• 한국건설관리학회논문집
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• 제25권2호
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• pp.69-80
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• 2024

Currently rebar spacing inspection is carried out by human inspectors who heavily rely on their individual experience, lacking a guarantee of objectivity and accuracy in the inspection process. In addition, if incorrectly placed rebars are identified, the inspector need to correct them. Recently, laser scanning and AR technologies have been widely used because of their merits of measurement accuracy and visualization. This study proposes a technology for rebar spacing inspection and fixing by combining laser scanning and AR technology. First, scan data acquisition of rebar layers is performed and the raw scan data is processed. Second, AR-based visualization and fixing are performed by comparing the design model with the model generated from the scan data. To verify the developed technique, performance comparison test is conducted by comparing with existing drawing-based method in terms of inspection time, error detection rate, cognitive load, and situational awareness ability. It is found from the result of the experiment that the AR-based rebar inspection and fixing technology is faster than the drawing-based method, but there was no significant difference between the two groups in error identification rate, cognitive load, and situational awareness ability. Based on the experimental results, the proposed AR-based rebar spacing inspection and fixing technology is expected to be highly useful throughout the construction industry.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.13-22
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• 2020

Reinforcement steel fixing is a skilled and manually intensive construction trade. Current practice for the quality assessment of reinforcement steel fixing is normally performed by fabricators and has high potential in having errors due to the tedious nature of the work. In order to overcome the current inspection limitation, this study presents an approach that provides visual assistance and inspection enhancement for inspectors to assess the dimensional layout of reinforcement steel fixing. To this end, this study aims to establish an end-to-end framework for rebar layout quality inspection using laser scanning and Augmented Reality (AR). The proposed framework is composed of three parts: (1) the laser-scanned rebar data processing; (2) the rebar inspection procedure integrating with AR; and (3) the checking and fixing the rebar layout through AR visualization. In order to investigate the feasibility of the proposed framework, a case study assessing the rebar layout of a lab-scaled formwork containing two rebar layers is conducted. The results of the case studies demonstrate that the proposed approach using laser scanning and AR has the potential to produce an intuitive and accurate quality assessment for the rebar layout.

• 대한토목학회논문집
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• 제33권6호
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• pp.2509-2518
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• 2013

증강현실(Augmented Reality, AR) 기술은 현실 환경을 기반으로 컴퓨터에서 생성한 가상의 객체정보를 중첩해봄으로써 가상현실 상에서 느낄 수 없는 실감형 모델을 구현하는 기술이다. 본 연구에서는 토목공사 철근배근 작업에 증강현실 기술을 적용하는 방법론과 시스템 시제품을 구성하여 철근공사 작업의 증강현실 적용성을 검증하고 있다. 토목공사 현장의 여러 작업들 중에서 철근공사는 절차화된 매뉴얼방식보다는 숙련공의 경험적 방식에 의해 작업이 진행되는 대표적 공정이다. 이러한 공정에 증강현실을 적용하면 당초 계획도면과 비교하여 누락된 철근배근 및 상이한 배근 상태를 시각화하여 계측할 수 있으므로 시공성을 향상시킬 수 있다. 구축된 시스템은 3차원으로 모델링 된 철근객체를 실제 시공현장에 중첩하여 시각화함으로써 철근 조립공정들의 작업 이해도를 높이고, 검측단계에 활용함으로써 철근조립작업에서 발생할 수 있는 하자와 재작업으로 인한 비용증가를 억제할 수 있을 것이라 기대된다.

• 한국구조물진단유지관리공학회 논문집
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• 제15권1호
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• pp.281-287
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• 2011

GFRP 보강근은 콘크리트의 알칼리성분에 의해 손상 받을 수 있다. 본 논문은 이형 GFRP 보강근의 알칼리에 대한 내구성을 증진시키기 위한 방법에 대한 실험적 연구이다. 기존 개발된 이형 GFRP 보강근의 표면물질에 삽입되는 초단유리섬유는 콘크리트와의 부착성능을 향상시키는 것으로 알려져 있다. 본 논문에서는 초단 알칼리저항섬유(AR-glass)와 E-glass 섬유를 표면이형의 구성물질로 활용하였을 때, 보강근의 내구성능에 미치는 영향을 흡습시험과 ISS 실험을 통하여 규명하고자 하였다. 혹독한 실내실험조건을 위하여 $40^{\circ}C$의 온도가 적용되었다. 실험결과, 표면성형을 위한 레진과의 합성물로써, E-glass와 AR-glass를 사용하였을 때, 내구성능에 큰 차이는 없는 것을 확인하였다. 오히려, 레진과 섬유의 혼합비가 작업성과 성형성에 영향을 미치고, 이것이 표면 이형부에 공극을 만들게 됨으로써, 큰 영향을 미치는 것으로 나타났다. 따라서, 장기적인 내구성능 확보를 위해서 혼입률의 결정에 주의를 기울여야 한다.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.129-136
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• 2020

Augmented reality (AR) technology assists construction workers by superimposing additional virtual information onto their real worksite environments. Ideally, this provides them with a better understanding of their tasks and hence boosts task performance. However, the additional information that AR places in users' field of view could limit their ability to understand what is going on in their surroundings and to predict how conditions may change in the near future. AR-assisted systems on construction sites could therefore expose their users to safety risks due to disturbance from the system. Hence, it is important to understand how AR-assisted systems can block users' understanding of their immediate environments, and in turn, how worksite safety in the construction industry could be improved through better design of such systems. This preliminary research conducted a laboratory experiment that simulated rebar inspection tasks and compared the situational awareness of AR users against that of subjects using traditional paper-based inspection methods, as measured by the Situation Awareness Rating Technique. Based on the results, we discuss the safety impact of head-mounted AR-assisted displays on situational awareness during construction tasks.