• International Journal of Railway
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• 제5권1호
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• pp.10-21
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• 2012

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.160-165
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• 1998

A theoretical analysis has been undertaken to show the influence of bearing geometry on the steady state characteristics of air lubricated spherical tilting pad bearings. The geometry variations considered are the number of pads, the eccentricity ratio, the direction of load, and the preloading.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1450-1459
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• 2007

Line type rigid bearings for Open-Steel-Plate-Girder railway bridges have several problem in service, and they are unstable structurally. Thus, spherical bearings having advanced maintenance capability and device to resistance up-lift are developed and replace the existing ones. A experiment of maintenance for a new placed spherical bearings under real Open-Steel-Plate-Girder bridge is conducted and their good maintenance performance is proved. The dynamic behavior of the bridge is measured and analyzed for the two cases of the existing and replacing bearings. Therefore, the effect of the new spherical bearings on the railway bridge is assessed.

• Structural Engineering and Mechanics
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• 제73권2호
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• pp.123-132
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• 2020

Steel spherical hinged bearings have high loading capacity, reliable load transfer, flexible rotation with universal hinge and allowance of large displacement and rotation angle. However, bearings are in complex forced states subject to various load combinations, which lead to the significant influence on integral structural safety. Taking the large-tonnage complex steel spherical hinged bearings of Terminal 2 of Guangzhou Baiyun International Airport as an example, full-scale rotation and shear behaviour tests of the bearings subject to axial tensile load are carried out, and the corresponding finite element simulation analyses are conducted. The results of experiments and finite element simulations are in good agreement with the coincident development tendency of stress and deformation. In addition, the measured rotational moment is less than the calculated moment prescriptive by the code, and the relationship between horizontal displacement and horizontal shear force is linear. Finally, based on these results, the rotation and shear stiffness models of bearings subject to axial tensile load are proposed for the refinement analysis of integral structure.

• Tribology and Lubricants
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• 제17권2호
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• pp.116-123
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• 2001

A theoretical analysis has been undertaken to show the influence of bearing geometry on the steady state characteristics of air lubricated spherical tilting pad bearings. The geometry variations considered are the number of pads, the eccentricity ratio, the direction of load, and the preloading. Dynamic characteristic equations are derived with pad assembly method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1729-1734
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• 2008

This study developed a new separated shperical bridge bearing that can be used for replacement of existing bridge bearings without crushing bearing-concrete. The separated spherical bearing have the upper and lower sole plate connected by bolts to the upper plate under bridge-girders and the lower plate on bearing-concrete. The targets of the separated spherical bearing are the maximum 3 mm of up-lifting height during replacement and the maximum required time of 30 minutes. Four separated spherical bearings are manufactured and replaced the existing bearings of a railway bridge in service and the replacing tests was performed. The number of the tests is two and the target of maximum 3 mm and 30 minutes was satisfied.

• 한국철도학회논문집
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• 제15권1호
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• pp.62-70
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• 2012

철도 판형교의 선받침, 스페리칼받침 및 디스크받침의 차량주행에 의한 동적 거동을 측정 분석 하고, 각 받침에 따른 판형교의 동적 거동을 분석하였다. 이를 위해 각 받침은 고정단과 가동단의 형태에 따라 차량주행에 의한 수직변위가 측정되었고, 비교 분석하였다. 또한, 가동단의 스페리칼받침과 디스크받침의 내부에 설치된 PTFE판의 변형 및 이 변형이 교량의 거동에 미치는 영향을 분석하였다. 판형교에 설치된 교량받침에서 들림 현상이 관측되는데, 받침 형태에 따른 들림량을 분석하였다. 중앙 거더의 수직변위를 교량받침 별로 비교하여 교량받침 교체에 의한 교량 수직변위 변화를 분석하였으며, 각 받침에 따른 중앙 거더의 수직변위와 고유진동수의 변화를 상관적으로 분석하여 설명하였다.

• 한국철도학회논문집
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• 제11권2호
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• pp.165-175
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• 2008

철도판형교에 있어 선받침은 사용 중에 많은 문제를 야기하고 있으며, 구조적으로 불안정하다. 기존 선받침의 문제점을 파악하기 위해 수평저항능력 실험을 수행하였다. 유지보수에 용이하고 들림현상에 저항할 수 있는 개선된 스페리칼받침을 개발하여 기존받침을 교체하였다. 개선된 스페리칼받침의 교체성능 실험과 부반력 저항능력 실험이 수행되어, 유지보수 성능 및 부반력 저항능력이 증명되었다. 선받침 상태 및 스페리칼받침으로 교체된 상태에서 판형교의 동적 거동 및 각 교량받침의 동적 거동을 계측하여 거동의 차이를 분석하였다. 이러한 실험 및 분석을 통하여 개선된 스페리칼받침이 철도 판형교에 교량받침으로 사용하기에 적합함을 알 수 있었다.

• Tribology and Lubricants
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• 제30권6호
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• pp.350-355
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• 2014

This study proposes a sustainable bearing remanufacturing process using the ultrasonic nanocrystal surface modification (UNSM) technique. The UNSM technique is a newly developed and sophisticated surface modification technique that can increase the mechanical properties and improve the friction and wear performance of materials. Taking advantage of the bearing manufacturing process is the most significant way of optimizing the life of a bearing. The proper maintenance and usage of repaired bearings can increase their life to be equal to or greater than that of new bearings. This paper discusses the restoration of certain mechanical properties of worn, damaged, and discarded bearings, and suggests a remanufacturing process for used bearings, which can impart them with a lifespan equivalent to that of new bearings. The most damaged part of the discarded bearings is the raceway, which is the site of accumulated fatigue. The existing polishing or barrel finishing processes can recover the accumulated fatigue only partially. Rolling contact fatigue tests performed on UNSM-treated new and used specimens polished after $4{\times}10^6$ cycles reveal that UNSM-treated new specimens exhibit the longest fatigue life compared to other specimens. This study verifies the proposed complete fatigue recovery process, which can increase the fatigue life of used bearings to a level greater than that of new bearings.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.589-592
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• 2009

In this paper is presenting the shape design and elastomer bearings, which functioned as a joint connecting sub-structures and upper-structures with a railway bridge bearing systems. The elastomeric spherical bearing shaped and composed of alternated 17-layered metal shim plates and 18-layered elastomer plates, respectively. The elastomeric spherical bearing a high compressive load for perpendicular axis to layered plates and flexible motions are provided coincidently for other axes. The three types of elastomers, which were developed due to a designed shear modules were applied. Nonlinear analysis based on the material properties of designed bearing were accomplished. Therefore, the Nonlinear Analysis results were compared with the calculation results and the optimized shapes were designed.