• 제목/요약/키워드: repair and reinforcement

검색결과 277건 처리시간 0.033초

급냉 제강 슬래그의 대체율에 따른 수중 경화형 에폭시 모르타르의 공학적 특성 (The Engineering Properties of Underwater-Hardening Epoxy Mortar According to the Replacement Proportion of RCSS)

  • 곽은구;조성현;박상훈;배기선;장원석;김진만
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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    • pp.401-404
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    • 2005
  • Because the underwater structures are subjected to the deterioration according to use environment, it is necessary to repair and reinforce when the durable performance are considered in structures. Epoxy mortar in the underwater used to the repair and reinforcement for durability. Epoxy mortar in the underwater-harding maked epoxy and filler. Filler is divided aggregate and powder system. Because aggregate take a matter too seriously to supply that alternation material is used to rapidly chilled steel slag. As result of study, it is possible that rapidly chilled steel slag can be applied for replacement materials about aggregate in epoxy mortar because the strength is not different.

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국제 표준화를 위한 화재이후의 유지관리 시스템 개발 (The Standardized Methods for Improvement of Maintenance Deterioration caused by Fire damage)

  • 권영진;구인혁;김동은;서동구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
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    • pp.230-231
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    • 2013
  • A fire outbreak in a reinforcement concrete structure looses the organism by different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So, concrete reinforcement structure is damaged partial or whole structure system. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. In this study, consider case of investigation methods and repair work in fire damaged structure concrete.

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폴리머-강섬유를 혼입한 고강도 콘크리트 보의 보수·보강 (Repair and Rehabilitation of Polymer-Steel Fibrous High Strength Concrete Beams)

  • 곽계환;김원태
    • 한국구조물진단유지관리공학회 논문집
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    • 제6권2호
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    • pp.135-143
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    • 2002
  • This study is to investigate its use by applying stainless steel wire mash reinforcement method of construction, which is newly developed, on the high strength concrete beam mixed with polymer-steel fiber. In this test, it is investigated and observed such as follows: the ultimate load, the initial flexure crack load, the initial diagonal tension crack load, the relation between load and deflection, load-strain relation, and also crack growth and fracture aspect by increasing load. The results of this test are; first, the stainless steel wire showed some useful reinforcement effects in multiplying the steel's resisting force of moment to the tensile force of beam or slab: second, the promoting strength and internal force was made in the process of the integration at the same reaction by using the penetrating polymer-mortar with an excellent durability and physical property. On the basis of this results, because such instances in applying stainless steel wire Mash reinforcement method of construction have been few so far, through the experimental investigation such as this test over and over again, the efficient and useful method must be developed for the practice.

반건상근 건을 이용한 아킬레스건 재파열의 치료 (Free Semitendinosus Tendon Graft in Re-ruptured Achilles Tendon)

  • 지종훈;김원유;김영율;이연수;윤종성
    • 대한족부족관절학회지
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    • 제10권2호
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    • pp.259-263
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    • 2006
  • The acute Achilles tendon rupture usually occurs to the people who participate in sports-related activities between 30 and 40 years of age. Recently surgical repair is the standard treatment in acute Achilles tendon rupture. After the Achilles tendon rupture in the left ankle, a 30-years old young man had been suffered from re-rupturing within three months after the primary repair. 2 years later, right-side Achilles tendon was reruptured after primary repair consequently. In the revision surgery, we performed V-Y advancement of the gastrocnemius-soleus fascia and reinforcement of the semitendinosus tendon. None of the English-literature was reported about using the semitendinosus tendon in revision surgery of the Achilles tendon retear previously. Therefore, we report this case and surgical technique because of the simple technique and the excellent results.

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Deep reinforcement learning for optimal life-cycle management of deteriorating regional bridges using double-deep Q-networks

  • Xiaoming, Lei;You, Dong
    • Smart Structures and Systems
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    • 제30권6호
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    • pp.571-582
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    • 2022
  • Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.

단열소재 종류 및 조합에 따른 외벽단열 패널용 시멘트 복합체의 공학적 특성 (Engineering Properties of Cement Composite Panel for Outer Wall Depending on the Types and Combinations of Insulation Materials)

