• 한국지반공학회논문집
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• 제37권7호
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• pp.25-34
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• 2021

연약지반으로 이루어진 준설매립부지는 지반이 매우 연약한 상태이기 때문에 설계시 정확한 지지력을 계산하는 것은 어렵고 복잡한 요인들이 고려되어야 한다. 최근까지 준설매립지를 대상으로 다양한 연약지반처리공법을 설계하고 있지만, 초기 장비진입을 위해서 기존 Meyerhof(1974) 복합토층 지지력 계산으로 안전율을 예측하고 있다. 기존 방정식들은 시공성 안전을 확보한다는 차원에서 연약지반 지지력을 과소평가하여 경제적 비용이 증가될 수 있다. 따라서 본 연구에서는 현장여건이 고려된 지지력 식을 제안하였다. 이를 위하여 이론적인 방정식에서 고려되지 못하는 토목섬유의 봉합사 역할과 봉합인장강도가 지지력에 끼치는 영향을 실험으로 제시하여 적절한 연약지반 지지력을 평가할 수 있도록 제시하였다. 그리고, 현장시험으로 수정방정식 지지력의 안정성이 평판재하시험으로 실측한 값과 비교하여 적절성을 확인하였다. 향후 준설토 매립지반의 설계와 시공시 본 연구 결과가 기초자료로 활용될 것으로 판단된다.

• 설비공학논문집
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• 제18권9호
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• pp.753-760
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• 2006

The purpose of the present work is to investigate the influence of the refrigerant adulteration by LiBr solution on the cooling capacity and COP for three different types of abso게tion chillers: a single-effect type, a series-flow double-effect type and a parallel-flow with double-effect type. A simulation program has been prepared for the cyclic analysis of absorption chillers. With some assumptions, the calculations have been performed by solving the mass balance equation, energy balance equation and the state equation simultaneously. The range of the LiBr concentration of refrigerant was 0% to 20% in the present study. For the single-effect absorption chiller, the maximum decrease in the cooling capacity was 10% at the 20% of LiBr concentration. For the double-effect chiller, the capacity was decreased by 11.1% for the parallel-flow type and the series-flow type. Also, the COP was reduced by 3.0% in single-effect, 2.8% in series-flow type (SR=0.4) and 2.3% in parallel-flow type.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1172-1177
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• 2008

The best way to gain optimal results on the bearing capacity is to perform the plate bearing test on field but it is not always possible. In the case of not performing the bearing test but estimating bearing capacity equations, it is not yet determined what equation is appliable. In this paper the results of bearing capacity equation and the loading tests of 12 samples were compared and what the one is more reliable than others was verified. The comparison showed that the range of the values using Hansen's equation was 0.67 and 1.44 times of the measured, that of Vesic's was 0.71 and 1.27, that of Meyerhof is 0.69 and 1.1, and that of Terzaghi was 0.87 and 1.57.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.105-116
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• 2002

이 논문에서는 철근콘크리트 장주의 극한저항력을 효과적으로 산정할 수 있는 설계 관계식이 제안되었다. 철근콘크리트 기둥의 거동은 여러 설계변수들의 영향을 받는데 특히 콘크리트의 강도, 철근비, 세장비 및 편심 등에 의해 크게 영향을 받으므로 설계식의 제안을 위해 위의 4가지 변수들을 변화시켜가며 철근콘크리트 기둥의 비선형 해석을 수행하였다. 콘크리트의 균열 등을 포함한 재료의 비선형성을 고려하기 위해 적층단면법이 사용되었으며, p-△ 효과를 구현하기 위하여 기하강성행렬이 고려되었다. 해석결과로부터 각 변수의 변화에 따른 철근콘크리트 기둥의 저항력의 변화를 비교하였으며 이를 토대로 회귀분석 모델을 제안하였다. 또한 회귀분석을 수행하여 철근콘크리트 장주의 극한저항력을 효과적으로 산정할 수 있는 회귀분석식을 제안하였고, 기존의 설계기준과 비교하여 제안식의 효율성을 검증하였다.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.207-224
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• 2022

The mechanical behavior of prestressed concrete haunched beams (PSHBs) was investigated in depth using a finite element modeling technique in this study. The efficiency of finite element modeling was investigated in the first stage by taking into account a previous study from the literature. The first stage's findings suggested that finite element modeling might be preferable for modeling PSHBs. In the second stage of the research, a comprehensive parametric study was carried out to determine the effect of each parameter on PSHB load capacity, including haunch angle, prestress level, compressive strength, tensile reinforcement ratio, and shear span to depth ratio. PSHBs and prestressed concrete rectangular beams (PSRBs) were also compared in terms of capacity. Stochastic analysis was used in the third stage to define the uncertainty in PSHB capacity by taking into account uncertainty in geometric and material parameters. Standard deviation, coefficient of variation, and the most appropriate probability density function (PDF) were proposed as a result of the analysis to define the randomness of capacity of PSHBs. In the study's final section, a new equation was proposed for using symbolic regression to predict the load capacity of PSHBs and PSRBs. The equation's statistical results show that it can be used to calculate the capacity of PSHBs and PSRBs.

