• 대한토목학회논문집
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• 제29권5A호
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• pp.447-456
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• 2009

연속경간 강합성 플레이트 거더 및 박스 거더 단면을 현 도로교설계기준의 허용응력설계법(ASD)과 AASHTO-LRFD 설계기준에 근거하여 최근 교량설계핵심기술연구단을 중심으로 제안된 하중저항계수설계법으로 설계하였다. 두 방법으로 설계된 강거더 단면의 강재량과 구조성능을 분석하였으며, 휨파괴에 대한 신뢰도해석을 수행하고 신뢰도지수를 비교 및 분석하였다. ASD법으로 설계 시에는 현 도로교설계기준에 규정된 DB-24 및 DL-24 설계활하중을, LRFD법으로 설계 시에는 최근 국내 통행차량 측정결과 통계에 근거하여 제안된 설계활하중을 적용하였다. 3경간 연속교의 경간비를 4:5:4로 가정하고 중앙부 최대경간장은 30~80 m를 고려하였다. 두 방법으로 설계된 강합성거더 단면의 휨파괴에 대한 신뢰도해석은 국내에서 생산된 16,000여 구조용 강재 표본의 항복강도 통계적 특성이 반영된 휨저항강도의 통계를 이용하여 수행하였다.

• 대한토목학회논문집
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• 제30권3A호
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• pp.317-328
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• 2010

이 연구에서는 강섬유보강 초고강도 콘크리트 보의 휨강도를 산정하기 위한 실제적인 기법을 제시하였다. 14개의 보 부재에 대해 휨실험을 수행하여 휨거동 특성을 분석하였으며, 실험결과를 기존의 설계기준 및 제안기법에 의한 예측결과와 비교 분석하였다. ACI 544 위원회의 휨강도 제안식에 의한 예측값은 실험값을 과소평가하고 있으며, 이는 인장응력블록을 너무 작게 산정하기 때문이다. 인장응력블록을 정밀하게 모델링하기 위하여 노치를 갖는 프리즘 시편의 3점 휨인장실험자료의 역해석을 수행하였으며, 역해석을 통해 산정한 인장연화곡선을 인장응력블록 모델링에 적용하였다. 휨강도 실험값에 대한 제안기법에 의한 예측값의 비는 0.98~1.14를 나타내고 있다. 따라서, 이 연구에서의 제안기법은 강섬유보강 초고강도 콘크리트 보의 휨강도를 더욱 정확하게 예측할 수 있다고 판단된다.

• 대한토목학회논문집
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• 제30권1A호
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• pp.35-43
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• 2010

프리캐스트 패널은 교량바닥판의 합성 구조부재로서 사용된다. 프리캐스트 패널의 횡방향 강재는 교량바닥판의 주철근 역할을 하며, 또한, 패널 상부의 현장타설 콘크리트 시공시 거푸집 대용으로 적용된다. 그러나 프리캐스트 패널의 장점을 살리기 위해서는 필연적으로 갖게 되는 구조적 특징이자 취약점이 될 수 있는 이음부 부분에 대한 이해와 지식이 필요하다. 특히, 교량바닥판은 차량하중과 같은 반복하중을 받는 구조물이므로 피로하중에 대한 이음부의 거동 및 성능 평가가 이루어져야 한다. 본 연구에서는 전단철근과 루프이음부를 갖는 프리캐스트 패널 합성바닥판의 피로실험을 수행하였다. 피로실험은 고정점 반복하중과 윤하중을 적용하여 수행되었다. 피로에 대한 현행 설계기준을 고려하고 이음부의 피로파괴 특성과 반복하중하에서의 사용성 평가를 위해 결과 분석을 수행하였다.

• 한국안전학회지
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• 제29권3호
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• pp.72-78
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• 2014

The minimum thickness of long-span deck slab is proposed by checking the limit state according to the Korean highway bridge design code(limit state design). Both minimizing thickness and ensuring safety of deck slab are important design factors to increase a competitive price of the long span deck slabs. The required thicknesses for satisfying flexural capacity, preventing punching shear failure and limiting deflection were calculated by considering KL-510 load model which has increased total load compared to DB 24 from 432 kN to 510 kN. The results of the required thickness for various limit states were compared to propose the minimum thickness as a function of span length of deck slabs. The proposed minimum thickness is influenced by satisfying flexural capacity and limiting deflection. It turns out to be similar compared to the results of the previous study by ultimate strength design method even if the live load model was increased in total weights.

• 한국측량학회지
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• 제35권4호
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• pp.231-240
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• 2017

This paper aims to study a method to estimate precise carbon absorption by quantification of forest information that uses accurate LiDAR data, hyperspectral image. To estimate precise carbon absorption value by using spatial data, a problem was found out of carbon absorption value estimation method with statistical method, which is already existed method, and then offered optimized carbon absorption estimation method with spatial information by analyzing with methods of compare digital aerial photogrammetry and LiDAR data. It turned out possible Precise classification and quantification in case of using LiDAR and hyperspectral image. Various classification of tree species was possible with use of LiDAR and hyperspectral image. Classification of hyperspectral image was matched in general with field survey and Mahalanobis distance classification method. Precise forest resources could be extracted using high density LiDAR data. Compared with existing method, 19.7% in forest area, 19.2% in total carbon absorption, 0.9% in absorption per unit area of difference created, and improvement was found out to be estimated precisely in international code.

