• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.262-271
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• 1998

Recent, more and more steel deck bridges are adopted for the design of long span bridges and the upgrading of existing concrete deck bridges, mainly because of reduced self weight, higher stiffness and efficient erection compared to concrete decks. The main objective of this study is to propose on formulation of the design optimizations to develop an optimal desist program required for optimum desist for orthotropic steel-deck bridges. The objective function of the optimization is formulated as a minimum initial cost design problem. The behavior and design constraints are formulated based on the ASD and LRFD criteria of the Korean Bridge Design Code(1996). The optimum design program developed in this study consists of two steps. In the first step the system optimization of the steel box girder bridges is carried out. And in the second step the program provided the optimum design of the orthotropic steel-deck with close ribs. In the optimal design program the analysis module for the deck optimization is based on the Pelican Esslinger method. The optimizer module of the program utilizes the ADS(Automated Desist Synthesis) routines using the optimization techniques fuor constrained optimization. From the results of real application examples, The cost effectiveness of optimum orthotropic steel-deck bridges designs based on both ASD and LRFD methods is investigated by comparing the results with those of conventional designs, and it may be concluded that the design developed in this study seems efficient and robust for the optimization of orthotropic steel-deck bridges

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.128-136
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• 2001

This paper presents an optimum deck and girder system design for minimizing the life-cycle cost (LU) of steel box girder bridges. The problem of optimum LCC design of steel box girder bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost, expected retrofit costs for strength, deflection, and crack. To demonstrate the effect of LCC optimum design of steel box girder bridges, the LCC optimum design is compared with conventional design method for steel box girder bridges design. From the numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on LCC will lead to more rational, economical and safer design.

• 한국구조물진단유지관리공학회 논문집
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• 제2권3호
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• pp.235-244
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• 1998

In the design of bridges, the points of concem are the landscape design, the function, safety and economical efficiency. But most of studies have been performed on structural engineering. The study on the landscape design of bridges has not been done in korea. Therefore, in this research, the design method of bridges by the judgement of structural engineering and landscape engineering has been proposed, through the process to decide the shape of bridges. Also, the research studies a problem about the visual safety of the structural shape in the landscape design of bridges. The visual experiments applied to the seven models about the shape of hunch in bridge pier. The experiment was made in moving velocity of view point, steady looking time and track of eyeball movement.

• 한국강구조학회 논문집
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• 제13권4호
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• pp.337-349
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• 2001

교량은 계속적으로 변하는 하중 환경에 의해서 다른 구조물에 비해 비교적 빨리 노후화 되기 때문에 초기비용 이외에도 교량의 유지관리, 교통의 원활한 소통 또는 적체 등에 따른 비용, 교량의 손상에 따른 보수보강 및 교량의 해체 재건설 등 추가적인 비용의 영향이 크므로 공용간 생애주기 비용(LCC)을 설계단계에서부터 체계적이고 합리적으로 고려되어야 한다. 이에 본 연구에서는 강상판교의 설계에 있어서 주형의 휨 전단, 사용성, 피로에 대한 보강기대비용 등을 포함하는 LCC에 근거한 비용함수모형을 이용하여 이를 최적설계에 적용하고 기존의 설계방법과 비교 분석하였다. 적용예제의 결과에 나타난 바와 같이 LCC를 고려한 강상판 교량의 최적설계는 더욱 합리적이고, 경제적이며, 안전한 설계를 유동할 수 있으리라 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1037-1043
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• 2007

The railroad systems with the ballast tracks have been widely used for a long time. But recently, the use of the slab track is being increased gradually with a technical developments. So, this paper deals with the appliance of the slab tracks on the railroad bridges. Firstly, review the design criteria of the railroad bridges related to the slab tracks for the stability and serviceability, based on DIN and EURO code. Then, perform the analysis of the railroad prestressed concrete bridges, and check whether the results of the analysis satisfy the design criteria. Finally, find the construction condition of bridges that all the design criteria are satisfied. As a result, to maintain the stability and serviceability of the bridges, bridges must have some restrictions, including a time of installation of the slab tracks. So, the construction schedule for the erection of the bridges will be carefully considered in case of the concrete railroad bridges with the slab tracks.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.125-130
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• 2001

