• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 가을 학술발표회 논문집
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• pp.95-100
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• 1990

The behavior of short span filled spandrel arch bridge of 10 and 21 m span with various axis line, rise and backill height were investigated under the design loads(self weight, earth pressure, temperature load, live load, etc). Even though the behaviors of arch were known as relatively complicated, the followings can be concluded within the limits of this study. The design value of arch bridge increase as the rise decreases, the effects of temperature load become dominant for the design of arch bridge, and governing design factors are occured at springing.

• 산업기술연구
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• 제19권
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• pp.313-320
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• 1999

Steel railway bridge gets vibration from moving load ; additionally, this kind of moving load is going to be a sufficient reason, which causes fatigue damage to steel railway bridge. Fatigue damage and stress curve were raised by moving load depends on span length in steel railway bridge. In other words, stress curve appears index regarding every axial load in short span, but self weight lets stress curve's change decrease in proportion to increasing span length. Thereby, we have studied that how the steel railway bridge appear fatigue damage in proportion to span length of steel railway bridge. Dynamic strain was measured in 4 steel plate-girder railway bridge during the trains was passing, which is located on the line of Kyoung-chun railway. And time history response analysis has been done in order to ensure actual survey. The results of this study show the decreased of the fatigue damage in steel railway bridge according to length of span. This paper ends is bases research of fatigue design in steel railway bridges according to span length.

• Smart Structures and Systems
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• 제13권5호
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• pp.775-796
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• 2014

This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen the health condition of short span bridges in terms of a drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge was observed. Observations also demonstrated the possibility of diagnosis of bridges by comparing patterns of identified bridge dynamic parameters through periodical monitoring. It was confirmed that the moving vehicle method identifies the damage location and severity well.

• 콘크리트학회논문집
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• 제28권5호
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• pp.545-553
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• 2016

이 논문에는 교량바닥판의 지간장이 짧은 단지간용 프리캐스트 콘크리트패널에 대해 수행한 정적하중 재하실험 결과들을 나타내었다. 단지간용 콘크리트패널은 콘크리트패널 하면에 콘크리트리브가 부착되어 있으며, 기존 LB-DECK과 달리 콘크리트패널 상면에 Top bar가 없는 단면이다. 콘크리트패널에 부착되는 콘크리트리브의 개수와 단면 상세는 교량바닥판의 지간장과 철근콘크리트바닥판 두께 변화에 따른 설계하중에 대해 변수해석 결과를 토대로 결정하였다. 콘크리트패널 상면에는 현장타설되는 콘크리트와 합성거동을 위해 전단철근을 배치하였다. 변수해석을 통해 산정된 콘크리트패널이 설계하중에 대해 사용성과 안전성을 만족하는 가를 확인하기 위해 정적하중 재하실험을 수행하였다. 지간장 1.6 m인 단지간 콘크리트패널 실험체 3개 제작한 후 정적하중 재하하면서 각 실험체의 처짐, 균열, 그리고 최종 파괴양상을 살펴보았다. 설계하중이 작용할 때 각 실험체의 처짐, 균열하중, 그리고 균열폭을 토대로 사용성을 평가하였다. 또한 각 실험체의 최종 파괴양상과 극한강도를 토대로 계수설계하중에 대한 안전성을 평가하였다. 실험 결과 단지간용 콘크리트패널이 사용성과 안전성을 만족하는 것을 확인할 수 있었다. 추가적으로 단지간용 콘크리트패널을 적용할 수 있는 교량바닥판의 지간장 범위를 검토하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.193-200
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• 1998

The precast prestressed concrete girders of I-type section are frequently employed to design the short-to-medium span bridge. However, its beam depth is greatly increased as its span length is increased over than about 30m. Therefore, the economic and aesthetic effectiveness are rapidly decreased in case of the span length over 30m. The purpose of this paper is to verify the structural safety on the new spliced two span bridge and analyze the variation of member forces and stress distribution according to the construction stages and time. The new spliced technique is performed by partial post tensioning and release in the U-type girders. The structural characteristics of this technique is the introduction of secondary moment to reduce the bending moment by self weight of precast U-type girders constructed in simply supported beam type. So, it is expected that the structural efficiency of this spliced bridge may be improved more than other techniques.

• Earthquakes and Structures
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• 제8권4호
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• pp.859-887
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• 2015

Structural health monitoring (SHM) has gained in popularity in recent years since it can assess the performance and condition of instrumented structures in real time and provide valuable information to the asset's manager and owner. Operational modal analysis plays an important role in SHM and it involves the determination of natural frequencies, damping ratios and mode shapes of a constructed structure based on measured dynamic data. This paper presents the operational modal analysis and seismic response characterization of the Tsing Ma Suspension Bridge of 2,160 m long subjected to different earthquake events. Three kinds of events, i.e., short-distance, middle-distance and long-distance earthquakes are taken into account. A fast Bayesian modal identification method is used to carry out the operational modal analysis. The modal properties of the bridge are identified and compared by use of the field monitoring data acquired before and after the earthquake for each type of the events. Research emphasis is given on identifying the predominant modes of the seismic responses in the deck during short-distance, middle-distance and long-distance earthquakes, respectively, and characterizing the response pattern of various structural portions (deck, towers, main cables, etc.) under different types of earthquakes. Since the bridge is over 2,000 m long, the seismic wave would arrive at the tower/anchorage basements of the two side spans at different time instants. The behaviors of structural dynamic responses on the Tsing Yi side span and on the Ma Wan side span under each type of the earthquake events are compared. The results obtained from this study would be beneficial to the seismic design of future long-span bridges to be built around Hong Kong (e.g., the Hong Kong-Zhuhai-Macau Bridge).

