• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.59-65
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• 2003

For safe passing the waterway crossing bridge without collision with bridge-piers under poor visibility circumstances, it is very important that the pier should be detected definitely as earlier as possible by radar, In this study, the required length of Projecting part of the bridge pier for definite radar recognition was obtained by theoretical and experimental analyses. By presenting the required values depending on the maximum vessel size and passing condition, it is expected possible to design the bridge pier protecting system appropriately suitable to traffic environment of the waterway.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.441-455
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• 1997

The need for rehabilitation of the existing bridges is a growing concern in many countries and has been emphasized in various research reports and publications. Many bridges constructed between 1960s and 1970s in Korea were designed for relatively light traffic volumes, speeds and the weight, thus they are inadequate for the present traffic conditions. This together with some design deficiencies, has resulted in deficiencies of various degrees of many bridges. One strengthening method which has significant advantages is the application of external post-tensioning tendons. This paper presents an example of three span continuous composite bridge strenghtened by application of external post-tensioning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.155-161
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• 2013

This paper presented an augmented reality based mobile application of maintenance and management for concrete bridges. For the development of augmented reality system, it was necessary to establish the concrete bridges detail information and history of maintenance that build the database of those. Also, the augmented reality based system required that concrete bridge information presented by the mobile smart phone. Therefore, this study developed an augmented reality based concrete bridge information mobile application-All about Bridge based on android smart phone and smart pad. The proposed All about Bridge application supports a various bridge informations simultaneously using smart phone and augmented reality technology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1261-1270
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• 2013

The current domestic design criteria of live load employs DL-24 load and DB-24 load. Particularly for long span bridges above 45meters, DL-24 load is forced to apply and design them, since the shearing force and the moment of DL-24 load appears more dominate than those of DB-24. But it appeared that this DL-24 load didn't meet the vehicles traveling load, which affected bridges in real use. Hence this paper defined ML-24 load similar to the load applied to real bridges and also defined a new live load model, RL-24 load, after adjusting the existing DL-24 load, which doesn't meet the moment and the shearing force of ML-24. As the result of applying and reviewing RL-24 load to simple bridges of span of 45~60m, the results satisfying both the moment and the shearing force applied to bridges in real use by traveling load were attained. Besides, the applicability of it was examined in comparison with live load models of home and abroad.

• Journal of the Korean Society for Railway
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• v.14 no.6
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• pp.545-554
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• 2011

In order to get dynamic serviceability of a train travelling on a railway bridge, comfort limits with the deflection of bridge and vertical acceleration on car body are proposed in Eurocode, Shinkansen design criteria, The design guideline of the Honam High-speed railway. The design guideline of the Honam High-speed railway has quoted Eurocode. Therefore it is expected that supplementation of comfort limit of railway bridge according to expansion of span length and the improvement traveling speed of trains in the future would relatively fall behind developed countries in railway. Therefore, in order to secure technological competitiveness in world market, the study was conducted to propose the deflection limit based on vibration serviceability of railway bridges that can consider bridge-train interaction and travelling speed increase. The parameter study and bridge-train dynamic interaction analysis was conducted to figure out the correlation of vertical acceleration on car body and bridge displacement according to the increase in travelling speed. Also, the trend of increasing vertical acceleration on car body according to the increase in travelling speed was confirmed, and the amplification coefficient of vertical acceleration on car body was suggested. And the deflection form and vibration of the bridge were assumed to be in harmonic motion, and transfer function and the amplification coefficient were used to develop the dynamic serviceability deflection limit of the high-speed railway bridge as a formula.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.120-130
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• 2012

As long span and complex bridges are constructed often recently, safety estimation became a big issue. Various types of measuring instruments are installed in case of long span bridge. New wireless technologies for long span bridges such as sending information through a gateway at the field or sending it through cables by signal processing the sensing data are applied these days. However, The case of occurred accidents related to bridge in the world have been reported that serious accidents occur due to lack of real-time proactive, intelligent action based on recognition accidents. To solve this problem in this study, the idea of "communication among things", which is the basic method of RFID/USN technology, is applied to the bridge monitoring system. A sensor node module for USN based intelligent bridge system in which sensor are utilized on the bridge and communicates interactively to prevent accidents when it captures the alert signals and urgent events, sends RF wireless signal to the nearest traffic signal to block the traffic and prevent massive accidents, is designed and tested by performing TinyOS based middleware design and sensor test free Space trans-receiving distance.

