• 한국도로학회논문집
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• 제17권6호
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• pp.37-45
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• 2015

PURPOSES : The purpose of this study is to validate the design criteria of the concrete modular road system, which is a new semi-bridge-type concept road, through a comparison of numerical analysis results and actual loading test results under static axial loads. METHODS : To design the semi-bridge-type modular road, both the bridge design code and the concrete structural design code were adopted. The standard truck load (KL-510) was applied as the major traffic vehicle for the design loading condition. The dimension of the modular slab was designed in consideration of self-weight, axial load, environmental load, and combined loads, with ultimate limit state coefficients. The ANSYS APDL (2010) program was used for case studies of center and edge loading, and the analysis results were compared with the actual mock-up test results. RESULTS : A full-scale mock-up test was successfully conducted. The maximum longitudinal steel strains were measured as about 35 and 83.5 micro-strain (within elastic range) at center and edge loading locations, respectively, under a 100 kN dual-wheel loading condition by accelerating pavement tester. CONCLUSIONS : Based on the results of the comparison between the numerical analysis and the full-scale test, the maximum converted stress range at the edge location is 32~51% of the required standard flexural strength under the two times over-weight loading condition. In the case of edge loading, the maximum converted stresses from the Westergaard equation, the ANSYS APDL analysis, and the mock-up test are 1.95, 1.7, and 2.3 times of that of the center loading case, respectively. The primary reason for this difference is related to the assumption of the boundary conditions of the vertical connection between the slab module and the crossbeam module. Even though more research is required to fully define the boundary conditions, the proposed design criteria for the concrete modular road finally seems to be reasonable.

• Journal of the Korean Wood Science and Technology
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• 제32권5호
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• pp.66-74
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• 2004

내화 성능은 표준 화염 조건에 노출된 목구조물의 안전성 평가를 위한 중요한 기준이 된다. 내화 성능의 기준으로 여러 나라에서 지속 시간과 파괴 시까지의 시간이 사용되고 있다. 본 연구에서는 화염에 대한 신뢰성 설계의 기초 연구로서 화염에 노출된 목재 마루 시스템의 신뢰성 해석이 진행되었다. 해석은 수치 해석적 방법과 결정론적 방법 두 가지를 모두 사용하였다. 두 방법 간에는 큰 차이를 보이지 않았다. 화염에 노출된 마루시스템의 신뢰도는 부재의 변이계수에 크게 의존하였으며 부재의 강도나 하중은 신뢰도에 크게 영향하지 않았다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1572-1579
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• 2005

New procedure for evaluation of creep reduction factor using performance limit strain concept was introduced and confirmed through the creep test results. To determine the performance limit strain of the textile geogrid used in this study, the Sherby-Dorm Plots were applied and the results were compared with the results that applied existed limit strain criteria (GRI test method GG-4). The limit creep strain of the geogrid samples that determined by using the Sherby-Dorm Plots were all 11%. This value is more higher than the existed criteria as 10%. From this 11% limit strain the creep reduction factors were calculated at 100,000 hours design. It was resulted in 1.45 for all of the geogrid samples(8t/m, 10t/m). Finally, when it was compared with the creep reduction factors that using 10% criteria, there were some decrease of reduction factor values about $0.06{\sim}0.14$.

• 콘크리트학회논문집
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• 제17권6호
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• pp.911-922
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• 2005

섬유보강 콘크리트 보의 전단강도와 거동 특성을 규명하기 위해서 이론적 연구를 수행하였다. 섬유보강 콘크리트 보의 단면에 작용하는 전단력은 압축대와 인장대에 의해서 지지된다. 압축대의 전단성능은 단면의 휨모멘트에 의해서 발생하는 수직응력과의 상관관계를 고려하여 정의하였으며, 인장대의 전단성능은 섬유보강 콘크리트의 균열 후 인장강도를 고려하여 정의하였다. 보의 휨변형에 따라서 수직응력의 크기와 분포가 변화하므로, 보의 전단성능은 휭변형의 함수로 정의하였다. 전단성능곡선과 전단요구곡선의 교점에서, 보의 전단강도와 위험단면의 위치가 결정된다. 제안된 설계 방법은 섬유보강 콘크리트와 일반 콘크리트 보를 위한 통합전단강도모델로 사용 할 수 있다.

• 한국전산구조공학회논문집
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• 제25권6호
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• pp.525-532
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• 2012

근래에 지어진 건축물의 경우 지진에 대한 안전성을 확보하고 있지만 1983년 개정이전의 건축물은 내진설계가 미반영 되어 있어 지진에 대해 매우 취약하다. 본 연구에서는 내진성능이 부족한 기존 건축물의 지진 발생 시의 안전성 확보를 위한 내진보강 방안으로 격자강판 내진보강벽을 제안한다. 축력과 반복수평력을 받는 성능실험을 수행하였으며, 실험체는 벤치마크 용도로 순수 철근콘크리트 프레임(BM-RC)과 프레임 내부에 격자강판 내진보강벽(SW-RC)을 설치한 2개의 실험체를 제작하여 실험을 수행하였고, 축력과 횡하중 가력을 위하여 500kN용량의 엑츄에이터 2대와 2,000kN용량의 엑츄에이터 1대를 사용하였다. 실험결과를 통해 벤치마크 실험체와 비교하여 강도, 강성, 연성 및 에너지소산능력을 평가하였다.