• 국제강구조저널
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• 제18권4호
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• pp.1252-1264
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• 2018

Long span bridges such as steel cable stayed and suspension bridges are usually more flexible than short to medium span bridges and expected to have large deformations. Deflections due to live load for long span bridges are important since it controls the overall heights of the bridge for securing the clearance under the bridge and serviceability for securing the comfort of passengers or pedestrians. In case of sea-crossing bridges, the clearance of bridges is determined considering the height of the ship master from the surface of the water, the trim of the ship, the psychological free space, the tide height, and live load deflection. In the design of bridges, live load deflection is limited to a certain value to minimize the vibrations. However, there are not much studies that consider the live load deflection and its effects for long span bridges. The purpose of this study is to investigate the suitability of live load deflection limit and its actual effects on serviceability of bridges for steel cable-stayed and suspension bridges. Analytical study is performed to calculate the natural frequencies and deflections by design live load. Results are compared with various design limits and related studies by Barker et al. (2011) and Saadeghvaziri et al. (2012). Two long span bridges are selected for the case study, Yi Sun-Sin grand bridge (suspension bridge, main span length = 1545 m) and Young-Hung grand bridge (cable stayed bridge, main span length = 240 m). Long-term measured deflection data by GNSS system are collected from Yi Sun-Sin grand bridge and compared with the theoretical values. Probability of exceedance against various deflection limits are calculated from probability distribution of 10-min maximum deflection. The results of the study on the limitation of live load deflection are expected to be useful reference for the design, the proper planning and deflection review of the long span bridges around the world.

• Structural Engineering and Mechanics
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• 제81권3호
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• pp.293-303
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• 2022

As infrastructure ages and traffic load increases, serious public concerns have arisen for the well-being of bridges. The current health monitoring practice focuses on large-scale bridges rather than short span bridges. However, it is critical that more attention should be given to these behind-the-scene bridges. The relevant information about the construction methods and as-built properties are most likely missing. Additionally, since the condition of a bridge has unavoidably changed during service, due to weathering and deterioration, the material properties and boundary conditions would also have changed since its construction. Therefore, it is not appropriate to continue using the design values of the bridge parameters when undertaking any analysis to evaluate bridge performance. It is imperative to update the model, using finite element (FE) analysis to reflect the current structural condition. In this study, a FE model is established to simulate a concrete culvert bridge in New South Wales, Australia. That model, however, contains a number of parameter uncertainties that would compromise the accuracy of analytical results. The model is therefore updated with a neural network (NN) optimisation algorithm incorporating Monte Carlo (MC) simulation to minimise the uncertainties in parameters. The modal frequency and strain responses produced by the updated FE model are compared with the frequency and strain values on-site measured by sensors. The outcome indicates that the NN model updating incorporating MC simulation is a feasible and robust optimisation method for updating numerical models so as to minimise the difference between numerical models and their real-world counterparts.

• 대한토목학회논문집
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• 제36권3호
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• pp.375-384
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• 2016

현행, 도로교설계기준에서는 교량바닥판에 대해 지간이 짧은 다거더 플레이트 거더교 위주의 규정을 두고 있으며, 강합성 소수 거더교에 적용되는 장지간 바닥판에 대한 설계규정은 명확하게 없는 실정이다. 이는 소수 거더교의 장지간 바닥판에 적용하기에는 한계가 있으므로 합리적인 설계를 위해서는 관련 규정을 보완할 필요가 있다. 따라서, 본 연구에서는 내측부 교량바닥판의 지간 6.0~12.0m 범위를 대상으로 도로교설계기준의 KL-510 하중을 적용하여 교축방향(종방향)과 교축직각방향(횡방향)에 대한 설계휨모멘트를 제안하였다. 설계휨모멘트는 바닥판의 직교 이방성, 거더의 강성, 그리고 다차로재하계수의 영향이 반영되었으며, 이를 기존의 DB-24 하중에 대한 설계휨모멘트와 비교하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.509-516
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• 2003

In tile design of base isolation system for building and short-span bridge, shift of the natural period of the structure is main objective. But, most long-span bridges such as a cable-stayed bridges have a number of long-period modes due to their flexibility and small structural damping. thus the design concept of base isolation system for building and short-span brigde may be difficult to use directly to these structures. However, the effectiveness of LRB for cable-stayed bridges is indicated by Ali and Abdel-Ghaffar. In this study, the design procedure and guidelines of LRB for a seismically excited cable-stayed bridge are investigated. The design properties of LRB are chosen that the design index(DI) is minimized or little changed for variation of properties. This result show that the stiffer rubber and bigger lead core size are need to cable-stayed bridges. And the seismic performance of designed LRB is also investigated. The consequences show that the perforamnce of designed LRB is better than that of Naeim-Kelly mettled designning LRB for general building structures. Moreover, the design properties of LRB are researched to several diffrent dominant frequency of earthquake. The results present that the plastic and elastic stiffness of LRB are affected by the dominant frequency of earthquake.