소된다. 지질조사를 기초로하여 구조도를 작성하고 이를 활용한 채취물량의 산정 결과 현장의 공사에 필요한 암편의 최소 크기를 고려할 때 채취 물량은 암반(기반암)체적의 61%인 4,018,000m$^3$이며, 표토와 풍화암이 포함된 욕망산 체적의 48%에 해당된다.

• Journal of Korean Neurosurgical Society
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• 제60권4호
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• pp.441-447
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• 2017

Objective : Computed tomography (CT)-based method of three dimensional (3D) analysis ($MIMICS^{(R)}$, Materialise, Leuven, Belgium) is reported as very useful software for evaluation of OPLL, but its reliability and reproducibility are obscure. This study was conducted to evaluate the accuracy of $MIMICS^{(R)}$ system, and inter- and intra-observer reliability in the measurement of OPLL. Methods : Three neurosurgeons independently analyzed the randomly selected 10 OPLL cases with medical image processing software ($MIMICS^{(R)}$) which create 3D model with Digital Imaging and Communication in Medicine (DICOM) data from CT images after brief explanation was given to examiners before the image construction steps. To assess the reliability of inter- and intra-examiner intraclass correlation coefficient (ICC), 3 examiners measured 4 parameters (volume, length, width, and length) in 10 cases 2 times with 1-week interval. Results : The inter-examiner ICCs among 3 examiners were 0.996 (95% confidence interval [CI], 0.987-0.999) for volume measurement, 0.973 (95% CI, 0.907-0.978) for thickness, 0.969 (95% CI, 0.895-0.993) for width, and 0.995 (95% CI, 0.983-0.999) for length. The intra-examiner ICCs were 0.994 (range, 0.991-0.996) for volume, 0.996 (range, 0.944-0.998) for length, 0.930 (range, 0.873-0.947) for width, and 0.987 (range, 0.985-0.995) for length. Conclusion : The medical image processing software ($MIMICS^{(R)}$) provided detailed quantification OPLL volume with minimal error of inter- and intra-observer reliability in the measurement of OPLL.

• Advances in concrete construction
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• 제16권3호
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• pp.127-139
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• 2023

In this study, the steel fiber and the polypropylene fiber were used to enhance the mechanical properties of fully recycled coarse aggregate concrete. Natural crushed stone was replaced with recycled coarse aggregate at 100% by volume. The steel fiber and polypropylene fiber were used as additive material by incorporating into the mixture. In this test two parameters were considered: (a) steel fiber volume ratio (i.e., 0%, 1%, 1.5%, 2%), (b) polypropylene fiber volume ratio (i.e., 0%, 0.1%, 0.15%, 0.2%). The results showed that compared with no fiber, the integrity of cubes or cylinders mixed with fibers after failure was better. When the volume ratio of steel fiber was 1~2%, the width of mid-span crack after flexural failure was 5~8 mm. In addition, when the volume ratio of polypropylene fiber was 0.15%, with the increase of steel fiber content, the static elastic modulus and toughness of axial compression first increased and then decreased, and the flexural strength increased, with a range of 6.5%~20.3%. Besides, when the volume ratio of steel fiber was 1.5%, with the increase of polypropylene fiber content, the static elastic modulus decreased, with a range of 7.0%~10.5%. The ratio of axial compression toughness first increased and then decreased, with a range of 2.2%~8.7%. The flexural strength decreased, with a range of 2.7%~12.6%. On the other hand, the calculation formula of static elastic modulus and cube compressive strength of fully recycled coarse aggregate with steel-polypropylene fiber was fitted, and the optimal fiber content within the scope of the test were put forward.

• 대한토목학회논문집
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• 제38권3호
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• pp.477-485
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• 2018

건설공사시 발생하는 환경부하 관리를 위해서는 시공시 실제 투입되는 물량을 면밀히 파악할 필요가 있다. 현재 건설공사에서는 2D도면을 활용한 설계의 경우에는 실제 설계 도서간 물량산출 값의 오차, 설계항목의 누락이 발생하고 있으며 건설 공사의 경우 불확실한 요소들로 인하여 시공 중에도 빈번히 설계변경 및 오류가 발생하고 있다. 또한 2D 설계를 바탕으로 하는 LCA평가의 경우 도면, 내역서 등을 이용하여 작업자가 수기로 작업공종에 투입되는 자재를 산출해야하는 어려움이 있다. 본 연구에서는 2D 설계를 바탕으로한 물량산출과 BIM기반의 물량산출을 바탕으로 LCA 분석을 비교하여 시공과정에서 활용 할 수 있는 신뢰도 높은 환경부하평가 방법을 검증하고자 한다. 또한 설계도서를 활용한 내역기반의 2D설계의 물량산출 및 LCA 평가 방법을 제시하고, 3D 기반의 평가 프로세스를 비교 분석하여 BIM 설계기법 도입에 따른 LCA 평가 활용 가능성을 제시하고자 한다.