• International Journal of Railway
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• 제2권3호
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• pp.124-126
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• 2009

Energy savings can be achieved with optimum energy consumptions, brake energy regeneration, efficient energy storage (onboard, line side), and primarily with light weight vehicles. Over the last few years, the rolling stock industry has experienced a marked increase in eco-awareness and needs for lower life cycle energy consumption costs. For rolling stock vehicle designers and engineers, weight has always been a critical design parameter. It is often specified directly or indirectly as contractual requirements. These requirements are usually expressed in terms of specified axle load limits, braking deceleration levels and/or demands for optimum energy consumptions. The contractual requirements for lower weights are becoming increasingly more stringent. Light weight vehicles with optimized strength to weight ratios are achievable through proven design processes. The primary driving processes consist of: $\bullet$ material selection to best contribute to the intended functionality and performance $\bullet$ design and design optimization to secure the intended functionality and performance $\bullet$ weight control processes to deliver the intended functionality and performance Aluminium has become the material of choice for modern light weight bodyshells. Steel sub-structures and in particular high strength steels are also used where high strength - high elongation characteristics out way the use of aluminium. With the improved characteristics and responses of composites against tire and smoke, small and large composite materials made components are also found in greater quantities in today's railway vehicles. Full scale hybrid composite rolling stock vehicles are being developed and tested. While an "overdesigned" bodyshell may be deemed as acceptable from a structural point of view, it can, in reality, be a weight saving missed opportunity. The conventional pass/fail structural criteria and existing passenger payload definitions promote conservative designs but they do not necessarily imply optimum lightweight designs. The weight to strength design optimization should be a fundamental design driving factor rather than a feeble post design activity. It should be more than a belated attempt to mitigate against contractual weight penalties. The weight control process must be rigorous, responsible, with achievable goals and above all must be integral to the design process. It should not be a mere tabulation of weights for the sole-purpose of predicting the axle loads and wheel balances compliance. The present paper explores and discusses the topics quoted above with a view to strengthen the recommendations and needs for the weight optimization by design approach as a pro-active design activity for the rolling stock industry at large.

• 산업기술연구
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• 제17권
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• pp.305-312
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• 1997

Shear connections in steel structures should satisfy dual criteria of shear strength and rotational flexibility and ductility. The connection should be strong enough to transfer the shear reaction of the beam, and should have sufficient rotational flexibility and ductility to rotate easily and supply the end rotation demand of the beam. This paper is concerned with the behavior of double-angle shear connections where the parameters are numbers of high strength bolts, bolt pitch, the length of angle leg, and connection method. An experimental investigation of shear connection was conducted by testing 12 beam-to-column joint specimens. Based on experimental and analytical study, the failure modes are developed and proposed design formulas.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.81-86
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• 2001

The concrete bridge decks are in need of replacement and rehabilitation due to decreasing load carrying capacity. In this study, to propose a strengthening technique that improves usability and structural performance of the bridge deck and to propose an efficient strengthening design technique which satisfies both the strength End serviceability of the bridge deck, this paper shows the failure characteristics of the strengthened bridge decks and proposes an empirical yield criterion. Therefore, strengthening efficiency was proposed based on the experiment and yield line analysis result. The yield line theory which adopts the modified criteria of Johansen is considered to predict the ultimate strength about all strengthening material(Carbon Fiber Sheet, Carbon Fiber Rod, Grid Type Carbon Fiber).

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.270-273
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• 2006

Bond between reinforcing bar and the surrounding concrete is made up of three components. There are chemical adesion, friction, and mechanical interaction between the rib of the bar and the surrounding concrete. bond of deformed bars depends primarily on the beraing of rib deformation anainst the surrounding concrete. The final objective of the study is to enhance structural stability, and workability thorough increasing the bond strength between deformed bar and surrounding concrete. The results of this study will be used to shorten bond and development length by $20{\sim}30$ percent and it will facilitate to use of high strength and high-relative rib area bars.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.119-126
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• 2003

In the conventional reinforced-concrete bridge deck, concrete and steels are likely to be deteriorated and corroded under the influence of noxious environment. To cope with these problems caused in the conventional reinforced-concrete bridge deck, pultruded composite bridge deck having light weight, high strength, corrosion resistence and durability is developed. Based on the previous study, Pultruded composite bridge deck is designed. For the DB24 truck load finite element analysis is performed to verify whether it meets both strength and serviceability design criteria. For the fabricated and assembled deck panel, structural testings are conducted. This paper present structural details and field application and testing results of composite bridge deck are presented. of composite bridge deck.