• Korean Journal of Construction Engineering and Management
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• v.18 no.2
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• pp.108-116
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• 2017

It is expected that the maintenance cost of domestic bridges will increase considerably due to the increase of bridge service time. In response to this situation, the government and relevant ministries are focusing on developing ways to efficiently allocate limited budgets and to rationally select maintenance bridge. In this study, to develop a risk - based bridge maintenance priority decision model, 14 common risk factors causing damage to bridges were extracted and AHP analysis was performed to select 5 important factors. Based on the existing literature review and expert consultation, we derive the evaluation criteria and the impact weights of the selected factors, and based on this, I presented risk based bridge maintenance priority model. Using this model in combination with existing maintenance priority methods will lead to more reasonable bridge maintenance priorities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.64-72
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• 2015

Risk Based Inspection (RBI) Period was proposed for highway bridges in Korea. Hazard factors affecting bridge condition deterioration were found by analyzing condition data from Highway Bridge Management System (HBMS). Certain level of correlations between those factors and condition deterioration were found. They are used to evaluate hazard score. Summarizing several hazard factors, final hazard is classified as three level;high, moderate, low. Vulnerability is assessed only by the current state of bridge. Then, risk matrix is suggested for inspection periods. Inspection periods of the bridges with grade C, D, and E are maintained the same as before. But, those of grade A and B with moderate and high hazard score are elongated to maximum 6 years while the maximum inspection period is three years at present. By adjusting inspection period according to risk assessment, it was shown that 27% of average inspection manpower can be saved.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.185-195
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• 2017

In recent years, unexpected bridge fire accidents have increased because of augmenting the number of traffic volumes and hazardous materials by the increment in traffics and distribution business. Furthermore, in accordance with the effort of using the under space of bridges, the ratio of occupied by combustible materials like oil tanker or lorry has been increased. As a result, the occurrence of bridge fire has been growing drastically. In order to mitigate the accident of bridge fire, risk assessment of bridge fire has been studied, however, practical risk models considering safety from users' viewpoints were scarce. This study represented quantitative risk assessment model applicable to national road bridges in Korea. The primary factors with significant impacts on bridge fire accidents was chosen such as clearance height, materials of bridges, arrival time of fire truck and fire intensity. The selected factors were used for Fire Dynamics Simulation (FDS) and the peak temperature calculated by FDS in accordance with the fire duration and fire intensity. The risk assessment model in bridge fire reflected the FDS analysis results, the fire damage criteria, and the grade of fire truck arrival time was established. Response plans for bridge fire accidents according to the risk assessment output has been discussed. Lastly, distances between bridges and fire stations were calculated by GIS network analysis. Based on the suggested assessment model and methodology, sample bridges were selected and graded for the risk assessment.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.31-43
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• 2004

Seismic risk assessment of bridge is presented using fragility curves which represent the probability of damage of a structure virsus the peak ground acceleration. In theseismic fragility analysis, the structural damage is defined using the rotational ductility at the base of the bridge pier, which is obtained through nonlinear dynamic analysis for various input earthquakes. For the assessment of seismic risk of bridge, peak ground accelerations are obatined for various return periods from the seismic hazard map of Korea, which enables to calculate the probability density function of peak ground acceleration. Combining the probability density function of peak ground acceleration and the seismic fragility analysis, seismic risk assessment is performed. In this study, seismic fragility analysis is developed as a function of not the surface motion which the bridge actually suffers, but the rock outcrop motion which the aseismic design code is defined on, so that further analysis for the seismic hazard assessment may become available. Besides, the effects of the friction pot bearings and the friction pendulum bearings on the seismic fragility and risk analysis are examined. Lastly, three regions in Korea are considered and compared in the seismic risk assessment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.123-134
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• 2006

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of the maritime bridge. Method II which is a probability based analysis procedure is used to select the design vessel for collision impact from the risk analysis results. The analysis procedure, an iterative process in which a computed annual frequency of collapse(AF) is compared to the acceptance criterion, includes allocation method of acceptance criterion of annual frequency of bridge component collapse. The AF allocation by weights seems to be more reasonable than the pylon concentration allocation method because this AF allocation takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. From the assessment of ship collision risk for each bridge pier exposed to ship collision, a representative design vessel for all bridge components is selected. The design vessel size varies much from each other in the same bridge structure depending upon the vessel traffic characteristics.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.287-292
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• 1999

