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변위제어를 이용한 무도상 강교량 레일장대화 공법의 적용성 분석
채수호,유용,임철수,최상현 한국철도학회 2019 한국철도학회논문집 Vol.22 No.2
The piers of an open deck steel railway bridge, most of which are gravity-type plain concrete piers withspread footing, are vulnerable to horizontal action, and this is one of the main reasons that prevents installing CWR(Continuous Welded Rail). In this paper, a new construction method for installing CWR on an open deck steel railwaybridge, utilizing displacement control at abutments to avoid horizontal reaction at piers, is proposed, and the applicabilityand effectiveness of the method are examined. The proposed method includes constructing a continuous superstructure,installing movable supports on piers and fixed supports on abutments, and eliminating horizontal reactions of piers. The applicability and effectiveness of the method are reviewed via numerical analysis using the commercial finite elementprogram, ABAQUS. Based on the analysis results, in which the amplitude level of the additional axial rail stressusing the abutment-displacement-control method is similar to that of the existing method, the proposed method is effectiveand advantageous, considering that there are no horizontal reaction forces at piers. The greater horizontal reactionlevel at abutments can be controlled using such techniques as reinforcing abutments or installing a semi-fixed support,which allows a restricted amount of longitudinal displacement.
내진보강용 탄소섬유 복합사 하이브리드 그리드 직물 제조 및 공학적 성능 평가. I. 탄소섬유 복합사 제조 및 최적 직물 설계
연우,차주희,채철수,이형호,전한용,Yan, Yu,Cha, Ju Hee,Chai, Charles,Lee, Hyeong Ho,Jeon, Han Yong 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.4
In this study, a carbon fiber composite yarn with the desired stiffness and ductility was fabricated for use in hybrid grid fabrics for seismic reinforcement, and the optimum structures of the grid fabrics were evaluated. Carbon fiber composite yarn was prepared by a double-covering process with carbon fiber/aramid fiber/high-strength PET fiber. It was confirmed that the strength of the carbon fiber composite yarn was greatly increased compared to that of carbon fiber, and the elongation increased by about 0.5%. The TPU (thermoplastic polyurethane) extrusion coating method was more suitable for the carbon fiber composite yarn than urethane impregnation for the coating process. Meanwhile, in the evaluation of yarn fineness and grid structure, thick fibers had greater strengths. When comparing the strength and elongation, the bi-directional grid showed no advantages over the unidirectional grid.
다경간 완전일체형 연속철도교량 장대레일의 축력 변화 해석
유용(Yong Yoo),채수호(Sooho Chae),임철수(Churlsoo Lim),최상현(Sanghyun Choi) 한국도시철도학회 2019 한국도시철도학회논문집 Vol.7 No.1
일체형교량은 교량받침, 신축이음 등 교량부속품의 설치가 필요 없어 시공 및 유지보수 비용을 절감할 수 있는 장점이 있으나, 국내 철도의 경우 현재까지 궤도의 안전성에 대한 우려로 인하여 극히 제한적인 연구만이 수행된 상황이다. 이 연구에서는 장대레일에 발생하는 부가축응력 변화 검토를 통하여 완전일체형 교량 공법의 철도 적용 가능성을 검토하였다. 유한요소해석을 이용하여 교대부와 교각의 강성 및 궤도 종저항력 변화와 교량의 경간 수 증가에 따른 레일의 부가축응력을 검토한 결과, 완전일체형 교량의 경우 궤도 안정성 확보를 위하여 교대부 강성이 가장 중요하며, 충분한 교대부 강성이 확보될 경우 장연장, 다경간 및 연속화된 완전일체형 철도교량의 건설에 문제가 없을 것으로 판단된다. The integrated bridge, which does not have to install bridge components such as bearings and expansion joints, has advantages of reducing construction and maintenance costs. In domestic railways, however, considering the track instability, little research has been conducted to date. In this paper, the feasibility of constructing the fully integrated railroad bridge is examined via investigating the change in the additional axial stress of the continuous welded rail. The results of the finite element analysis on the changes of additional rail stress depending on the stiffness of abutments and piers, longitudinal track stiffness, and the number of bridge spans show that the stiffness of the abutment is most important in securing track stability. Once enough abutment stiffness is ensured, a long, multi-span, continuous fully integrated railroad bridge can be constructed.