• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.777-784
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• 2000

During past earthquakes several bridges have failed due to a loss of support at their bearings, seats, and/or expansion joints. Most efforts to prevent this have been directed toward tying bridges together at their bearings and expansion joints. Longitudinal restrainers are installed to limit the relative displacement at joints and thus decrease the chance of a loss of support as these locations. Transverse restrainers are necessary in many cases to keep the superstructure from sliding off in the transverse direction. Vertical restrainers are used at bearings to prevent uplifting deck, but usually not economically justified unless additional bearing retrofit is being performed. To obtain this three function of restrainer, a universal restrainer is developed. The load capacities were evaluated in static and dynamic experimental test. The test results show that the measured capacity or strength of the bridge deck restrainer is similar to that of design value.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.159-165
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• 1998

중트럭 통행으로 인한 철근콘크리트 교량바닥판의 열화는 교량구조물을 유지보수하는데 있어 심각한 문제 중 하나이며, 프리캐스트 바닥판을 이용한 교량바닥판의 시공 및 교체 방법이 실용적이며 효과적인 방법으로 인식되고 있다. 본 연구에서는 횡방향 ddusruf부에 종방향 프리스트레싱을 도입한 프리캐스트 바닥판의 모델을 제작하여 바닥판간 횡방향 연결부의 강성 평가 및 연결부의 피로 거동을 파악하기 위해서 피로실험을 수행하여 피로하중하에서의 휨강성의 변화, 균열발생 및 파괴하중 등을 측정하였다. 실험결과를 통해서 피로하중하에서 프리스트레스 프리캐스트 부재의 프리스트레스 효과를 평가하였으며, 현장타설에 의해서 시공되는 일반 RC 부재에 비해서 우수한 구조적 거동을 보여주는 적정량의 종방향 프리스트레스 크기를 결정하였다.

• International Journal of Concrete Structures and Materials
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• v.7 no.1
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• pp.79-93
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• 2013

One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits liveload deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.329-330
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• 2008

The 181,000 DWT Bulk Carrier has a different deck house type, which is not typical for previous bulk carriers, to meet the new international rules for bulk carriers. This new deck house has much smaller transverse breadth than the hull's transverse breath, resulting in large levels of the transverse response of the deck house. In addition, the longitudinal response of the funnel showed rather a large magnitude of vibration, which are excited by the ship's main excitations such as the main engine H-moment and the propeller surface forte when the ship operates at the NCR and the MCR speeds In the ballast condition. To solve these issues, the global forced vibration analysis has been performed for the ship and the ship structure has been modified to reduce the vibration level by increasing the girder depth and adjusting the engine room tank arrangement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.251-255
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• 2012

Structural intensity has been mainly utilized to identify vibration energy flow in a vessel. In this paper, the structural intensity of a shuttle tanker subjected to H-moment of the main engine was calculated using a finite element model. From the analysis, it was found that the top-bracing elements, which support the main engine onto the hull structure to prevent the excessive transverse vibration of the main engine, play the role of the dominant path and sink for vibration energy flow from the main engine. Therefore, the structural intensity was controlled by the modification of stiffness and damping characteristics of the top-bracing elements. As a result, it is observed that the transverse vibration level at the center of navigation bridge deck decreased after the control of structural intensity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.73-83
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• 2006

The failure mechanism of a hollow bridge deck which is made of fiber reinforced polymer (FRP) to improve its durability and life time significantly is investigated using both experiments and analyses. While the Load-displacement behavior of the deck in the longitudinal direction is almost linear just before the failure, the behavior in the transverse direction shows a strong nonlinearity even in its initial response with relatively small magnitude of loads. We found that the nonlinearity is due to the imperfection of the connection between the flange and the web; a plastic deformation can t라e place in the connection. The argument is demonstrated using a simple structural model in which a rigid plastic hinge is introduced to the connection. We also checked the contribution of the delamination mechanism to the failure. But the delamination is not the main mechanism which initiates and causes the failure of the bridge deck. In order to improved the structural behavior of the deck in the transverse direction, we suggested that the empty space of the bridge deck is filled with a foam and confirmed the improved behavior by a numerical analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.433-445
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• 2009

The panels are used as a composite part of the completed deck. They replace the main bottom transverse deck reinforcement and also serve as a form surface for the cast-in-place concrete upper layer that contains the top of deck reinforcement. Research has also demonstrated that mechanical shear ties on the top of the panels are required. In a composite deck with precast panels, it is required to notice behavior of transverse joints between panels. In this paper, static tests of composite deck with shear ties and loop joints were conducted. From the results, the validity of loop joints for continuity of deck was observed. Also, a composite behavior was abserved between precast panel and slab concrete. Tested composite decks with shear ties have 140~164% ultimate strength than have no shear ties due to the increase of composite action. Therefore, the shear ties between the slabs were sufficient to enforce composite flexural behavior to failure.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.493-496
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• 2008

The risk of transverse cracking in concrete decks of composite bridges is affected by many factors related to the bridge design, materials, and construction. Among others, the thermal and shrinkage stresses are the most important factors that affect the transverse cracking in early-age concrete decks. The thermal stress at the concrete deck is mainly affected by both ambient temperature and solar radiation. The shrinkage stress at the general strength concrete deck is mainly affected by drying shrinkage and the high strength concrete deck is mainly affected by autogeneous shrinkage. Three-dimensional finite element models of composite bridges were made to investigate the stress due to thermal and shrinkage stress.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.333-339
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• 2003

Recently, the bridges become greater according to development of a construction technology. This phenomenon requires long span bridge, so that increases the dead weight. The orthotropic steel deck bridges have much advantages such as the light dead weight and the reduction of construction period. And almost whole process of carried out is manufactured at factory, so it can cause the increase of quality authoritativeness. But orthotropic steel deck bridge is consist of structure by welding, it can not avoid a lot of welding jobs, defects and transformation by welding are becoming problem accordingly. Specially, topical stress concentration phenomenon in cross connection area of longitudinal and transverse rib causes fatigue failure. The Bulkhead Plate for prevention of this stress concentration phenomenon was applied by changing the orthotropic steel deck of Williamsburg bridge in USA. But, it is principle that a Bulkhead Plate is not established in the domestic design standard. Therefore, it is estimated that the study for installation of Bulkhead Plate is needed. This treatise with considering these circumstances proves efficiency of Bulkhead Plate and will be presented optimal design details through finite element analysis according to change the geometrical of Bulkhead Plate and tile cross-connection area of longitudinal and transverse rib.

• Wind and Structures
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• v.6 no.1
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• pp.53-70
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• 2003

Tsing Ma Bridge in Hong Kong is the longest suspension bridge in the world carrying both highway and railway. It has two H-shape concrete towers, each of which is composed of two reinforced concrete legs and four deep transverse prestressed concrete beams. A series of wind tunnel tests have been performed to measure the aerodynamic coefficients of the tower legs and transverse beams in various arrangements. A 1:100 scaled 3D rigid model of the full bridge tower assembled from various tower components has been constructed for different test cases. The aerodynamic coefficients of the lower and upper segments of the windward and leeward tower legs and those of the transverse beams at different levels, with and without the dummy bridge deck model, were measured as a function of yaw wind angle. The effects of wind interference among the tower components and the influence of the bridge deck on the tower aerodynamic coefficients were also investigated. The results achieved can be used as the pertinent data for the comparison of the computed and field-measured fully coupled buffeting responses of the entire bridge under yaw winds.