집중하중을 받는 철근콘크리트 깊은 보의 전단거동에 관한 실험적 연구

이진섭,김상식,Lee, Jin-Seop,Kim, Sang-Sik 한국콘크리트학회 1999 콘크리트학회지 Vol.11 No.1

집중하중을 받는 단순지지 철근콘크리트 깊은 보를 대상으로 콘크리트의 압축강도, 전단스팬비, 웨브 수직 및 수평 보강철근비를 변수로 하여 깊은 보의 구조거동과 전단강도를 실험적으로 조사하였으며, 각 변수의 영향을 고찰하고 규준식 및 제안식 등과 비교, 검토하였다. 42개의 시험체를 실험한 결과, 모든 시험체는 전단스팬 내에서 콘크리트의 과도한 균열 및 압괴에 의해 파괴되었고, 시험체의 초기강성은 압축강도에 관계없이 전단 스팬비가 작을수록 크게 나타났으며, 경사균열 발생 이후 보의 강성이 점진적으로 감소되었다. 전단스팬비가 증가함에 따라 경사균열 및 최대하중은 일정하게 감소하며, 콘크리트 압축강도가 증가할수록 최대하중은 증가하나 경사균열 하중은 거의 변화가 없었고, 전단스팬비의 증가에 따라 콘크리트의 압축강도가 전단강도에 미치는 영향 또한 일정하게 감소하는 것으로 보인다. 웨브의 전단보강근 효과는 전단스팬비의 영향을 받으며, 전단스팬비가 작아지면 수평보강근의 효과가, 전단스팬비가 커지면 수직보강근의 효과가 상대적으로 커짐을 알 수 있었다. 실험결과와 비교하여, 이론식은 de Paiva의 제안식이, 규준식은 CIRIA guide가 실험결과에 가장 부합하는 것으로 나타났으며, 국내 규준식은 실험값에 비해 상당히 낮은 강도로 계산되고 있어 안전 측에 있는 것으로 판단된다. The shear behavior of simply supported reinforced concrete deep beams subject to concentrated loads has been scrutinized experimentally to verify the influence of the structural parameters such as concrete strength, shear span-depth ratio, and web reinforcements. A total of 42 reinforced concrete deep beams with compressive strengths of 250 kg/$cm^2$ and 500 kg/$cm^2$ has been tested at the laboratory under one or two-point top loading. The shear span-depth ratio have been taken as three types of 0.4, 0.8 and 1.2, and the horizontal and vertical shear reinforcements ratio, ranging from 0.0 to 0.57 percent respectively. In the tests, the effects of the shear span-depth ratio, concrete strength and web reinforcements on the shear strength and crack initiation and propagation have been carefully checked and analyzed. From the tests, it has been observed that the failures of all specimens were due to shear and the shear behaviors of specimens were greatly affected by inclined cracks from the load application points to the supports in shear span. The load bearing capacities have changed significantly depending on the shear span ratio, and the efficiency of horizontal shear reinforcements were increased as the shear span-depth ratio decreased. The test results have been analyzed and compared with the formulas proposed by previous researchers and the design equation from the code. While the shear strengths obtained from the tests showed around 1.4 and 1.9 times higher than the values calculated by CIRIA guide and the domestic code, they were closely coincident with the formulas given by de Paiva's equation.

건설업 KOSHA 18001 인증제도의 실효성 제고에 관한 연구

이진섭 ( Jin Seop Lee ),이명구 ( Myeong Gu Lee ),이동율 ( Dong Yul Lee ),오태근 ( Tae Keun Oh ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.3

The industrial accidents in the construction business have decreased on the basis of the accreditation of KOSHA 18001, one of the occupational health and safety management system. However, the interest and investment into the KOSHA 18001 has grown down because of the worsened construction business so that the construction companies that maintain the system as a mere formality has begun to be displayed. In this regard, this study performed the interview with the internal and external review board as well as the question investigation from the persons concerned in order to apprehend the current problems in the KOSHA 18001. First of all, the internal reviewers in the KOSHA are lack in the comparison with the number of new and renew accreditation. Secondly, many persons concerned with the KOSHA has required the quantitative criteria for the accreditation. Consequently, the manpower supplement associated with the external reviewers, the grading evaluation would be strong solutions to improve the effectiveness of KOSHA 18001.

