재하속도가 철근 콘크리트 보-기둥 접합부의 거동에 미치는 영향

정란,조동철,박현수 대한건축학회 1988 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.8 No.2

탄소섬유판을 이용한 철근콘크리트보의 전단내력 보강공법에 관한 실험적 연구

정란,문희종 단국대학교 1999 論文集 Vol.34 No.-

Reinforced concrete structures often exhibit structural and nonstructural cracking due to a variety of reasons. The purpose of this study is to evaluate the rehabilitation effects of R/C beam for shear with Carbon Fiber Laminate(C.F.L) Test parameters are the depth of R/C beam, existence of stirrups and thickness of Carbon Fiber Laminate(C.F.L) Carbon fiber laminate was attached to the concrete using epoxy mortar. The behavior of R/C beam strengthened with carbon fiber laminate(C.F.L) is analyzed from the test results. According to the test results the rehabilitation effects for the shear capacity of specimen with stirrups were clearly observed. However, the specimen which had not stirrups did not show clear rehabilitation effects. Also, the increasement of shear capacity was shown when the beam has higher effective depth.

초보자 프로그래밍 과정의 특성 분석과 지원 방안

鄭蘭 三陟大學校 1996 論文集 Vol.29 No.1

Teaching programming in schools is a particularly hot topic now. A reasonable pedagogical philosophy is "The more we know about what students know, the better we can teach them". The main motivation for this paper is to improve the quality of programming education. Through a bet­ter understanding of what goes wrong, we can find more effective teaching strategies and more appropriate teaching categories. In this paper, novice mistakes, characteristics of mental representation of novice, and debugging features of novice are investigated. Based on them, teaching effective problem-solving skills for introductory computer programming courses are suggested.

재하상태에서 보강된 철근 콘크리트보의 보강 재료에 따른 구조적 거동

정란,이영재,문희증,이경언,정상진,Chung, Lan,Lee, Young-Jea,Moon, Heui-Jeung,Lee, Kyung-Un,Jung, Sang-Jin 한국콘크리트학회 1999 콘크리트학회지 Vol.11 No.1

철근콘크리트 구조물은 과도한 하중과 유지관리의 소홀 등 여러 가지 이유로 보수${\cdot}$보강을 필요로 하는 경우가 많다. 이에 대해 국내에서는 철근콘크리트구조체의 보강방법으로 강판, 탄소섬유쉬트, 탄소섬유판을 사용하고 있다. 그러나 이들 보강재료의 성능에 대하여 신뢰할 만한 연구 결과가 아직까지 충분치 않은 실정이다. 본 연구는 보강재의 종류, 균열폭, 하중의 재하상태를 변수로 보강된 철근콘크리트보의 거동을 규명하고자 하였다. 보수시험체의 경우 기준시험체와 내력과 연성은 비슷한 거동을 나타냈으나 파괴형상은 인장부위 콘크리트의 탈락과 지압파괴가 발생하였다. 보강시험체의 경우, 보강의 효과는 뚜렷이 나타났으나 보강재의 물성을 100% 발휘하지는 못하였다. 탄소섬유쉬트의 경우 접착제의 성능이 완벽하지 않아 최대 내격시의 변형률이 파단시의 변형률과 비교하여 66%정도로 나타났다. 또한 보강시의 균열폭과 하중의 유${\cdot}$무는 부재의 내력과 거동에 영향을 거의 미치지 않는 것으로 나타났다. In recent years, strengthening by steel plate, carbon fiber sheets, and carbon fiber laminate is spotlighted in order to repair and rehabilitation of R/C structures. In this study, 3 methods of rehabilitation technique were analyzed from the test results. Test parameters were the width of cracks, the method of repair and rehabilitation, the magnitude of pre-load. Deflections, failure loads, strains of reinforcing bar, strains of carbon fiber sheet, carbon fiber laminate and steel plate were measured during the tests. The primary purpose of this research was to analyze the failure mode and structural behavior of strengthened RC beams with/without superimposed pre-load. Test results should that no significant difference was observed between with pre-loaded specimens and no-loaded specimens during rehabilitation.

