• Architectural research
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• 제2권1호
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• pp.61-69
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• 2000

This research focused on the hysteretic energy performance of 12 steel moment-resisting frames, which were intentionally designed by three types of design philosophies, strength control design, strength and drift control design, and strong-column and weak-beam control design. The energy performances of three designs were discussed In view of strength increase effect, stiffness increase effect, and strong-column and weak-beam effects. The mean hysteretic energy of the 12 basic systems were statically processed and compared to that of single-degree-of-freedom systems. Hysteretic energy was not always increased with an increase of strength and stiffness in the steel moment-resisting frames. Hysteretic energy between strong-column and weak-beam design and drift control design with the same stiffness was not sensitive each other for these types of mid-rises of steel moment-resisting frames.

• International Journal of Concrete Structures and Materials
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• 제10권3호
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• pp.393-406
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• 2016

Axially loaded reinforced concrete columns are hardly exist in practice due to the development of some bending moments. These moments could be produced by gravity loads or the lateral loads. First, the current paper presents a detailed analysis on the overall structural behavior of 15 eccentrically loaded columns as well as one concentrically loaded control one. Columns bent in either single curvature or double curvature modes are tested experimentally up to failure under the effect of different end eccentricities combinations. Three end eccentricities ratio were studied, namely, 0.1b, 0.3b and 0.5b, where b is the column width. Second, an expression correlated the decay in the normalized axial capacity of the column and the acting end eccentricities was developed based on the experimental results and then verified against the available formula. Third, based on the equivalent column concept, the equivalent pin-ended columns were obtained for columns bent in either single or double curvature modes. And then, the effect of end eccentricity ratio was correlated to the equivalent column length. Finally, a simplified design procedure was proposed for eccentrically loaded braced column by transferring it to an equivalent axially loaded pin-ended slender column. The results of the proposed design procedure showed comparable results against the results of the ACI 318-14 code.

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.39-45
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• 2007

분리벽형 증류탑의 구조 설계를 위한 shortcut 방법으로서 기존의 Fenske-Underwood 식을 3기 일반 증류탑 배열에 확장 적용하는 방법을 제안하였다. 제안된 방법으로 초기 설계 단계에서 분리벽형 증류탑의 공급단 위치, 분리벽 구간, 중간 제품 생산단의 위치를 간편하면서도 효과적으로 결정할 수 있는 것을 확인하였다. 제안된 방법에 의하여 구조 설계가 이루어진 분리벽형 증류탑과 기존의 연속 2기 증류공정 간의 분리 효율을 비교하기 위해 HYSYS를 사용하여 다양한 원료 조건에 대하여 전산모사 실험을 수행하였다. 그 결과 제안된 분리벽형 증류탑이 기존 연속 2기 증류공정 대비 16％에서 65％까지 에너지를 절약할 수 있음을 확인하였다. 또한 분리벽형 증류탑에 의한 분리 성능 향상 정도는 중간 비점 물질의 조성에 크게 의존하며 중간비점 조성이 우세할수록 유리함을 확인하였고, 최적 에너지 분포 영역 경향은 원료 혼합물의 ESI 값에 의하여 결정됨을 알 수 있었다.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.21-27
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• 2018

나프타분리공정은 원유에서 증류 공정에 의해 얻어지는 풀레인지납사(Full Range Naphtha)를 원료로 하여 끓는점 차이에 의해 각각 경질납사, 중질납사 및 등유 반제품으로 순차적으로 분리한다. 이러한 전통적인 분리 방법은 2성분을 분리하는 Column을 연속으로 설치하여 생산한다. 이러한 분리방법은 리보일러에서 소비되는 에너지가 증류탑 내부 고비점 성분을 분리시키는 데 사용되고 이 에너지의 대부분은 탑정의 냉각기에서 응축열로 버려지게 때문에 에너지 낭비가 큰 것으로 알려져 있다 본 연구에서는 납사분리공정의 2개의 Column을 Petlyuk Column으로 설계하였다. 탑내 조성분포가 평형관계만으로 계산되는 이상적 단수 효율 하에서 stage to stage 계산방법으로 구조적 설계를 하였고 일반 증류탑과 비교한 결과 제시된 Petlyuk Distillation Column의 설계 방법이 기존의 3-column 모델법보다 설계 시간이 단축될 뿐만 아니라 증류탑내의 액의 조성분포를 평형증류 조성곡선과 유사하도록 설계함으로써 에너지 효율 측면에서도 효율적임을 입증하였다. 또한 같은 tray 단수하에서 Petlyuk Column은 일반 증류탑 대비 약 12.3% 에너지가 절약될 뿐만 아니라 초기 투자비도 절약됨을 알 수 있었다.

