• 한국철도학회논문집
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• 제9권2호
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• pp.160-168
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• 2006

The major objective of this study is to investigate the effects and application of external post-tensioning method far steel plate girder bridge. It analyzed the mechanical behaviors of steel plate girder bridge with applying external post-tensioning on the finite element analysis, field test and laboratory test fur the lateral dynamic characteristics. As a result, the reinforcement of steel plate girder bridge the external post-tensioning method are obviously effective for the lateral dynamic response which is non-reinforced. The analytical and experimental study are carried out to investigate the post-tension force decrease lateral acceleration and deflection on steel plate girder bridge for serviceability. And the external post-tensioning method reduce dynamic maximum displacement(about $10{\sim}24%$), the increase of dynamic safety is predicted by adopting external post-tensioning method. From the dynamic test results of the servicing steel plate girder bridge, it is investigated that the change degree of natural frequency is very low with applying the external post-tensioning method The servicing steel plate girder bridge with external post-tensioning has need of the reasonable reinforcement measures which could be reducing the effect of lateral dynamic behavior that degradation phenomenon of structure by an unusual response characteristic and a drop durability.

• 한국구조물진단유지관리공학회 논문집
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• 제13권4호통권56호
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• pp.137-147
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• 2009

본 논문에서는 프리스트레스트 콘크리트 거더의 긴장력 변화에 따른 몇 가지 휨 진동 응답 특성을 실험적으로 분석하였다. 이를 위해, 먼저 구조물의 진동응답특성을 추출하기 위한 기법들을 선정하였다. 진동응답특성은 기존에 많이 이용되는 고유진동수도 포함하였다. 다음으로, 프리스트레스트 콘크리트 거더의 긴장력과 휨 진동 응답 사이의 관계를 살펴보기 위해 모형 프리스트레스트 콘크리트 거더를 제작하고, 긴장력 변화 시나리오에 따라 진동응답실험을 수행하였다. 마지막으로, 긴장력 변화 시나리오에 따라 취득된 동적응답신호를 이용하여 선정된 진동응답특성 분석기법을 적용하였으며, 긴장력과 휨 진동 응답특성 관계를 분석하였다. 선정된 기법들에 의한 진동응답특성은 전체적으로 긴장력 감소에 따라 감소하는 경향이 있으며, 긴장력 감소가 나타나는 초기에는 비교적 선형적으로 감소하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.954-959
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• 2011

The intensity of train load in the railway bridges is relatively large and continues to repeat. Also, the speed of vehicles is very fast. For these reasons, analyses for dynamic response under train load are necessary in the railway bridges. In other words, the dynamic characteristics of steel-composite bridges under train loads should be investigated considering effects of dynamic responses such as vibrations, repeated displacements and acceleration of bridge members. Therefore, in this study, static and dynamic analyses for the steel box girder bridges and I-girder bridges are carried out. Based on analyses results, we investigated and compared dynamic response considering the impact factors of domestic and foreign design specifications.

• 한국소음진동공학회논문집
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• 제17권7호
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• pp.632-637
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• 2007

The dynamic behavior of two steel bridges crossed by the Korean High Speed Train(KHST) has been investigated experimentally and the results are compared with the specification requirement of BRDM and other typical PSC Box bridge's responses. The investigated bridges are a 2-girder steel bridge of 1@40m span length(E-Won Bridge), 2@50m span length (Ji-Tan Bridge), and a PSC Box girder bridge of 2@40m span length (Yeon-Jae Bridge). A set of experimental tests were performed during operation of KHST, and a number of accelerometers, LVDTs and ring-type displacement transducers were utilized for measurement of three kinds of dynamic responses (acceleration, deflection, and end-rotation angle). Measured responses show that the vertical deflections and end-rotation angles of the three bridges are all satisfying the spec. requirement with large margin, but it was also found acceleration responses which are very close or exceed the limit value. Most of the excessive acceleration responses were found when the passing velocity of the KHST is close to the critical velocity ($V_{cr}$) which causes resonance. No noticeable differences of dynamic responses due to the different materials(steel or concrete) could be found within these experimental results.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.131-137
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• 1996

To perform condition monitoring of P.C. Box girder bridge under ambient traffic, dynamic characteristics were identified using the results of load test an analysis. It was found that natural frequencies obtained from the measured acceleration data for the forced vibration part and free vibration part were nearly identical. Thus it can be concluded that dynamic parameters are properly determined under ambient traffic condition. Finite element model for analysis was calibrated using measured frequencies. Change of dynamic characteristics were predicted through analysis of the established finite element model with anticipated change.

