• Structural Engineering and Mechanics
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• 제72권4호
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• pp.421-432
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• 2019

In high-speed railway (HSR) system, the structure-borne noise inside viaduct at low frequency has been extensively investigated for its mitigation as a research hotspot owing to its harm to the nearby residents. This study proposed a novel acoustic optimization method for declining the structure-borne noise in viaduct-like structures by separating the acoustic contribution of each structural component in the measured acoustic field. The structural vibration and related acoustic sourcing, propagation, and radiation characteristics for the viaduct box girder under passing vehicle loading are studied by incorporating Finite Element Method (FEM) with Modal Acoustic Vector (MAV) analysis. Based on the Modal Acoustic Transfer Vector (MATV), the structural vibration mode that contributes maximum to the structure-borne noise shall be hereinafter filtered for the acoustic radiation. With vibration mode shapes, the locations of maximum amplitudes for being ribbed to mitigate the structure-borne noise are then obtained, and the structure-borne noise mitigation performance shall be eventually analyzed regarding to the ribbing conduction. The results demonstrate that the structural vibration and structure-borne noise of the viaduct box girder mainly occupy both in the range within 100 Hz, and the dominant frequency bands both are [31.5, 80] Hz. The peak frequency for the structure-borne noise of the viaduct box girder is mainly caused by $16^{th}$ and $62^{th}$ vibration modes; these two mode shapes mainly reflect the local vibration of the wing plate and top plate. By introducing web plate at the maximum amplitude of main mode shapes that contribute most to the acoustic modal contribution factors, the acoustic pressure peaks at the field-testing points are hereinafter obviously declined, this implies that the structure-borne noise mitigation performance is relatively promising for the viaduct.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.294-297
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• 2006

The purpose of this study is to introduce design practice for prestressed concrete box girder with AASHTO LRFD Design Specification. Distinctive features of viaduct girder of Incheon Bridge are pre-tensioned transverse tendon, 3-dim. transverse analysis, enlarged opening in diaphragm and so on.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.159-166
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• 1998

To study temperature effect of P.C. box girder bridge, field measurement was performed for six months, along with thermal analysis for the newly constructed viaduct of Gangbyun Highway in Seoul. Thermocouples were installed inside and surface of the flange and web of the box and temperature of box section md ambient temperature was measured. Measured environmental data are incorporated in finite element thermal analysis and computed temperature of the section was compared with measured one. Temperature gradient from thermal analysis was compared with Korean Highway Specification(1996)and the New Zealand Ministry of Works and Development code(1976). Thermal stress distribution across the box section was also compared.

• Interaction and multiscale mechanics
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• 제3권4호
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• pp.373-387
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• 2010

This study is intended to assess low frequency sound radiated from a viaduct under normal traffic. The bridge comprises steel box girders and wide cantilever decks on which vehicles pass. The low frequency sound and the acceleration response of the bridge under normal traffic are measured to investigate how bridge vibrations affect the low frequency sound observed near the bridge. Observations demonstrate that strong relationships exist between frequency characteristic of bridge's acceleration response and the sound pressure level of low frequency sound. A noteworthy point is that the dynamic feature of the sound pressure level is mostly affected by dynamic feature of the span locating near the observation point.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.507-518
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• 2020

With the rapid development of rail transit, rail transit noise needs to be paid more and more attention. In order to accurately and effectively analyze the characteristics of low-frequency noise, a prediction model of vibration of box girder was established based on the hybrid FE-SEA method. When the train speed is 140 km/h, 200 km/h and 250 km/h, the vibration and noise of the box girder induced by the vertical wheel-rail interaction in the frequency range of 20-500 Hz are analyzed. Detailed analysis of the energy level, sound pressure contribution, modal analysis and vibration loss power of each slab at the operating speed of 140 km /h. The results show that: (1) When the train runs at a speed of 140km/h, the roof contributes more to the sound pressure at the far sound field point. Analyzing the frequency range from 20 to 500 Hz: The top plate plays a very important role in controlling sound pressure, contributing up to 70% of the sound pressure at peak frequencies. (2) When the train is traveling at various speeds, the maximum amplitude of structural vibration and noise generated by the viaduct occurs at 50 Hz. The vibration acceleration of the box beam at the far field point and near field point is mainly concentrated in the frequency range of 31.5-100 Hz, which is consistent with the dominant frequency band of wheel-rail force. Therefore, the main frequency of reducing the vibration and noise of the box beam is 31.5-100 Hz. (3) The vibration energy level and sound pressure level of the box bridge at different speeds are basically the same. The laws of vibration energy and sound pressure follow the rules below: web

• Structural Engineering and Mechanics
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• 제47권5호
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• pp.661-678
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• 2013

As a new type of vibration reduction, the ladder track system has been successfully used in engineering. In this paper, a numerical model of the train-track-viaduct system is established to study the dynamic responses of an elevated bridge with ladder track. The system is composed of a vehicle submodel, a track submodel and a bridge submodel, with the measured track irregularities as the system self-excitation. The whole time histories of a train running through an elevated bridge with $3{\times}27m$ continuous PC box girders are simulated. The dynamic responses of the bridge such as deflections, lateral and vertical accelerations, and the vehicle responses such as derailment factors, offload factors and car-body accelerations are calculated. The calculated results are partly validated through the comparison with the experimental data. Compared to the common slab track, adapting the ladder sleeper can effectively reduce the accelerations of the bridge girder, and also reduce the car-body accelerations and offload factors of the train vehicle.

• 한국강구조학회 논문집
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• 제9권3호통권32호
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• pp.431-440
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• 1997

본 논문에서는 교량 단면 내의 시간 종속적 온도 분포를 결정하기 위해, 기존의 열 전달 이론 및 태양 에너지 전달에 대한 이론을 바탕으로 기상관측소 및 현장에서 측정한 기상 자료로부터 교량 온도의 예측에 관한 이론적 모델에 대해 기술하였다. 특히 이 모텔에서는 주간에 교량의 온도 상승에 지배적인 영향을 미치는 태양일사(solar radiation)에 대해 태양 에너지 관련 분야의 여러 실험적 연구 결과를 바탕으로 태양일사량의 계산에 대해 기존에 연구되어 있는 식들 중에서 가장 적합한 식을 제시하였다. 이 해석 모델의 타당성은 사당 고가차도의 장기 계측된 온도 측정 결과와 비교 검토되었다. 또한 장기간 측정된 온도 결과로부터 교량 온도 예측에 대한 해석적 기준(analytical criteria)을 제시하기 위해, 교량의 축 방향 신축의 원인이 되는 단면평균온도, 그리고 곡률 변형을 유발하는 단면온도차 등 교량 단면의 온도 분포와 관련된 변수들과 대기온도, 일사량 등 기상 자료와 관련된 변수들 간의 선형 상관관계(linear correlation)에 대해 기술하였다.