• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2006년도 추계 학술발표회
• /
• pp.551-561
• /
• 2006

Incheon bridge project is to construct total 12km long bridges on the sea consist of 800m span length cable stayed bridge, approach bridge and viaduct bridge based on LRFD design specification. To design pile foundations by RCD of each bridge unit, total 4 number of preliminary full scale pile load tests with Osterberg cell method were carried out on the piles for testing. The test load was planned to more than the expected design ultimate capacity and about 29,000tons maximum load was recorded. From the interpretation of test results, design parameters are evaluated and applied to the design. Preliminary pile load test plan and detailed execution of pile load tests are introduced and summarized. The resistance factors are presented for pile design of Incheon Bridge Project in LRFD considering variation of ground conditions and number of test piles.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.225-228
• /
• 2005

In this paper, an example of nonlinear analysis for partial prestressing design is presented. For partial prestressing design, the stress redistribution, after concrete cracking has occurred, should be accurately investigated by nonlinear analysis tools. Direct and iterative methods of nonlinear analyses were adopted for the tender design of the Incheon Bridge viaducts. Stress variations in the prestressing tendons and reinforcing bars were investigated and presented in this paper for both the in-service condition and during construction.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
• /
• pp.221-224
• /
• 2005

The purpose of this study is to introduce design practice for transverse reinforcement in piles where the top of the pile is free-standing above the ground in accordance with AASHTO LRFD Design Specification. Based on the relevant requirements, the amount and spacing of transverse spiral reinforcement is given for the two different pile types, namely piles with pile cap and pile bents. In addition, a recommended design procedure is introduced depending on the predicted behaviour of the piles from the analysis.

• 한국유체기계학회 논문집
• /
• 제18권3호
• /
• pp.33-37
• /
• 2015

A numerical study on the IPM/Bridge Diode cooling and coil cooling has been performed. Results are presented as plots of thermal resistance, temperature drop and RPM-ratio. CFD analysis for conventional cooling system has been performed as a reference case. As the RPM-Ratio was increased, heatsink thermal resistance and coil temperature were decreased. IPM/Bridge Diode thermal resistance and temperature of the coil is tended to be trade-off. The temperature of coil closest to the AC-motor fan showed the most significant change in accordance with duct design. The temperature of coil located at the top of DC-motor fan showed the most significant variation as the cooling air passes the heatsink fin area.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.561-564
• /
• 2004

Steel sheet pile can be alternative material for bridge abutment for. The steel sheet pile bridge abutment is new and replacement bridge abutment due to its aesthetically attractive and cost effective. Use of embedded steel sheet piling brings savings in dead load, provides a compliant retaining wall, and permits speedier construction. In addition, for replacement bridge projects, traffic interruption can be minimized. It is hoped that this study will encourage designers and constructors to consider a steel substructure option more frequently during the conceptual and preliminary design phases of projects and thereby to take advantage of the potential to construction more efficiently. In this paper, an analysis of stress and strain for steel sheet pile bridge abutment was conducted. From the analysis results, the stress and strain characteristics of steel sheet pile bridge abutment with variations of steel sheet pile parameters is suggested.

• Structural Engineering and Mechanics
• /
• 제29권3호
• /
• pp.259-278
• /
• 2008

This paper presents a nonlinear finite element procedure accounting for the effects of geometric as well as material nonlinearities for reinforced concrete bridge piers supported by laminated rubber bearings. Reinforced concrete bridge piers supported by laminated rubber bearings and carrying a cyclic load were analyzed by using a special purpose, nonlinear finite element program, RCAHEST. For reinforced concrete, the proposed robust nonlinear material model captures the salient response characteristics of the bridge piers under cyclic loading conditions and addresses with the influence of geometric nonlinearity on post-peak response of the bridge piers by transformations between local and global systems. Seismic isolator element to predict the behaviors of laminated rubber bearings is also developed. The seismic performance of reinforced concrete bridge piers supported by laminated rubber bearings is assessed analytically. The results show good correlation between the experimental findings and numerical predictions, and demonstrate the reliability and robustness of the proposed analytical model. Additionally, the studies and discussions presented in this investigation provide an insight into the key behavioral aspects of reinforced concrete bridge piers supported by laminated rubber bearings.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2006년도 추계 학술발표회
• /
• pp.562-573
• /
• 2006

