• Computers and Concrete
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• 제1권1호
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• pp.15-30
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• 2004

In this study, a design process for reinforced concrete structures using the nonlinear FEM analysis is developed. Instead of using the nonlinear analysis to evaluate the required performance after design process, the nonlinear analysis is applied before designing the reinforcement arrangement inside the RC structures. An automatic reinforcement generator for computer aided reinforcement agreement is developed for this purpose. Based on a nonlinear FEM program for analyzing the reinforced concrete structure, a smart fictitious material model of steel, is proposed which can self-adjust the reinforcement to the required amount at the cracking location according to the load increment. Using this tool, the reinforcement ratio required at design load level can be decided automatically. In this paper, an example of RC beam with opening is used to verify the proposed process. Finally, a trial design process for a real size underground RC LNG tank is introduced.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.253-257
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• 1996

A basic assumption in the current design and analysis of reinforced concrete(RC) box structures, which are constructed by the open cut and fill method, is that the displacements and forces are uniform in the longitudinal direction of the structure. The solution may be therefore obtatined from the analysis of a unit wide strip along longitudinal axis. This strip is said to be in a plane strain condition, meaning that the out of plane deformations are vanished. The current design of box structure is carried out by the result of planar frame model for the sake of simplicity. The purpose of this study is to show more rational design method of box culverts considering a rigid zone of corner joints. The current analysis of box structures will be compared with the plane strain analysis as well as 3-d shell model. Reinforcement quantity is also determined to resist the tensile force in corner joints of box structures using strut-tie model which has been developed through the elastic analysis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.597-600
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• 2006

In Marine Land underground reinforced concrete structures, such as electric box power structure, water and chloride ion penetrated into concrete through the cracks of concrete and its permeable property, cause the corrosion of reinforcing steel bar, which accelerates the expansive cracks and deterioration of concrete. The purpose of this paper is to evaluate on deterioration of durability concrete through instrumental analysis such as schmidt hammer and carbonation, chloride content. Under the reclaimed marine land, the main cause of deterioration of concrete structures is the steel corrosion due to the penetration of chlorides and the deterioration of outer concrete itself by chemical attack.

• 한국터널지하공간학회 논문집
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• 제13권2호
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• pp.149-158
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• 2011

최근 장기 부식 등 일반적인 건설재료의 문제점을 보완할 수 있는 대체 재료로서, 섬유강화 복합재료의 활용이 증대되고 있다. 하지만 일반적으로 선형의 섬유강화 복합재료를 아치형인 터널구조물의 부재로서 활용하는 데는 많은 문제점이 대두된다. 본 연구에서는 FRP 복합부재의 거동특성 파악을 위한 수치해석적 사전검토 연구를 토대로, 터널 지보구조물로서 활용성 분석을 위한 FRP와 콘크리트 합성부재에 대한 하중재하 실험을 수행하였다. 또한 역학적 거동분석을 위하여 동일 조건에 대한 수치해석을 수행하였다. 하중재하 실험 및 수치해석결과, FRP와 콘크리트 합성부재는 두 부재 계면의 휨 인장에 의한 전단거동에 큰 영향을 받는 것으로 나타났다.

• 한국터널지하공간학회 논문집
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• 제3권4호
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• pp.25-34
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• 2001

산지가 70%를 차지하고 있는 우리나라 지형특성상 고속도로 건설에 비례하여 터널연장의 증가는 필연적이라 할 수 있다. 본 연구에서는 터널 내,외부의 온도차이에 의한 균열에 저항할 수 있도록 하기위해 터널 입,출구부에 설치되는 철근콘크리트 라이닝의 시공성 및 안전성,경제성을 확보할 수 있는 방안으로 강섬유보강 콘크리트(Steel Fiber Reinforcement Concrete, SFRC)의 적용성에 대해 연구하였다. SFRC의 특징을 조사하고 터널 갱구부 라이닝 구조부재로서 구조해석과 현장 시험시공을 통해 SFRC의 적용방안과 차후 확대 적용을 위한 개선방안을 제시하였다.

• 한국농공학회지
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• 제40권5호
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• pp.68-79
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• 1998

In the years, the concern about high-strength concrete which is new material has been heightened as a result of active research and development. Recently, as the building structure has been being bigger, higher, longer and more specialized, the demand of material with high-strength concrete for building has been increasing. The demand of high -strength concrete is expected to increase with expansion of usage about the complex concrete structures such as bridge structure as well as nuclear plants, underground structures, hydraulic structures and arctic area sturctures. In this research, silica-fume was used as an admixture in order to get a high-strength concrete. Water/binder ration was limited no more than 18 percent and the amount of unit cement was increased. In this study, a number of trial in concrete mix was carried out to get optimal mix design, and the target slump with $10{\pm}2cm$ was set for in-situ construction. High-strength concrete with cylinder strength of 1,200kgf/$cm^2$ in the 28-days was produced and tested. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns, fracture modes. The load versus strain and load versus deflection relations were obtained form the static test. The test results were compared with the shear strengths predicted by the equations of ACI code 318-89 and orther researchers. Based on the test results, shear strength equation of reinforced concrete beam using high strength concrete was proposed. Form an evaluation of the results of this experimental investigation, it was concluded that shear strength after diagonal tention cracking diminished with the increase in compressive strength for beams.

