• Title/Summary/Keyword: expansion joint

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Comparative Analysis of Track-Bridge Interaction of Sliding Slab Track and Rail Expansion Joint for Long-Span Railway Bridge (장경간 철도 교량에 적용된 슬라이딩 궤도와 레일신축이음장치의 궤도-교량 상호작용 비교)

  • Lee, Kyoung Chan;Jang, Seung Yup;Lee, Jungwhee;Choi, Hyun Sung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.2
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    • pp.169-177
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    • 2016
  • Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.

An Experimental Study on the Influence of Masonry InFilled Walls on the Seismic Performance of Reinforced Concrete Frames with Non-seismic Details (정적실험을 통한 조적채움벽체가 비내진상세 RC 골조의 내진성능에 미치는 영향 평가)

  • Kim, Kyoung-Min;Choen, Ju-Hyun;Baek, Eun-Rim;Oh, Sang-Hoon;Hwang, Cheol-Seong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.3
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    • pp.114-120
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    • 2017
  • In this paper, the effect of the masonry infill walls on the seismic performance of the reinforced concrete(RC) frames with non-seismic details was evaluated through the static test of an masonry infilled RC frame sub-assemblage with non-seismic details of real size, and comparison with the test results of the RC frame sub-assemblage with non-seismic details. As the test results, lots of cracks occurred on the surface of the entire frame due to the compression of the masonry infilled wall, and the beam-column joint finally collapsed with the expansion of the shear crack and buckling(exposure) of the reinforcement. On the other hand, the stiffness of the shear force-story drift relationship decreased due to the wall sliding crack and column flexural cracks, and the strength finally decreased by around 60% of the maximum strength. The damage that concentrated on the upper and lower parts of columns was dispersed in the entire frame such as columns, a beam, and beam-column joints due to the wall, and the specimen was finally collapsed by expansion of the shear crack of the joint, not the shear crack of the column. Also, the stiffness of RC frame increased by 12.42 times and the yield strength by 3.63 times, while the story drift at maximum strength decreased by 0.18 times.

The Development of Third-Rail System Applied to Turn-out Section for Urban Maglev (도시형 자기부상열차 분기기 구간의 제3궤조 전차선 시스템 개발)

  • Min, Byong-Chan;Heo, Young-Tae;Hong, Du-Young;Lee, Won-Joo;Jo, Su-Yeon;Jeong, Nam-Cheol
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.3046-3051
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    • 2011
  • The third-rail system is an important device supplying power directly to the Maglev train through physical contact with the collecting shoe. It is directly related to safety and reliability for the running of Maglev. However, most the third-rail system used in Korea depend on foreign product or technologies, Korea Urban Maglev in the development of appropriate power feeding is urgent. In particular, the turnout section is the weakness point in the system because bending force by turnout section movement and fatigue caused by repetitive motion as well as the expansion by temperature, the forces by Maglev collecting shoe is added th the third-rail. Therefore, this paper proposes the third-rail system appropriate for Korean Urban Maglev of turnout section. To verify the structural stability of POSCO ICT third-rail system, the finite element analysis and physical testing was performed. The third-rail is fixed on each side of the turn-out section steel structure by epoxy insulation supporter and the integral behaviors are occurred. Therefore, the maximum horizontal displacements of each support are investigated and then, it is applied to finite element model of the third-rail to investigate the moments and stress. Also, the bending test about one million times and Expansion Joint for the third-rail was performed. The third-rail system safety and reliability was identified by test line on Korea Institute of Machinery & Materials in Deajeon for under the actual usage environment such as the Maglev and turn-out operation.

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Strengthened and flexible pile-to-pilecap connections for integral abutment bridges

  • Lee, Jaeha;Kim, WooSeok;Kim, Kyeongjin;Park, Soobong;Jeong, Yoseok
    • Steel and Composite Structures
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    • v.20 no.4
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    • pp.731-748
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    • 2016
  • Pile-to-pilecap connection performance is important as Integral abutment bridges (IABs) have no expansion joints and their flexible weak-axis oriented supporting piles take the role of the expansion joint. This connection may govern the bridge strength and the performance against various lateral loads. The intention of this study is to identify crack propagation patterns when the pile-to-pilecap connection is subjected to lateral loadings and to propose novel connections for improved performance under lateral loadings. In this study, eight different types of connections were developed and modeled, using Abaqus 6.12 to evaluate performances. Three types were developed by strengthening the connections using rebar or steel tube: (i) PennDOT specification; (ii) Spiral rebar; and (iii) HSS tube. Other types were developed by softening the connections using shape modifications: (i) cylindrical hole; (ii) reduced flange; (iii) removed flange; (iv) extended hole; and (v) slot hole connection types. The connections using the PennDOT specification, HSS tube, and cylindrical hole were shown to be ineffective in the prevention of cracks, resulting in lower structural capacities under the lateral load compared to other types. The other developed connections successfully delayed or arrested the concrete crack initiations and propagations. Among the successful connection types, the spiral rebar connection allowed a relatively larger reaction force, which can damage the superstructure of the IABs. Other softened connections performed better in terms of minimized reaction forces and crack prevention.

