• 비파괴검사학회지
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• 제22권3호
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• pp.239-245
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• 2002

현재까지 다양한 토목구조물들은 여러 가지 요인에 의한 노후화와 축척된 손상에도 불구하고 별다른 조치 없이 계속해서 사용되고 있었다. 따라서, 이러한 구조물들의 효율적인 유지관리를 유해 계측관리가 중요시되었다. 이에 본 논문에서는 비파괴계측에 의해 사장교의 실시간 계측모니터링시스템을 개발하고자 하며 이를 통해 교량의 안전관리를 하고자 하였다. 계측모니터링시스템은 교량의 유지관리를 도모하고, 교량 관리의 경제적 비용을 줄이게 되며 사장교의 새로운 설계 및 분석방법을 개발하는데 중요한 데이터를 제공할 것이다.

• Structural Monitoring and Maintenance
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• 제4권1호
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• pp.1-15
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• 2017

Installation of sensors networks for continuous in-service monitoring of structures and their efficiency conditions is a current research trend of paramount interest. On-line monitoring systems could be strategically useful for road infrastructures, which are expected to perform efficiently and be self-diagnostic, also in emergency scenarios. This work researches damage detection in composite concrete-steel structures that are typical for highway overpasses and bridges. The techniques herein proposed assume that typical damage in the deck occurs in form of delamination and cracking, and that it affects the peak power spectral density of dynamic curvature. The investigation is performed by combining results of measurements collected by long-gauge fiber optic strain sensors installed on monitored structure and a statistic approach. A finite element model has been also prepared and validated for deepening peculiar aspects of the investigation and the availability of the method. The proposed method for real time applications is able to detect a documented unusual behavior (e.g., damage or deterioration) through long-gauge fiber optic strain sensors measurements and a probabilistic study of the dynamic curvature power spectral density.

• Smart Structures and Systems
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• 제1권4호
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• pp.325-338
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• 2005

Utilizing robotic based reconfigurable nodal structural health monitoring systems has many advantages over static or human positioned sensor systems. However, creating a robot capable of traversing a variety of civil infrastructures is a difficult task, as these structures each have unique features and characteristics posing a variety of challenges to the robot design. This paper outlines the design and implementation of a novel robotic platform for deployment on ferromagnetic structures as an enabling structural health monitoring technology. The key feature of this design is the utilization of an attachment device which is an advancement of the common magnetic base found in the machine tool industry. By mechanizing this switchable magnetic circuit and redesigning it for light weight and compactness, it becomes an extremely efficient and robust means of attachment for use in various robotic and structural health monitoring applications. The ability to engage and disengage the magnet as needed, the very low power required to do so, the variety of applicable geometric configurations, and the ability to hold indefinitely once engaged make this device ideally suited for numerous robotic and distributed sensor network applications. Presented here are examples of the mechanized variable force magnets, as well as a prototype robot which has been successfully deployed on a large construction site. Also presented are other applications and future directions of this technology.

• International Journal of Internet, Broadcasting and Communication
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• 제10권3호
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• pp.136-145
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• 2018

The disaster monitoring technique by combination of the measurement method and the fine precision of the sensor collecting the satellite-based information that can determine the displacement space is available in a variety of diagnostic information and the GIS/GNSS by first sensor it is being requested from them. Be large and that the facility is operated nationally distributed torsional displacement of the terrain and facilities caused by such natural disasters progress of various environmental factors and the surroundings. To diagnose this spatial information, which contains the various sensors and instruments tracks the precise fine displacement of the main construction structures and the first reference in the Geospatial or more three-dimensional detailed available map and location information using the installed or the like bridges and tunnels produced to a USN/IoT change at any time, by combining the various positioning analysis of mm-class for the facility main area observed is required to constantly in the real time information of the USN/IoT environment sensor, and to utilize this as a precise fine positioning information by UAV/Drone to the precise fine displacement of the semi-permanent infrastructures. It managed to be efficient management by use of new technologies, analyzing the results presented to a method capable of real-time monitoring for a large structure or facility to construction disaster prevention.

• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.255-268
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• 2019

Civil infrastructures, such as bridges and tunnels are most important assets and their failure during service will have significant economic and social impact in any country. Behavior of a bridge can be evaluated only through actual monitoring/measurements of bridge members under the loads of interest. Theoretical analysis alone is not a good predictor of the ability of a bridge. In some cases, theoretical analyses can give less effect than actual since theoretical analyses do not consider the actual condition of the bridge, support conditions, level of corrosion and damage in members and connections etc. Hence actual measurements of bridge response should be considered in making decisions on structural integrity, especially in cases of high value bridges (large spans and major crossings). This paper describes in detail the experimental investigations carried out on an open web type steel railway bridge. Strain gages and displacement transducers were installed at critical locations and responses were measured during passage of locomotives. Stresses were evaluated and extrapolated to maximum design loading. The responses measured from the bridge were within the permissible limits. The methodology adopted shall be used for assessing the structural integrity of the bridge for the design loads.

