유한요소 해석을 이용한 WUF-W 접합부 최적의 파단 예측 반응지표 선정

한상환,김영우,김태오,Han, Sang Whan,Kim, Young Woo,Kim, Tae O 한국지진공학회 2017 한국지진공학회논문집 Vol.21 No.5

The WUF-W moment connection is a pre-qualified connection that can be used for special moment frames specified in current seismic design specifications. Since the stress distribution near the connection varies according to access hole configuration, the cyclic performance of WUF-W connections is strongly affected by the access hole configurations. To evaluate the connection performance according to various access hole configurations, it is expensive to conduct experiments with many connection specimens. Instead, finite element analyses (FEA) can be performed. Throughout the FEA, stress and strain distribution in the connection can be monitored at each loading step. The purpose of this study is to construct nonlinear 3-dimensional FE models for accurately predicting the cyclic behavior of WUF-W connections. For predicting connection fracture using FEA, an appropriate response index detecting the incidence of connection rupture is proposed.

반복하중을 받는 고강도강 기둥을 적용한 WUF-W 접합부의 이력 거동

한상환,김종민,문기훈,Han, Sang-Whan,Kim, Jong-Min,Moon, Ki-Hoon 대한건축학회 2011 대한건축학회논문집 Vol.27 No.7

This study's purpose is to evaluate the seismic performance of Welded Unreinforced Flange-Welded Web connections with the column composed of high-performance steel. The study involved the inelastic cyclic loading test of 4 full-scale exterior connection specimens to evaluate the effect of column strength and beam depth. All specimens are designed as strong column-weak beam and strong panel zone. They are observed at the peak deformation of each cycles with the unaided eye. 3 of 4 specimens including 2 specimens consisted of high-performance steel column are achieved total story drift of 0.04 rad or more prior to failure. The test results showed that ductility capacity of connections with high-performance steel column is sufficient in light of current AISC seismic design. Energy dissipation in specimens consisting of high-performance steel column is less than those of normal strength steel column. Also, K120TG, which is the developed weld metal for 800MPa grade steel, is estimated as good material in case of welding between normal strength steel and high-performance steel through this study.

크롬 폭로가 자매염색분체교환 빈도 및 8-hydroxydeoxyguanosine 농도에 미치는 영향

한상환,조수헌,김헌,하미나,주영수,박수민,권호장,김용대,정명희,Han, Sang-Hwan,Cho, Soo-Hun,Kim, Heon,Ha, Mi-Na,Joo, Young-Soo,Park, Soo-Min,Kwon, Ho-Jang,Kim, Yong-Dae,Chung, Myung-Hee 대한예방의학회 1995 예방의학회지 Vol.28 No.2