레이저치료 후 재발한 기저세포암

이진섭 ( Jin Sub Lee ),장용현 ( Yong Hyun Jang ),이석종 ( Seok Jong Lee ),김도원 ( Do Won Kim ),이원주 ( Weon Ju Lee ) 대한피부과학회 2013 大韓皮膚科學會誌 Vol.51 No.11

Background: In our outpatient clinic, we sometimes encounter basal cell carcinoma (BCC) patients that have a history of laser treatment without skin biopsy at private clinics. Objective: To investigate BCC that recurred after laser ablation. Methods: We performed a retrospective analysis of clinical reports of 635 BCC patients biopsy-proven from January 1997 to December 2012. Histopathological examination for BCC that recurred after laser ablation was done. Results: Out of 635, 85 had a history of one or more laser treatments for BCC before visiting our hospital. The mean age of patients was 66.3 years, and the ratio of male to female was 1 : 1.24. The most common site was the face (91.1%). Out of 85, 19 were treated by dermatologists and 8 by non-dermatologists. Out of 85, 58 did not remember the doctor`s specialty. Histopathological examination for BCC showed basaloid tumor cell nests and peripheral palisading in all patients and pigment deposits in over two third of the patients. One patient had accompanying intradermal nevocytic nests without transformation of nevus cell to basal cell carcinoma. Conclusion: BCC can be misdiagnosed as pigmented nevus and subsequently mistreated with laser ablation. Skin biopsy or dermoscopy should be considered to make a correct diagnosis when an ambiguous pigmented lesion is detected in a patient. (Korean J Dermatol 2013;51(11):858∼862)

SD600, SD700 철근의 기계적 이음

이용준(Yong-Jun, Lee),이진섭(Jin-Seop, Lee),이왕희(Wang-Hee, Lee),이용진(Yong-Jin, Lee),김길희(Kil-Hee, Kim) 한국콘크리트학회 2015 콘크리트학회지 Vol.27 No.3

외부 심사원을 통한 건설업 KOSHA 18001 활용도 개선에 관한 연구

이진섭 ( Jin Seop Lee ),이동율 ( Dong Yul Lee ),오태근 ( Tae Keun Oh ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.4

At the end of 2014, ordering organizations, 25 general contractors and 80 specialty contractors were certified by the KOSHA 18001 for the establishment of safety & health management system. However, safety management departments in the certified companies have been disrupted due to the financial difficulty and CEO’s indifference, which has resulted in the cancellation of more than 30% of the certifications. Furthermore, the KOSHA 18001 due to the shortage of internal evaluators in KOSHA and the increase of applications for new certification & the extension of the certification is placed in a difficult situation in the near future. Therefore, it is necessary to enhance the KOSHA 18001 by solutions such as introducing outside evaluators, which is the key point of this study. This study was performed through the questionnaire survey & the interviews with the construction companies, ordering organization and KOSHA 18001 specialists The content is centered on the introduction of external evaluators. As a result, the introduction of external evaluators is necessary through amending certification regulation because only internal evaluators cannot afford to process all the new application and the extension of existing certifications.

단관 파이프의 좌굴특성에 대한 수평연결재 및 기울기의 영향

이진섭 ( Jin Seop Lee ),이연수 ( Yeon Su Lee ),오태근 ( Tae Keun Oh ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.2

The number of collapse accidents relevant to form support since 2003 is 30 on the basis of statistical data from Ministry of Employment and Labor,. Total number of casualty was 138 (47 for deaths and 91 for injuries). The accident severity rate was high because the 4.6 casualties per one accident were occurred averagely although the incident rate was relatively low. Especially, one of form support members, the pipe supports have not been equipped adequately so that the accidents could have happened. In this regard, this study performed buckling test related to the effect of horizontal connection and slope in the single pipe which is one of typical pipe supports. The buckling load, which was estimated from the single pipe with the horizontal connectors theoretically and experimentally, was increased as more than 2 times compared to the buckling load obtained from the pipe supports without the connector. The buckling load was reduced as more than 26%, 34% slope of the single pipe comparing with 5% and 10% slope, respectively. Thus, the purpose of this study is to provide the guideline for installation and the maintenance of the pipe supports legally and institutionally to prevent the collapse accidents of the pipe supports.

크롬鍍金의 被覆力(Covering Power)改良方法에 對하여

李晋燮(J. S. Lee) 한국표면공학회 1972 한국표면공학회지 Vol.5 No.1

파이프 서포트의 좌굴특성에 대한 지지조건의 영향

이진섭 ( Jin Seop Lee ),이연수 ( Yeon Su Lee ),오태근 ( Tae Keun Oh ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.2

Recently, a lot more disasters in the temporary structures happen because the stabilities of the temporary structures are disregarded by the reduction of the unit cost, using defective materials, the existing materials and so on. Pipe supports, which are one of the temporary structures, are basically used for the most constructing works such as buildings, bridges, plants and so on. In the most sites, adequate support installations of the pipe supports have not been performed although the presence of the guideline legally and institutionally. In this study, therefore, the collapse accidents of the pipe supports were investigated on the basis of theoretical analysis as well as the buckling tests by simulating the site support condition. Both the theocratical analysis and test results show that the buckling load in the fixed ends is at least 4 times larger than one in the pinned ends. This results will be utilized for safety assurance as well as accident prevention the in the field application.

살두께 및 선단이 확장 보강된 PHC파일의 재료 및 지지력 특성

이진섭(Lee, Jin-Seop),송기용(Song, Ki-Yong) 대한건축학회 2010 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.30 No.1(구조계)

크롬鍍金의 제반문제와 다공성(多孔性) 크롬에 對하여

李晋燮(J. S. Lee) 한국표면공학회 1972 한국표면공학회지 Vol.5 No.3