• Title/Summary/Keyword: 적절한 보강방법

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아라미드섬유 및 탄소섬유 시트로 보강된 철근 콘크리트보의 전단특성

  • 구봉근;김태봉;김창운;류택은
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 1997.11a
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    • pp.165-169
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    • 1997
  • 기존 구조물의 보강을 하는 데는 휨모멘트 및 전단력에 대하여 충분한 보강 효과를 가지는 것과 함께 시공성을 만족해야만 한다. 현재 연속 섬유시트 중 아라미드섬유시트(AFS) 및 탄소섬유시트(CFS)는 기존구조물의 보강재로 사용한 사례가 증가하고 있으나 합리적인 보강설계방법이 확립되어 있지 않은 현 시점에서는 적절한 보강이 이루어지지 않는 경우가 많다 AFS 및 CFS에 의해 RC보의 적절한 보강을 위해서는 AFS 및 CFS를 이용한 기존 콘크리트 구조물의 보강설계방법의 구축이 급선무이다. (중략)

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A study on Development of Methods to Rehabilitate the Damaged Prestressed Concrete beam Using Glass Fiber (유리섬유를 이용한 손상된 프리스트레스트 콘크리트 보의 보강공법 개발연구)

  • Kang, Won-Ho;Han, Man-Yop;Lee, Taek-Sung;Rhu, Young-Min
    • Magazine of the Korea Concrete Institute
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    • v.11 no.2
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    • pp.167-175
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    • 1999
  • Many composite girder bridges have been constructed for about thirty five years. Nowadays they are aged or deteriorated because of the increase in traffic and vehicle loads. In this study, the effect of strengthening with glass fiber sheet is investigated to estimate the possibility for applying to damaged prestressed concrete bridges. One normal and eight cracked specimens which had been preloaded were tested. The cracked specimens were strengthened with either external prestressing or bonding glass fiber sheet, or using both methods. The results showed that the maximum loads are almost same for both methods. So it seems that the strengthening with glass fiber sheet can be used for strengthening damaged prestressed concrete girders. It is important that proper devices should be selected to prevent glass fiber sheet from premature bonding failure below its maximum load, which is similar to end anchorage problem in external prestressing method. It is proved that the devices proposed in this paper have sufficient anchoring capability to increase load carrying capacity.

A Study on the Restraint-Effect of Ground Settlement by Nail Reinforcement of Tunnel in Soft Ground (토사NATM 터널의 네일 보강에 의한 지반침하 억제효과에 관한 연구)

  • 임종철;고호성;박이근;오명렬
    • Journal of the Korean Geotechnical Society
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    • v.16 no.2
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    • pp.51-59
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    • 2000
  • 네일(또는 락볼트)은 토사터널의 NATM 시공 시 보강재로 사용되어진다. 그러나, 네일의 적절한 설치방법이 아직까지 정립되지 않았다. 본 연구에서는 네일의 길이와 위치를 변화하여, 그 효용성을 연구하였다. 그 결과, 네일이 지반보강을 위하여 토사지반에 사용될 시 경제적인 길이는 터널직경의 0.5배이다. 보강의 효용성은 네일의 위치에 따라 터널라이닝 측벽의 하부, 중부, 상부의 순서이다.

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Weighting-Factored Evaluation Method for Determination of Seismic Retrofitting Schemes for Existing Bridges (기존 도로교의 내진성능향상 방법 선정을 위한 가중치 평가기법)

  • Ha, Dong-Ho;Lee, Ji-Hoon;Park, Kwang-Soon;Lee, Yong-Jae
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.3 s.55
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    • pp.43-52
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    • 2007
  • This study suggests a method to determine optimal seismic retrofitting schemes for existing bridges based on weighting-factored evaluation. According to the recognition for potential seismic risk, various kinds of retrofitting methods are applied to improve the seismic performance of existing bridges. However, the relevant technique is not available to select optimal retrofitting scheme for bridges now. This suggested method weights five factors, structural compatibility, economic efficacy, environmental factor, consturctability and maintenance, and draws out optimal seismic retrofitting schemes. The application of the developed method to one hundred sixty existing bridges verifies the adaptability of this method. As a result, this study provides an idealized retrofitting schemes, and the suggested method could be a guideline to determine the more cost-effective and optimal retrofitting schemes for existing bridges in Korea.

An Experimental Study on the Stress Behavior of Coped Stringers in Steel Railway Bridge - II : Repair · Strengthening Method (철도교 세로보 절취부에서의 응력거동에 관한 실험적 연구 - II : 보수·보강 방법)

  • Li, Guang Ri;Park, Young Suk
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.4A
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    • pp.307-313
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    • 2009
  • In this study, in order to research the repair-strengthening methods, when fatigue crack occurs in the coped stringers of a steel railway bridge, we manufacture the full size of crossbeam-stringer and floor system model. Also the experimental test is performed on the coped stringers applying the repair-strengthening methods using the stop hole, combination plate, connection plate, bracket, and so on. The results indicate that, the most effective method is to set up connection plate and bracket in the top flange and bottom flange of the stringers, while we can consider the method of punching stop holes in the end of the crack as a subsidiary method. It is necessary to set up the combination plate when the length of crack is quite long.

