• 전산구조공학
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• 제12권4호
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• pp.69-69
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• 1999

Design of Dangsan Steel Railway Bridge(a part of Seoul Subway Line NO. 2), which is supposed to be replaced after its 15years survice, was done, and the reconstruction has begun in Dec. 1997. The design include new superstruc-ture and bridge piers, retrofitting of the foun-dation, rail system, electric and signal, etc. In this paper, design of the structure is mainly summarized. The main span superstructure, across Han river, is composite section which is com-posed of steel box and reinforced concrete deck slab with 9 span continuous. The superstructure for the approaches is bottom througth type 2-cell steel box girder with steel floor system and concrete deck slab with 3 or 4 span continuous. The bridge piers was planned to be reconstructed based upon the result from the various investi-gations, while the foundation(cassion and pile foundation) was planned to be retrofitted. For superstructure erection, the method of combination of barge bent and heavy lifting and the launching truss method was investigated for the main span and approach spans, respectively.

• 설비공학논문집
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• 제16권7호
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• pp.658-666
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• 2004

In this paper, a two-dimensional transient ground-coupled numerical model for slab-on-grade foundation is developed and integrated into EnergyPlus. A validation analysis is first presented to ensure that for the developed building foundation heat transfer module is properly implemented within EnergyPlus. Then, the predictions from the developed model are compared to those obtained from the simplified building foundation model currently used in EnergyPlus. The results show that the developed foundation heat transfer module accounts better for the effects of the ground thermal mass attributed to the ground than the simplified foundation model currently used in EnergyPlus.

• 한국지진공학회논문집
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• 제5권3호
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• pp.19-27
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• 2001

구조물의 지진해석시 구조물-지반 상호작용의 영향을 무시할 수 없으며, 기초지반강성에 따른 구조물의 지진응답에 커다란 차이가 있다는 것은 이미 잘 알려져 있다. 이러한 인식에도 불구하고, 현재 벽식구조 아파트의 지진해석시 기조지반의 특성을 무시하고 기초가 매우 단단한 것으로 가정하여 지진해석을 수행하고 있다 본 연구에서는 구조형식이 독특한 의식구조 아파트 지진해석을 연약지반을 고려하여 수행하고, 지진응답을 암반과 UBC-97 지반조건의 연약지반을 고려한 지진응답과 비교분석하였다. 깊은 연약지반 위에 세워진 중, 저층 벽식구조 아파트의 내진거동은 기조의 절연효과로 지진응답이 크게 감소된 강체거동을 보여 UBC-97 설계응답스펙 트럼으로 내진설계를 하는 것은 보수적인 설계로 안전은 하지만 상당히 비경제적인 것으로 판단되었다.

• Geomechanics and Engineering
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• 제17권2호
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• pp.119-131
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• 2019

Time dependent creep settlements are one of the most important causes of material deteriorations for the huge water structures such as concrete faced rockfill dams (CFRDs). For this reason, performing creep analyses of CFRDs is vital important for monitoring and evaluating of the future and safety of such dams. In this study, it is observed how changes viscoplastic behaviour of a CFR dam depending the time. Ilısu dam that is the longest concrete faced rockfill dam (1775 m) in the world is selected for the three dimensional (3D) analyses. 3D finite difference model of Ilısu dam is modelled using FLAC3D software based on the finite difference method. Two different special creep material models are considered in the numerical analyses. Wipp-creep viscoplastic material model and burger-creep viscoplastic material model were rarely used for the creep analyses of CFRDs in the last are taken into account for the concrete slab and rockfill materials-foundation, respectively. Moreover, interface elements are defined between the concrete slab-rockfill materials and rockfill materials-foundation to provide interaction condition for 3D model. Firstly, dam and foundation are collapsed under its self-weight and static behaviour of the dam is evaluated for the empty reservoir conditions. Then, reservoir water is modelled considering maximum water level of the dam and time-dependent creep analyses are performed for maximum reservoir condition. In this paper, maximum principal stresses, vertical-horizontal displacements and pore pressures that may occur on the dam body surface during 30 years (from 2017 to 2047) are evaluated in detail. According to numerical analyses, empty and maximum reservoir conditions of Ilısu dam are compared with each other in detail. 4 various nodal points are selected under the concrete slab to better seen viscoplastic behaviour changes of the dam and viscoplastic behaviour differences of these points during 30 years are graphically presented. It is clearly seen that horizontal-vertical displacements and principal stresses for maximum reservoir condition are more than the empty reservoir condition of the dam and significant pore pressures are observed during 30 years for maximum reservoir condition. In addition, horizontal-vertical displacements, principal stresses and pore pressures for 4 nodal points obviously increased until a certain time and changes decreased after this time.

