• 한국구조물진단유지관리공학회 논문집
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• 제4권2호
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• pp.139-149
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• 2000

In the preliminary design stage of prestressed concrete (PSC) box girder bridges, the design factors decided by inexperience designer could heavily affect to the results of final design. There is a possibility that the design ends up with an excessively wasteful design. To achieve an economical design with preventing an excessive design, the optimal design technique has been developed using ADS optimal program and SPCFRAME in this study. The objective function for the optimal design problem is the material cost of box girders and constrained functions are constituted with design specifications and workability. The Sequential Unconstraint Minimization Technique (SUMT) is used for the optimal design in this study. We designed an uniform cross-section bridge and an ununiform cross-section bridge in the same design condition by optimal design technique developed in this study. Analyzing the results obtained for various tendon layouts, we suggest a standard tendon layout which gives the most effective structural behavior.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2788-2802
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• 2021

Multigroup cross section (MG XS) generation by the UNIST in-house Monte Carlo (MC) code MCS for fast reactor analysis using nodal diffusion codes is reported. The feasibility of the approach is quantified for two sodium fast reactors (SFRs) specified in the OECD/NEA SFR benchmark: a 1000 MW_th metal-fueled SFR (MET-1000) and a 3600 MW_th oxide-fueled SFR (MOX-3600). The accuracy of a few-group XSs generated by MCS is verified using another MC code, Serpent 2. The neutronic steady-state whole-core problem is analyzed using MCS/RAST-K with a 24-group XS set. Various core parameters of interest (core k_eff, power profiles, and reactivity feedback coefficients) are obtained using both MCS/RAST-K and MCS. A code-to-code comparison indicates excellent agreement between the nodal diffusion solution and stochastic solution; the error in the core k_eff is less than 110 pcm, the root-mean-square error of the power profiles is within 1.0%, and the error of the reactivity feedback coefficients is within three standard deviations. Furthermore, using the super-homogenization-corrected XSs improves the prediction accuracy of the control rod worth and power profiles with all rods in. Therefore, the results demonstrate that employing the MCS MG XSs for the nodal diffusion code is feasible for high-fidelity analyses of fast reactors.

• Steel and Composite Structures
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• 제31권2호
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• pp.173-185
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• 2019

This paper presents experimental and numerical investigations of aluminum tubular members subjected to combined bending and web crippling. A series of tests was performed on square hollow sections (SHS) fabricated by extrusion using 6061-T6 heat-treated aluminum alloy. Different specimen lengths were tested to obtain the interaction relationship between moment and concentrated load. The non-linear finite element models were developed and verified against the experimental results obtained in this study and test data from existing literature for aluminum tubular sections subjected to pure bending, pure web crippling, and combined bending and web crippling. Geometric and material non-linearities were included in the finite element models. The finite element models closely predicted the strengths and failure modes of the tested specimens. Hence, the models were used for an extensive parametric study of cross-section geometries, and the web slenderness values ranged from 6.0 to 86.2. The combined bending and web crippling test results and strengths predicted from the finite element analysis were compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for aluminum structures. The findings suggest that the current specifications are either quite conservative or unconservative for aluminum square hollow sections subjected to combined bending and web crippling. Hence, a bending and web crippling interaction equation for aluminum square hollow section specimens is proposed in this paper.

• Structural Engineering and Mechanics
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• 제83권3호
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• pp.387-400
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• 2022

The practice of using encased steel-concrete columns in medium to high-rise structures has expanded dramatically in recent years. The study evaluates existing methodologies and codal guidelines for estimating the ultimate load-carrying characteristics of concrete-encased short columns experimentally. The present condition of composite column design methods was analyzed using the Egyptian code ECP203-2007, the American Institute of Steel Construction's AISC-LRFD-2010, Eurocode EC-4, the American Concrete Institute's ACI-318-2014, and the British Standard BS-5400-5. According to the codes, the axial load carrying characteristics of both the encased steel and concrete sections was examined. The effect of load-carrying capacities in different forms of encased steel sections on encased steel-concrete columns was studied experimentally. The axial load carrying capacity of twelve concrete-encased columns and four conventional reinforced columns were examined. The conclusion is that the confinement was not taken into account when forecasting the strength and ductility of the encased concrete, resulting in considerable disparities between codal provisions and experimental results. The configuration of the steel section influenced the confining effect. Better confinement is achieved with the laced and battened section than with the infilled steel tube reinforced and conventionally reinforced section. The ECP203-2007 code reported the most conservative results of all the codes used.

