• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.35-44
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• 2010

For efficient maintenance management of bridges, an establishment of asset management system is necessary which helps prediction of maintenance cost and strategic allocation of budget in consideration of top priority. The main purpose of this study is to suggest asset valuation method, which is practical in conformity with domestic situations, through researches on asset valuation method of bridges. This study has researched asset valuation method of bridge, which is appropriate for domestic situations by finding out advantages and disadvantages through investigating domestic and foreign application examples of asset valuation method for bridge facilities. In this study, asset valuation method by historical cost and replacement cost were suggested and a valuation model for bridges was established. In addition, two suggested valuation methods were applied to actual bridges which is used in Korea. As the result, it was analyzed that bridge asset valuation method in consideration of historical cost is desirable for the accounting purpose. And, it was analyzed that valuation method utilizing depreciated replacement cost(DRC), which could consider various factors, is desirable for the maintenance decision supporting purpose.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.93-110
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• 2018

In order to provide a novel strategy for long-span bridge health monitoring system design, this paper proposes a novel ultimate bearing capacity ratios based bridge internal force monitoring design method. The bridge ultimate bearing capacity analysis theories are briefly described. Then, based on the ultimate bearing capacity of the structural component, the component ultimate bearing capacity ratio, the uniformity of ultimate bearing capacity ratio, and the reference of component ultimate bearing capacity ratio are defined. Based on the defined indices, the high bearing components can then be found, and the internal force monitoring system can be designed. Finally, the proposed method is applied to the bridge health monitoring system design of the second highway bridge of Wuhu Yangtze river. Through the ultimate bearing capacity analysis of the bridge in eight load conditions, the high bearing components are found based on the proposed method. The bridge internal force monitoring system is then preliminary designed. The results show that the proposed method can provide quantitative criteria for sensors layout. The monitoring components based on the proposed method are consistent with the actual failure process of the bridge, and can reduce the monitoring of low bearing components. For the second highway bridge of Wuhu Yangtze river, only 59 components are designed to be monitored their internal forces. Therefore, the bridge internal force monitoring system based on the ultimate bearing capacity ratio can decrease the number of monitored components and the cost of the whole monitoring system.

• Structural Monitoring and Maintenance
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• v.1 no.4
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• pp.371-392
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• 2014

Long-span cable-supported bridges are flexible structures vulnerable to unsymmetric loadings such as railway traffic and strong wind. The torsional dynamic response of long-span cable-supported bridges under running trains and/or strong winds may deform the railway track laid on the bridge deck and affect the running safety of trains and the comfort of passengers, and even lead the bridge to collapse. Therefore, it is eager to figure out the torsional dynamic response of long-span cable-supported bridges under running trains and/or strong winds. The Tsing Ma Bridge (TMB) in Hong Kong is a suspension bridge with a main span of 1,377 m, and is currently the world's longest suspension bridge carrying both road and rail traffic. Moreover, this bridge is located in one of the most active typhoon-prone regions in the world. A wind and structural health monitoring system (WASHMS) was installed on the TMB in 1997, and after 17 years of successful operation it is still working well as desired. Making use of one-year monitoring data acquired by the WASHMS, the torsional dynamic responses of the bridge deck under rail traffic and strong winds are analyzed. The monitoring results demonstrate that the differences of vertical displacement at the opposite edges and the corresponding rotations of the bridge deck are less than 60 mm and $0.1^{\circ}$ respectively under weak winds, and less than 300 mm and $0.6^{\circ}$ respectively under typhoons, implying that the torsional dynamic response of the bridge deck under rail traffic and wind loading is not significant due to the rational design.

• 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 Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.206-216
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• 2020

As the number of aging railway bridges in Korea increases, maintenance costs due to aging are increasing and continuous management is becoming more important. However, while the number of old facilities to be managed increases, there is a shortage of professional personnel capable of inspecting and diagnosing these old facilities. To solve these problems, this study presents an improved model that can detect Local damage to structures using machine learning techniques of AI technology. To construct a damage detection machine learning model, an analysis model of the bridge was set by referring to the design drawing of a non-ballasted plate-girder railroad bridge. Static strain data according to the damage scenario was extracted with the analysis model, and the Local damage index based on the reliability of the bridge was presented using statistical techniques. Damage was performed in a three-step process of identifying the damage existence, the damage location, and the damage severity. In the estimation of the damage severity, a linear regression model was additionally considered to detect random damage. Finally, the random damage location was estimated and verified using a machine learning-based damage detection classification learning model and a regression model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.5
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• pp.62-68
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• 2024

