• Structural Engineering and Mechanics
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• 제40권5호
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• pp.719-743
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• 2011

A hybrid damage monitoring scheme using parallel acceleration-impedance approaches is proposed to detect girder damage and support damage in steel plate-girder bridges which are under ambient train-induced excitations. The hybrid scheme consists of three phases: global and local damage monitoring in parallel manner, damage occurrence alarming and local damage identification, and detailed damage estimation. In the first phase, damage occurrence in a structure is globally monitored by changes in vibration features and, at the same moment, damage occurrence in local critical members is monitored by changes in impedance features. In the second phase, the occurrence of damage is alarmed and the type of damage is locally identified by recognizing patterns of vibration and impedance features. In the final phase, the location and severity of the locally identified damage are estimated by using modal strain energy-based damage index methods. The feasibility of the proposed scheme is evaluated on a steel plate-girder bridge model which was experimentally tested under model train-induced excitations. Acceleration responses and electro-mechanical impedance signatures were measured for several damage scenarios of girder damage and support damage.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.287-292
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• 2001

Static behaviors of railway plate girder bridges designed by the L-22, a standard load type of the railway specification in Korea, are evaluated by widely eight load cases. The load cases are three real loads, which contain three locomotive types of Saemaul PMC, diesel, and Korea Train Express(KTX), and three design loads, L-22, L-18, and HL-25 loads, in railway specification. Plate girders for analysis have the length of spans of six types：6m, 9m, 12m, 22m, 24m, and 30m. For analysis SAP2000n ,a commercial FEM tool, is used. Dominant axial load types are taken from these results that are maximum deflections, reaction forces, and absolute maximum bending moment in girders.

• Journal of Welding and Joining
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• 제21권5호
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• pp.491-499
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• 2003

• 한국전산구조공학회논문집
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• 제17권2호
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• pp.95-104
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• 2004

최근 건설이 증가하고 있는 곡선교는 1960년대 까지는 직선 거더의 조합으로 구성하여 건설되어 왔으나, 현재 곡선 거더의 사용이 증대되고 있는 추세이다. 곡선 거더를 사용하는 경우에는 시간과 건설비용의 절감 뿐 아니라 미관상으로도 유리하다. 판형교에서는 전단좌굴을 방지하기 위하여 전단 좌굴강도의 검토와 보강재의 설계가 반드시 필요하다. 직선 복부판과 비교하여 곡선 복부판은 형상비와 곡률에 따라 전단좌굴 강도가 변화하나, 현재까지 곡선 복부판의 전단좌굴강도에 대한 연구는 그다지 이루어지지 않은 실정이다. 따라서 본 연구에서는 곡선복부판의 선단좌굴 강도를 유한요소해석을 통하여 알아보고 이론 산정하는 간략식을 제시하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.401-410
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• 2007

Form the application of long rail system the non-ballast steel plate bridges, fatigue strength increase and rail noise reduction can be expected. This is mainly form the reduction of the rail impact at the rail joint locations which already made to behave together from welds. In the high speed rail, application of long rail system is essential because without long rail system, the required serviceability level can not be achieved. But even with this long rail systems, the thermal expansion from the girder can not be absorbed in the normal bearing systems, and these expansion cause between girder and rail. Also unexpected rail buckling and fracture through rail thermal tension may happen. It was found through numerical analysis and field measurement that these problems can be avoided by semi-fixed bearing system. In this study, the benefits of non-ballast plate bridge through long rail system, especially at the point of girder stability, girder stiffness increase and bearing maintenance will be reviewed.

