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Large number of concrete structures built in the era of rapid economic growth will exceed fifteen years old in next 10 to 20 years. Developing maintenance and health monitoring techniques for these existing concrete structures is inevitable problem to be resolved. JAEA have tackled to that problem on collaborative research, having achieved to crack detection technique for surface on the concrete of railroad tunnel (1). The technique reported in ref. (1), however, is focusing on the surface cracks, not taking into account the condition of the deep region, including a steel reinforcing bar (rebar) in a reinforced concrete structure. This work supposes a new approach for detecting deteriorated rebar in concrete structure based on laser-ultrasonic. Irradiating the one end of a rebar by nanosecond laser pulses repetitively generates ultrasonic wave propagating along it. The waveform of the ultrasonic received the other end is analyzed to extract the information about its condition.

Oral presentation

Study on assessment of effects on reinforced concrete structure with internal equipment subjected to projectile impact, 1; Impact test on a reinforced concrete structure with internal pseudo equipment subjected to projectile impact

Okuda, Yukihiko; Kang, Z.; Nishida, Akemi; Tsubota, Haruji; Li, Y.

no journal, ,

When a projectile collides with a building of a nuclear facility, the stress waves generated at the time of the impact propagate from the impacted wall to the inside of the building. This stress wave may excite vibrations including high frequencies in the building, and it is an issue to evaluate the influence on safety related equipment. In this study, in order to contribute to the assessment of effects on internal equipment in the building, we will obtain data related to stress wave propagation in the building and the impact response of internal equipment, and develop an impact response analysis method considering the coupling of the building and the equipment. At first a projectile impact test with a building including a pseudo equipment will be conducted to investigate the stress wave propagation characteristics inside the building and the impact response characteristics of the pseudo equipment inside the building. In this paper, we will report the outline of the target test specimen of the projectile impact test, the test method and the test results.

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Development study of concrete reinforcement made of aramid fiber-reinforced plastic rods with high radiation resistance, 1; Epoxy resin compounds with a handling at room temperature impregnation

Electrical insulation characteristics of -ray irradiated epoxy-coated reinforcing steel bar

Application of epoxy-coated rebars to large electric structure for electrical insulation

Application of epoxy-coated rebars to large electric structure for electrical insulation

Application of epoxy-coated reinforcing bars to large electric structure for electric insulation

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Trends of non destructive inspection

Laser ultrasonic approach for detecting a deteriorated rebar in concrete

Study on assessment of effects on reinforced concrete structure with internal equipment subjected to projectile impact, 1; Impact test on a reinforced concrete structure with internal pseudo equipment subjected to projectile impact