A existing design method of PSC girder bridges, according to total service loads, stress required tendon force at a time. Because this design method increases beam depth, design of long span is difficult. However, As UC girder stressing at difficult loading stages reduces sectional depth of PSC girder, both design and operation of long span bridges is possible. so, this study analyzes the effect of design parameter (Girder Strength, Girder Spacing, Span Length, Joint Strength) on the beam depth of IPC girder continuous bridges, and shows sectional depth of UC girder for design of long span bridges. According to analysis, when a continuous bridges of same length span is at strength of joint over strength of girder of 600kg/$cm^{2}$, a change of beam depth is observed and when a continuous bridges of different span length is at strength of joint below strength of girder of 600kg/$cm^{2}$, a change of beam depth is observed. In two case, a change of beam depth is mostly observed over strength of girder of 350kg/$cm^{2}$ according to analysis of deflection data, a continuous bridges of IPC girder is nearly satisfied.

• 한국전산구조공학회논문집
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• 제15권4호
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• pp.557-566
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• 2002

본 논문에서는 강상자형교의 바닥판과 주형에 대한 생애주기비용(Life-Cycle Cost : LCC)를 고려한 최적설계 방법을 제안하였다. 생애주기비용의 최적설계 문제는 초기비용, 유지관리비용 그리고 강도와 처짐 그리고 균열에 대한 파손 기대비용의 최소화 문제로 정식화할 수 있다. 기존의 재래적인 설계방법과의 비교를 동해서 강상자형교의 생애주기비용 최적설계의 우수성을 입증하였다. 또한 수치적인 결과의 고찰을 통하여 LCC에 근거한 최적설계가 여타의 설계방법들보다 좀 더 합리적이고 경제적이며 안전한 설계를 유도하는 것으로 분석되었다.

• 콘크리트학회논문집
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• 제12권6호
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• pp.13-22
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• 2000

In order to resolve the problem of increasing traffic entailed by the economic development, road system is reorganization and new highways are built, and long span bridges over 40m are being constructed in environmental and aesthetic considerations. Most long span bridges that are currently being constructed are in general steel box girder and preflex girder bridges; however these types of breiges are less efficiency than PSC I-type girder bridges in terms of construction cost and maintenance. Therefore, in these study, structural efficiency of PSC I-type girders based on section parameters, concrete compressive strength and other design parameter is observed to develope new PSC I-type girder for long span bridges. As a results of analysis, most important design parameters that control the stress of the girder are found to be the top flange width and the height of girder. In this light, the relationship between the two variables is determined and cross-section details of the girder that most appropriates for the long span bridges are proposed. The use of high strength concrete appears to increase the general design span however the increase rate of the span from increasing concrete ultimate strength appears to be reduced depending on the span. Also, the optimal girder spacing is determined through the parameter studies of design span using the proposed girder.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.154-161
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• 2001

A procedure of the design optimization for steel box girder bridges using micro genetic algorithms(μGA) is developed. The effect of population size is investigated and the efficiency and reliability of μGA is demonstrated in the optimum design of steel box girder bridges. Optimum design problems of steel box girder bridges are formulated, where tile design of concrete slab is based on the USD specifications and steel box girder based on LRFD respectively. Design of optimizations of single-span and 2-span steel box girder bridges are performed with the population size of 5, 40, 80, and 120, respectively The μGA-based optimum design of the 3-span steel box girder bridge is compared with SQP results.

• Earthquakes and Structures
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• 제4권5호
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• pp.527-555
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• 2013

This paper proposes probabilistic models for estimating the seismic demands on reinforced concrete (RC) bridges with base isolation. The models consider the shear and deformation demands on the bridge columns and the deformation demand on the isolation devices. An experimental design is used to generate a population of bridges based on the AASHTO LRFD Bridge Design Specifications (AASHTO 2007) and the Caltrans' Seismic Design Criteria (Caltrans 1999). Ground motion records are used for time history analysis of each bridge to develop probabilistic models that are practical and are able to account for the uncertainties and biases in the current, common deterministic model. As application of the developed probabilistic models, a simple method is provided to determine the fragility of bridges. This work facilitates the reliability-based design for this type of bridges and contributes to the transition from limit state design to performance-based design.