• 한국해양공학회지
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• 제18권1호
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• pp.22-27
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• 2004

An orthotropic steel deck system is widely adapted form for a long-span bridge. It has many advantages, such as the big reduction of dead weight, the simplicity for erection, and the reduction of the construction period. However, an orthotropic steel deck system requires a lot of welding work, which may result in defects and deformation of connection. Therefore, the research for the general behavior and fatigue strength of the several details in orthotropic steel deck bridge is necessary. The fatigue failure with distortion results from secondary stress by out-of-plane deformation; these kinds of cracks are very difficult to measure, and can not be precisely calculated through finite element analysis. This stress concentration phenomenon generates the fatigue failure around the lower scallop of the transverse rib. This paper presents improved details of the intersection between the longitudinal rib and the transverse rib of an orthotropic steel deck bridge by the third dimensional hit size test, and the finite element method, which can minimize local stress through parametric study.

• Wind and Structures
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• 제19권2호
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• pp.145-167
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• 2014

Wind-vehicle-bridge (WVB) interaction can be regarded as a coupled vibration system. Aerodynamic forces and moment on vehicles and bridge decks play an important role in the vibration analysis of the coupled WVB system. High-speed vehicle motion has certain effects on the aerodynamic characteristics of a vehicle-bridge system under crosswinds, but it is not taken into account in most previous studies. In this study, a new testing system with a moving vehicle model was developed to directly measure the aerodynamic forces and moment on the vehicle and bridge deck when the vehicle model moved on the bridge deck under crosswinds in a large wind tunnel. The testing system, with a total length of 18.0 m, consisted of three main parts: vehicle-bridge model system, motion system and signal measuring system. The wind speed, vehicle speed, test objects and relative position of the vehicle to the bridge deck could be easily altered for different test cases. The aerodynamic forces and moment on the moving vehicle and bridge deck were measured utilizing the new testing system. The effects of the vehicle speed, wind yaw angle, rail track position and vehicle type on the aerodynamic characteristics of the vehicle and bridge deck were investigated. In addition, a data processing method was proposed according to the characteristics of the dynamic testing signals to determine the variations of aerodynamic forces and moment on the moving vehicle and bridge deck. Three-car and single-car models were employed as the moving rail vehicle model and road vehicle model, respectively. The results indicate that the drag and lift coefficients of the vehicle tend to increase with the increase of the vehicle speed and the decrease of the resultant wind yaw angle and that the vehicle speed has more significant effect on the aerodynamic coefficients of the single-car model than on those of the three-car model. This study also reveals that the aerodynamic coefficients of the vehicle and bridge deck are strongly influenced by the rail track positions, while the aerodynamic coefficients of the bridge deck are insensitive to the vehicle speed or resultant wind yaw angle.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.739-744
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• 2001

The concrete bridge deck is quitely required to be replaced or strengthened due to decreasing load carrying capacity. In this study, to increase load capacity of the reinforced concrete slab, bridge deck is reinforced with the glass fiber sheets. they are examined on the strengthen effect and the static behavior, This paper considers relation of load-displacement and strain-distance. The static behavior of the slab strengthened is represented to maximum load. Owing to that, they are examined on increasing load carrying capacity of reinforced bridge deck and strengthen effect about on the crack.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.697-700
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• 2000

Fatigue damage to reinforced concrete bridge decks have been found in many bridges. Failure mode of most reinforced concrete decks is caused by local punching shear rather than flexural moment due to cumulated damage. In this study, mechanical degradation of unstrengthened and strengthened bridge deck specimens is experimentally investigated. The unstrengthened deck specimens were damaged under the pulsating loading condition. After the test, deteriorated deck specimens were strengthened with Carbon Fiber Sheet, then loaded to observe the improvement of the fatigue behavior. It is shown that fatigue damaged specimens are similar to real bridge rather than static damaged specimens.

• 한국도로학회논문집
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• 제10권3호
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• pp.189-197
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• 2008

본 연구는 2003년도부터 2007년도까지의 고속도로 포장관리시스템 운영에 의한 포장상태 측정자료를 이용하여 고속도로 교량부 평탄성 불량 구간과 그 원인을 조사 분석하여 도로교량 구간 평탄성을 향상시킬 수 있도록 관리체계를 개선하고 교량평탄성 불량구간이 효과적으로 유지보수 될 수 있도록 하는데 중점을 두었다. 고속도로 포장유지관리 시스템으로부터 추출한 데이터 분석과 이에 대한 현장 검증 결과, 교량구간의 평탄성이 토공부에 비해 상당히 좋지 않은 것으로 분석되었다. 그 원인과 개선방안에 대해 살펴보면, 교량구간의 평탄성 불량 원인은 교면포장(접속부 포함)의 조기손상뿐만 아니라 뒷채움부 침하에 의한 접속부 포장의 단차가 주요 원인인 것으로 분석되었다. 이에 따라 교량구간은 현재 정기적으로 시행하고 있는 조사장비에 의한 포장상태 측정과 병행하여 뒷채움부 침하가 원인인 단차를 측정하여 교량구간의 평탄성 불량지점을 효과적으로 개선할 수 있도록 조사 및 평가체계를 수립하였다.