An Experiment of Flexural Behavior for the Damaged Low Reinforced Concrete Beams Rehabilitated with External Tendons (손상된 저보강 RC보의 외부 긴장 보강 후 휨거동 실험)

  • Yoo, Sung Won;Suh, Jeong In
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.3
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    • pp.40-47
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    • 2013
  • Most experiments carried out in the previous studies dealt with the highly reinforced concrete beams (RC beams) in case of rehabilitating with external tendon. However, the reinforcing effect of external tendons cannot be clearly analyzed in this kind of RC beams because the rehabilitating tendon quantity for it is too small. By this reason, this study chose the low RC beams rehabilitated with external tendons. Therefore, in this study, 7 test beams were manufactured and flexural behavior tests were performed to assess the reinforcing effect and to find more proper rehabilitating method by external tendon. The reinforcing effect increased according to the quantity of tendons, and was especially added by repairing cracks with epoxy resin. It was shown that the design equations of AASHTO 1994 and ACI-318 did not show a good agreement with test results. The result of this study will be able to be used effectively in finding the more proper rehabilitating method of the damaged RC beams.

Experimental Method for Evaluating Debonding Strength of FRPs Used for Retrofitting Concrete Structures (콘크리트 휨부재 보강용 FRP의 부착성능 평가를 위한 실험방법 연구)

  • Utui, Nadia;Kim, Hee-Sun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.2 no.3
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    • pp.36-41
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    • 2011
  • This study proposes a experimental method to evaluate bonding strength of FRPs used for retrofitting concrete structures. Specimens are designed so that debonding failure of FRPs can be induced from reinforced concrete beams retrofitted with two layers of carbon and glass FRPs. And three-point loading tests are performed to see if debonding failure with proper debonding strength is observed from the specimens. The test results show that the tested beams are failed due to debonding of FRPs, therefore, the proposed test method is capable of evaluating debonding strength of FRPs using relatively small normal strength concrete beams.

Slab Effect on Inelastic Behaviors of High Strength RC Beam-Column Joints (고강도 RC 보-기둥 접합부의 비탄성 거동에 대한 슬래브의 영향)

  • 장극관;김윤일;오영훈
    • Magazine of the Korea Concrete Institute
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    • v.9 no.2
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    • pp.167-177
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    • 1997
  • In thtx design of ductile moment -1csist1ng frnmcls (DMRFs) f'ollow~ng the. stlong columnweakbeam design philosophy, it is desirable that the joint and column remain essentiallyelastic in order to insure proper energy dissipation and lateral stability of the structure.Thv joint has been identifid as the "weak link: in DMRFs because any stiffness orstrength deterioration in this region can lead to substantial drifts and the possibility ofcollapse due to t'-delta effects. h3oreove1.. the tngintw is faced with the difficult task ofdetailing an element whose size is determined by theframing members, but \vhich mustresist a set of loads very different from those used in the design of the beams and columns.Four 3 -scale beam-column-slab joint assemblies were designed according to existing cod\ulcornerrequirements of' ACI 318-89. representing perimeter joints of DMRFs with reinforced highstrength concrete. The influence on aseismic behavior of beam-column joints due tomonolithic slab, has been investigated.lab, has been investigated.

Behaviors According to the Reinforcing Method of the Support Diaphragm Manhole in Steel Box Girder Bridge (강박스거더 지점부 다이아프램 맨홀의 보강방법에 따른 거동)

  • Lee, Seong Haeng;Kim, Kyoung Nam;Jung, Kyoung Sup
    • Journal of Korean Society of Steel Construction
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    • v.17 no.6 s.79
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    • pp.649-660
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    • 2005
  • Since the diaphragm manhole of steel box girder bridges is designed generally from experience, it has become the primary factor in the excessive cost of steel bridge construction. For the economical and efficient manufacture of diaphragm manholes, it is necessary to study the exact behavior of the diaphragm manhole in a steel box girder bridge. In this study, both an experimental test and a structural analysis are performed to verify the behavior of the diaphragm manhole in a steel box girder bridge. A detailed structural analysis was performed according to various diaphragm manhole shapes, and in conclusion, the suitable reinforcement method for the support of diaphragm manholes in steel box bridges is presented.

Flexural Behavior of Steel-Concrete Composite Beams Strengthened by Post Tension Method (포스트 텐션 공법으로 보강된 SC 합성보의 휨 거동)

  • Ryu, Soo-Hyun;Kim, Heui-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.3
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    • pp.186-195
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    • 2010
  • This study has attempted to suggest a proper reinforcement method by strengthening unbonded post -tensioning through height of an anchorage hole, form of a saddle, and loading time point as parameters and evaluating the reinforcement method through a bending experiment. The result of this experiment indicated effects of reinforcement since the maximum strength ratio(the ratio of an experimental value to theoretical value) of SC composite beams before prestressed was 0.97 and after prestress were 1.00~1.21. As a result of analysis on displacement and strain, irrespective of height of an anchorage hole and loading time point, the D120-series specimen where an anchorage hole was installed on the neutral axis after reinforcement showed that its deflection continuously increased without sudden load reduction after maximum load and it stably behaved with relatively low strain of each part. In terms of reinforcement effects, the maximum strength of SCR-UD120 specimen prestressed after pre-loading was increased 1.72 times comparing to SC composite beams so SCR-UD120 specimen prestressed after pre-loading was shown to be the best.