• 한국수자원학회논문집
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• 제47권12호
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• pp.1199-1212
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• 2014

본 연구에서는 댐 저수용량에 대한 이변량 빈도해석을 수행함으로써 재현기간 개념을 이용한 댐의 용수공급능력 평가방법을 제안하였다. 제안된 방법은 대청댐에 적용되어 검토되었다. 추가적으로 국내의 대표적인 가뭄사상에 대한 대청댐의 재현기간을 산정하고, 그결과를검토하였다. 그 결과를 정리하면 다음과 같다. 먼저, 본 연구에서는 이변량 빈도해석을 수행하기 위해 한국의 기후 특성을 반영한 댐의 용수공급능력 평가인자를 고려하였으며 5월 저류량 및 6~10월의 저류량 차이를 대상 변량으로 결정하였다. 둘째, 재현기간의 개념을 이용하여 대청댐의 용수공급능력을 평가한 결과, 대청댐은 재현기간 20년 미만에 대한 용수공급능력을 확보하는 것으로 나타났다. 마지막으로, 본 연구에서 제안된 방법은 한반도에 발생했던 대표적인 가뭄사상들을 분석하고, 해당 사상들에 대한 재현기간을 산정하는데 있어서도 유효함을 확인하였다.

• Geomechanics and Engineering
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• 제11권2호
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• pp.309-323
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• 2016

As the forefront of structural design method, capacity spectrum method can be applied conveniently, and through this method, deformation demand of structure can be considered. However, there is no research for the seismic application in the structure of sheet pile retaining wall to report. Therefore, focusing on laterally loaded stabilizing sheet pile wall, which belongs to flexible cantilever retaining structure and meets the applying requirement of capacity spectrum method from seismic design of building structure, this paper studied an approach of seismic design of sheet pile wall based on capacity spectrum method. In the procedure, the interaction between soil and structure was simplified, and through Pushover analysis, seismic fortification standard was well associated with performance of retaining structure. In addition, by comparing the result of nonlinear time history analysis, it suggests that this approach is applicable.

• Earthquakes and Structures
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• 제19권5호
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• pp.379-393
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• 2020

The purpose of this study is to first evaluate the seismic behavior of ageing arch bridges by using the Intensity Measure - based demand and DCFD format, which is referred to as the fragility-hazard format. Then, an investigation is performed for their seismic vulnerability. Analytical models are created for bridges concerning different features and these models are subjected to Incremental Dynamic Analysis (IDA) analysis using a set of 22 earthquake records. The hazard curve and results of IDA analysis are employed to evaluate the return period of exceeding the limit states in the IM-based probabilistic performance-based context. Subsequently, the fragility-hazard format is used to assess factored demand, factored capacity, and the ratio of the factored demand to the factored capacity of the models with respect to different performance objectives. Finally, the vulnerability curves are obtained for the investigated bridges in terms of the loss ratio. The results revealed that decreasing the span length of the unreinforced arch bridges leads to the increase in the return period of exceeding various limit states and factored capacity and decrease in the displacement demand, the probability of failure, the factored demand, as well as the factored demand to factored capacity ratios, loss ratio, and seismic vulnerability. Finally, it is derived that the probability of the need for rehabilitation increases by an increase in the span length of the models.

• Steel and Composite Structures
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• 제23권1호
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• pp.53-66
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• 2017

Structures submitted to Fire-After-Earthquake loading situations, are first experiencing inelastic deformations due to the seismic action and are then submitted to the thermal loading. This means that in the case of steel framed structures, at the starting point of the fire, plastic hinges have already been formed at the ends of the beams. The basic objective of this paper is the evaluation of the rotational capacity of steel I-section beams damaged due to prior earthquake loading, at increased temperatures. The study is conducted numerically and three-dimensional models are used in order to capture accurately the nonlinear behaviour of the steel beams. Different levels of earthquake-induced damage are examined in order to study the effect of the initial state of damage to the temperature-evolution of the rotational capacity. The study starts with the reference case where the beam is undamaged and in the sequel cyclic loading patterns are taken into account, which represent earthquakes loads of increasing magnitude. Additionally, the study extends to the evaluation of the ultimate plastic rotation of the steel beams which corresponds to the point where the rotational capacity of the beam is exhausted. The aforementioned value of rotation can be used as a criterion for the determination of the fire-resistance time of the structure in case of Fire-After-Earthquake situations.

• 한국지반공학회지:지반
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• 제13권4호
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• pp.13-24
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• 1997

말뚝 해석 프로그램인 PAR에 의하여 말뚝의 극한 수직 및 수평 지지력을 예측할 수 있는 방법을 제안하였으며,현장에서 수행된 말뚝재하시험 결과들을 이용하여 PAR에 의한 사례연구를 수행하였다. PAR에 의해 해석된 말뚝의 극한지지력은 정재하시험에서 구한 지지력에 대하여 약 15%이내의 오차범위에 들었다. 또한, 강관말뚝들에 수행된 정재하시헙, 정.동재하시험 그리고 PDA 결과들을 비교하였으며, PAR에 의해 극한지지력을 예측하였다. PAR을 이용하면 말뚝의 축방향 하중의 분포를 예측할 수 있었으며, 여기서, 하중전이해석도 근사적으로 수행할 수 있었다.