• 한국지반환경공학회 논문집
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• 제15권12호
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• pp.87-95
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• 2014

최근 공동주택 수직증축 리모델링 사업 등 기초구조물을 보강하기 위한 기술적 수요가 증가하고 있다. 본 논문에서는 기존 구조물을 지지하는 기존말뚝에 보강말뚝을 추가로 설치할 경우 추가하중에 의한 기존말뚝과 보강말뚝의 하중분담 특성을 연구하였다. 정사각형의 기초판에 설치된 기존말뚝 4본에 허용하중을 재하한 후, 기초판 중앙에 보강말뚝 1본을 추가로 설치하고 추가하중을 재하하였다. 실험결과로부터 기존말뚝에 재하되는 하중이 허용지지력을 초과한 이후에 기존말뚝과 보강말뚝이 하중을 균등하게 분담하는 것으로 분석되었다. 기존말뚝에 허용하중 재하 후, 허용하중 대비 60 %, 80 %, 100 %까지 제하(unloading)하고, 보강말뚝을 설치한 후 추가하중을 재재하(reloading)하는 실험을 수행하였다. 연구 결과 제하 하중의 양이 증가함에 따라 재재하 시 기존말뚝과 보강말뚝이 하중을 균등하게 분담하는 재재하 하중이 감소하는 경향을 파악하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.982-987
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• 2002

Recently, as size of building structure becomes larger, mat area of building structure is supported on Inhomogeneous foundation. The equipment machineries in building are mostly on basement story. The slab of the lowest basement story with equipment machineries is considered as plate supported on foundation with concentrated masses. In this paper, vibration analysis of rectangular thin plate is done by use of rectangular finite element with 4 nodes. The solution of this paper are compared with existing solution and natural frequencies of thin plates, with concented mass, on inhomogeneous Pasternak foundation are calculated

• 한국철도학회논문집
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• 제11권2호
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• pp.195-202
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• 2008

교량과 토공의 접속부은 궤도의 대표적인 취약구간으로서 교대배면의 부등침하로 인한 궤도틀림발생이 빈번하여 유지관리에 많은 어려움을 겪고 있는 구간 중의 하나이다. 콘크리트궤도부설구간의 경우에는 교대배면의 부등침하를 방지하기 위하여 접속슬래브 부설이 일반화되고 있는 추세이다. 이 경우, 접속슬래브를 지지하고 있는 노반의 침하로 인하여 접속슬래브에 경사처짐이 발생하게 되면 궤도도 경사처짐이 발생하게 된다. 이로 인해 이 구간을 통과하는 차량의 주행안정성과 승차감의 저하, 그리고 과도한 충격에 의한 궤도의 손상을 유발하게 되므로 접속슬래브의 단부에서의 침하를 제한할 필요가 있다. 따라서 본 연구에서는 콘크리트 궤도 부설 교량과 토공의 접속부에 부설되는 접속슬래브의 단부에서의 처짐한도를 알아보기 위하여 접속슬래브의 길이와 단부처짐량을 매개변수로 한 차량-궤도 상호작용 해석을 실시하여 차체가속도, 윤중변동률, 레일 저부응력, 그리고 체결구에 발생하는 상향압력을 조사하였으며, 수치해석결과와 각 검토항목별 허용한도와의 비교검토를 통하여 접속슬래브의 길이에 따른 단부처짐의 허용한도를 제시하였다.

• 산업기술연구
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• 제17권
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• pp.191-197
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• 1997

For each construction material used, there is certain theoretical limit in sizes. For tall building construction, the reduction in slab weight is the first step to take in order to break such size limits. In this paper, the feasibility of such objective is proven and given by numerical analysis result. For a typical building slab, both concrete and advanced composite sandwich panels are considered. The concrete slab is treated as a special orthotropic plate to obtain more accurate result. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, in this paper. The influence of the modulus of the foundation on the natural frequency is thoroughly studied.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.333-336
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• 1999

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as mat-slab of nuclear reactor buildings, dams or large footings, foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, pre-cooling which lowers the initial temperature of fresh concrete with ice flake, pipe cooling which cools the temperature of concrete with flowing water, design change which considers steel bar reinforcement, operation control and so on. The Aim of this paper is to verify the effect of low heat blended cement in reducing thermal stress in slab type's mass concrete such as container harbor structures.

• 콘크리트학회지
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• 제22권5호
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• pp.71-77
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• 2010