• Wind and Structures
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• 제32권4호
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• pp.293-308
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• 2021

For the past three decades a significant amount of research has been conducted on bridge flutter. Wind tunnel tests for a 2000 m class twin-box suspension bridge have revealed that a twin-box deck carrying 4 m tall 50% open area ratio wind screens at the deck edges achieved higher critical wind speeds for onset of flutter than a similar deck without wind screens. A result at odds with the well-known behavior for the mono-box deck. The wind tunnel tests also revealed that the critical flutter wind speed increased if the bridge deck assumed a nose-up twist relative to horizontal when exposed to high wind speeds - a phenomenon termed the "nose-up" effect. Static wind tunnel tests of this twin-box cross section revealed a positive moment coefficient at 0° angle of attack as well as a positive moment slope, ensuring that the elastically supported deck would always meet the mean wind flow at ever increasing mean angles of attack for increasing wind speeds. The aerodynamic action of the wind screens on the twin-box bridge girder is believed to create the observed nose-up aerodynamic moment at 0° angle of attack. The present paper reviews the findings of the wind tunnel tests with a view to gain physical insight into the "nose-up" effect and to establish a theoretical model based on numerical simulations allowing flutter predictions for the twin-box bridge girder.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.922-927
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• 2006

There is a concern with worldwide deterioration of highway bridges, particularly reinforced concrete. The advantages of fibre reinforced plastic(FRP) composites over conventional materials motivate their use in highway bridges for replacement of structures. Recently, an FRP deck has been installed on a state highway, located in New York State, as an experimental project. In this paper, a systematic approach for analysis of this FRP deck bridge is presented. Multi-step linear numerical analyses have been performed using the finite element method to study the structural behavior and the possible failure mechanism of the FRP deck-superstructure system Deck's self-weight and ply orientations at the interface between steel girders and FRP deck are considered in this study. From this research, the results of the numerical analyses were corroborated with field test results. Analytical results reveal several potential failure mechanism for the FRP deck and truss bridge system The results presented in this study may be used to propose engineering design guideline for new and replacement FRP bridge deck structure.

• Computers and Concrete
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• 제23권5호
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• pp.329-334
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• 2019

Traffic flow capacity of some old road bridges is insufficient due to limited deck width. In such cases bridge deck widening is a common solution. For multi-girder reinforced concrete (RC) bridges it is possible to add steel-concrete composite girders as the new outermost girders. The deck widening may be combined with bridge strengthening thanks to thickening of the existing deck slab. Joint action of the existing and the added parts of such bridge span must be ensured. It refers especially to the horizontal plane at the interface of the existing slab and the added concrete layer as well as to the vertical planes at the external surfaces of the initially outermost girders where the added girders are connected to the existing bridge span. Since the distribution of the added concrete is non-uniform in the span cross-section the structure is particularly sensitive to the added concrete shrinkage. The shrinkage induces shear forces in the aforementioned planes. Widening of a 12 m long RC multi-girder bridge span is numerically analysed to assess the influence of the added concrete shrinkage. The analysis results show that: a) in the vertical plane of the connection of the added and the existing deck slab the longitudinal shear due to the shrinkage of the added concrete is comparable with the effect of live load, b) it is necessary to provide appropriate longitudinal reinforcement in the deck slab over the added girders due to tension induced by the shrinkage of the added concrete.

• 한국도로학회논문집
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• 제10권1호
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• pp.11-18
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• 2008

본 논문은 하중재하시 강상판교의 방수층과 교면포장에서 발생하는 거동을 유한요소해석을 통하여 분석하였다. 포장표면에 연직방향으로 작용하는 차량하중과 수평방향으로 작용하는 차량의 제동하중의 크기에 따른 포장체와 방수시트에 발생되는 응력을 산정하였다. 그리고 강상판 두께 및 강성. 포장층 두께, 차량제동하중, 온도 등의 변수가 포장체의 응력변화에 어떠한 영향을 미치는지에 대하여 분석하였다. 방수층의 전단응력은 강상판의 두께가 얇아지고 강성이 감소할수록 증가하였으며, 강상판의 두께가 150mm이상의 경우와 탄성계수가 $2{\times}10^{5}MPa$이상의 경우에는 그 영향이 미비하였다 또한 교면 포장의 두께가 얇아지고 온도가 낮아질수록 방수층의 전단응력이 증가하였다. 포장체 하부에서 발생하는 인장변형률은 고온에서 최대가 되었으며 두께가 증가할수록 감소하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.545-550
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• 2007

Due to many advantages such as lightweight, high durability and speedy construction, increasing number of bridges of various girder types are being built recently with glass-fiber reinforced composite deck. A profile of the composite deck, called 'Delta deck', is developed which has 3 trapezoidal cells of 200mm depth. This paper introduces how to develop 'Delta deck' and its application to the world largest composite-deck bridge, which is 300m long and 35m wide and is currently under construction.