• Structural Engineering and Mechanics
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• 제19권2호
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• pp.173-184
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• 2005

For reducing construction cost, two-plate-girder bridges are getting popular in Japan. This type of bridge employs a PC slab, which is often cast-in-place. In such a case, concrete is not usually cast over the whole slab at one time: some portions are constructed earlier than the rest. Therefore, a construction joint is inevitably created. Due to the drying shrinkage of concrete, tension stress may occur in concrete slab. High tensile stress can be expected near the construction joint where concretes with different ages meet. Moreover, prestressing is not applied over the whole length of slab at one time. This may also serve as a source of tensile stress in the slab. Thus there is a chance that cast-in-place PC slab, especially near the construction joint, may be subjected to tensile cracking. In the present study, stress states near the construction joint in the cast-in-place PC slab of a two-plate-girder bridge are investigated numerically. The finite element method is employed and the three-dimensional analysis is conducted to see the influence of dry shrinkage and prestressing. The stress states in the PC slab thus obtained are discussed. The simplified model of a plate girder for this class of analysis is also proposed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.684-689
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• 2002

This paper represents the life-cycle cost(LCC) of steel bridges which are located on the train-network. Corrosion problems are mainly considered in the steel members such as steel plate girder, box girder, truss and arch. Based on the current value, initial construction cost, maintenance cost and demolition cost are calculated and life-cycle costs are formulated for the several types of bridges. From the comparison on each LCC, an effective painting method is recommended for reducing the LCC of steel bridges. Even though the initial cost of Super Weather Resistance Heavy Duty Paintings (Resin Fluoride) is expensive, because of the long endurance, the LCC of steel bridges painted with Super Weather Resistance Heavy Duty Paintings (Resin Fluoride) is less than that painted with General Heavy Duty (Rubber Chloride).

• 한국지진공학회논문집
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• 제12권6호
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• pp.13-23
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• 2008

본 논문에서는 거더교 형식을 갖는 교량구조물의 격자 유한요소모델에 대한 모델개선을 위해 하이브리드 유전자 알고리즘에 기초한 유한요소 모델개선기법을 제안하였다. 하이브리드 유전자 알고리즘은 유전자 알고리즘과 심플렉스 최적화방법에 기초한 직접탐색기법으로 구성하였다. 제안된 기법에 적용할 수 있도록 고유진동수, 모드형상 및 정적 처짐에 대한 계측값과 유한요소해석 결과를 사용한 적합함수를 제시하고, 강성과 질량을 동시에 개선할 수 있도록 이들 세 가지 적합함수의 선형 조합 형태를 갖는 다중목적함수를 제시하였다. 제안된 방법은 2경간 연속 격자 유한요소모델의 수치예제와 단경간 플레이트 거더교에 대하여 검증하였다. 수치예제의 경우, 랜덤 노이즈를 고려한 계측오차의 영향을 수치해석적으로 평가하였다. 수치해석과 실험적 검증을 통해, 제안된 방법이 거더교 형식의 교량에 대한 유한요소 모델개선에 적합하고 효과적임을 검증하였다.

• 한국강구조학회 논문집
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• 제14권5호통권60호
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• pp.593-602
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• 2002

콘크리트와 강판, PS강재의 구조적 장점을 극대화하여 낮은 형고로 경간을 장대화할 수 있는 새로운 교량 상부구조형식으로서 강재로 구속된 프리스트레스트 콘크리트 합성거더(Steel-Confined Prestressed Concrete Girder; SCP Girder)를 개발하였다. 개발된 SCP 합성거더의 효과적인 설계 및 제작을 위하여 설계프로그램을 개발하고 제작절차를 확립하였다. 이를 바탕으로 설계된 SCP 합성거더를 실물크기로 제작하여 시공성을 확인하였으며, 재하실험을 통해 설계의 타당성과 구조적 안전성 및 실적용 가능성에 대하여 검증하였다.

• 한국해양공학회지
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• 제22권1호
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• pp.75-82
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• 2008

A vibration-based damage-monitoring scheme is proposed that would generate an alarm showing the occurrence and location of damage under temperature-induced uncertainty conditions. Experiments on a model plate-girder bridge are described, for which a set of modal parameters was measured under uncertain temperature conditions. A damage-alarming model is formulated to statistically identify the occurrence of damage by recognizing the patterns of damage-driven changes in the natural frequencies of the test structure and by distinguishing temperature-induced off-limits. A damage index method based on the concept of modal strain energy is implemented in the test structure to predict the location of damage. In order to adjust for the temperature-induced changes in the natural frequencies that are used for damage detection, a set of empirical frequency correction formulas is analyzed from the relationship between the temperature and frequency ratio.