• 대한토목학회논문집
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• 제28권3A호
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• pp.315-322
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• 2008

본 연구에서는 외부 후 긴장 보강 공법을 공용중인 무도상 철도 판형교 보강 방안으로서 적용 할 경우 긴장재 강성 및 도입 긴장력의 크기가 동적 거동 특성 변화에 미치는 영향을 실험 및 해석적으로 평가 하였다. 연구 결과 긴장재 강성에 의해 고유 진동수가 증가하나 긴장력 크기 증가에 의한 고유 진동수 감소에 의해 필요 긴장력 도입시 최종적으로 고유 진동수가 미소하게 감소하는 것으로 나타났으며, 외부 후 긴장력과 고유 진동수 변화 양상에 대한 명확한 관계 정립을 위한 추가적인 연구가 필요한 것으로 나타났다. 또한, 외부 후 긴장에 의해 동적 처짐, 동적 휨 응력 및 중력 방향 가속도가 감소하는 것으로 나타났다. 한편, 외부 후 긴장에 의하여 중력 방향 가속도의 70% 수준인 횡 방향 가속도가 최대 20% 정도 증가하는 것으로 나타나 이에 대한 추가적인 연구가 필요한 것으로 판단된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 춘계학술대회 논문집
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• pp.435-442
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• 2001

A substructural model for a part of a long continuous bridge is identified using measured acceleration at limited locations within the part. Boundary spring constants and structural properties are idenfitied using a system identification method. The proposed method has been examined through simulation studies for static and dynamic responses and the results are discussed in the paper. The method is applied to an actual plate-girder gerber bridge with modal response obtained from a moving truck and construction blasting vibration

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.231-238
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• 1999

The longitudinal dynamic behaviors of the bridge system consisting of multiple simply supported spans under seismic excitations are examined considering pounding effects. The pounding phenomena between adjacent girders which may consequently result in the span collapses are modeled by using the multi-degree-of-freedom system, The inelastic behavior of the RC pier is also considered by adopting the hysteresis loop model and the p-$\delta$ effect. Motions of the foundation and abutment are also considered but the local damage resulting from the girder pounding assumed to be neligible. The developed model is found to give the appropriate information of the dynamic characteristics of the bridge behavior. It is observed that the pounding effect becomes significant as the peak acceleration of the seismic excitation increases. Under minor earthquakes the pounding tends to increase the relative displacements while under strong earthquakes it tends to decrease the relative displacements by restricting the longitudinal girder motions, therefore it is suggested that the pounding effects should be considered in the analysis of the relative displacements of the longitudinally adjacent girder motions.

• 한국정밀공학회지
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• 제16권9호
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• pp.166-171
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• 1999

An overhead crane system consists of trolley, girder, rope, object, trolley motor, girder motor, and hoist motor. An analytic model which derived from the modelling of the overhead crane system is nonlinear model which includes the swing and the twist angle of the object. this model consists of the equation of motion for motors and object. If the swing angle and the acceleration of Z for the object are small, this model becomes a simple nonlinear model which doesn't include the swing and the twist angle of the object. From the results of computer simulation, the characteristics of an actual overhead crane system could be predicted by the simple nonlinear model.

• Structural Monitoring and Maintenance
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• 제7권2호
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• pp.149-166
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• 2020

This paper presents the results of an experimental investigation on a vibration-based damage identification framework for a steel girder type and a truss bridge based on acceleration responses to operational loading. The method relies on sensor clustering-based time-series analysis of the operational acceleration response of the bridge to the passage of a moving vehicle. The results are presented in terms of Damage Features from each sensor, which are obtained by comparing the actual acceleration response from the sensors to the predicted response from the time-series model. The damage in the bridge is detected by observing the change in damage features of the bridge as structural changes occur in the bridge. The relative severity of the damage can also be quantitatively assessed by observing the magnitude of the changes in the damage features. The experimental results show the potential usefulness of the proposed method for future applications on condition assessment of real-life bridge infrastructures.