크롬염 안료제조공장 근로자를 대상으로 크롬 폭로와 말초혈액 림프구의 8-OH-dG 농도의 상관성을 직접 관찰함으로써 크롬의 암 발생기전에 산소유리기(oxygen free radical)가 관여하는지 여부와 크롬폭로에 따라 자매염색분체교환 빈도가 증가하는지를 밝힐 목적으로 본 연구를 수행하였다. 안료공장에 1년 이상 근무한 근로자 38명을 대상으로 설문지를 통하여 근무기간, 연령, 성, 크롬 폭로와 관련된 자각적 증상 등을 조사하였으며, 이들의 크롬 폭로 수준을 평가할 수 있는 생물학적 지표로서 혈중 및 크레아티닌 보정 요중 크롬 농도를 측정하였다. 크롬에 의한 생물학적 영향지표로서 말초혈액 림프구로 부터 dG에 대한 8-OH-dG의 몰 농도비를 측정하였으며, 분열 중기의 세포 30개를 관찰하여 세포당 자매염색분체교환 빈도를 계수하여 염색체 46개당 평균 자매 염색분체교환 빈도로 환산하였다. 분석결과 현재 크롬 폭로 수준을 판단하는 생물학적지표로 가장 많이 사용되는 크레아티닌 보정 요중 크롬 농도와 림프구에서의 dG에 대한 8-OH-dG의 물 농도비는 유의한 상관관계(r=0.47, p<0.01)를 보이는 것으로 분석되었으며, 현재의 흡연수준을 보정하고 분석한 결과에서는 상관계수가 증가하는 결과(r=0.62, p<0.05)를 나타내었다. 한편 자매염색분체교환 빈도와 크롬 폭로수준간에는 유의한 상관관계가 관찰되지 않았다. 이러한 결과는 크롬의 발암성에 DNA 부가체(adduct)의 형성이 중요한 기전일 수 있다는 기존의 연구결과와 일치하며, 따라서 8-OH-dG는 크롬에 의한 발암성을 예측할 수 있는 생물학적 영향지표로서 활용될 수 있음을 시사한다고 할 수 있다. To elucidate some DNA adducts as a biological marker for workers of chromate pigment, the effects of chromium exposure on the formation of 8-hydroxydeoxyguanosine(8-OH-dG) and sister chromatid exchanges(SCEs) frequency in 38 workers of a pigment plant in Bucheon which utilized lead chromates, were examined. The chromium contents of venous blood and urine were measured as working environmental exposure level. The concentrations of 8-OH-dG in DNA isolated from lymphocytes were determined with high performance liquid chromatography and electrochemical detector and denoted as a molar ratio of 8-OH-dG to deoxyguanosine(dG). The SCEs frequency were analyzed in DNA isolated from lymphocytes. A significant correlation was found between creatinine adjusted urine chromium concentration and the molar ratio of 8-OH-dG to dG(r=0.47, p<0.01). After adjusting the current smoking habit, the correlation coefficient was increased(r=0.62, p<0.05). However, there was no significant correlation between the SCE frequency and chromium exposure. This significant results between molar ratio of 8-OH-dG to dG and chromium exposure are in good agreement with in vitro studies that support the importance of DNA adduct formation for the carcinogenic effect of chromium.

오미자(五味子) 전탕액(煎湯液)의 투여(投與)가 흰쥐의 혈청(血淸) cholesterol 대사(代射)에 미치는 영향(影響)

한상환,Han, Sang-Hwan 대한한방내과학회 1998 大韓韓方內科學會誌 Vol.19 No.1

It was investigated effect of Fructure schizandra chinesis Water extract on the white rat which was induced hypercholesterolemia by fatty diet. The results obtained were summarized as follows; Neutral lipid level in blood lipid was greatly decreased on the group being fed animal fat diet and Fructure schizandra chinesis Water extract, total cholesterol was decreased on the group being fed vegetative fat diet, HDL-cholesterol was shown that the group being fed vegetative fat diet and Fructure schizandra chinesis Water extract at a time more increased HDL-cholesterol in a little than the other group, and normal fat diet group show to highest figure,38.5mg/dl. Animal fat diet group is 20.75 mg/dl. but, the group being fed Fructure schizandra chinesis Water extract was increased to 31.00mg/dl. LDL-cholesterol had no difference between fat diet group and the group being fed Fructure schizandra chinesis Water extract.

두충(杜沖) 전탕액(煎湯液)이 흰쥐의 혈청(血淸) 지질(脂質) 대사(代謝)에 미치는 영향(影響)

한상환,Han, Sang-Hwan 대한한방내과학회 2000 大韓韓方內科學會誌 Vol.21 No.3

The effects of 3% Cortex Eucommiae extracts on serum lipid contents were evaluated in rats. Forty-two male Sprague-Dawley rats weighing $100{\pm}10g$ were divided into seven groups and fed different fat diets for four weeks. Each group was administered with following group: Control, basal fat diet, saturated fat diet and unsaturated fat diet respectively was fed 1% cholesterol, Cortex Eucommiae extracts 3%. The contents of serum lipid contents triglyceride in the basal fat diet group were higher than those of control group. The contents of total-cholesterol in serum of the saturated fat diet group was significantly higher than other group. The contents of HDL-cholesterol in serum of the 3% Cortex Eucommiae extract group were higher than those other fat diet group. The contents of LDL-cholesterol in serum of the 3% Cortex Eucommiae ex1ract group was lower than other fat diet groups. These results suggest that 3% Cortex Eucommiae extract group may reduced elevated levels of serum lipid contents in rats different fed fat diet.