• Geomechanics and Engineering
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• 제10권5호
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• pp.617-633
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• 2016

A numerical study has been conducted to examine the improvement achieved in the ultimate pullout capacity of horizontal circular anchor plates embedded in undrained clay, by constructing granular columns of varying diameter over the anchor plates. The analysis has been carried out by using lower bound theorem of limit analysis and finite elements in combination with linear programming. The improvement in uplifting capacity of anchor plate is expressed in terms of an efficiency factor (${\xi}$). The efficiency factor (${\xi}$) has been defined as the ratio of ultimate vertical pullout capacity of anchor plate having diameter D embedded in soft clay reinforced by granular column to the vertical pullout capacity of the anchor plate with same diameter D embedded in soft clay only. The variation of efficiency factor (${\xi}$) for different embedment ratios and different diameter of granular column has been studied considering a wide range of softness of clay and different value of soil internal friction angle (${\phi}$) of the granular material. It is observed that ${\xi}$ increases with an increase in diameter of the granular column ($D_t$) and increase in friction angle of granular material. Also, the effectiveness of the usage of granular column increases with decrease in cohesion of the clay.

• Steel and Composite Structures
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• 제12권3호
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• pp.183-205
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• 2012

This paper presents an investigation of the effect of inclined stiffeners on the load-carrying capacity of simply-supported hot-rolled steel I-beams under various load conditions. The study is carried out using finite element analysis. A series of beams modeled using 3-D solid finite elements with consideration of initial geometric imperfections, residual stresses, and material nonlinearity are analyzed with and without inclined stiffeners to show how the application of inclined stiffeners can offer a noticeable increase in their lateral-torsional buckling (LTB) capacity. The analysis results have shown that the amount of increase in LTB capacity is primarily dependent on the location of the inclined stiffeners and the lateral unsupported length of the beam. The width, thickness and inclination angle of the stiffeners do not have as much an effect on the beam's lateral-torsional buckling capacity when compared to the stiffeners' location and beam length. Once the optimal location for the stiffeners is determined, parametric studies are performed for different beam lengths and load cases and a design equation is developed for the design of such stiffeners. A design example is given to demonstrate how the proposed equation can be used for the design of inclined stiffeners not only to enhance the beam's bearing capacity but its lateral-torsional buckling strength.

• Steel and Composite Structures
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• 제10권4호
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• pp.361-371
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• 2010

Enhancement in the seismic buckling capacity of steel tanks caused by the addition of fiber reinforced polymers (FRP) retrofit layers attached to the outer walls of the steel tank is investigated. Three-dimensional non-linear finite element modeling is utilized to perform such analysis considering non linear material properties and non-linear large deformation large strain analysis. FRP composites which possess high stiffness and high failure strength are used to reduce the steel hoop stress and consequently improve the tank capacity. A number of tanks with varying dimensions and shell thicknesses are examined using FRP composites added in symmetric layers attached to the outer surface of the steel shell. The FRP shows its effectiveness in carrying part of the hoop stresses along with the steel before steel yielding. Following steel yielding, the FRP restrains the outward bulging of the tank and continues to resist higher hoop stresses. The percentage improvement in the ultimate base moment capacity of the tank due to the addition of more FRP layers is shown to be as high as 60% for some tanks. The percentage of increase in the tank moment capacity is shown to be dependent on the ratio of the shell thickness to the tank radius (t/R). Finally a new methodology has been explained to calculate the location of Elephant foot buckling and consequently the best location of FRP application.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2007년도 추계학술발표대회 논문집
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• pp.37-43
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• 2007

In recent years, the cultural industry is considered to a major industry in the 21 century, and performing culture is growing rapidly in Korea. Also, rapid development in terms of quality and quantity can be found in the diversification of usage, a trend focusing on the space for performance, and an emphasis on the accessibility between the stage and auditorium. In addition, active research is being conducted on the performing arts facilities, a relationship between the stage and auditorium, and a space programfor each space considering users. However, most of the current studies are conducted byviewing the facilities in a two-dimensional space. Similar to other cultural facilities, such as museums and galleries, performing arts facilities have been planned in the thinking that the ratio of capacity increases in proportion to the area. Considering a dimensional capacity in the spatial composition of performing arts facilities is important, but it has been ignored until now. Therefore, in order to analyze performing arts facilities in the three dimensional approach, this study is conducted centering on the actual capacity and provides basic data that can be used for planning a construction of future performing arts facilities.

• 아태비즈니스연구
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• 제13권3호
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• pp.493-504
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• 2022

Purpose - This study investigate the effect of innovative capacity on corporate export performance and moderating flexibility. Design/methodology/approach - For this, hypotheses were established by reviewing previous studies and an empirical analysis was conducted for testing. Using SPSS 22.0, a frequency analysis of related variables was conducted. Through an exploratory factor analysis, validity and reliability tests of measuring tools were conducted and a descriptive statistics was analyzed for collected data result and hypotheses testing. Findings - Finally, with a verified model, the hypotheses and the moderating effects were tested. The results are as follows; The innovationa capacities have a positive effect on export performance and flexibility However, the flexbilitiy was not moderator in the relationship between innovative capacity and export performance. Research implications or Originality - According to the results above, this study presents directions to improve export performance of technological innovative type SMEs. The innovative capabilities, marketing capacity, organization innovative capacity and process innovative capactity, has an positive effect on