건축물의 설계, 시공, 유지관리 단계별 구조안전 위협요소에 관한 고찰

정란,김종호 단국대 부설 리모델링연구소 2003 리모델링 연구소 논문집 Vol.1 No.2

Eight years have been passed after the collapse of Sampoong Department Store. Although more than five hundred people were killed at once due to the collapse, many irrational system and specifications which blew that disaster still alive. In this paper, some irtational system and specifications were reviewed. Better rational system and specification were suggested at various levels of design, construction and maintenance of buildings.

철근이 부식된 철근콘크리트 슬래브의 구조성능 ( Structural Performace of Corroded Reinforced Concrete Slab )

정란,이창복 대한건축학회 2002 大韓建築學會論文集 : 構造系 Vol.18 No.2

재생에너지 보조금과 WTO 보조금협정의 ‘특정성’ 원칙

정란 국제법평론회 2020 국제법평론 Vol.0 No.57

As climate change threatens to become a major global problem, many governments are adopting a variety of measures to reduce green house gases. The conclusion of the Paris Agreement would spark a new climate regime and also participate the enactment and implementation by each country of additional measures to battle climate change. Renewable energy is a key tool in the fight against climate change. Governments are eager to reduce reliance on fossil fuels which release carbon dioxide. Thus, governments are implementing various renewable energy subsidy policies. Because of the specific features of electricity and the nature of electricity markets, government intervention will be necessary in order to secure an electricity supply that is safe and sustainable. The WTO’s Agreement on Subsidies and Countervailing Measures (“SCM Agreement”) regulates subsidies at the international level. These Agreement seeks to avoid or limit the market-distorting effects of protectionists policies. Recently, a growing number of countries have alleged that other countries’ renewable energy support programs constitute illegal subsidies under the SCM Agreement. Governments depend on the interpretation of the WTO Dispute Settlement Body (“WTO DSB”) to formulate and implement renewable energy policies in a manner that does not cause disputes with other countries in violation of SCM Agreement. This is why WTO panel and Appellate Body reports have important implications as to whether renewable energy subsidies can play a role to mitigate global warming. Although Canada-Renewable Energy / Feed-in Tariff Program case shed some light on the relationship between renewable energy programs and the SCM Agreement, the extent to which the SCM Agreement regulates governmental-sponsored renewable energy programs remains highly uncertain. As of July 2019, the WTO’s adjudicatory bodies have never found that the SCM Agreement regulates government-sponsored renewable energy support programs. Today, governments generally do not know whether or not their renewable energy subsidies violate the SCM Agreement, on which only subsidies specifically within the meaning of Article 2 SCM Agreement can be subject to the discipline on the agreement. Therefore, the understanding and application of the “specificity” play key roles in order to achieve effective and sound implementation of multilateral subsidy discipline. WTO panels and the appellate body have determined “specificity” as a unit of “subsidy program”. Most of the renewable energy subsidies will be deemed specific if the determination of their specificity is based on each law or regulation. This is caused by the dominance of fossil fuels in the energy industry and the fact that most forms of renewable energy subsidies are producer/production subsidies. Unfortunately, the SCM Agreement does not include any exceptions to these programs. Under such circumstances, a practical solution should be found within the existing framework and be derived from an interpretation of the present SCM Agreement. Therefore, the WTO DSB should fully consider the value and significance of renewable energy subsidies as countermeasures against climate change in interpreting the “subsidy programme” in Article 2(1)(c) of the SCM Agreement. The interpretation of the WTO covered agreement is governed by Articles 31 to 33 of the Vienna Convention on the Law of Treaties (“VCLT”). Article 3(2) of the Understanding on Rules and Procedures Governing the Settlement of Disputes(“DSU”) provides that the WTO DSB role is to clarify the existing provisions of those agreements in accordance with customary rules of public international law interpretation. Article 1.1(a)(1)(iii) of the SCM Agreement explicitly excludes the provision of ‘general infrastructure’ from the definition of the ‘financial contribution by the government’. As it is properly interpreted and considered as the ‘context’ of a treaty, t...