• 한국농공학회지
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• 제27권4호
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• pp.61-67
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• 1985

This study is concerned with the optimum design of reinforced concrete frame structure with multi-stories and multi-bays by Limit State Design Method aimed to establish a synthetical optimal method that can simultaneously acomplish structural analysis and sectional desig. For optimum solution, the Successive Linear Programming known as effective to nonlinear optimization problem: including both multi-design variables and mulit-constrained condition was applied. The developed algorithm was applied to an actual structure and reached following results. 1)The developed algorithm was rvey effective converging to an optimal solution with 3 to 5 iteration. 2)An optimal solution was showed when bending moment redistribution factor a was 0.80. 3)The column was, regardless of story, controlled by the long column when unbraced, while in case of braced column, it is designed with 3 short column controlled by thrust and bending moment, and the supporting condition had little effect on the optimization results.

• International Journal of Aeronautical and Space Sciences
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• 제15권1호
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• pp.20-31
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• 2014

This paper deals with the development of a realistic shape optimization of damaged columns that are subjected to conservative and non-conservative forces, using the Genetic Algorithm (GA). The analysis is based on the design of the most optimized shape of the column under the constraint of constant weight, considering the Static, Vibrational, and Flutter characteristics. Under the action of conservative and non-conservative longitudinal forces, an elastic column loses its stability. A numerical analysis based on FEM has been performed on a uniform damaged column, to compute the fundamental buckling load, vibration frequency, and flutter load, under various end restraints. An optimization search based on the Genetic Algorithm is then executed, to find the optimal shape design of the column. The optimized column references the one having the highest buckling load, highest vibration frequency, and highest flutter load, among all the possible shapes of the column, for a given volume. A comparison is then made between the values obtained for the optimized damaged column, and those obtained for the optimized undamaged column. The comparison reveals that the incorporation of damage in the column alters its optimal shape to only a certain extent. Also, the critical load and frequency values for the optimized damaged column are comparatively low, compared with those obtained for the optimized undamaged column. However, these results hold true only for moderate-intensity damage cases. For high intensity damage, the optimal shape may not remain the same, and may vary, according to the severity of damage.

• Geomechanics and Engineering
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• 제22권4호
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• pp.305-318
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• 2020

Stone columns are widely used to treat soft clay ground. Optimizing the design of stone columns based on cost-effectiveness is always an attractive subject in the practice of ground treatment. In this paper, the design of stone columns is optimized using the concept of robust geotechnical design. Standard deviation of failure probability, which is a system response of concern of the stone column-reinforced foundation, is used as a measure of the design robustness due to the uncertainty in the coefficient of variation (COV) of the noise factors in practice. The failure probability of a stone column-reinforced foundation can be readily determined using Monte Carlo simulation (MCS) based on the settlements of the stone column-reinforced foundation, which are evaluated by a deterministic method. A framework based on the concept of robust geotechnical design is proposed for determining the most preferred design of stone columns considering multiple objectives including safety, cost and design robustness. This framework is illustrated with an example, a stone column-reinforced foundation under embankment loading. Based on the outcome of this study, the most preferred design of stone columns is obtained.

• Steel and Composite Structures
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• 제45권1호
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• pp.101-118
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• 2022

The seismic performance of the reinforced concrete (RC) special-shaped column to steel beam connections with steel jacket used in the RC column to steel beam fabricated frame structures was investigated in this study. The three full-scale specimens were subjected to cyclic loading. The failure mode, ultimate bearing capacity, shear strength capacity, stiffness degradation, energy dissipation capacity, and strain distribution of the specimens were studied by varying the steel jacket thickness parameters. Test results indicate that the RC special-shaped column to steel beam connection with steel jacket is reliable and has excellent seismic performance. The hysteresis curve is full and has excellent energy dissipation capacity. The thickness of the steel jacket is an important parameter affecting the seismic performance of the proposed connections, and the shear strength capacity, ductility, and initial stiffness of the specimens improve with the increase in the thickness of the steel jacket. The calculation formula for the shear strength capacity of RC special-shaped column to steel beam connections with steel jacket is proposed on the basis of the experimental results and numerical simulation analysis. The theoretical values of the formula are in good agreement with the experimental values.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.314-317
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• 2006

In the present study, design methodologies for effective width of slabs in slab-column connections were evaluated in comparison with the experimental results on the full-scale slab-column connections. The design methodologies are as follows: the methodology proposed by Jacob S. Grossman and the methodology proposed by Choi & Song. The former does not predict the stiffness change of the slab-column connection due to the change in the column section shape and the latter overestimates the stiffness when edge length of the column section in the loading direction is long. Accordingly, the equation to calculate the effective width of slabs should be modified to reflect the effect of the change in the column section shape.

• 자동차안전학회지
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• 제5권2호
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• pp.57-61
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• 2013

A column for streetlamp has been damaged by severe wind loads such as typhoon. The stress concentration around the inspection hole may cause the collapse of the column for streetlamp. In this paper, the effects due to the wind load of 60 m/s and the car crash to the column at the speed of 48 km/h were considered to examine the design stability analysis of the column for streetlamp. The maximum von Mises stress did not exceed the yield stress of the material. Considering the car crash, the column for streetlamp was not collapsed.