• 한국강구조학회 논문집
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• 제16권3호통권70호
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• pp.325-332
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• 2004

강합성거더 교량의 단면은 강거더와 콘크리트 슬래브의 합성정도에 따라 각각 비합성, 부분합성 그리고 완전합성 단면들로 구분 할 수 있다. 국내의 경우 강합성거더 교량의 단면을 합성시키기 위하여 일반적으로 전단 연결재 중 스터드를 사용하도록 규정하고 있고, 진단 연결재가 없는 경우 즉 비합성 단면의 경우에는 바닥판 앵커를 설치하도록 경험적으로 규정하고 있다. 그러나 바닥판 앵커를 사용한 단면의 실제 거동은 비합성 거동이 아닌 부분합성의 거동을 나타낸다. 그러한 이유로 본 연구에서는 바닥판 앵커를 사용한 플레이트거더교의 부분합성에 관한 해석 및 실험연구를 수행하였다. 실험연구를 통해서 바닥판 앵커의 초기강성을 산정하였고, 해석연구를 통해서 바닥판 앵커를 사용한 단순 및 2경간 연속 플레이트거더교의 합성정도를 비교$\cdot$분석하였다. 또한, 실험에 의해 산정된 강성 값에 근거하여, 2경간 연속 플레이트거더교에 바닥판 앵커를 적용하였을 때 발생할 수 있는 내부지점부 콘크리트의 인장응력 저감 효과를 검토하였다.

• 한국방재학회 논문집
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• 제2권2호
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• pp.105-113
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• 2002

강합성 교량은 자중의 감소, 강성의 증대, 장지간의 적용 등의 재료적 특성에 힘입어 1920년대 이래로 사용되어져 왔다. 그러나 연속교의 경우 내부지점부에서 발생하는 부모멘트로 인하여 콘크리트 부분에 균열이 생기고 콘크리트의 건조수축이나 Creep으로 인한 문제들이 제기 됨에 따라 슬랩앵커를 이용한 부분합성교량이 제기 되었다. 부분합성의 경우 어느 정도의 슬립을 허용하여 이러한 문제를 극복할 수 있다. 본 연구에서는 슬랩앵커의 탄성구간에서의 초기 강성값을 실험을 통하여 알아내고, 단순지지인 경우와 연속교의 경우에 대하여 범용 프로그램을 이용하여 슬래브와 강재를 연결시키는 조인트 요소의 강성값을 변화시켜 전단연결재의 강성값에 따른 합성정도와 내부지점부의 콘크리트 슬래브의 인장응력이 어떤 변화양상을 나타내는지 파악하고자 한다.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.713-723
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• 2017

As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.869-881
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• 1999

Inchon International Airport Elevated Road Way is located between the Passenger Terminal Building and Transportaion Center which are Inchon International Airport core construction projects. The deck of the bridge is consists of 5-span or 6-span continuous pre-stressed concrete slab. Steel form has been used to enhance the quality of texture on concrete slab. Steel form has been used to enhance the quality of texture on concrete surface, lower surface of deck slab with the two way arch has been manufactured by highly professional manner in order to get an beautiful exterior architectural looks. The prestressed concrete deck slab is mass concrete structures with a high-specified concrete strength and a varying section in the range of 0.95-2.8m thickness. Therefore high risks of thermal cracking occurrence by heat of hydration highly are expected. To resolve such problem, we adopted type 1 cement and pipe cooking method at construction site through mass concrete specimen test and 3-dimensional analysis. For Pipe cooling we used 25mm diameter stainless pipes with wrinkles. Cooling pipe with spacing 50-60cm has been installed. And continuous pipe cooling with cooling water of 15$^{\circ}C$ was conducted for 2days. In present 8 span of all 29 spans construction has been completed. No thermal cracking heat hydration has been observed yet.

