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Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outdoor-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine hammering test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 
15 ns) with a compact geometry enough to mount on the inspection vehicle (4.2 m 
0.8 m). Dramatic speed-up of the inspection is expected by the combination of this new laser system and a laser scanning frequency measurement system.
Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outside-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 15 ns) with a small-scale geometry enough to mount on the inspection vehicle (4.2 m 0.8 m). In this presentation, we will report a potential to demonstrate 5 J output.
Mikami, Katsuhiro; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kawachi, Tetsuya
no journal, ,
An outdoor-use laser system to improve the performances of existing tunnel inspection techniques is studied. One of the typical concepts is that the blow by hammer in routine hammering test is replaced by the laser pulse irradiation. This new laser system is required to provide high average output power (5 J, 50 Hz, 15 ns) with a compact geometry enough to mount on the inspection vehicle (4.2 m 0.8 m). Dramatic speed-up of the inspection is expected by the combination of this new laser system and a laser scanning frequency measurement system.
Mikami, Katsuhiro; Kurahashi, Shinri*; Kitamura, Toshiyuki*; Hasegawa, Noboru; Okada, Hajime; Kondo, Shuji; Kotyaev, O.*; Shimada, Yoshinori*; Kawachi, Tetsuya
no journal, ,
A lot of infrastructure constructions were built in the 1940s and 1950s in Japan and these decrepitude are seriously concerned that leading to a serious accident. Recently, a novel inspection method using laser systems which consists of impact laser and detection laser, is energetically developing because of its significant advantages. A role of the impact laser is to induce the vibration on concrete walls by the high energy laser pulse behaving like hammering. Then, the detection laser set in laser differential interferometer that which detects the vibration of the concrete surface. For putting into actual utilization, the inspection speed which is about several ten meters per night should be improved for the exceedingly-long train-tunnels. The inspection speed of impact laser and detection systems is required a high-frequency measurement. In this study, we developed a new prototype inspection system to realize high speed inspection for defects inside concrete.
Hasegawa, Noboru*; Nishikino, Masaharu*; Mikami, Katsuhiro*; Okada, Hajime*; Kondo, Shuji*; Kawachi, Tetsuya*; Shimada, Yoshinori*; Kurahashi, Shinri*; Kitamura, Toshiyuki*; Kotyaev, O.*; et al.
no journal, ,
no abstracts in English