• 한국지반공학회논문집
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• 제28권2호
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• pp.57-70
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• 2012

연약지반에 시공되는 송전철탑의 경우 말뚝기초가 주로 사용되나, 부등침하로 인한 철탑구조물의 손상이 유발될 수 있으며, 이에 따라 미국과 일본에서는 4각의 기초를 연결보로 연결한 연결형 기초의 사용을 추천하고 있다. 본 연구에서는 송전철탑에 작용하는 하중조건과 연결보의 강성조건이 연결형 말뚝기초의 수평거동에 미치는 영향을 조사하기 위해서 1/8 규모의 축소모델을 이용한 연결형 말뚝기초의 수평재하시험을 수행하였다. 본 시험결과 연결형 기초는 말뚝기초에 비하여 지지력이 크고 부등변위등의 송전철탑의 안전성을 저해하는 요인에 저항하는 효율적인 기초 형식인 것으로 나타났으며, 특히 연결보의 상대강성에 따른 효과를 분석한 결과 연결보의 강성이 매트의 강성대비 25%에서 연결형 기초의 형식으로 사용의 효율성이 좋은 것으로 나타났다.

• 한국지반공학회논문집
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• 제27권3호
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• pp.27-40
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• 2011

본 연구에서는 점토지반에 근입된 송전철탑 연결형 기초를 대상으로 모형수평재하시험을 수행하고, 연결형 기초의 파괴기준을 제안하였다. 본 연구를 위해 전라북도 익산에 위치한 점토지반에서 연결형 기초의 모형수평재하시험을 수행하였으며, 연결형 기초의 하중-변위특성을 분석하였다. 본 실험을 위해, 강성의 변화를 고려할 수 있는 연결형 기초 모형체를 제작하였으며, 요소 및 기초전반의 거동을 파악하기 위하여 다양한 계측장치를 설치하여 실험을 수행하였다. 실험결과를 토대로, 연결형 기초의 지지력을 측정하고 비교 분석하였으며, 수평지지력 결정을 위한 파괴기준을 제안하였다.

• 대한토목학회논문집
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• 제33권1호
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• pp.219-227
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• 2013

본 연구에서는 연약점토지반에 근입된 송전철탑 기초를 대상으로, 기초부보강공법의 하나인 연결형 기초 형식의 거동과 연결보 특성에 따른 성능발휘 효과를 분석하였다. 이를 위해 유한요소 해석 모델을 구축하였으며, 송전철탑 기초에 연결보의 매트와 닿는 면적비율변화에 의한 거동 및 저항력 특성을 분석하였고, 송전철탑 연결형 기초 모형실험 결과를 이용하여 구축된 유한요소 해석 모델의 타당성의 검증을 실시하여 다양한 매개변수 해석을 통해 연결보의 강성 증가에 따른 효과를 분석하여 송전철탑 연결형 기초의 거동에 효과적인 연결보의 강성을 선정 하였다. 또한, 연결보 자체 휨 모멘트 분포를 확인하여 취약부 분석을 실시하였다.

• 한국건축시공학회지
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• 제4권3호
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• pp.109-116
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• 2004

Normally easy task of plat in urban architecture is that using underground full of activities for increase building site efficiency. Especially for using underground space for the parking lot. Also utilize underground is more increase for fulfill requirement in modern society considered with environmental friendly architecture. The primary objective of this study is to apply analyzed formal foundation type for selecting the optimum type of parking lots considered with structural stability, economical efficiency, construction efficiency, construction duration. This study aim to on criteria decided through the questionaries for the selection considered with in the scale of second stories parking lots underground, parking volume is 80 and reinforced concrete structure. The bearing capacity is 6～8m and downward from surface, healthy ground bearing capacity is 40 t/m2. This study comparative analysis and discuss economical efficiency, construction efficiency, construction duration based constructivist stability which applied Single foundation, Mat foundation, Drop Mat foundation. The result of this study is as follows: First, the result of economical efficiency is that on the basis of single foundation, Drop Mat foundation is 1.88, Mat foundation 2.04 as a comparative analysis on the basis of total construction cost included material cost, labor coast and machinery cost. Second, the result of construction efficiency order is single foundation, Drop Mat foundation, Mat foundation as a comparative analysis on the based connected characteristics. Third, the result of construction duration is that on the basis of Mat Foundation, Drop Mat foundation is 1.33, single foundation is 1.87 as a comparative analysis Critical Path. Forth, Each foundational type characteristics order through the matrix method is that overall each formal type of foundation contraries at economical efficiency and construction efficiency, construction duration. Also expect contradiction between engineers and owners due to engineer pursuit construction duration and ewer to begin with economical efficiency. Fifth, The selection of suitable foundation formal type needs that based consider project characteristic and field condition as according to above result of a comparative analysis. As a result, a comparative analysis economical efficiency, construction efficiency, construction duration of Mat foundation, Drop Mat foundation, single foundation with 3Bay reinforced structure underground parking lots on the healthy ground.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.221-228
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• 2005