• 소성∙가공
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• 제21권1호
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• pp.58-66
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• 2012

The work roll surface temperature rises and falls repetitively during hot slab rolling because the work roll surface is cooled continuously by water. This study focused on Std. No. 7 to determine a cooling method which significantly reduces the tangential tensile stresses on the work roll surface of the hot slab mill at Hyundai Steel Co. in Korea. A series of finite element analyses were performed to compute the temperature distribution and the tensile stresses in the circumferential direction of the work roll. The virtual slab model was used to reduce the run time considerably by assigning a high temperature to the virtual slab. Except for the heat generated by plastic deformation, this is equivalent to the hot rolling condition that a high temperature slab (material) would experience when in contact with the work rolls. Results showed that when the virtual slab model was coupled with FE analysis, the run time was found to be reduced from 2000 hours to 70 hours. When the work roll surface cooled with a certain on-off patter of water spray, the magnitude of the tangential stresses on the work rolls were decreased by 54.1%, in comparison with those cooled by continuous water spraying. Savings of up to 83.3% in water usage are possible if the proposed water cooling method is adopted.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.561-566
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• 2003

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under floating slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effects of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.447-450
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• 2005

A prefabricated composite hollow slab with perforated I-beams was suggested for the replacement of deteriorated concrete decks or the construction of new composite bridges with long-span slabs. Composite slabs with embedded I-beams have considerably higher stiffness and strength. For the application of prefabricated composite slabs to bridges, joints between slabs should satisfy the requirements of the ultimate limit state and the serviceability limit state. In this paper, three types of the detail for loop joints were selected and their structural performance in terms of strength and crack control was investigated through static tests on continuous composite slabs. A main parameter was the detail of the joint, such as an ordinary loop joint and loop joint with additional reinforcements. Even though there was no connection of the steel beams at the joints, the loop joints showed good performance in terms of strength. In terms of crack control, the loop joint with additional reinforcements showed better performance. In ultimate limit state, the continuous composite slabs showed good moment redistribution and ductility.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.220-223
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• 2000

A method of calculating the natural frequency corresponding to the modes of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the three span continuous reinforced concrete bridge with elastic intermediate supports is presented. Such bridge represents either concrete or sandwich type three span bridge on polymeric supports for passive control or on actuators for active control The concrete slab is considered as a special orthotropic plate. The influence of the modulus of the foundation and $D_{22}$, $D_{12}$, $D_{66}$ stiffnesses on the natural frequency is thoroughly studied.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.117-120
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• 2006

This study is for the strengthening method of continuous bridge through external tendon strengthening that is the most general and effective among concrete bridge's strengthening method. Recently, it is numerous that slab's parts between spans have continuity for improving trafficable ability. However, in this case, slab would have a crack; bridge's durability would be damaged, and also it is too difficult to manage and maintain bridge due to the tensile strength of negative moment. Therefore, the purpose of this study is to demonstrate load-carrying through experiments and develop new external pre-stressing strengthening method for reinforcing continuous bridge.

• 응용통계연구
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• 제34권3호
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• pp.491-505
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• 2021

본 연구에서는, 고차원상황(p ≫ n)에서의 회귀분석 모형을 고려하여 다양한 베이지안 회귀분석 방법들을 비교하였다. Spike and slab 사전분포는 고차원 베이지안 회귀분석에서 가장 많이 사용되는 사전분포 중 하나이지만, 탐험해야 하는 모형 공간이 너무 크기 때문에 유한 표본에서 좋지 않은 성능을 보일 수 있다는 문제가 있다. 이에 대한 대안으로, horseshoe 사전분포를 비롯한 다양한 연속 수축사전분포들이 제안되어 사용되고 있다. 비록 위 사전분포들 각각에 대해서는 많은 연구들이 진행되고 있지만, 이들에 대한 포괄적인 비교연구는 매우 드물게 진행되고 있다. 따라서 본 연구에서는, spike and slab 사전분포와 다양한 연속수축사 전분포들을 다양한 상황에서 비교하는 연구를 진행 하였다. 각 방법의 성능은 회귀계수 추정 측면과 변수선택 측면을 나누어 비교하였다. 최종적으로, 본 연구에서 진행된 시뮬레이션 연구에 기반하여, 사용시 몇 가지 주의점과 제안들을 제시하였다.