• 한국농공학회지
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• 제42권4호
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• pp.67-75
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• 2000

A simulation model for reservoir sizing was developed to be applied in a region with insufficient hydrological data. Reservoir storage balance equation was formulated on a monthly basis. Gajiyama equation was generalized to estimate monthly reservoir inflow more accurately. Monthly evaporation equation on a reservoir water surface was introduced , which was functioned with monthly mean temperature. Generalized Gajiyama equation was applied to estmate reservoir inflow of the Sayeon dam. Nash-Sutcliffe's model efficiency was 0.793. Using developed model for reservoir sizing, water supply capacity was analyzed with 118.000㎥/day on the Sayeon dam. This showed a reasonable result as compared with 110000㎥/day in other technical report. For general application of developed model, a virtual reservoir was considered and its dta of surface area and volume by elevation was prepared using DEM. Using the model, size of reservoir was determined and water supply capacity was anlayzed on a virtual reservoir.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.251-254
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• 2005

This study will have to define the shear strengthening effects of steel fiber in beam and column levels, as well as to suggest estimation method of maximum shear capacity of structural members. From review of literature surveys and perform structural member test results, following conclusion can be made; In beam level, steel fiber strengthening factor is suggested from the tensile splitting test results and beam test results. After suggesting shear capacity of beam without stirrups and beam with stirrups by proposed steel fiber strengthening factor, proposed equation is possible to evaluate the shear capacity of beam. In column level, with column test results and proposed steel fiber strengthening factor, shear capacity equation of steel fiber reinforced concrete in column is suggested.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 가을 학술발표회 논문집
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• pp.23-28
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• 1992

The ultimate capacity of end-plate connection is investigated through nonlinear finite element analysis. The example models are divided into stiffened case and unstiffened one. The refined finite element models are analyzed by utilizing a general purpose structural analysis computer program ADINA and the moment-rotation relationships of the connection are determined. The results are compared with the regression equation deduced by Krishnamurthy. It is planned to deduce a bilinear regression equation through a parametric study on various dimensions of the connection.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.401-414
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• 2010

Top Base Foundation(TBF) is a stabilization method for light weight structures particularly in the soft ground. It is widely used for the increment of bearing capacity and restraining settlement of foundations when the bearing capacity of ground is not enough. However, when the design values from exiting Japanese standard are compared with the observation values from the field measurement, the bearing capacity of exiting standard estimated smaller For this reason, it is necessary to establish more reasonable prediction technique considering to understand the behavior of TBF in soft ground. In this study, 1/5 scale model tests were performed in the laboratory. Also, full scale tests were carried out in order to investigate the behavior of TBF with various shapes. In addition, about 100 sites measurement data were evaluated to investigate the behavior of TBF in various ground conditions. Based on the results of the model tests and field measurement data, it was possible to establish more reasonable the bearing capacity equation of TBF considering various N-value of soil, the effect of underground water and failure shapes.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1927-1934
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• 2018

In this paper, we studied the state of charge (SOC) estimation algorithm of a high-capacity lithium secondary battery for electric vehicles (EVs) considering temperature characteristics. Nonlinear characteristics of high-capacity lithium secondary batteries are represented by differential equations in the mathematical form and expressed by the state space equation through battery modeling to extract the characteristic parameters of the lithium secondary battery. Charging and discharging equipment were used to perform characteristic tests for the extraction of parameters of lithium secondary batteries at various temperatures. An extended Kalman filter (EKF) algorithm, a state observer, was used to estimate the state of the battery. The battery capacity and internal resistance of the high-capacity lithium secondary battery were investigated through battery modeling. The proposed modeling was applied to the battery pack for EVs to estimate the state of the battery. We confirmed the feasibility of the proposed study by comparing the estimated SOC values and the SOC values from the experiment. The proposed method using the EKF is expected to be highly applicable in estimating the state of the high-capacity rechargeable lithium battery pack for electric vehicles.