Proposal of Non Contact Inspection Method for Concrete Structures Using High-Power Directional Sound Source and Scanning Laser Doppler Vibrometer

Abstract

Maintenance for concrete structures such as buildings, bridges, and tunnels is necessary, because it is thought that a lot of them show deterioration. As a periodic inspection, a hammering test is the most popular method. However, it has several problems. One of the problems is that it is difficult to inspect the places where people cannot reach. Therefore, non contact inspection methods have been developed. As a non-contact inspection method, we propose a system consisting of a high-power directional sound source and a scanning laser doppler vibrometer (SLDV). In this method, an air-borne sound wave is used for the excitation of a concrete wall, and then the vibration velocities on the concrete wall are measured two-dimensionally by the SLDV. From the vibration velocity, defective parts can be detected. In this paper, we describe two types of experiment on the feasibility of our proposed method. In these experiments, concrete wall test pieces, which have artificial defects, are used. From the experimental results, we confirmed the effectiveness of our proposed method as a non contact inspection method for concrete structures.

Detection of Multiple Cracks in Four-Point Bending Tests Using the Coda Wave Interferometry Method

“…The Non-Destructive Testing (NDT) technique is the highest quality assurance tool which allows the assessment of quality and condition of structure with out damaging the original structure. A wide variety of NDT methods have been developed and used for decades in the manufacturing industry and in the civil engineering domain, for example, ground penetrating radar [2][3][4], laser testing method [5,6], DIC [7][8][9] and FOS [10,11], etc. Among these methods, many of them can be used for long-term SHM.…”

Application of Impact-Echo Method to 3D SIBIE Procedure for Damage Detection in Concrete

“…As for remotely detecting elastic waves propagated through concrete, non-contact acoustic systems with a laser doppler vibrometer (LDV) for detecting signals have been reported [13][14][15]. These research approaches provide remote and rapid operations for inspection works based on the elastic wave method.…”

Proposal of Laser-Induced Ultrasonic Guided Wave for Corrosion Detection of Reinforced Concrete Structures in Fukushima Daiichi Nuclear Power Plant Decommissioning Site

“…The excited ultrasonic waves generated by the pulsed-laser are measured using a remote Laser Doppler Vibrometer (LDV). Akamatsu et al [12], on the other hand, presented a testing method using Long Range Acoustic Devices and LDV.…”