• 한국추진공학회지
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• 제23권2호
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• pp.87-94
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• 2019

액체로켓 추진기관 시험설비는 시험대상체가 상위 시스템에 장착되었을 때의 인터페이스 조건을 모사하여야 하며, 시험 시 파손이 발생할 수 있는 개발품의 특성상, 안전하게 시험이 이루어질 수 있게 구축되어야 한다. 이를 위해 추진기관 시험설비 기반시설은 안정적인 연소가 이루어지고 사고 시에도 안전이 보장되도록 구축되어야 한다. 본 논문에서는 액체로켓 엔진 추진기관 시험설비 기반시설의 구축 및 운영 시 고려해야 할 사항에 대해, 토목/건축, 시험 스탠드, 설비의 배치, 타 설비와의 운영 조합 및 공동구, 소화설비, 전력설비 측면에서 고찰하였다.

• 국제초고층학회논문집
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• 제9권4호
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• pp.351-360
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• 2020

Monitoring civil structures periodically is necessary for ensuring the fitness of the structures. Cracks on inner and outer surfaces of the building plays a vital role in indicating the health of the building. Conventionally, human visual inspection techniques were carried up to human reachable altitudes. Monitoring of high rise infrastructures cannot be done using this primitive method. Also, there is a necessity for more accurate prediction of cracks on building surfaces for ensuring the health and safety of the building. The proposed research focused on developing an efficient crack classification model using Transfer Learning enabled EfficientNet (TL-EN) architecture. Though many other pre-trained models were available for crack classification, they rely on more number of training parameters for better accuracy. The TL-EN model attained an accuracy of 0.99 with less number of parameters on large dataset. A bench marked METU dataset with 40000 images were used to test and validate the proposed model. The surfaces of high rise buildings were investigated using vision enabled Unmanned Arial Vehicles (UAV). These UAV is fabricated with TL-EN model schema for capturing and analyzing the real time streaming video of building surfaces.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1017-1023
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• 2022

Past research shows that the construction of new infrastructure accelerates economic growth in the region by attracting more people and commodities. However, the previous studies only considered large-scale infrastructures such as sea-cross bridges and channel tunnels. There is a paucity of literature on regional infrastructure and its impact on socio-economic indicators. This paper explores the impact of new bridge construction on the human population, particularly focusing on regional bridges constructed during the 2000s in the state of Georgia. The human population at a county level was selected as a single socio-economic factor to be evaluated. A total of 124 cases were investigated as to whether the emergence of a new bridge affected the population change. The interrupted time series analysis was used to statistically examine the significance of population change due to the construction by treating each new bridge as an intervention event. The results show that, out of the 124 cases, the population of 67 cases significantly increased after the bridge construction, while the population of 57 cases was not affected by the construction at a significance level of 0.05. The 124 cases were also analyzed by route type, functional class, and traffic volume, but the results revealed, unlike large-scale infrastructure, that no clear evidence was found that a new bridge would bring an increase in the human population at a county level.

• 한국결정성장학회지
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• 제25권6호
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• pp.290-293
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• 2015

최근 사회기반시설물의 구조물 유지관리 분야의 관심이 높아짐에 따라 새로운 유지관리 공법 및 신소재에 관한 연구가 활발히 진행되어지고 있다. 그중에서도 유지관리의 주요 대상인 교량 유지관리에는 탄소섬유를 이용한 공법이 주목을 받고 있다. 탄소섬유시트(Carbon Fiber Sheet, 이하 CFS)는 이미 여러 연구자들이 국내에서도 재료시험 및 보강공법에 관한 연구를 진행하여 연구결과가 보고되고 있지만, 탄소섬유 스트랜드 시트(Carbon Fiber Strand Sheet, 이하 CFSS)는 최근 새롭게 개발된 재료로써 아직까지 국내에는 연구 성과가 없는 실정이다. 따라서, 본 연구에서는 CFSS를 RC 상판 공시체에 접착보강하여 내피로성을 평가하였다. 그 결과, 무보강 RC 상판 공시체에 비해 약 25.3배의 보강 효과가 확인되었고, CFS 접착보강 RC 상판 공시체에 비교하여 약 1.2배의 보강 효과가 확인되었다.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.33-38
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• 2016

재난 현장의 붕괴된 건물 아래의 매몰자를 탐지하기 위해서는 구조 업무를 수행하는 인력이나 관리자가 현장의 실제 붕괴 정도 및 현재 상태를 신속하게 파악하여야 구조 업무가 순조롭게 진행될 수 있다. 하지만 붕괴 현장의 경우 사람의 접근 시 추가 붕괴의 위험 등으로 사건이 발생한 부분에 접근이 어려워 현장의 정보를 쉽게 파악하기 어렵다. 또한 제한된 인원으로 인하여 붕괴 현장에 매몰된 사람들의 위치를 파악하는 일 역시 힘든 일이다. 본 연구에서는 이러한 어려움을 극복하기 위하여 스테레오 비전 카메라를 장착한 무인비행장치 혹은 드론을 활용하여 붕괴지형의 정보를 파악하고자 한다. 스테레오 비전 카메라를 장착한 무인비행장치 제작을 위한 필요 기술 도출 및 제작 방법론 설명을 통해 붕괴지형 정보 획득을 위한 하드웨어 관련 기술을 제시하고자 한다. 다음으로 무인비행장치를 활용하여 획득한 자료를 바탕으로 붕괴지형을 3차원으로 모델링하는 과정을 통하여 본 연구에서 개발한 기기의 활용 가능성을 검증하고자 한다.