Due to the sewer induced ground subsidence, there is an increasing demand for the advanced visual inspection technique for the existing sewer pipe structures. This study aim to develop a new condition assessment method using visual inspection device with automatic crack extracting and real-time gas monitoring systems for large diameter glass-fiber reinforced plastic sewer pipes. In this paper, a high-precision image capturing system that automatically extracts cracks in the large-diameter sewer pipes and sewage culverts with a diameter of 1,000 mm or more, and a real-time gas detection sensor for investigator safety were considered. By analyzing the module technology of the visual inspection device, the test device and their software for system integration were developed. It is expected that the developed technique inspecting conditions of the GFRP sewer pipes using the proposed visual inspection device in this study can be effectively used for various types of underground structures in the future.

ABSTRACT
 1. 서 론
 2. 육안조사 장비의 설계
  2.1 육안조사 시험장비의 설계
  2.2 실시간 가스 모니터링 시스템
  2.3 균열결함 자동추출 시스템
 3. 육안조사 장비 시작품 제작
 4. 장비 제어 및 조사결과 전송 시스템 개발
 5. 현장 적용성 평가
 6. 결론
 References

• 박신전(㈜케이엠티엘 기술연구소) | Park Sinzeon
• 지기환(㈜케이엠티엘 기술연구소) | Jee Kee Hwan
• 유성원(가천대학교 토목환경공학과) | Yoo Sung Won