The economic growth brought the demand of bridge connected to island and land increasingly in Korea. Therefore, Civil engineer has faced a lot of problem to be considered such as structural stability, economic feasibility and constructional method. At the bridge site to be constructed, the depth of water is about 24m, the thickness of weathered rock overlaying bed rock is thicker than 36m. If open caisson foundation is supported in bed rock, the hight of foundation is about 60m. It is difficult to construct in these conditions. If open caisson foundation is supported in weathered rock, the size of the foundation should be increased. And If we apply the pile foundation, the higher construction cost will be needed. Under the circumstances, we need a new foundation type-composite foundation that is consisted of open caisson and cast-in-place piles. Because the design concept of composite foundation is not presented in Korea Bridge Design Standard, we are willing to clear the bearing behavior of composite foundation by numerical analysis in this paper.

• Steel and Composite Structures
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• 제44권2호
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• pp.171-181
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• 2022

Functionally graded material (FGM) has been spotlighted as an advanced composite material due to its excellent thermo-mechanical performance. And the buckling of FGM resting on elastic foundations has been a challenging subject because its behavior is directly connected to the structural safety. In this context, this paper is concerned with a numerical buckling analysis of metal-ceramic FG plates resting on a two-parameter (Pasternak-type) elastic foundation. The buckling problem is formulated based on the neutral surface and the (1,1,0) hierarchical model, and it is numerically approximated by 2-D natural element method (NEM) which provides a high accuracy even for coarse grid. The derived eigenvalue equations are solved by employing Lanczos and Jacobi algorithms. The numerical results are compared with the reference solutions through the benchmark test, from which the reliability of present numerical method has been verified. Using the developed numerical method, the critical buckling loads of metal-ceramic FG plates are parametrically investigated with respect to the major design parameters.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.777-781
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• 2014

The current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) using series connected two coils with twice triggering operation, which consists of series connected two coils and two superconducting (SC) modules with the inserting resistance, was analyzed. The feature of the suggested SFCL is that it can limit the fault current by triggering either one SC module or two SC modules comprising the SFCL depending on the amplitude of the fault current. To verify the current limiting operation of the suggested SFCL, the short-circuits in the fault location with the different fault currents were tested and its useful operations were described through the analysis on the tested results.

• 한국공간구조학회논문집
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• 제15권4호
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• pp.65-72
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• 2015

To overcome the weakness of spread foundation in large space structure, the research of precast pile for replace spread foundation have been conducted. The new type of joint between PHC pile and steel column is named HAT Joint(Hollow hAlf-sphere cast-sTeel Joint). It connected PHC Pile by bolt that verification of bolt connection should be accomplished. In this paper, pull-out test and flexural performance for HAT Joint to verifying the bolt connection is explained. As a result, the pull-out and flexural capacities of bolt were checked to use in real structure. Furthermore, the equation of pull-out strength was proposed.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.533-539
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• 2018

In this paper, the transformer type superconducting fault current limiter (SFCL) with additionally coupled circuit was suggested and its peak fault current limiting characteristics due to the fault condition to affect the fault current were analyzed through the fault current limiting tests. The suggested transformer type SFCL is basically identical to the previous transformer type SFCL except for the additional coupled circuit. The additional coupled circuit, which consists of the magnetically coupled winding to the primary and the secondary windings together with another superconducting element and is connected in parallel with the secondary winding of the transformer type SFCL, is contributed to the peak fault current limiting operation for the larger transient fault current directly after the fault occurrence. To confirm the fault current limiting operation of the suggested SFCL, the fault current limiting tests of the suggested SFCL were performed and its effective peak fault current limiting characteristics were analyzed through the analysis on the electrical equivalent circuit.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.1000-1003
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• 2012

The superconducting fault current limiter (SFCL) can quickly limit the fault current shortly after the short circuit occurs and recover the superconducting state after the fault removes and plays a role in compensating the voltage sag of the sound feeder adjacent to the fault feeder as well as the fault current limiting operation of the fault feeder. Especially, the flux-lock type SFCL with an isolated transformer, which consists of two parallel connected coils on an iron core and the isolated transformer connected in series with one of two coils, has different voltage sag compensating and current limiting characteristics due to the winding direction and the inductance ratio of two coils. The current limiting and the voltage sag compensating characteristics of a SFCL using a transformer winding were analyzed. Through the analysis on the short-circuit tests results considering the winding direction of two coils, the SFCL designed with the additive polarity winding has shown the higher limited fault current than the SFCL designed with the subtractive polarity winding. It could be confirmed that the higher fault current limitation of the SFCL could be contributed to the higher load voltage sag compensation.