고강도 경량골재콘크리트의 동결융해 저항성에 대한 실험적 연구

한상묵,최세규,김생빈 한국콘크리트학회 1998 콘크리트학회지 Vol.10 No.1

경량골재 콘크리트의 내구성과 경제성에 대한 인식 부족으로 조경재료나 인공토양 둥 구조부재 이외의 분야에 사용되고 있는 국내 실정에 비해서, 구미 여러나라에서는 고강도 경량골재를 장지간 교량과 고충건물에 사용하고 있다. 경량골재 콘크리트는 구조물의 재료비 단순비교에 있어서도 경제성이 있을 뿐만 아니라, 자중감소로 인한 구조적, 기하학적 장점도 있으며, 또한 고강도 경량골재의 개발로 경량골재가 가지고 있는 여러 문제점을 해소하여 사용성과 내구성에 있어서 보통골재 콘크리트와 큰 차이가 없는 상황이다. 그러나국내에서 생산된 경량골재는 닫힌 공극보다 열린 공극을 많이 내포하고 있어 수분흡수가 많고, 특히, 동결융해에 대한 내구성에 취약한 문제점을 가지고 있다. 본 논문에서는 내동해성 향상을 위해 10종류의 고강도 경량골재 콘크리트 공시체를 제작하여 실리카 흄, 물.시멘트비, AE제, 강섬유 등을 실험 변수로 하여동결융해 실험을 수행하였다. 연구결과 실리카흄, 물.시멘트 비는 어느 정도 내동해성을 향상시키지만 근본적인 해결방안이 되지 못하며, AE제를 첨가한 공시체와 강섬유를 사용한 공시체는 동결융해 내구성 지수가 90%이상으로 측정되어 내동해성을 개선시킬 수 있는 요소로 나타났다.

초고강도 섬유보강 직사각형 콘크리트보의 모멘트-곡률 관계

한상묵,궈칭용,Han,Sang-Mook,Guo,Qing-Yong 한국방재학회 2011 한국방재학회논문집 Vol.11 No.3

압축강도 100 MPa, 140 MPa 초고강도 섬유보강 콘크리트 직사각형보와 기하하적 조건 및 PS힘이 동일한 160 MPa RPC 직사각형보의 휨거동 비교를 통하여 압축강도가 낮은 초고강도 섬유보강 콘크리트 구조물의 거동 특성을 파악하였다. 직사각형보에 철근은 배근되지 않았으며 실험변수로는 강섬유, 콘크리트 압축강도, 프리스트레스 도입 방식, PS강재비 등이다. 모멘트-곡률관계와 하중-처짐관계를 통하여 압축응력이 작은 UHPC 직사각형보의 거동 특징을 분석하였다. 초고강도 섬유보강 콘크리트에 대한 간단한 형태의 응력-변형률 관계를 제안하였으며 이를 이용하여 UHPC 직사각형보에 대한 모멘트-곡률관계를 산정하였다. 실험에 의한 모멘트-곡률관계를 비교한 결과 상당히 일치함을 알 수 있었다. The flexural behavior of the UHPFRC rectangular beam which has 100 MPa, 140 MPa compressive strength were compared with that of the typical RPC rectangular beam which has same geometrical shape, prestressd force and 160 MPa compressive strength. UHPFRC beam was not reinforced at all and the variable of test is fraction of steel fiber, compressive strength of concrete, method of prestressing and ratio of prestressing bar. The behavior of UHPFRC beam was analysed by relationship of moment - curvature and load - deflection. Simple modeling of stress-strain of UHPFRC was proposed. Based on the proposed constituted, the flexural moment-curvature relationship was calculated and compared with experimental data on prestressed UHPFRC beams. Good agreement between calculated strengths and experimental data is obtained.

지진하중을 받는 빌딩 복합 모델의 추계론적 비선형 해석

한상묵 金烏工科大學校 1990 論文集 Vol.11 No.-

In modeling buildings for earthquake response analysis, the so-called "shear beam model" has been used extensively. The drawbacks in this simple model is the incapability of reflection the coupling between stories for weak-beam type building. For more quantitative assesment of damage a more detailed modeling would be necessary. The proposed structural model for multistory and multi-frame reinforced concrete building is essentially an extension of the conventional shear-beam model by dding elastic bending columns at each floor and connected to the floor by inelastic rotational springs.

지진하중을 받는 구조물과 비선형 이력거동에 대한 확률론적 해석

한상묵 國立金烏工科大學校附設生産技術硏究所 1989 産業技術開發硏究 Vol.5 No.-

This paper is suggested the method for evaluating the effect of soil-structure interaction or the dynamic response of nonlinear building-foundation system subjected to random seismic excitation. The subsystem approach is adopted to model soilstructure system. The super-structure is modeled as a shear-heam. The substructure is considered as a surface foundation on a halfspace. The nonlinear behavior in the substructure as well as in the superstructure is depicted by the smooth hysteretic model. The nonlinear behavior in the coupled system is associated with the material nonlinearity in the structure and soil deposit, as well as the geometric nonlinearity caused foundation uplifting.