도시화 및 산업화가 급속히 진행되어감에 따라 하천에는 수중구조물이 상당수 설치되어 있어서 교량에서의 세굴에 대한 안전성 여부 및 그에 대한 대책 수립이 매우 절실한 실정이다. 국내의 경우 성수대교 및 행주대교 붕괴사고 이후 특히 하천의 교각에 대한 세굴의 영향은 많은 학자들의 관심이 되어 왔다. 연구의 주된 관점은 세굴에 영향을 미치는 인자들의 역학적 거동에 대한 것으로써 세굴을 일으키는 인자들의 최대 영향 및 최대 세굴심도를 예측하고 세굴로부터 보호하는 공법에 주력하고 있다. 그동안의 조사결과에 의하면 교각이나 교대의 하부구조가 세굴로 인한 위험성이 상당히 내재되어 있는 것으로 알려지고 있다. (중략)

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.743-750
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• 2008

Recently Bridges crossing waterway are constructed in navigable waterway, so marine accidents near bridges navigable waterway often occurred bemuse that has affect dangerous element for. This paper analysed the necessary environmental factors to navigate safely near bridges and how to set up the environmental factors. Marine accidents elements occurred near bridges relate to span of bridge, size of navigating ship, length of straight way and traffic volume except mistake of mariners. As results of marine accident parameter analysis, Span of bridge is necessary more than 300m at least based on marine accident's analysis, and in case of more than ship's Length 150m, span of bridge is necessary more than 500m, $3{\sim}4L$(L; Ship's Length). Length of straight way before bridge is necessary more than 8L to minimize the marine accident.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.11-19
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• 2006

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of suspension bridge. Method II in AASHTO LRFD bridge design specifications which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. From the assessment of ship collision risk for each bridge pier exposed to ship collision, the design impact lateral strength of bridge pier is determined. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed annual frequency of collapse(AF) is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. This AF allocation method is compared to the pylon concentration allocation method to obtain safety and economy in results. This method seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. The design vessel for each pier corresponding with the design impact lateral strength obtained from the ship collision risk assessment is then selected. The design impact lateral strength can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.864-867
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• 2009

고속도로를 주행하는 차량에 작용하는 순간적인 강풍은 차량의 주행경로이탈, 차체의 수평회전 과다와 전도를 발생시키는 원인이 되며, 이로 인한 교통사고는 치명적인 대형사고로 이어질 가능성이 높다. 최근에 건설되거나 추진중인 고속도로는 고속운행에 필요한 도로선형을 확보하기 위해 계곡부를 통과하는 높은 위치에 교량을 건설하거나 산악터널을 내는 경우가 많으며, 지형적인 특성으로 발생하는 국지적인 강풍의 영향이 매우 크기 때문에 적극적인 강풍저감대책이 필요하다. 본 연구에서는 강풍 발생지역을 주행중인 차량의 안전성 및 쾌적성확보를 위하여 차량의 동역학적 거동을 규명하고 차종별 주행속도와 순간풍속의 상관관계를 정립하였다. 또한 차량사고의 영향인자별 분석을 통하여 기존에 제시된 연구결과와 기준안에 대한 고찰을 실시하였고, 강풍발생 지역을 통과하는 차량에 대한 규제와 운영방법에 대해 위험풍속을 정의하고 차량속도규제(안)을 제시하였다.

• Journal of Korean Society of societal Security
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• v.1 no.3
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• pp.51-57
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• 2008

The long-term behaviors of prestressed concrete cable-stayed bridges are considerably influenced by the time dependant material characteristics such as creep and shrinkage. This study investigated the influences of the change of relative humidity by application of the CEB-FIP model and ACI model, which are generally used in the prediction of long-term behavior of concrete structures. In case of the moment of girder, CEB-FIP model predicted a bigger effect of relative humidity change than the ACI model. Furthermore, the effect was significant. Also, the long-term behaviors between these models were different each other even under the same material condition. Therefore, the prediction of the long-term behavior should be compensated after comparative analysis with the results of material tests of each construction site and between the different models.