• Steel and Composite Structures
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• 제30권3호
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• pp.217-230
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• 2019

One of the most important design criteria in underground structure is to design lightweight protective layers to resist significant blast loads. Sandwich blast resistant panels are commonly used to protect underground structures. The front face of the sandwich panel is designed to resist the blast load and the core is designed to mitigate the blast energy from reaching the back panel. The design is to allow the sandwich panel to be repaired efficiently. Hence, the underground structure can be used under repeated blast loads. In this study, a novel sandwich panel, named RC panel - Helical springs- RC panel (RHR) sandwich panel, which consists of normal strength reinforced concrete (RC) panels at the front and the back and steel compression helical springs in the middle, is proposed. In this study, a detailed 3D nonlinear numerical analysis is proposed using the nonlinear finite element software, AUTODYN. The accuracy of the blast load and RHR Sandwich panel modelling are validated using available experimental results. The results show that the proposed finite element model can be used efficiently and effectively to simulate the nonlinear dynamic behaviour of the newly proposed RHR sandwich panels under different ranges of free air blast loads. Detailed parameter study is then conducted using the validated finite element model. The results show that the newly proposed RHR sandwich panel can be used as a reliable and effective lightweight protective layer for underground structures.

• 한국지반공학회논문집
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• 제20권3호
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• pp.23-31
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• 2004

일반적으로 코팅은 철근 콘크리트를 보호하기 위해 사용되어지며, 이러한 목적으로 사용되어지는 코팅에는 무기계 뿐만 아니라 유기계 코팅이 있다. 무기계 코팅의 장점은 자외선 흡수성이 적고 불연성이라는 것이며, 반면 유기계 코형의 장점은 $CO_2, SO_2$투과성 및 물의 투수성이 낮으며, 철근 콘크리트의 보호능력은 유기계 코팅이 더 우수하다. 그러나 에폭시, 우레탄 및 아크릴과 같은 유기계 코팅은 콘크리트와의 열팽창계수와 탄성계수 차이로 인해 장기 접착강도가 저하되고, 통기성이 부족하여 형성된 막에 들뜸이 발생된다. 또한 유기계 코팅이 콘크러트의 습윤면에 적용될 경우에는 접착의 문제가 발생된다. 본 연구에서는 콘크리트를 보호하기 위해 폴리머와 세라믹을 합성시켜 개발된 코팅제의 물리 성능과 내구 성능 및 용출 안전성에 대한 시험을 하였다. 개발된 코팅계에 대하여 유기계 코팅재 및 에폭시와 비교하였으며, 시험결과 개발된 코팅재는 콘크리트를 보호하기 위한 유기계 코팅재에 비해 성능이 떨어지지 않았고, 반면 용출 안전성 측면에서는 에폭시보다 더 우수함을 보였다. 특히 물과 접해 있는 지하 콘크리트구조물을 보호하는 데에 적합하며, 무기계와 유기계 코팅재의 장점을 갖은 콘크리트 보호용 코팅재라고 판단된다.

• 한국터널지하공간학회 논문집
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• 제12권6호
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• pp.451-461
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• 2010

장기 부식 등 일반적인 건설재료의 문제점을 보완할 수 있는 대체재료로서, 섬유강화 복합재료의 활용이 증대되고 있다. 하지만 일반적으로 선형의 섬유강화 복합재료를 아치형인 터널구조물의 부재로서 활용하는 데는 많은 문제점이 대두된다. 따라서, 본 연구에서는 섬유강화 복합부재를 일정곡률로 인발성형 할 수 있는 신개념의 곡면 FRP 부재 성형장비를 개발하고 시제품을 생산하였으며, 시제품에 대한 물리적 특성 시험을 수행하였다. 이어, 곡면 FRP 시제품과 합체되어 제작된 콘크리트 복합부재에 대한 수치해석 검토 및 분석을 통하여 시제품의 터널 구조체로써의 적용성을 평가하였다. 수치해석적 적용성 검토 결과, 곡면 FRP 부재를 터널 구조물로 적용함에 있어서 터널 안정성을 충분히 확보할 수 있는 것으로 파악되었다.

• 국제초고층학회논문집
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• 제10권3호
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• pp.211-218
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• 2021

A new type of earthquake resilient reinforced concrete (RC) shear wall structure, installed with replaceable coupling beams and replaceable corner components at the bottom of wall piers, is proposed in this study. At first, the mechanical behavior of replaceable components, such as combined dampers and replaceable corner component, is studied by cyclic loading tests on them. Then, cycling loading tests are conducted on one conventional coupled shear wall and one new type of coupled shear wall with replaceable components. The test results indicate that the damage of the new type of coupled shear wall concentrates on replaceable components and the left parts are well protected. Finally, a case study is introduced. The responses of one conventional frame-tube structure and one new type of structure installed with replaceable components under the wind and the earthquake are compared, which verify that the performance of new type of structure is much better than the conventional structure.