교량받침 하부의 공극(공동)이 교량받침에 미치는 영향에 관한 연구

서일우(Il-Woo Seo),조영선(Young-Sun Cho),최동철(Dong-Chul Choi),원용덕(Young-Duk Won),임보람(Bo-Ram Yim) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.10

교량받침은 교량상부 구조물과 하부 구조물 사이에 위치하여 교량상부구조물의 하중을 지지하고 온도변화, 풍하중과 같은 수평변위를 수용하며, 차량통과하중에 의한 회전변형을 수용하는 장치이다. 교량받침의 가설은 교량받침을 교대 및 교각 위에 거치시키고 몰탈을 타설하여 설치하게 되는데 교량받침 하판은 평면으로 구성되어 있어 몰탈이 차오름에 따라 하판을 한번에 덮어 미쳐 빠져나가지 못하고 갇힌 공기로 인하여 공동이 형성된다. 이러한 현상은 현장에서 자주 발생되고 있고 교량받침의 크기가 클수록 더 큰 공동이 형성된다. 이에 따라 교량받침 하부의 공동, 공극이 교량받침에 미치는 영향에 대하여 연구하였고 그에 대한 대책인 공극방지시스템(돔플레이트)에 대해서 소개하였다. Bridge bearing is located between bridge supper structure and under structure. It supports vertical load of bridge supper structure, accepts horizontal displacement by wind load or temperature and rotational deformation by vehicle load. Normally bridge bearing is installed by placing mortar on under structure. With mortar fill up, confined air caused by plat under plate of bearing makes void in concrete under bearing. It means that the size of bearing is bigger, the void in concrete of size bigger. The void caused by plat shape of under plat of bearing often appeared in many construction site. Therefore we studied on influence to bridge bearing by void in concrete under bridge bearing and also introduced void preventing system(dome plate) for measure of void in concrete.

EP(Engineering Plastic)를 적용한 스페리컬 받침의 개발

윤한울(Hanul Yun),지용수(Yongsu Ji),이유인(Youin Lee),임강섭(Kangsup Lim),박재일(Jaeil Park) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.11

오늘날 교량받침으로 사용하고 있는 제품은 크게 고무받침, 포트받침, 우레탄받침 그리고 스페리컬 받침이다. 이중 철도교량으로 가장 많이 쓰이고 있는 제품으로는 고력황동 스페리컬 받침이 있다. 고력황동 스페리컬 받침은 다른 교량 받침에 비하여 큰 회전수용 능력, 연직 하중에 대한 작은 처짐량 그리고 부반력 기능을 가지고 있다. 하지만 오늘날 사용되고 있는 고력황동 스페리컬 받침은 1990년대 초에 일본에서 개발된 오래된 제품으로 다른 것들의 성능에 비하여 가격이 높고 그 크기가 크기 때문에 철도교량을 제외하고는 거의 사용되지 않고 있다. 또한 미끌림 요소인 STS 판과 고력황동은 모두 금속계열 재료이기 때문에 부식에 대한 위험성이 존재하고 있다. 따라서 이러한 단점을 보완하기 위하여, 고력황동이 아닌 Engineering Plastic을 사용하여 새로운 스페리컬 받침을 개발하였으며, 그 구조를 최적화 하여 Engineering Plastic Spherical Bearing(이하 ESB)을 실용화 하였다. Recently, bearings have been applied for the bridge are Rubber Bearing, Pot bearing, Urethane bearing and spherical bearing. Among them, High strength brass Spherical bearing has been predominantly used as a railway bridge bearing. High strength brass Spherical bearing has larger rotational capacity and lower deflection about the vertical load than other bearing’s and function to prevent negative reaction force. But High strength brass Spherical bearing developed in Japan in the early 1990s are not almost used in bridge except railway bridge because it has high price and big size comparing with the equivalent performance of others. It always exists dangerous about corrosion. Friction elements of STS plate and High strength brass are all metallic materials as well. Therefore the new spherical bearing was developed to improve its disadvantage with using not High strength brass but EP(Engineering Plastic). We optimized structural composition of the bearing and commercialized Engineering Plastic spherical Bearing(below called ESB).