• 건축역사연구
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• 제31권3호
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• pp.7-16
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• 2022

Fen(分°) is the proportional dimension unit of the standard timber section on Yingzaofashi(營造法式), and there is a phrase that not only structural members but the whole structural design of a building also use Fen as the dimension unit on the book. But in fact only the section dimensions of structural members are recorded by Fen, but the design dimensions are recorded by Chi(尺) on the book. Other historical records also described the building size by Chi. So there has been long-standing debate on the phase in Chinese architectural history society, including the recent confrontation on the analysis of survey figures of the east great hall of Foguangsi temple(佛光寺 東大殿). This paper analyzes all the records about the size of structural members and section planning on the book to make various calculation and evaluation. And it makes a survey of Cai(材) as the dimension and design unit between Chi and Fen through geometric analysis. Cai might be a rough unit of measurement in terms of structural and proportional scheming on Yingzaofashi, and the full size Cai(足材) had been a building scheming module before the Song dynasty.

• Computers and Concrete
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• 제30권2호
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• pp.127-141
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• 2022

In this paper, a numerical procedure is proposed for achieving the minimum cost design of reinforced concrete polygonal column cross-sections under compression and biaxial bending. A methodology is developed to integrate the metaheuristic algorithm Quantum Particle Swarm Optimization (QPSO) with an algorithm for the evaluation of the strength of reinforced concrete cross-sections under combined axial load and biaxial bending, according to the design criteria of Brazilian Standard ABNT NBR 6118:2014. The objective function formulation takes into account the costs of concrete, reinforcement, and formwork. The cross-section dimensions, the number and diameter of rebar and the concrete strength are taken as discrete design variables. This methodology is applied to polygonal cross-sections, such as rectangular sections, rectangular hollow sections, and L-shaped cross-sections. To evaluate the efficiency of the methodology, the optimal solutions obtained were compared to results reported by other authors using conventional methods or alternative optimization techniques. An additional study investigates the effect on final costs for an alternative parametrization of rebar positioning on the cross-section. The proposed optimization method proved to be efficient in the search for optimal solutions, presenting consistent results that confirm the importance of using optimization techniques in the design of reinforced concrete structures.

• 한국해양공학회지
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• 제23권6호
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• pp.131-135
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• 2009

We present an optimum design method for a rectangular reinforced concrete beam using Genetic Algorithms. The optimum design procedure in this paper employs 2 design cases: i) all of the design variables (b, d, As) of the rectangular reinforced concrete section are used pseudo-continuously, ii) one is pseudo-continuous for the concrete cross section (b, d) and the other is discrete, using an index for the steel area (As). The optimum design in this paper uses Chakrabarty's model. In this paper, the Genetic Algorithms use the method of Elitism and penalty parameters to improve the fitness in the reproduction process, which leads to very practical designs. The optimum design of the steel area in the examples uses ASTM standard reinforcing bars (#3~#11, #14, #18).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.675-678
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• 2004

Comparative analysis it did the interior noise of the KTX vehicle and the P-P Semaeul vehicle from the conventional line Homan Seodaejeon-Hanam section from the research which it sees. The test result KTX vehicle appeared when the P-P Semaeul vehicle compared to 20 - 25 KM/H speed up operating commerce operation speed even, the standard values 66 dBA the lowers 55 - 62 dBA. P-P Semaeul vehicle interior noise of the identical test section 63 dBA it will compare and there is a possibility the KTX vehicle knowing from the existing line operating hour interior noise.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.288-295
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• 1996

This work presents an optimality criteria method applicable io the design of plane frames with I-shape sections. All kinds of constraints are treated properly to ensure the mathematical rigour of the method as ever. Among the various properties of a section, the cross-sectional area is chosen as the design variable associated with the member. Then other properties, moment of inertia and depth, are determined from the cross-sectional area using relationships established in advance from the sectional data for AISC standard W shapes. The optimality criteria established in this work is perfect in mathematical terms provided that the relationships between properties of a section are correct. A redesign algorithm is derived relying heavily on the Newton-Raphson method to solve the system of nonlinear constraint equations. A worked example is also Presented.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.499-500
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• 2009

본 연구에서는 현장 부착강도시험을 통해 콘크리트의 단면복구재로 사용되는 국내 폴리머시멘트 모르타르 제품에 대한 부착강도 특성을 평가하였다. 부착강도시험에는 직접 인발시험기를 적용했으며, 시험결과는 단면복구재에 대한 국내 산업규격의 품질기준에 대한 타당성 검토를 위한 기초자료로 제시한다.