군용 항공기 이륙소음이 청력, 혈압, 스트레스 및 주관적 인지도에 미치는 영향

한상환,조수헌,고경심,권호장,하미나,주영수,신명희,Han, Sang-Hwan,Cho, Soo-Hun,Koh, Kyung-Shim,Kwon, Ho-Jang,Ha, Mi-Na,Ju, Yeong-Su,Shin, Myung-Hee 대한예방의학회 1997 예방의학회지 Vol.30 No.2

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed are3. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups (males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. Th, audiometric, test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p<0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly in high frequency, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group.

WUF-W 접합부의 액세스 홀 형상변수 타당성 평가를 위한 경험식 제안

한상환,윤용,Han, Sang Whan,Yoon, Yong,Kim, Y. Debbie 한국강구조학회 2017 韓國鋼構造學會 論文集 Vol.29 No.4

WUF-W 접합부는 부재의 접합이 모두 용접으로 이루어진 접합부이며, 특수모멘트골조(SMF) 인증접합부 중 하나이다. 하지만 선행 연구들을 통해 일부 WUF-W 접합부 실험체가 4% 층간변위비의 특수모멘트골조(SMF) 요구성능을 만족하지 못하였으며, 이는 액세스 홀 형상과 연관이 있음이 보고되었다. 본 연구에서는 비선형 유한요소 해석을 이용하여 WUF-W 접합부의 요구성능을 만족하기 위한 주요 액세스홀 형상변수의 허용범위를 결정하였다. 또한 WUF-W 접합부 설계과정에서 주요 액세스 홀 형상변수의 타당성을 평가할 수 있는 간단한 경험식을 제안하였다. The welded unreinforced flange-welded web(WUF-W) connection is an all-welded moment connection, which is qualified for special moment frame(SMF) connections. However, previous studies reported that some WUF-W connections did not meet the drift requirement specified for SMF connections and such unexpected connection performance was resulted from weld access hole geometry. The objective of this study is to determine the permissible ranges of major access hole parameters such as access hole slope and the length of flat portion that lead to the satisfactory performance of WUF-W connections using Nonlinear finite element analyses are conducted. This study also proposes simple empirical equations to check the validity of access hole parameters to be selected in design process.

리브 보강된 콘크리트 충전 HSS 가새부재의 이력 거동

한상환,여승민,김욱태,Han, Sang Whan,Yeo, Seung Min,Kim, Wook Tae 한국강구조학회 2005 韓國鋼構造學會 論文集 Vol.17 No.1

The purpose of this study is to improve the seismic behavior of the bracing members. Lee and Goel's (1987) concrete filling in the hollow structural section (HSS) reduced the severity of local buckling and increased the fracture life. However, concrete filling in the HSS did not prevent the occurrence of local buckling in the midsection of the bracing member, which resulted in continuous strength degradation. This study investigated the seismic behavior of the concrete-filled HSS bracing member, which is reinforced by ribs in the midsection of the bracing member. The main variable of the specimens is rib length. The test results showed that buckling mode, cyclic compression strength, and energy dissipation capacity of the bracing members were affected by rib length. Specimen reinforced with ribs with a length of 63% had better structural performance. 본 연구의 목적은 가새 골조에서 사용되는 가새 부재를 보강하여 가새 골조의 이력 거동을 향상시키는 것이다. HSS(Hollow Structural Section) 가새 부재는 국부 좌굴의 발생으로 인하여 인장측 성능에 비해 압축측 성능이 취약한 단점이 있다. 국부 좌굴의 심각성을 감소시키기 위하여 가새 부재에 콘크리트를 충전하는 방법이 사용되었다. Lee and Goel(1987)의 연구 결과에 따르면 콘크리트 충전은 HSS 가새 부재의 국부좌굴의 심각성을 감소시켜 파괴 수명을 증가시켰으나, 가새 부재 중앙부의 국부좌굴을 방지하지 못하여 지속적인 압축 강도의 저감이 나타났다. 따라서 본 연구에서는 가새 부재의 압축 강도를 증가시키고 중앙부의 국부 좌굴을 방지하기 위하여 콘크리트 충전 HSS 가새 부재의 중앙부를 리브로 보강한 실험체를 제작하여 실험하였다. 이를 위하여 리브 보강길이를 변수로 한 총 4개의 실물 크기의 가새 부재를 제작하였다. 하중은 압축과 인장이 대칭인 하중이력을 사용하였다. 본 실험에서 좌굴 모드, 사이클 최대 압축강도와 에너지 소산능력에서 나타난 리브 보강 가새 부재의 성능은 리브 보강길이에 따라 다르게 나타났으며, 63%의 길이로 보강한 실험체가 가장 우수한 성능을 나타내었다.