철근콘크리트 구조물의 강재를 이용한 내진성능 보강효과

정란,박태원 단국대 부설 리모델링연구소 2003 리모델링 연구소 논문집 Vol.1 No.2

This paper studied the efficiency of retrofitting of reinforced concrete structure which was not designed to endure an earthquake. The earthquake in Kobe, Japan showed that there was a great possibility of having an earthquake even in big city and the damages were concentrated on mid or low story buildings which were not considered to be protected from an earthquake. This experiment used reinforced concrete structure which restrained side-by-side displacement-to test durability against an earthquake. This study deals with the structural performance of reinforced concrete frame structures strengthened with steel materials.

탄소섬유판으로 횡보강된 콘크리트 압축부재의 보강성능

정란,이희경,김성철,유성훈,김중구,Chung, Lan,Lee, Hee-Kyoung,Kim, Sung-Chul,Yoo, Seong-Hoon,Kim, Joong-Koo 한국콘크리트학회 1998 콘크리트학회지 Vol.10 No.6

본 연구에서는 에폭시 모르터를 접착제로 사용한 탄소섬유판 접착공법을 사용하여 철그콘크리트 구조물의 주요부재인 압축부재를 간격, 두께, 폭, 겹수 및 이음길이의 변수로 하여 횡보강한 콘크리트 압축부재의 구조적 거동에 관한 연구를 실험적으로 진행하였다. 파괴양상은 보강된 시험체 모두가 보강재인 탄소섬유판의 인장파단과 동시에 급작스러운 취성파괴로 파괴를 보여주었다. 연구결과 압축부재 시험체를 동일한 조건으로 횡보강할 경우, 시험체의 지름에 대한 길이의 비가 다르더라고 횡보강도니 시험체의 구조적 거동은 같게 나타났다. 압축부재 시험체의 보강효과는 보강재의 간격이 좁을수록 동일하중에서의 변위는 작아지고, 연성이 커지는 것으로 나타났으며, 보강재의 폭이 다르더라도 보강량과 보강겹수가 같으면 횡보강효과는 거의 같은 것으로 나타났다. 또한 횡보강 시, 보강재 두께가 증가하면 그와 비례하여 횡보강효과도 증가하는 것으로 나타났다. 보강재의 겹수가 증가할 경우 보강재 겹수 증가에 의한 보강효과 증가는 비례적이지 않을 것으로 나타났다. Compressive strength of concrete compression members strengthend with carbon fiber laminate(CFL) were studied from the test results. Test parameters are spacing, thickness, width, ply and spliced length of carbon fiber laminates. Specimens strength with sheets failed with sudden tensile rupture of the laminate, which indicate very brittle failure mode. Test result shows that closer spacing and to increas thickness of CFL is more effective. But strengthening ratio with 1-ply CFL is more effective than that of specimen with 2-ply CFL. Compressive strength capacity of specimen splied 24cm shows almost similar strength to that of non-spliced specimen. The ultimate load carrying of specimen strengthened with CFL ranges 1.11~1.86 times of that of non-strengthened specimen.

반복하중을 받는 철근의 부착 응력도에 관한 실험적 연구

정란,박현수,조동철 단국대학교 신소재기술연구소 1991 신소재 Vol.1 No.-

지진하중에 대한 철근콘크리트 구조물의 거동을 예측하기 위해 지금까지 진행하였던 많은 실험들이 단순증가 반복하중을 작용시키고 있다. 그러나 실제 지진에 의해 발생되는 하중은 불규칙 반복하중으로써 이전까지 관례적으로 행해졌던 규칙적인 단순증가 반복하중에 의한 실험결과가 얼마만큼 신빙성이 있는가를 검토할 필요가 있다. 본 연구에서는 지진하중에 대한 실험에서는 어떠한 하중을 가져야 실제 거동과 근사한 결과를 얻을 수 있는가를 예측하기 위하여 철근콤크리트 구조물의 구조적 취약부분인 보-기둥 접합부에 규칙적인 단순증가 반복하중과 불규칙 반복하중을 작용시켜 접합부의 부착응력도의 분포를 비교 분석하였다. The prediction and estimation of R/C structure behavlor subjected to earthquake type loading is partly based on the experimental results of the monotonically increased cyclic loading, rather than that of the irregularly increased cyclic loading. However, actual earthquake is typical random vibration. In this respect, comparing and analysing experimental test results of R/C specimens subjected to monotonically increased cyclic loading and irrcgularly increased cyclic loading, this study proposes the research direction of irregularly increased cyclic loading during earthquake.