• 한국강구조학회 논문집
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• 제20권1호
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• pp.1-8
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• 2008

강재 박스거더교의 바닥틀을 구성하며, 바닥판의 활하중과 고정하중을 지지하는 가로보와 세로보의 설계 합리화를 위한 연구가 수행되었다. 가로보는 일반 거더교의 수직 브레이싱 규정을 근거로 6m 이하의 간격으로 조밀하게 배치되며, 세로보는 가로보 사이에 배치된다. 또한 가로보와 세로보는 바닥판과 슬래브 앵커로 연결되지만, 허용응력은 횡비틀림좌굴의 발생을 고려하여 보수적으로 결정 된다. 강박스거더교의 경제성을 도모하고 가설 및 유지관리시의 편의성을 증진시키기 위하여 가로보의 간격을 10m로 증가시켜 세로보와 가로보 의 단면 및 이음부 설계에 대해 검토하였다. 세로보의 지간이 증가함에 따라 응력이 증가하여 고강도의 강재를 사용해야 하지만, 제작 및 유지관리면에서 세로보의 지간을 증가시키는 것이 바람직하며, 경제적으로도 유리할 것으로 판단된다. 바닥판과 세로보 및 가로보의 부착 강도를 충분히 확보하기 위해서는 기존에 사용되고 있는 슬래브 앵커 보다는 전단연결재를 활용하는 것이 바람직한 것으로 판단된다.

• 한국안전학회지
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• 제20권3호
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• pp.134-142
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• 2005

This study is to find out how organic solvent will be propagated from painting inside the steel box girder of bridge. $2.9m{\times}3.0m$ of inside size of steel box girder is not suitable for painters to do his work comfortably and hygienically. Substance density(ppm)inside the space of the box unsatisfactory hygienical condition. Most of organic solvent(mainly toluene) came down to 0.5m in two minutes and 53sec. But personal protection for painter should be properly kept against flying this heavy organic solvent. longitudinally 27.1m in length is a cell unit of the whole length of bridge. Model XP-3l6A made in Japan is a main instrumentation adjusted to sense organic solvent especially toluene which can be measured up to 10,000ppm. Scenario analysis by computer program, safer release 2.0 has been performed first to estimate how the organic solvent will be propagated. And then actual test was done as a model. This has been measured for approximately five(5) minutes, with 30 sec interval. Actual measurement results showed much higher $10{\sim}20%$ than result analyzed by the computer program, meaning that this painting work can give worse effect to the worker who is painting inside the box girder of the bridge. The first meas urement level over the floor set up at 30cm height from the floor, because organic solvent was estimated to stay at the level. and then, they were measured at 1.0m, 1.5m level respectively, more.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.381-388
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• 2000

The steel piers and the concrete-filled steel piers, in spite of reasonable strength, high ductility, small section, and fast construction, have not been considered as the alternatives to the RC piers even in the highly populated urban area where aseismic safety, limited space and fast construction are indispensably required. In this paper, a steel pier and 4 box type concrete-filled steel piers were tested with the quasi-static cyclic loading to estimate the ductility and the strength. Additional devices such as base rib, turn-buckle, and anchor bolted added at the to increase the ductility with minimum additional cost. The result showed that the concrete filled-in steel piers had higher energy absorbtion and strength than steel piers had, but also showed that slight overlooking in the design and fabrication could lead to the abrupt fracture just after small local buckling at the bottom.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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• pp.80-86
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• 1997

Recently, the box-girder bridge became quite popular because of the effectiveness of the box section against torsional deformation, and the finite element method has been one of the powerful and versatile method for obtaining the solution of box-girder bridge. The finite element method is used to solve a box girder which is built up with flat plates such as flanges, webs and diaphragm, and box girder is idealized by 8-nodes 2-dimensional isoparmetric finite element. To investigate the stress of diaphragm, substructure analysis is performed with two Parameters which are the location of support and slope of web.

• Structural Engineering and Mechanics
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• 제69권2호
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• pp.193-204
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• 2019

This paper presents results from experimental and numerical studies on the response of steel-concrete composite box bridge girders under certain localized fire exposure conditions. Two composite box bridge girders, a simply supported girder and a continuous girder respectively, were tested under simultaneous loading and fire exposure. The simply supported girder was exposed to fire over 40% of its span length in the middle zone, and the two-span continuous girder was exposed to fire over 38% of its length of the first span and full length of the second span. A measurement method based on comparative rate of deflection was provided to predict the failure time in the hogging moment zone of continuous composite box bridge girders under certain localized fire exposure condition. Parameters including transverse and longitudinal stiffeners and fire scenarios were introduced to investigate fire resistance of the composite box bridge girders. Test results show that failure of the simply supported girder is governed by the deflection limit state, whereas failure of the continuous girder occurs through bending buckling of the web and bottom slab in the hogging moment zone. Deflection based criterion may not be reliable in evaluating failure of continuous composite box bridge girder under certain fire exposure condition. The fire resistance (failure time) of the continuous girder is higher than that of the simply supported girder. Data from fire tests is successfully utilized to validate a finite element based numerical model for further investigating the response of composite box bridge girders exposed to localized fire. Results from numerical analysis show that fire resistance of composite box bridge girders can be highly influenced by the spacing of longitudinal stiffeners and fire severity. The continuous composite box bridge girder with closer longitudinal stiffeners has better fire resistance than the simply composite box bridge girder. It is concluded that the fire resistance of continuous composite box bridge girders can be significantly enhanced by preventing the hogging moment zone from exposure to fire. Longitudinal stiffeners with closer spacing can enhance fire resistance of composite box bridge girders. The increase of transverse stiffeners has no significant effect on fire resistance of composite box bridge girders.