Post-Northridge WUF-B 접합부 골조의 내진 성능 평가

한상환,문기훈,정지은,이기학,Han, Sang Whan,Moon, Ki Hoon,Jung, Ji Eun,Lee, Ki Hak 한국강구조학회 2007 韓國鋼構造學會 論文集 Vol.19 No.6

본 연구에서는 Welded Unreinforced Flange-Bolted web(WUF-B) 접합부로 설계된 골조의 내진 성능 평가를 수행 하였다. WUF-B 접합부의 설계는 FEMA 350에서 제시한 방법을 사용하였으며, FEMA 350에 따르면 WUF-B 접합부 골조를 보통모멘트 골조(Ordinary Moment Resisting Steel Frames: OMFSFs)로 사용을 제한하고 있다. 이를 위해 WUF-B 접합부 실험결과를 바탕으로 패널존 강도 비를 변수로 하여 Post-Northridge WUF-B 접합부 해석 모델을 제안하였다. 이 해석 접합부 모델을 이용하여 SAC Phase II에서 사용된 3층, 9층 골조를 모델링 하고 내진 해석을 수행하였다. 해석 방법 중 비선형 정적 푸쉬오버 해석을 통하여 Post-Northridge 접합부 골조의 연성능력과 최대 모멘트 강도비, 최대 층간변위비를 구하였고, Incremental Dynamic Analysis(IDA)를 통해 각 성능 레벨(IO, CP)지점에서의 최대 층간변위비를 구하였다. 해석 결과는 Pre-Northridge 접합부 골조와 ductile 접합부 골조의 성능과 비교 검토 하였으며 접합부 상세 보강이 이루어진 Post-Northridge 접합부 골조의 성능이 Pre-Northridige 접합부 골조보다 향상된 것을 확인 할 수 있었다. The purpose of this study is to evaluate the seismic performance of the frame which is assumed to be used with Welded Unreinforced Flange-Bolted web (WUF-B) connections and detailed in compliance with FEMA 350 recommended seismic design criteria. In FEMA 350, these types of connections are only valid for Ordinary Moment-Resisting Steel Frames (OMRSFs). For this purpose, based on test results, we proposed an analytical model for the Post-Northridge WUF-B connections with different panel zone strength ratios. Using the connection model, SAC Phase II three and nine-story frames were modeled and analyzed. From a nonlinear static pushover analysis, ductility, maximum strength, and the maximum interstory drift ratio were investigated for buildings with Post-Northridge details. Moreover, the maximum interstory drift ratio of each performance level (IO and CP) was also investigated through Incremental Dynamic Analysis (IDA). Analytical results were compared with those of buildings with either Pre-Northridge connection or ductile connections with no fracture. The analytical results showed that buildings with Post-Northridge WUF-B connections provide superior strength and interstory drift ratio capacity than buildings with Pre-Northridge WUF-B connections.

중공 전이슬래브의 휨 및 전단강도

한상환,유연호,박영미,김준삼,임주혁,Han, Sang-Whan,Rew, Youn-Ho,Park, Young-Mi,Kim, Jun-Sam,Im, Ju-Hyeuk 대한건축학회 2011 대한건축학회논문집 Vol.27 No.2

The transfer slab system is widely used in high apartment building and is a structural system that transfers the loads from the upper shear wall structure to the lower columns. This system has convenience in construction but is noneconomic system due to a very thick slab. The fault is overcame by voids in the slab. Because the structural performance is, however, decreased by the voids, the strength prediction of the void slabs is very important. However, the current code doesn't provide a clear calculation provision for the strength of void slabs. In this study, experimental study was conducted to investigate the flexural strength and the one-way shear strength of the void transfer slab. The flexural and the shear strength of the specimens was predicted by current code and prior researches. In result, the flexural strength of void slabs is accurately predicted by the equation of the current code, and the shear strength is accurately predicted by shear equation of the code considering slab effective section of 45 degree from a support.