鐵筋콘크리트보의 材料非線形 有限要素 解析

韓相默 國立金烏工科大學校附設生産技術硏究所 1987 産業技術開發硏究 Vol.3 No.-

In this paper, the finit element method for the material nonlinear analysis of reinforced concrete beam is developed. Parabolic-linear and bilinear-parabolic approximations of the stress-strain curves are used for concrete and reinforcing steel, respectively. This method is capable of predicting the respense of these structures througout their service load range as well as throughout elastic, enelastic and collapse load ranges. An incremental load method combined with unbalanced load iterations for each increment is used for the solution of the nonlinear equilibrium equations. And the results are compared with experimental data obtained by other investigator.

프리스트레스트 콘크리트 뼈대구조물의 시간의존적 효과를 고려한 기하학적 및 재료적 비선형 해석

안기업,한상묵 金烏工科大學校 1994 論文集 Vol.15 No.-

An efficient numerical procedure for the material and geometric nonlinear analysis of prestressed concrete frames including the time-dependent effects due to load history, temperature history, creep shrinkage and aging of concrete and relaxation of prestress is developed. The procedure is capable of predicting the response of these structures throughout their service load history as well as throughout elastic, inelastic and ultimate load ranges. Pre-tensioned, post-tensioned bonded and unbonded frames are analyzed distinguishing three distinct stages of loading; i,e. before, at the after the transfer of prestress. A numerical example is presented to study the applicability of the present method. The results are compared with experimental results and the analytical results obtained by other investigators.

유한요소법을 이용한 철근콘크리트보의 비선형 해석

박정섭,장일영,송재호,한상묵 金烏工科大學校 1998 論文集 Vol.19 No.-

The method of finite element analysis is modified in this study to predict the material nonlinear behavior of reinforced concrete structure more properly. It is difficult to predict the behavior of reinforced concrete structure due to the development of concrete crack, the behavior of compressive failure, bond properties between concrete and steel, and shear resistance. To predict the material nonlinear behavior of reinforced concrete structure more properly, the stress-strain relationship of confined concrete which proposed by Attard, Setunge is considered. Also, shear retention model is considered. To prove the efficiency of the analysis, analytical results are compared to experimental results.

초고강도 섬유보강 콘크리트 프리스트레스트 거더의 극한 전단력

한상묵,오향국 한국방재학회 2008 한국방재학회논문집 Vol.8 No.2

This study is to investigate the ultimate shear load of prestressed girder made of Ultra High Performance Fiber Reinforced Concrete (UHPFRC). Nine girders were tested until failure in shear. An analytical model to predict the ultimate shear load was formulated based on the Two Bounds Theory. A fiber reinforcing model was constituted based on the random assumption of steel fiber uniform distribution. The predicted values were compared with the conventional predictions and the test results. The proposed equations for computing the ultimate shear strength can be used for the ultimate failure status analysis, which could also be utilized for numerical limit analysis of prestressed UHPFRC girder. The established fiber reinforcing theoretical model can also be a reference for micro-mechanics analysis of UHPFRC. 본 연구는 전단철근이 없는 초고강도 섬유보강 콘크리트 프리스트레스 I형거더의 극한전단파괴하중 산정에 대한 이론적 근거를 마련하는데 있다. 9개의 초고강도 섬유보강 콘크리트 거더에 대한 극한 전단하중을 측정하였다. 전단하중을 산정하기 위한 해석식은 두 경계이론을 근거로 유도되었다. 섬유가 부담하는 전단력 산정모델은 섬유가 방향과 길이면에서 균일하게 분포한다는 가정하에서 구성되었다. 본 논문에서 제안한 초고강도 섬유보강 콘크리트 거더에 대한 전단 강도식을 기존의 섬유보강 콘크리트 전단강도식과 실험에 의한 전단하중과 비교한 결과 비교적 정확한 산정값을 보여주었다.

지진하중을 받는 구조물의 확률론을 이용한 비선형 동적해석

張基泰,韓相默 金烏工科大學校 1986 論文集 Vol.7 No.-

In many methods of the nonlinear random vibration analysis, this paper choose a equivalent linearization of hysteretic system with smoth restoring forces. The hysteretic restoring force is modeled by a nonlinear differential equation and the equation of motion is linearized directly in closed form. The coefficient of the linearized system if obtained exactly as simpl algebraic function of the repose variable statictics. Compared with previosly proposed similar methods, the formulation of the present method is verified well against Monta-Carlo simulation for all response levels. It has a great potential in the analysis of multi-degree of freedom and degrading system.

유한요서법을 이용한 하중분배계수에 관한 연구

송재호,장일영,한상묵 金烏工科大學校 産業技術開發硏究院 1999 産業技術開發硏究 Vol.15 No.-

AASHTO specification has been found to be approximate value because these methods are based on equivalent orthogonal plate theory and semicontinuum theory. This study compared the results of field tests to confirm validity of the proposed formulas which is developed rational finite element model and carried out finite element analysis and statistic techniques. Parametric studies of load distribution on box-girder bridges are performed. The parameters affecting load distribution factors include girder spacing, span length, bridge width, and number of girders. Results of proposed formula are compared with those of AASHTO specification, AASHTO-LRFD specification.