• 한국항공우주학회지
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• 제46권8호
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• pp.671-678
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• 2018

헬리콥터 소음예측은 저소음 헬리콥터 기술 개발에 필수적인 과정이다. 본 논문에서는 헬리콥터 통합성능해석프로그램 CAMRAD-II와 자체개발한 소음해석코드를 이용하여 소음예측 기법을 구축하였다. 또한 헬리콥터 소음 중 가장 큰 원인인 블레이드-와류 간섭 소음을 분석하여 해석기법을 검증하였다. 실제적인 소음예측을 위해 국제민간항공기구(ICAO)에서 기준으로 하고 있는 헬리콥터 소음 측정 비행조건인 Flyover, Approach 조건에 대해서 소음해석을 수행하였으며, 최종적으로 비행시험결과 와의 비교 분석을 통해 해석방법의 적합성을 확인하였다.

• 한국안전학회지
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• 제25권5호
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• pp.44-53
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• 2010

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. However, in the domestic and abroad code, the equation of ultimate stress of external tendon is not suggested yet, and the equation of ultimate stress of internal unbonded tendon is used instead of that of external tendon. Therefore, in this paper, after effective variables of ultimate stress of external tendon were analyzed, the analytical equation of ultimate stress of external tendon was proposed. And the reasonable coefficients were proposed by statistical work of test results of 25 beam with external tendon. Finally, the practical proposed equation of ultimate stress of external tendon was proposed with analytical and statistical model. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of external tendons in analysis and design.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1987년도 학술발표회 발표강연집
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• pp.51-80
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• 1987

In this studys a numerical analysis on the defomation of foundation layer was carried out by indroducing joint element. The method using the joust element between adj assent different materials has been originally developed for rock behavior(Goodman, et al. 1968) . The application of this method to the interface between the footing and soil layer proved satisfactory(Ghaboussi p et at. 1973). Authors tried to obtain the deformation of rrcompound foundation layerg", which vertically or horizontally or both consists of the natural(or intact) soft clay layer and the layer improved artificially in order to get high stiff-fness with replacement or chemical treatment to reduce the excessively detrimental settlemellt or lateral displacement in case of banking or building the civil structure on the soft layer. The joint conditions were classified into three categories : contacts sliding and separation. By coupling "JOINT" as a subroutine into multi-purpose code for the finite element method of the foundatlion daveloped by authors on the assumption that shearing and normal displacement can not be coupledl which terms pinon-dilatant" and by selecting modified Cam-clay modeIP the deformation analysis was performmed. The results using joint element were compared with those secured without introduction of joint element Nain results analized are as follows : 1. For the prediction of settlement and lateral desplacement, the result due to joint element was evaluated larger, which was regarded safe. 2. For the determination of ultimate bearing capacetyi the value using joint element appeared smaller by 20%, which was also safe.

• 한국산업융합학회 논문집
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• 제4권4호
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• pp.419-426
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• 2001

Concrete mix proportioning is a process of selecting the right combination of many materials such as cement, fine aggregates, coarse aggregates, water, and admixtures to make concrete satisfying for specification and cost. In determining proportioning of concrete mixes, code information, specification, and the experience of experts are needed. However, all factors regarding mix proportioning factor cannot be considered. Therefore, the final acceptance depends on concrete quality control test results. The proportioning of concrete mixes and the adjustments are somewhat complicated, time-consuming, and uncertain tasks. In this paper, as a tool to predict the factor of the proportioning of concrete mixes, an artificial neural network is used. To consider the varieties of material properties, the standard mixed table of two companies of ready mixed concrete are used. The results show that neural net works is successfully applied to the prediction of concrete mix proportioning factor.

• 한국중재학회지:중재연구
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• 제25권1호
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• pp.47-64
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• 2015

Pursuant to Article 109(1) of the Attorney-at-Law Act of Korea, a person, not an attorney-at-law, who receives or promises to receive money, articles, entertainment or other benefits or who gives or promises to give those things to a third party, in compensation for providing or mediating legal services, such as examination, representation, arbitration(emphasis added), settlement, solicitation, legal consultation, making of legal documents, etc. shall be punished by imprisonment with prison labor for not more than 7 years or by a fine not exceeding KRW 50 million or may be punished by both and there is no specific provision on qualification of arbitrator except on nationality of an arbitrator in the Arbitration Act of Korea. Then, the question arises, can any non-lawyer arbitrator who receives arbitrator's fees be punished in accordance with the Attorney-at-Law Act in Korea? To search for an answer for this matter, this paper examines the Arbitration Act or the Civil Procedure Code of 33 major countries in the world and explains a research on the participation ratio of non-lawyer arbitrators in all 360 arbitration cases registered in 2012 at the Korean Commercial Arbitration Board (KCAB).