• Magazine of the Korea Concrete Institute
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• v.10 no.1
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• pp.179-188
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• 1998

캔틸레버 공법으로 시공되는 프리스트레스트 콘크리트 박스거더 교량의 구조적 거동은 단계적 시공에 따른 구조물의 순차적 변화 및 콘크리트의 재료적 특성에 의해 시간 의존적 거동을 나타낸다. 콘크리트의 시간의존적 특성, 즉 콘크리트의 크리프 및 건조수축 특성은 현장타설 세그멘탈 캔딜레버공법으로 가설되는 콘크리트 교량의 설계 및 시공에서 매우 중요한 역할을 한다. 본 연구에서는 콘크리트의 크리프 및 건조수축 특성이 교량의 시간의존적 거동, 특히 처짐 및 텐던응력예측에 미치는 영향을 연구하였다. 교량해석은 본 연구진에 의해 개발된 프리스트레스트 콘크리트 교량해석기법 및 프로그램을 이용하여 크리프의 ACI 모델, CEB-FIB모델, 그리고 국내 도로교 시방서 모델을 고려하여 해석하였다. 해석결과 최종크리프 값의 크기에 따라 장기처짐의 발생량이 차이가 큰 것으로 나타나고 있으며, 최종건조수축량과 상대습도도 영향을 주는 것으로 나타났다. 또한 ACI 모델과 CEB-FIB모델간에도 차이가 큰 것으로 나타나 실제교량의 크리프 특성 및 건조수축 특성의 정확한 예측이 교량의 정밀시공 및 거동예측에 매우 중요한 것으로 나타나고 있다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.638-641
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• 2006

In this paper, A calculating cost method of maintenance and repair for bridge which is built up by new construction technique named Up-Down Precast Concrete(UDPSC). After 2000, 109 Bridges which are using UDPSC technique have been built up, 37 bridges's construction work are processing, and 194 designs are presented for construction. Because this technology has developed recently, there are few field data for analyzing the maintenance and repair cost. Therefore, the maintenance and repair cost is computed using Construction and Transportation Ministry's guide line for computation and former research's data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3A
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• pp.161-169
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• 2012

This paper presents the safety and strength of simplified composite H-beam panel bridges (SCHPBs) using 3-dimentional finite-element program, ABAQUS (2007) and experimental tests. Two finite-element models (one-steel-girder-and-composite-deck model and four-steel-girder-and-wide-composite-deck model) were reviewed to predict the strength and load distribution factor (LDF) values of the composite bridges. Based on the results of the finite-element analyses, the behaviors of the two models were investigated, and deflection and strain gauges for the experimental specimens were set up to obtain the ultimate strengths and the LDF values. The ultimate strength of the one-steel-girder-and-composite-deck specimen was estimated to be 840 kN. The yield and plastic moments of the four-steel-girder-and-wide-composite-deck specimen were obtained to be 2.4 and 4.1 times the design moment based on the live loading condition of the Korea Bridge Design Specifications (2005). The SCHPB were found to have enough strength for safety under and after construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.67-74
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• 2019

In this paper the response factor is investigated for middle and small size-RC slab aged bridges. The response factor consists of static and dynamic response factors and is a main parameter in the frequency based-bridge load carrying capacity prediction model. Static and dynamic response factors are determined based on the frequency variation and the impact factor variation respectively between current and previous (or design) states of bridges. Here, the impact factor variation is figured out using the impact factor response spectrum which provides the impact factor according to the natural frequency of bridges. In this study, four actual RC slab bridges aged over 30 years after construction are considered and their span length is 12m. The dynamic loading test in field using a dump truck and eigenvalue analysis with FE models are conducted to identify the current and previous (or design) state-natural frequencies of the bridges, respectively. For more realistic considerations in the moving loading situation, the impact factor response spectrum is developed based on tri-axle moving loads representing the dump truck load distribution and various supporting conditions such as simply supported and both ends fixed conditions. From the results, the response factor is widely ranged from 0.21to 0.91, showing that the static response factor contributes significantly on the results while the dynamic response factor has a small effect on the result. Compared to the results obtained from the impact factor response spectrum based on the single axle-simply supported condition, the maximum percentage difference of the response factors is below 3.2% only.