• 한국안전학회지
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• 제31권5호
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• pp.102-108
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• 2016

This paper presents a new strength method of underground box structures under additional surface load. An L-bracing using pre-flexed steel member threads called the "Pre-flex strength method" is used to improve capacity of the RC box structure under earth pressure due to additional surface load. The pre-flexed steel member is fixed the top and bottom of the structure after chemical anchor was installed by drilling hole on the box structure. The structural performance was evaluated analytically. 3 types of underground RC box structure were used; $2.0m{\times}2.0m$, $3.0m{\times}3.0m$ and $4.0m{\times}4.0m$. For the performance evaluation, structure analysis were performed on moment and shear resisting structures with and without pre-flex strength method. Numerical results confirmed that the proposed strength member system installed on underground RC box structures enhanced the strength capacity. The feasible region of the proposed pre-flex strength method in accordance with the earth pressure due to additional surface depth was evaluated.

• 상하수도학회지
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• 제31권6호
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• pp.619-628
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• 2017

As the 3D laser scanning technology capable of databaseing large sewage box culverts becomes possible, it is necessary to develop a standardization manual that can clearly distinguish the structural and operational defect types of box culver and analyze the defect data. In this study, we collected and analyzed defects in sewage box culverts of 14,827m in total by selecting three districts in Korea. The major defects were surface damages, and their defect densities were $2.17m^2/m$, $0.27m^2/m$ and $0.10m^2/m$ for aggregate exposure, Steel reinforcement exposure, and Steel reinforcement projecting. In order to support the decision of the box culverment management, it was divided into five grades and each defect code and defect score were allocated. The results of this study are useful for the diagnosis of the sewage box culverts in Korea and it is expected to support a decision making for management.

• 한국강구조학회 논문집
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• 제15권2호
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• pp.125-135
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• 2003

BEF유사법과 Ritz의 방법을 이용한 매개변수 해석과 유사한 결과를 보이는 격벽이 없는 직선 및 곡선 강상자형 교의 3차원 모델을 구현하였고, 여기에 격벽을 추가하여 A-10, A-20, A-30, B-10, B-20, B-30모델에 대한 격벽의 적정 간격을 산정하였다. 그 결과 지간 50m의 곡선 강상자형교의 적정 격벽수는 전술한 모델의 순서대로 5개(8.3m), 7개(6.25m), 8개(5.5m), 4개(10m), 6개(7.1m), 7개(6.25m)이다. 또한 3차원 유한요소 모델을 해석한 결과를 바탕으로 뒤틀림응력과 휨응력의 비를 계산하는 수식을 제안하였다.

• 콘크리트학회논문집
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• 제26권6호
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• pp.707-714
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• 2014

콘크리트 충전강관(CFT)은 강관의 내부에 콘크리트로 채워진 기둥이다. CFT는 강재와 콘크리트로 구성되며, 강재는 콘크리트를 내부에서 구속시켰고, 내부 콘크리트는 기둥의 압축하중을 감당한다. 본 실험에서 73~100MPa급 고강도 콘크리트에 관해 유동성실험, 압축강도실험, 압송압력실험을 실시하였으며, CFT용 고강도 콘크리트의 물리적 성질을 알아보기 위해 슬럼프, 슬럼프 플로우, 공기량, U-box시험, O-Lot시험, L-flow시험이 진행되었다. 이러한 연구의 결과를 바탕으로 Mock-up테스트에서 콘크리트 충전성 시험, 수화열 측정 시험, 응력계측 시험을 수행하였다. 현장적용은 상암동 및 서강대 현장의 두 곳에 각각 ${\Box}-566{\times}566{\times}10$, ${\Box}-400{\times}400{\times}25$의 대상기둥을 선정하여 현장계측을 진행하였다. CFT기둥의 장기거동 예측에 관하여 설계하중에 대해 콘크리트의 탄성변형과 건조수축, 크리프 수축을 고려한 ACI 209 재료모델을 사용한 결과는 계측결과와 거의 일치하였다.

• 한국강구조학회 논문집
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• 제23권2호
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• pp.249-259
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• 2011

본 연구에서는 비틀림 하중을 받는 U형 강박스 거더의 뒤틀림 거동을 해석적으로 분석하여 거더 내부에 설치되는 수직브레이싱의 각 부재에 발생하는 부재력을 산정하는 수식이 개발되었다. 편심하중 또는 거더의 곡률에 의해 발생하는 비틀림하중을 박스단면내 상대적인 변형과는 무관한 순수 비틀림 성분력과 박스 단면내 뒤틀림을 유발하는 뒤틀림 성분력으로 분해하여 뒤틀림 성분력과 이에 저항하는 내부 수직브레이싱의 상호작용 효과를 분석함으로써 각 부재에 발생하는 부재력을 비틀림하중의 함수로 도출하였다. 제안식의 타당성을 검증하기 위하여 편심하중을 받는 단경간 직선거더 및 전경간 일정한 곡률을 가지는 3경간 거더 예제를 선정하여 3차원 유한요소 모델링을 수행하고 해석을 통해 얻은 내부 수직브레이싱의 각 부재력을 제안식으로 산정된 값과 비교 분석하였다. 해석 및 제안식으로 결정된 각각의 부재력은 높은 수준으로 일치함을 보였다.