• 한국철도학회논문집
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• 제9권1호
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• pp.12-17
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• 2006

The bridge to be analyzed is a self-anchored suspension bridge which is constructed within the country. Forced vibration test was performed with oscillator for verification of safety, maintenance and management. In this study, the feasibility of deduction was verified with the modified analysis model by comparing natural frequency, natural mode and damping ratio of the real bridge, which are obtained from the vibration test of the whole bridge after construction of 3-dimensional self-anchored cable suspension bridge, with the eigenvalue of analytic computation model and evaluating them. As a result of study, the friction of bridge bearing must be considered to get the natural frequencies of flexural vibration, and evaluating the polar moment of inertia is critical factor in analysis modeling in case of torsional vibration. The logarithmic damping ratio of the test appeared to exceed the ordinary one assumed at the design phase.

• Smart Structures and Systems
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• 제14권2호
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• pp.129-144
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• 2014

In this paper, a fuzzy inference system and an analytical hierarchy process-based online evaluation technique is developed to monitor the condition of the 32-km Donghai Bridge in Shanghai. The system has 478 sensors distributed along eight segments selected from the whole bridge. An online evaluation subsystem is realized, which uses raw data and extracted features or indices to give a set of hierarchically organized condition evaluations. The thresholds of each index were set to an initial value obtained from a structure damage and performance evolution analysis of the bridge. After one year of baseline monitoring, the initial threshold system was updated from the collected data. The results show that the techniques described are valid and reliable. The online method fulfills long-term infrastructure health monitoring requirements for the Donghai Bridge.

• 건설관리
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• 제14권6호
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• pp.59-61
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• 2013

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.65-75
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• 2015

Among the destruction instances of half-through arch bridges, the shorter hangers are more likely to be ruined. For a thorough investigation of the hanger system durability, we have studied vehicle impact effect on hangers with vehicle-bridge coupling method for a half-through concrete-filled-steel-tube arch bridge. A numerical method has been applied to simulate the variation of dynamic internal force (stress) in hangers under different vehicle speeds and road surface roughness. The characteristics and differences in impact effect among hangers with different length (position) are compared. The impact effect is further analyzed comprehensively based on the vehicle speed distribution model. Our results show that the dynamic internal force induced by moving vehicles inside the shorter hangers is significantly greater than that inside the longer ones. The largest difference of dynamic internal force among the hangers could be as high as 28%. Our results well explained a common phenomenon in several hanger damage accidents occurred in China. This work forms a basis for hanger system's fatigue analysis and service life evaluation. It also provides a reference to the design, management, maintenance, monitoring, and evaluation for this kind of bridge.

• Journal of Construction Engineering and Project Management
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• 제1권2호
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• pp.1-10
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• 2011

Bridges are critical and valuable components in any road and rail transportation network. Therefore bridge remediation has always been a top priority for asset managers and engineers, but identifying the nature of true defect deterioration and associated remediation treatments remains a complex task. Nowadays Decision Support Systems (DSS) are widely used to assist decision makers across an extensive spectrum of unstructured decision environments. The main objective of this research is to develop a requirements-driven methodology for bridge monitoring and maintenance which has the ability to assess the bridge condition and find the best remediation treatments using Simple Multi Attribute Rating Technique (SMART); with the aim of maintaining a bridge within acceptable limits of safety, serviceability and sustainability.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.489-492
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• 2008

Nowadays in order to estimate safety diagnosis of bridge, a lot of data like static and dynamic displacement, accelerometer, wind velocity and so on are demanded. When it comes to measure these data, cabled sensor is essential equipment. But cabled sensors have also inefficient factors. From this point of view, considering practical aspects of using these expensive equipments which have been used to examine safety diagnosis, measuring by cabled sensors is restrictive in some respect. Recently to improve theses problems, Wireless sensor system was introduced. But this system can't perform intelligent reaction because database of this system is just based on internet. In this paper, the intelligent bridge safety management model which can be installed easily, measured at all times and dealing intelligently with various situations is developed to improve these problems.

• 대한안전경영과학회지
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• 제23권4호
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• pp.67-72
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• 2021

To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.449-456
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• 2009

Image processing has been applied to steel bridge defect recognition since 1990s. Compare to human visual inspection, image processing provides a more objective and accurate way of assessment. Since shade and shadow may sometimes occur when taking bridge coating images, non-uniform illumination problems should be considered. By means of color image processing, this paper aims to mitigate the illumination effect for bridge coating assessment. Furthermore, the adaptable ellipse method (AEM) is proposed to recognize mild rust colors. Finally, AEM will be compared to the K-Means algorithm, a popular recognition method, to show its advantage.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.52-57
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• 2011

Bridges are essential and valuable elements in road and rail transportation networks. Bridge remediation is a top priority for asset managers, but identifying the nature of true defect deterioration and associated remediation treatments remains a complex task. Nowadays Decision Support Systems (DSS) are used extensively to assist in decision-making across a wide spectrum of unstructured decision environments. In this paper a requirements-driven framework is used to develop a risk based decision support model which has the ability to quantify the bridge condition and find the best remediation treatments using Multi Attribute Utility Theory (MAUT), with the aim of maintaining a bridge within acceptable limits of safety, serviceability and sustainability.

• 한국재난관리표준학회지
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• 제2권4호
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• pp.35-41
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• 2009

교량 상시계측시스템을 이용하여 교량을 감지할 경우 지속적인 교량의 거동이력을 확인할 수 있어 손상의 진행을 관리자가 손쉽게 확인할 수 있으며, 지진이나 홍수와 같은 대규모의 재난상황이 발생할 경우 교량의 상태변화를 정량적으로 파악하여 교량 통제 및 통행제한 등 적절한 사전 조치 등 취할 수 있다. 또한 보수 및 보강 등의 교량 성능향상 작업시점을 적절하게 판단할 수 있어 생애주기를 통한 교량 유지관리 비용을 절감할 수 있다. 교량 상시계측시스템에 적용되고 있는 다양한 계측시스템의 계측항목별 관리 기준치 설정방법 중 범용 유한요소 해석프로그램을 이용하여 교량의 관리기준치를 설정하는 방법을 분석하고 강상자형교에 대한 계측항목별 관리기준을 설정하여 유한요소 해석프로그램을 통한 강상자형교 상시계측시스템 계측항목별 관리기준치 설정의 기준을 제시하였다.