  • 한민철;조병영;이건철;노상균;전규남
    • 한국건축시공학회지
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    • 제11권2호
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    • pp.127-135
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    • 2011
  • 본 연구에서는 단열소재 종류 및 조합의 치환률 변화에 따른 외벽단열패널의 공학적 특성에 대하여 분석하였는데, 그 결과 굳지않은 모르터의 플로우의 경우 단열소재 치환률이 증가할수록 급격히 저하되는 결과를 나타내었으며, 공기량의 경우 단열소재 치환률이 증가될수록 점차 증가되는 결과를 나타내었다. 경화 모르터의 휨강도의 경우 단열소재 치환률이 증가될수록 전반적으로 플레인에 비해 점차 강도가 저하되는 경향을 나타내었으나 PL 2% 치환 시 증가되는 결과를 나타내었다. 열전도율의 경우 단열소재 치환률이 증가될수록 급격히 낮아지는 경향을 나타내었으며, 단위용적 질량과 열전도율의 상관관계의 경우 단위용적질량이 감소할수록 열전도율은 우수한 결과를 나타내었다. 단열소재 종류 및 조합에 따른 휨강도의 경우 전반적으로 플레인과 유사한 강도값을 나타내었으나 V+CB+PL을 3% 치환한 조합의 경우 모르터 내부가 밀실해짐에 따라 강도값이 증가되는 결과를 나타내어 단열소재 종류 및 조합 가운데 가장 우수한 결과를 도출할 수 있었다.

탄소섬유시트로 보강된 철근콘크리트 보의 연성거동에 관한 실험적 고찰 (Experimental Study on the Ductile Behavior of Reinforced Concrete Beams with Carbon Fiber Sheets)

  • 박현정;박성수
    • 한국구조물진단유지관리공학회 논문집
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    • 제5권3호
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    • pp.181-189
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    • 2001
  • Recently, the need for strengthening reinforced concrete(R.C.) structure has been increased, particularly when there is an increase in load requirements, a change in use, a degradation problem, or design/construction defects. The use of composite materials for structural repair presents several advantages and has been investigated all over the world. It is well known that the incorporation of carbon fiber sheet(CFS) with concrete is one of the most effective ways to strengthen the R.C. structure. In this papers, experimentally investigated the ductile behavior of the R.C. beams strengthened with CFS, and provided the basic data for design of R.C. beams strengthened with CFS. Tests were carried out with 15 beams ($20cm{\times}30cm{\times}240cm$) reinforced with CFS, and with parameters including and the ratio of tensile reinforcement to that of balanced condition and number of CFS. The results show that strengthened and non-strengthened beams exhibit different ductile behovior. Non-strengthened beams showed increase of ductility as amount of the tensile reinforcement decreased. However, bearing capacity of the CFS-strengthened beams are dictated by the strength of the CFS layers that a very high ductility is indicated for the beams with large number of CFS.

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공시체 압축강도에 미치는 철근의 영향 평가 (Assessing the Compressive Strength of Cylinders within Reinforcing Bars)

  • 고훈범;차은호;오강환
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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    • pp.143-144
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    • 2016
  • The core drilling method is considered to be the most effective and common method of assessing the compressive strength of concrete in existing reinforced concrete buildings for structural repair and retrofit. In general, core specimens within reinforcing bars are not permitted in the regulations with regard to assessing concrete strength even if the core specimens can contain the bars in some cases. The purpose of this study is to investigate the effects of the reinforcement arrangement on the concrete compressive strength as a basic research to propose the quantitative criteria of strength for core specimens containing reinforcements. To complete the basic research, cylinder specimens inserted in a variety of reinforcement arrangements were prepared and tested.

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탄소섬유시트에 의한 콘크리트 보의 휨보강효과에 관한 실험연구 (An Experimental Study on Flexcural Performance of Repaired R/C Beams with CFS)

  • 이리형;이용택;김승훈;강윤구
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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    • pp.605-610
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    • 1997
  • An experimental investigation was conducted to examine the feasibility of Carbon Fiber Sheet(CFS), a kind of high strength fiber, for a repair and reinforcement method of concrete structures. The experimental program included tests of flexural beams different in wrapping method and amount of CFS. The beams were subjected to monotonic loading. Although the flexural strength for concrete members increases with wrapping methods of CFS., the reduction factor due to the distribution, amount bond of CFS should be completely examined. This study approached the effectiveness and application of CFS, along with reinforcement effects of CFS on reinforced concrete beams through tests. Test results indicated that the increase in the number of CFS layer caused the increase in strength of beams in strength.

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침투성 함침제에 따른 콘크리트 표층부의 개질특성 (Surface Layer Change of Concrete with Concrete Impregnant)

  • 송훈;신현욱;추용식;이종규
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2013년도 추계 학술논문 발표대회
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    • pp.200-201
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    • 2013
  • This study is interested in manufacturing the concrete surface impregnants including tetra ethyl ortho silicate, alkali silicate for the repair of the exposed concrete and the color concrete requiring the advanced function in view of the concrete appearance. The surface layer change and porosity properties was tested for the review of application. The result of this study show that the effective silicate are tetra ethyl ortho silicate and alkali silicate t. The adhesion in tension is slightly increased but the reinforcement of concrete substrate is slight. So, the concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.

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