The Republic of Korea experiences four distinct seasons, with significant temperature differences between summer and winter, causing bridges to undergo large temperature variations throughout the year. When the temperature changes, the dynamic characteristics of bridge structures also change. However, during load-bearing capacity assessments in domestic bridge maintenance, this temperature effect is not considered, and only the natural frequency measured over a short period is used for evaluation. In this paper, we theoretically analyze the impact of changes in natural frequency on bridges and extract daily estimated natural frequency data from bridges with continuous vertical acceleration measurements taken over more than a year to confirm temperature-induced changes. The results show that a 1% decrease in natural frequency corresponds to an approximately 2% decrease in the load-bearing capacity of the bridge. Additionally, it was found from the measurement data that a 10℃ increase in temperature did not affect the natural frequency of RC slab bridges and Rahmen bridges, but in PSC-I girder bridges and steel box girder bridges, the natural frequency decreased by approximately 1.04% to 2.48%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.312-313
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• 2018

As global climate change leaded to extensive natural disaster and radical deterioration of infrastructures, there was increased attentions for the evaluation of infrastructures. After the collapse of Seongsu Bridge in 1994, Korea has enacted the "Special act on safety and maintenance of facilities" and secured the safety of facilities using systematic and periodic safety inspections. However, current facility inspections are mainly performed by the physical defect and structural analysis, and do not properly consider the serviceability of infrastructure such as capacity of facility and user's satisfaction. Thus, the purpose of the study is to develop an evaluation criteria for serviceability of infrastructures and finally leading to the revision of "Special Act on safety and maintenance of facilities in rational manner.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.606-607
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• 2015

The traffic volume on the road shows various trends reflecting regional characteristics for monthly and hourly, and economic loss affecting users varies according to the selected period for the maintenance of road pavements. Therefore, in this study, the user cost (or delay cost) for monthly and hourly on the work zone near the Maesang Bridge Section on Poseung-Gu, Pyeongtaek-si, Gyeonggi-do was calculated using the time series models and VISSIM, and based on the result, the effect of user cost reduction according to the selection of best maintenance period was examined. The analysis result showed that the month of the lowest user cost occurred due to the maintenance of target section was January (10,293,258 KRW/Day×1km) and the month of the greatest user cost occurred was November (13,337,495 KRW/Day×1km).

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.137-144
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• 2019

For the structures near the seismogenic fault, the evaluation of seismic performance against near-fault ground motions is important as well as for design ground motions. In this study, characteristics of seismic behaviors and seismic performance of the pile-bent bridge constructed on the thick soft soil site with various weak soil layers were analyzed. The input ground motions were synthesized by the directivity pulse parameters for intra-plate regions. The ground motion acceleration histories of each layer were obtained by one-dimensional site response analysis. Each soil layer was modeled by equivalent linear springs, and multi-support excitations with different input ground motions at each soil spring were applied for nonlinear seismic analyses. The analysis result by the near-fault ground motions and ground motions matched to design spectra were compared. In case of the near fault ground motion input, the bridge behaved within the elastic range but the location of the maximum moment occurred was different from the result of design ground motion input.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.2107-2124
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• 2013

The inspections that are being done on current bridges in our country are made to go through a process of being recorded on the management system and then converted by the computer. This has deteriorated the credibility of manual-analog types of data, inefficient care of information, and produced potential problems of the structures of bridges through subjective evaluations. In order to solve these troubles, this research has aimed at effectiveness, management, and convenience so that the inspector at the actual scene of the bridge structures will be able to achieve the primary purpose of infrastructure safety through precise supervision. To assist this, this study has suggested a state of the art IT intellectual management system that has applied RFID. This system has been designed to decrease the inspecting time on the actual scene, which will provide more time for efficient inspection and by using the converted DB, managing and utilizing high quality data will come naturally and through the objective evaluation, it will be possible to make exact judgments of the structures of the bridge. Also, regardless of the location, it has been found that the work performance was excellent through highly effective management.