An Investigation into the Nurturing Strategy of Korean Young Designers in the International Market Expansion - Based on London's Young Designers' Support Programs - (국내 신진패션디자이너의 해외시장 진출 전략 연구 - 영국 런던시의 지원 사업을 기초로 -)

  • Kim, Hye Eun
    • Fashion & Textile Research Journal
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    • v.18 no.3
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    • pp.272-281
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    • 2016
  • From the year 2000 on, Seoul has aimed to be a fashion city, and thus has been supporting young designers through Seoul Fashion Creative Studio, Generation Next, Le Dome, Concept Korea, etc. London is famous for nurturing young designers through the joint help of government, schools and industries: Alexander McQueen, Christopher Kane and Peter Pilotto are successful cases. Therefore, this research aims to suggest a direction for policies aimed at helping young designers in the international market, on the basis of London's nurturing programs and ideas from a literature review and case studies. The results are below. Firstly, a step-by-step supporting program is recommended. Secondly, long-lasting, sustainable programs are considered essential to support designers after the end of their contracts. Thirdly, practical assistance is preferred to monetary funding in order to lighten the designers' lot and in the interests of transparency. The mentoring service should be strengthened for the designers to eventually become independent. The support should be tailor-made according to items. Fourthly, the supporting programs should be promoted. Fifthly, government and industries should collaborate. Sixthly, 'de minimis' against overlapped support should be legislated. For these, the change of supporting method can be helpful; an independent administrative organisation plans and collects funds from governments and companies. Through these programs and any subsequent studies, Seoul could become a fashion city where young designers play active roles at a global level.

A Study on the Assembly Process and Reliability of COF (Chip-On-Flex) Using ACFs (Anisotropic Conductive Films) for CCM (Compact Camera Module) (ACF를 이용한 CCM (Compact Camera Module)용 COF(Chip-On-Flex) 실장 기술 및 신뢰성 연구)

  • Chung, Chang-Kyu;Paik, Kyung-Wook
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.2
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    • pp.7-15
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    • 2008
  • In this paper, the Chip-On-Flex (COF) assembly process using anisotropic conductive films (ACFs) was investigated and the reliability of COF assemblies using ACFs was evaluated. Thermo-mechanical properties of ACFs such as coefficient of thermal expansion (CTE), storage modulus (E'), and glass transition temperature $(T_g)$ were measured to investigate the effects of ACF material properties on the reliability of COF assemblies using ACFs. In addition, the bonding conditions for COF assemblies using ACFs such as time, temperature, and pressure were optimized. After the COF assemblies using ACFs were fabricated with optimized bonding conditions, reliability tests were then carried out. According to the reliability test results, COF assemblies using the ACF which had lower CTE and higher $T_g$ showed better thermal cycling reliability. Consequently, thermo-mechanical properties of ACFs, especially $T_g$, should be improved for high thermal cycling reliability of COF assemblies using ACFs for compact camera module (CCM) applications.

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Comparison on postural control between abdominal draw-in maneuver and abdominal expansion maneuver in persons with stroke

  • Choi, Ho-Suk;Shim, Yu-Jin;Shin, Won-Seob
    • Physical Therapy Rehabilitation Science
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    • v.5 no.3
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    • pp.113-119
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    • 2016
  • Objective: The effect of abdominal expansion maneuver (AEM) and abdominal draw-in maneuver (ADIM) on postural control in an unsupported position in stroke patients. Design: Randomized controlled trial. Methods: A total of 36 persons with hemiplegic stroke participated in this study. The subjects were randomly divided into an AEM experimental group (n=12), an experimental ADIM group (n=12), and a control group (n=12). We collected the general characteristics of all subjects and the pre-test results before the intervention and after 4 weeks of the intervention. The trunk stabilization training of the ADIM and AEM group were performed 15 minutes a day, 3 times a week for 4 weeks, and general physical therapy was performed 2 times a day, 30 minutes per session, 5 times a week for all three groups. The control group received joint mobilizations, muscle strengthening, endurance strengthening, and gait exercises along with treatment of the central nervous system, such as neuro-developmental treatment, mat, and gait training. The AEM is an inspiratory phase of tidal breathing expanding the lateral lower ribcage in a lateral direction with minimal superior movements of the chest. Then the lower abdomen expands and the navel moves in an anterior-caudal direction. The ADIM is a repeated contraction and relaxation of the anal sphincter during inspiration. The navel pulls the lower abdomen to the direction of the spine without the movement of the trunk and pelvis. Results: Before and after the interventions, medial-lateral axis movement distance, anterior-posterior axis movement distance, sway mean velocity, and sway area 95% was a statistically significant change in all three groups (p<0.05). The post-hoc test showed a significant improvement in medial-lateral axis movement distance, anterior-posterior axis movement distance, sway mean velocity, and sway area in the AEM group compared with the control group, and in the ADIM group compared with the control group (p<0.05). Conclusions: In conclusion, both AEM training and ADIM training are necessary interventions to maintain the independent sitting position according to the characteristics of the patient.