교량받침용 세라믹 마찰재 적용을 위한 실험적 연구

박지훈,이정우,곽종원 한국건설순환자원학회 2023 한국건설순환자원학회 논문집 Vol.11 No.4

This paper conducted a study on the application of ceramic materials for bridge bearing that can complement the durability of PTFE, a conventional bridge bearing friction material, and exhibit low coefficient of friction and friction behavior without lubricant. The ceramic material was zirconia (ZrO₂), and the friction behavior was evaluated according to the roughness coefficient. The roughness coefficient was divided into 0.8 and 0.027, and the average coefficient of friction was calculated to be 0.16 under 15 MPa surface pressure. Afterward, ceramic was made into friction material and applied to the bridge bearing, and performance comparison with PTFE bridge bearing was conducted through compression test and friction test. In the compression test, the ceramic and PTFE bridge bearing showed ideal compression behavior depending on the load. No fractures or defects were observed in the ceramic bridg bearing, but lubricant loss was observed in the PTFE bridge bearing. The average coefficient of friction of the ceramic bridge bearing analyzed through friction behavior was 0.16. The inherent material properties of the physical and chemical properties of ceramics, the excellent mechanical properties derived from the performance evaluation, and the coefficient of friction of 0.16 suggest that it can be considered as a friction material. 본 논문은 기존의 교량받침 마찰재인 PTFE의 내구성을 보완하고 낮은 마찰계수 발현 및 윤활제 미사용에서 마찰거동을할 수 있는 세라믹 소재의 교량받침 적용을 위한 연구를 수행하였다. 세라믹 소재는 지르코니아계(ZrO₂)를 설정하였으며, 조도계수에 따른 마찰거동 평가를 수행하였다. 조도계수는 0.8 및 0.027로 구분하였으며, 15 MPa 면압조건에서 평균마찰계수는 모두 0.16으로 산정되었다. 이후, 세라믹을 마찰재로 제작하여 교량받침에 적용하였으며, PTFE 적용 교량받침과의 압축실험 및 마찰실험을 통해 성능비교를 수행하였다. 압축실험에서 세라믹 및 PTFE 적용 교량받침은 하중 재하에 따라 이상적인압축거동을 나타냈다. 세라믹 적용 교량받침은 파손 및 결함이 관찰되지 않았지만, PTFE 적용 교량받침에서는 윤활제 소실이관찰되었다. 마찰거동을 통해 분석한 세라믹 적용 교량받침의 평균마찰계수는 0.16으로 나타났다. 세라믹의 물리적 및 화학적특성의 고유 재료물성과 성능평가를 통해 도출된 우수한 역학적 특성 및 0.16 수준의 마찰계수는 마찰재로써 고려할 수 있는가능성을 제시한다.

Two-stage damage identification for bridge bearings based on sailfish optimization and element relative modal strain energy

Minshui Huang,Zhongzheng Ling,Chang Sun,Yongzhi Lei,Chunyan Xiang,Zihao Wan,Jianfeng Gu 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.86 No.6

Broad studies have addressed the issue of structural element damage identification, however, rubber bearing, as a key component of load transmission between the superstructure and substructure, is essential to the operational safety of a bridge, which should be paid more attention to its health condition. However, regarding the limitations of the traditional bearing damage detection methods as well as few studies have been conducted on this topic, in this paper, inspired by the model updating-based structural damage identification, a two-stage bearing damage identification method has been proposed. In the first stage, we deduce a novel bearing damage localization indicator, called element relative MSE, to accurately determine the bearing damage location. In the second one, the prior knowledge of bearing damage localization is combined with sailfish optimization (SFO) to perform the bearing damage estimation. In order to validate the feasibility, a numerical example of a 5-span continuous beam is introduced, also the noise robustness has been investigated. Meanwhile, the effectiveness and engineering applicability are further verified based on an experimental simply supported beam and actual engineering of the I-40 Bridge. The obtained results are good, which indicate that the proposed method is not only suitable for simple structures but also can accurately locate the bearing damage site and identify its severity for complex structure. To summarize, the proposed method provides a good guideline for the issue of bridge bearing detection, which could be used to reduce the difficulty of the traditional bearing failure detection approach, further saving labor costs and economic expenses.

무도상 철도교 레일 장대화를 위한 궤도-교량 상호작용 해석 및 개량방안 분석

윤재찬,이창진,장승엽,최상현,박성현,정혁상 한국도시철도학회 2018 한국도시철도학회논문집 Vol.6 No.4

본 연구에서는 비교적 경간이 긴 트러스교를 포함한 무도상 교량을 대상으로 장대레일을 부설할 때 궤도-교량 상호작용으로 인한 레일 부가 축응력과 교량 지점 반력 등의 변화를 검토하여 레일 장대화를 위한 개량 방안을 분석하였다. 연구결과에 따르면 무도상 교량에서 장대레일을 부설할 경우 레일 부가 축응력과 지점 반력이 큰 폭으로 증가하는 것으로 나타났다. 레일 부가 축응력은 횡저항력을 충분히 확보할 경우 수용 가능하지만, 지점 반력이 증가하게 될 경우 받침이나 교각의 손상이 우려되고 대규모 보수 보강을 필요로 하므로 지점 반력을 완화시킬 수 있는 방안을 강구할 필요가 있다. 교량 가동단의 마찰저항을 고려하는 경우 레일 부가 축응력은 감소하지만 지점 반력에 미치는 영향은 매우 작은 것으로 나타났다. 반면 궤도 종저항력이 작아지면 레일 부가 축응력과 지점 반력이 모두 큰 폭으로 감소하는 것으로 나타났으며, 레일 부가 축응력이 큰 일부 구간에 ZLR 체결장치를 적용하는 경우 레일 부가 축응력 뿐 아니라 교량 지점 반력이 크게 감소하는 것으로 나타났다. 따라서 무도상 교량의 레일 장대화를 위하여 일부 ZLR 체결장치를 적용하고 궤도 종저항력을 줄이는 방안이 매우 효과적이라고 판단된다. This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.

Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

Choi, Eun-Soo,Yu, Wan-Dong,Kim, Jin-Ho,Park, Sun-Hee The Korean Society for Railway 2012 International Journal of Railway Vol.5 No.1

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.

Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

Eunsoo Choi,Wan-Dong Yu,Jinho Kim,Sunhee Park 한국철도학회 2012 International Journal of Railway Vol.5 No.1

Dynamic Characteristics of a Multi-Functional Bridge Bearing with Builtin Piezocomposite Element

Ha, Dong-Ho,Choo, Jinkyo F.,Lee, Chang Hyung,Jang, Won Seo,Goo, Nam-seo Trans Tech Publications 2013 Applied mechanics and materials Vol.432 No.-

<P> A multi-functional bridge bearing with built-in piezocomposite electricity generating element (PCGE) is being developed by our research team to respond to the growing demand of self-powered sensing devices for the monitoring of bridges by harvesting the energy produced by the traffic-induced vibrations. For the intended application, a multilayered piezoelectric PCGE structure composed of layers of piezoceramic, glass/epoxy, and carbon/epoxy, has been developed to improve the durability, output voltage and power of the piezoceramic. The output voltage of this PCGE can be used for real-time traffic monitoring like in bridge-weigh-in-motion systems and can eventually be exploited to generate the electricity needed for the lighting and functioning of other embedded sensors. This paper presents the results of the dynamic loading tests conducted on a prototype of the proposed multi-functional bridge bearing to enhance its design details and verify the accuracy of the measurement. The results show that the bearing provides reliable measurement for traffic monitoring and enable to conceive details for the improvement of the output voltage of the PCGE. Since bridge bearings, as indispensable devices transferring the loads and movements from the deck to the substructure and foundations of the bridge, are continuously subjected to traffic loads, the proposed bridge bearing appears to be a natural and economic solution that can be applied to existing or newly built bridges without modification of the conventional design while providing additional and valuable functions for the maintenance of the structure. </P>

Effect of a two bearing lines deck on the bridge substructure

Fatemeh Shaker,Alireza Rahai 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.2

This research evaluated the different types of deck to pier connections effects (one or two elastomeric bearing lines and rigid) on a concrete bridges. Three-dimensional bridge models behavior with different deck to pier connections and different distances of two bearing lines were studied under the service load. Also, the detailed connection system with two elastomeric bearing lines was modeled to evaluate the effect of changing distance between two-lines. Results indicated that the proper location of elastomeric bearings has a major impact on the transferring forces to the substructure. Double elastomeric bearing lines have a behavior between one line and rigid connections. Transferring bending moment to the substructure in two-lines is more than the corresponding value of the one line. Moreover, an increase in the distance of two-lines lead to a significant increase in the rotational stiffness of the connection, and an analytical solution was investigated for their relation. In fact, the semi-rigidity effect of this connection and its change due to the distance of bearings should be considered in the design process.

교량받침교체공사를 위한 단일앵커받침시스템의 효율성평가

강태우(T.W. Kang),김호배(H.B. Kim),김태원(T.W. Kim),김학규(H.K. Kim) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10

교량받침의 특성은 교량의 하부구조 설계에 중요한 인자로 인식되고 있다. 그 중에서도 받침연단거리는 교각 코핑폭을 결정하는 중요한 요소 중 하나이다. 근래에는 교량의 경제적인 설계를 위해 고강도의 콘크리트로 설계되는 경우가 일반적이며, 이로 인해 과거보다 교량의 경간장은 길어지고 하부구조의 크기는 상당히 소형화되고 있는 추세이다. 그럼에도 불구하고 받침연단거리를 만족하기 위해 코핑폭의 확대가 필요한 경우가 발생하여 경제적인 설계를 저해하기도 한다. 이에 본 연구에서는 받침연단거리 규정의 목적을 심도 깊게 고찰하여, 그 목적에 부합하면서도 교량의 경제적인 설계를 가능하도록 교량받침의 구조를 개선하였다. 이를 통해 실제 교량받침교체 공사에서 기존 하부구조물의 확장없이 경제적인 시공을 가능하게 하였다. It has been recognized for decades that the specification of bridge bearing is a major factor in the bridge substructure design. Among the many factors, minimum edge distance of bearing is a critical factor of the coping width. In these latter days, the high strength concrete has been normally used for a cost-effective design. As a result, the span length of the bridge has been longer and the substructure has been slender than in the past. Nevertheless, a cost-effective design of the bridge should be inhibited by the expansion of the coping width that it should be needed to satisfy the edge distance of the bearing. In this study, the structural system of the bridge bearing was improved to cost-effective substructure design answering the purpose of the code. So it has led to reduce the cost in some projects last year.