Incheon Bridge which will be the world's 5th long cable-stayed bridge in 2009 has been built under the management by Korea Highway Corporation. Incheon Bridge consists of several special-featured bridges and construction sections are divided into two groups, the private investment section with the foreign concessionaire and the government-financed section. 8 pile load tests were performed to investigate the behavior of rock-embedded large-diameter drilled shafts at both sections. Among these, 4 tests at the government-financed section have been utilized to adjust the detailed designs that were carried out individually as well as to find the actual bearing capacity of the ground prior to the commencement of constructions under the joint control of all contractors. Comprehensive procedures of the design and the construction of foundations using pile load tests were introduced.

• Computers and Concrete
• /
• 제5권2호
• /
• pp.135-154
• /
• 2008

This paper presents a nonlinear finite element analysis procedure for the seismic performance assessment of reinforced concrete bridge piers with unbonded reinforcing or prestressing bars. A computer program named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) is used to analyze reinforced concrete structures; this program was also used in our study. Tensile, compressive and shear models of cracked concrete and models of reinforcing and prestressing steel were used account for material nonlinearity of reinforced concrete. The smeared crack approach was incorporated. To represent the interaction between unbonded reinforcing or prestressing bar and concrete, an unbonded reinforcing or prestressing bar element based on the finite element method was developed in this study. The proposed numerical method for the seismic performance assessment of reinforced concrete bridge piers with unbonded reinforcing or prestressing bars is verified by comparison of its results with reliable experimental results.

• 한국지반공학회논문집
• /
• 제37권11호
• /
• pp.61-69
• /
• 2021

본 연구는 교각의 고유진동수를 통해 교각에 인접한 지반의 세굴 발생여부를 판단하기 위해 축소모형교각을 제작하여 충격하중을 이용해 일련의 비파괴 실험을 수행하였다. 축소모형교각은 길이별로 총 3개의 교각을 제작하였으며, 관입깊이는 0.35m로 일정하게 지반에 관입하였다. 세굴은 크게 2가지로 교각의 측면세굴과 기초바닥세굴을 모사하였으며, 0.05m씩 굴착하여 단계별로 step 0에서 step 12 까지 총 13단계의 실험을 모든 교각에 대해 수행하였다. 또한 고유진동수를 도출하기 위해 모형교각에 총 3개의 가속도계를 부착하여 충격하중을 측정하였다. 충격하중은 impact hammer를 사용하였으며, 타격방향은 모형교각 상단을 교축직각방향으로 타격하였다. 이 때 측정된 가속도 값을 바탕으로 고속 푸리에 변환(FFT)를 이용해 세굴진행도에 따른 고유진동수를 산정했다. 그 결과 세굴이 진행됨에 따라 모든 교각의 고유진동수는 감소하는 경향을 보였다. 세굴이 진행됨에 따라 최초 고유진동수의 70% 이상 수준에서는 측면세굴, 70% 미만에서는 기초바닥세굴이 발생하는 것을 판단할 수 있었다. 이 결과를 토대로 전도에 대한 안전율과 비교하여 교각기초의 피해정도를 분석할 수 있었다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.591-604
• /
• 2008

In this study, two design examples of drilled shafts on soft ground in Ho-Chi-Minh City, Vietnam are introduced. One is for a 27-story apartment and the other is for a Arch bridge over Saigon river. Unlikely the normal cases in Korea, all of the bored pile foundations are supposed to be placed on soil layers. Therefore, skin friction between pile and ground is the most crucial design parameter. Three methods using SPT N value of sandy soil -Korean Road Bridge Code(1996), Reese and Wright (1977), and O'Neill and Reese (1988)- were adopted to obtain an ultimate axial bearing capacity. In order to verify the calculated bearing capacity, 3 sets of static load test and a Osterberg Cell test were performed at an apartment site and a bridge site respectively. LRFD (Load Resistance Factored Design) method was compared with ASD (Allowable Stress Design) method. On application of ASD method, safety factor for skin friction was adopted as 2 or 3 while safety factor for end bearing was 3. The design bearing capacities from ASD method matched well with those from LRFD method when safety factor for skin friction was adopted as 2.