COMPLEX DISTRACTION OSTEOGENESIS ON HEMIMANDIBULAR HYPOPLASIA : A CASE REPORT (하악과두 골절후 발생한 편측성 하악골 형성부전의 치료로서 복합적 악골 신장술의 임상증례)

  • Oh, Sung-Hwan;Min, Seung-Gi;Kwon, Kyong-Hwan;Koh, Se-Wook;Lee, Kyong-Seuk
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.30 no.3
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    • pp.246-250
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    • 2004
  • Uni- or bilateral mandibular hypoplasia can be associated with various syndromes or is acquired after early traumatic or inflammatory disease in the temporomandibular joint(TMJ). Early treatment is necessary to avoid consequent impairment of midfacial growth. The standard treatment of these malformations consists of the application of bone grafts which can lead to unpredictable growth, but the new procedure of bone lengthening which was presented by McCarthy et al. represents a limited surgical intervention and therefore open up a new perspective of treatment, especially in younger children with severe deformities. Patients with hemifacial microsomia and facial asymmetry have a vertically short maxilla, a tilted occlusal plane, and a short mandible. A 14-years-old boy with facial asymmetry, who was fractured on both condyle and mandibular symphysis before 8 years ago, was treated by mandibular ramus lengthening, symphysial widening and surgically assisted rapid palatal expansion with corticotomy. After allowing 1 week for the healing of the periosteum, the distraction was performed at the rate of 0.5-1.0mm per day for 7 days on maxilla and 14 days on mandible. The device was maintained on maxilla and mandible for 12 weeks following distraction. The difference in ramus and mandibular transverse deficiency were corrected and facial asymmetry was improved with complex distraction osteogenesis.

Analysis of the Effect of Construction of Public Cremation Facilities in Jeongeup City on Cremators Number Using E-Haneul Funeral Information System in Jeollabukdo and on Cremation Rate

  • Choi, Jae-sil;Kim, Jeong-lae
    • International journal of advanced smart convergence
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    • v.10 no.1
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    • pp.117-124
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    • 2021
  • Based on a result of we research and analysis of this study, it was analyzed that the average annual cremators number using E-Haneul Funeral Information System among the five public cremation facilities in Jeollabukdo was 9,713 in total before the opening of public creation facilities in Jeongeup City (2013-2015), while the number was 12,159 after the opening of public cremation facilities in Jeongeup City (2016-2019); the number was increased by 2,446, compared to the opening period (2013-2015), with a large increase rate of 25.2%. In addition, the average annual cremation rate before the opening of public cremation facilities in Jeongeup City (from 2013 to 2015) was 71.6%, but the average annual cremation rate during the period after the opening (from 2016 to 2019) was 81.5%, which was a large increase rate of 9.9% compared to period before the opening of the facilities. Based on research results above, we have presented policy suggestions in order to increase the efficiency of operation and management of public cremation facilities by local governments as follows. First, in order to prepare for the increase in demand for cremation due to the increase in cremators number, a policy promotion for the expansion of "public cremation facilities" should be carried out as soon as possible, focusing on local governments whose supply has reached the limit. Second, in order to support the expansion and construction of public cremation facilities, the government subsidy rate and government subsidy at the level of current 70%, provided by the central government, should be further expanded. Third, overcoming theNIMBY conflict overlocation for public cremation facilities, theutilization rate should be enhanced, through the joint construction and facility operation of the public cremation facilities between local governments, and the ef iciency of the project implementation should be improved through the jointsharing of the facility operation cost.

A Study on Efficient Methods of Cadastral Resurvey Responsible Agency Operation (지적재조사 책임수행기관 운영의 효율화 방안 연구)

  • Lee, Jae-Hyuk;Hong, Sung-Eon
    • Journal of Industrial Convergence
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    • v.20 no.8
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    • pp.33-40
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    • 2022
  • In this study, we tried to suggest a plan to improve the efficiency of operation after analyzing the actual conditions by selecting case areas operated by the cadastral resurvey responsible agency system. The research results are as follows. In the evaluation of the selection of a cadastral resurvey agency, a method to raise the qualitative evaluation score was suggested. The expansion of support for the cadastral resurvey agency made it possible to automatically connect and install when the LandyGo program is updated, and suggested that prior training should be stipulated in the related regulations. In the performance of cadastral resurvey surveying and division of duties, the installation of temporary boundary monuments and determine boundary monuments should be integrated. And this suggested the direction of conserving the project cost of the cadastral resurvey agency through joint implementation. Also, in the short-term and long-term perspectives, a plan for realization of project cost distribution in connection with the expansion of the entrustment of the cadastral resurvey responsible agency was presented. If the responsible agency system is operated by reflecting the results of this research, it is expected to improve the satisfaction of the project participants and shorten the project period.